cas 1109-15-5, Tris(pentafluorophenyl)borane

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The solid-state structure of bis(pentafluorophenyl)zinc
Using the published method of Wiedenbruch, bis(pentafluorophenyl)zinc, 1, was prepared from anhydrous ZnCl2 and 2 equiv. of LiC6F5 in diethyl ether. Base-free 1 was obtained in 60-65% yield by repeated distillation of the initially formed bis(diethyl) ether adduct of 1. The X-ray quality crystals of 1 were obtained from benzene solution. The molecular structure of 1 revealed a near linear geometry for the two-coordinate zinc center (C(1)-Zn-C(7) = 172.6(2)°), typical of monomeric ZnR2 derivatives. In the crystal structure, stacking interactions between C6F5 rings on adjacent molecules is a dominant motif, with ring centroid to ring centroid distances of 3.503 and 3.563 A observed. A weak intermolecular C-F...Zn interaction between F(2) and an adjacent zinc center, as judged by the close contact of 2.849(2) A, also appears to be an important aspect of the crystal structure. Compound 1 is an effective but nonselective C6F5 transfer agent to BCl3; 1: monoclinic, space group P21/n, a = 11.902(2) A, b = 7.732(2) A, c = 13.735(2) A, β = 110.58(1)°, V = 1183.4(4) A3, Z = 4, R = 0.048, Rw = 0.069.
Sun, Yimin,Piers, Warren E.,Parvez, Masood
p. 513 - 517
(1998)
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σ- versus π-activation of alkynyl benzoates using B(C6F5)3
We have prepared a range of alkynyl benzoates in high yields and have investigated their reactivities with the strong Lewis acid B(C6F5)3. In such molecules both σ-activation of the carbonyl and π-activation of the alkyne are possible. In contrast to the reactivity of propargyl esters with B(C6F5)3 which proceed via 1,2-addition of the ester and B(C6F5)3 across the alkyne, the inclusion of an additional CH2 spacer switches off the intramolecular cyclization and selective σ-activation of the carbonyl group is observed through adduct formation. This change in reactivity appears due to the instability of the species which would be formed through B(C6F5)3 activation of the alkyne.
B?hr, Alexander,Wilkins, Lewis C.,Ollegott, Kevin,Kariuki, Benson M.,Melen, Rebecca L.
p. 4530 - 4547
(2015)
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Synthesis and photophysical properties of imine borane adducts towards vapochromic materials
A series of alkynyl aryl conjugated aldehydes and imines were prepared and their adducts with various Lewis acidic boranes have been studied via NMR, absorption, and luminescence spectroscopies in solution. The imine-B(C6F5)3 adduct showed remarkable solution stability, and was then trialled in vapochromism experiments using simple impregnated paper strips to examine the fluorescence responses.
Soltani, Yashar,Adams, Samuel J.,B?rger, Jennifer,Wilkins, Lewis C.,Newman, Paul D.,Pope, Simon J.A.,Melen, Rebecca L.
p. 12656 - 12660
(2018)
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Silica-Grafted Borato Cocatalysts for Olefin Polymerization Modeled by Silsesquioxane Borato Complexes
The syntheses and reactivity studies of silsesquioxane-borato complexes are described. Treatment of B(C6F5)3 with (c-C5H9)7Si8O12(OH) and (c-C5H9)7Si7O9(OH) 3 in the presence of a Br?nsted base yields the silsesquioxane-borates X+{[(c-C5H9)7Si8O 13]B(C6F5)3}- (1a, X+ = PhN(H)Me2+; 1b, X+ = Et3NH+) and X+{[(c-C5H9)7Si7(OH) 2O10]B(C6F5)3} - (1b, X+ = PhN-(H)Me2+; 2b, X+ = Et3NH+), respectively. When the more nucleophilic base pyridine is used, (C6F5)3B·NC5H5 (3) is formed instead, demonstrating the competition between B(C6F5)3 and H+ to react with the amine. The dimethylaniline in 1a and 2a is readily exchanged by NEt3 to form 1b and 2b. With the nucleophilic Lewis base NC5H5, the B-O bond in 1a and 2a is split, yielding (C6F5)3B·NC5H5 (3) and the free silsesquioxanes. Complexes 1 and 2 rapidly undergo hydrolysis under formation of the hydroxyl complexes X+{(C6F5)3BOH}- (4a, X+ = PhN(H)Me2+; 4b, X+ = Et3NH+). Likewise, alcoholysis of 1a and 2a with i-PrOH yields the alkoxide {PhN(H)Me2}+{i-PrOB(C6F5) 3}- (5). The B-O bond is only moderately stable toward early-transition-metal alkyls. Nevertheless, Cp2Zr(CH2Ph)2 + 1a and Zr(CH2Ph)4 + 2a form single-site ethylene polymerization catalysts. Detailed reactivity studies demonstrated that both B-O and B-C bond splitting plays a crucial role, as not 1a and 2a, but their decomposition product B(C6F5)3 is the actual cocatalyst. The solid-state structures of 1a and 4b were determined by single-crystal X-ray analysis.
Duchateau, Robbert,Van Santen, Rutger A.,Yap
p. 809 - 816
(2000)
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Borane Adducts of Hydrazoic Acid and Organic Azides: Intermediates for the Formation of Aminoboranes
The reaction of HN3 with the strong Lewis acid B(C6F5)3 led to the formation of a very labile HN3?B(C6F5)3 adduct, which decomposed to an aminoborane, H(C6F5)NB(C6F5)2, above ?20 °C with release of molecular nitrogen and simultaneous migration of a C6F5 group from boron to the nitrogen atom. The intermediary formation of azide–borane adducts with B(C6F5)3 was also demonstrated for a series of organic azides, RN3 (R=Me3Si, Ph, 3,5-(CF3)2C6H3), which also underwent Staudinger-like decomposition along with C6F5 group migration. In accord with experiment, computations revealed rather small barriers towards nitrogen release for these highly labile azide adducts for all organic substituents except R=Me3Si (m.p. 120 °C, Tdec=189 °C). Hydrolysis of the aminoboranes provided C6F5-substituted amines, HN(R)(C6F5), in good yields.
Bl?sing, Kevin,Bresien, Jonas,Labbow, René,Michalik, Dirk,Schulz, Axel,Thomas, Max,Villinger, Alexander
p. 6540 - 6544
(2019)
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Interaction of titanium(III) zwitterionic complex Cp[η 5-C5H4B(C6F5) 3]Ti with organic halides: Synthesis and X-ray crystal structure determination of zwitterionic titanocene monohalides
The reaction of the titanium(III) zwitterionic complex Cp[η 5-C5H4B(C6F5) 3]Ti (1) with CCl4 at 20 °C under Ar results in the formation of hexachloroethane and the zwitterionic titanocene monochloride Cp[η5-C5H4B(C6F 5)3]TiCl (3) containing a B(C6F 5)3 moiety in the η5-cyclopentadienyl ring. Under similar conditions, the reaction of 1 with 1,2-dibromoethane affords ethylene and the corresponding zwitterionic monobromide Cp[η 5-C5H4B(C6F5) 3]TiBr (4). An X-ray diffraction study of 3 and 4 revealed the presence of a coordinative bond between the ortho-fluorine atom of one of the C6F5 substituents and the positively charged titanium centre. In the interaction of 1 with n-propyl iodide at 20 °C, titanocene diiodide, B(C6F5)3 and propylene are produced. The mechanism of this interesting reaction is discussed. The synthesized zwitterions 3 and 4 are able to catalyze the ring-opening polymerization of ε-caprolactone in a toluene solution and in bulk. The highest activity in this process is exhibited by 3. The first X-ray diffraction study of Cp 2TiI2 has been carried out.
Strunkina,Minacheva,Lyssenko,Burlakov,Baumann,Arndt,Strunin,Shur
p. 557 - 565
(2006)
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Exploiting single-electron transfer in Lewis pairs for catalytic bond-forming reactions
A single-electron transfer (SET) between tris(pentafluorophenyl)borane (B(C6F5)3) andN,N-dialkylanilines is reported, which is operativeviathe formation of an electron donor-acceptor (EDA) complex involving π-orbital interactions as a key intermediate under dark conditions or visible-light irradiation depending on the structure of the aniline derivatives. This inherent SET in the Lewis pairs initiates the generation of the corresponding α-aminoalkyl radicals and their additions to electron-deficient olefins, revealing the ability of B(C6F5)3to act as an effective one-electron redox catalyst.
Aramaki, Yoshitaka,Hotta, Mao,Imaizumi, Naoki,Kumagai, Jun,Ooi, Takashi
p. 4305 - 4311
(2020)
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Methane activation by a borenium complex
The selective functionalization of methane under ambient conditions remains a formidable challenge for chemists. While most studies have focused on transition metal complexes, much less attention has been devoted to molecular complexes based on non-metal elements, despite them being more sustainable and less environmentally impactful. Here, we report that an N-heterocyclic carbene-stabilized borenium complex can activate methane under relatively mild conditions. The resulting methylborenium complex can readily transfer the methyl group to catecholborane (HBcat), which can lead to a synthetic cycle for the conversion of methane to MeBcat. Both experimental and theoretical mechanistic studies suggest that the C–H bonds of methane are activated via a σ-bond metathesis pathway. Such direct aliphatic C–H borylation can be extended to other alkanes, such as ethane and octane. The formed alkylborenium complexes can react with terminal alkynes via 1,2-alkylboration to install both the alkyl and boryl functionalities onto organic scaffolds.
Liu, Yizhen,Dong, Weishi,Li, Zhen Hua,Wang, Huadong
p. 1843 - 1851
(2021)
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Reaction of vinyl chloride with a prototypical metallocene catalyst: Stoichiometric insertion and β-Cl elimination reactions with rac-(EBI)ZrMe+ and catalytic dechlorination/oligomerization to oligopropylene by rac- (EBI)ZrmE2/MAO [15]
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Stockland Jr., Robert A.,Jordan, Richard F.
p. 6315 - 6316
(2000)
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A Dimer of Hydrogen Cyanide Stabilized by a Lewis Acid
A highly labile dimer of hydrogen cyanide, HCN???HCN, was extracted from liquid HCN by adduct formation with the bulky Lewis acid B(C6F5)3, affording HCN???HCN?B(C6F5)3, which was fully characterized. The influence of the solvent (HCN, CH2Cl2, and aromatic hydrocarbons) on the crystallization process was studied, revealing dimer formation when using HCN or CH2Cl2 as solvent, whereas aromatic hydrocarbons led to the formation of monomeric arene??HCN?B(C6F5)3 adducts, additionally stabilized by η6-coordination of the aromatic ring system similar to well-known half-sandwich complexes.
Bl?sing, Kevin,Bresien, Jonas,Labbow, René,Schulz, Axel,Villinger, Alexander
p. 9170 - 9175
(2018)
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1,3-Carboboration of iodonium ylides
Herein, we disclose the utilisation of iodonium ylides to access a range of boron dienolates. Heating of acyclic iodonium ylides in the presence of different aryl boranes leads to the formation of rare 1,3-carboboration products. This methodology could not be expanded to cyclic iodonium ylides which instead formed a Lewis acid-base adduct. Products proved to be remarkably stable under a wide range of conditions allowing for their long term storage.
Gazis, Theodore A.,Mohajeri Thaker, Bayan A. J.,Willcox, Darren,Ould, Darren M. C.,Wenz, Jan,Rawson, Jeremy M.,Hill, Michael S.,Wirth, Thomas,Melen, Rebecca L.
p. 3345 - 3348
(2020)
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Silyl cations in the solid and in solution
Reaction of silanes with triphenylmethyl tetrakis(pentafluorophenyl)borate (TPFPB) with excess silane as solvent yields a white solid that may be examined directly or dissolved for experiments in solution. The NMR properties of the material in a variety of solvents indicate that the anion is free and unperturbed by the presence of the silicon species. The 29Si chemical shift is highly dependent on the nucleophilicity of the solvent, with large downfield shifts (compared with the analogous silane, Δδ) in the order acetonitrile, sulfolane, toluene, benzene. The largest Δδ values for alkyl substituents in the arene solvents are ca. 100 ppm, far short of the expectation for a fully trigonal silylium ion. For tris(trimethylsilyl)silylium tetrakis-(pentafluorophenyl)borate, Δδ is 228.5 ppm, much closer to the trigonal ideal. The 29Si shifts of the solid, which had never been exposed to a solvent, are almost identical to those in benzene solution. For the case of methyldiisopropylsilane, with diastereotopic methyl groups, conversion to the TPFPB salt resulted in homotopic protons and carbons in a variety of solvents, which require a dynamic process between bound and unbound silyl species with a barrier of no more than about 13 kcal mol-1. The X-ray crystallographic structure of triethylsilylium tetrakis-(pentafluorophenyl)borate recrystallized from hexane/toluene contains silicon in a distorted pyramid with normal coordination to the methylene carbons (1.85 A?) and an experimentally unprecedented distant coordination to toluene (2.18 A?). This Si-C distance to the para position of toluene is equivalent to a bond order of 0.28 according to the Pauling equation. The coordinated toluene is planar and essentially unaltered by the interaction with silicon, in contrast to the crystal structures of known arenium ions (σ complexes). The solid state 13C spectrum indicates little transfer of positive charge to toluene. Thus the arenium ion model is rejected by experiment. The ions are best termed silyl cations with weak η1 π coordination to toluene.
Lambert, Joseph B.,Zhang, Shizhong,Ciro, Sol M.
p. 2430 - 2443
(1994)
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Control of Multicolor and White Emission by Adjusting the Equilibrium between Fluorophores, Lewis Acids, and Their Complexes in Polymers
Multicolor emissive materials consisting of a single luminophore, a Lewis acid, and their complex were developed. The emission colors can be tuned by changing the concentration of the solution and the ratio of mixed solvents. Various emission colors in the solid state were observed when the complexes were added to polymers in different amounts. The color change is due to equilibrium disruption between the single luminophore, the Lewis acid, and the complex thereof. White emission was observed by appropriately controlling the equilibrium by changing the amount of the complex in the polymer.
Mori, Toshiaki,Yoshigoe, Yusuke,Kuninobu, Yoichiro
p. 14457 - 14461
(2019)
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Bissilylated halonium ions: [Me3Si-X- SiMe3][B(C 6F5)4] (X = F, Cl, Br, I)
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Lehmann, Mathias,Schulz, Axel,Villinger, Alexander
p. 7444 - 7447
(2009)
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Synthesis, properties and photolysis of new iodonium tetrakis(pentafluorophenyl)gallate photoinitiators and comparison with their indate and aluminate analogs
A series of new iodonium tetrakis(pentafluorophenyl)gallates were synthesized in high yield via an improved preparation of the lithium gallate, their photoproducts analyzed by UV, 19F NMR and GC-MS spectra and a photolysis mechanism postulated. The stability of these photoinitiators was also compared with their borate, aluminate and indate analogs.
Ren, Kangtai,Malpert, John H,Gu, Haiyan,Li, Huiying,Neckers, Douglas C
p. 5267 - 5273
(2002)
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Structures and Stability of Complexes of E(C6F5)3 (E = B, Al, Ga, In) with Acetonitrile
Complexes formed by interaction of E(C6F5)3 (E = B, Al, Ga, In) with excess of acetonitrile (AN) were structurally characterized. Quantum chemical computations indicate that for Al(C6F5)3 and In(C6F5)3 the formation of a complex of 1:2 composition is more advantageous than for B(C6F5)3 and Ga(C6F5)3, in line with experimental observations. Formation of the solvate [Al(C6F5)3·2AN]·AN is in agreement with predicted thermodynamic instability of [Al(C6F5)3·3AN]. Tensimetry study of B(C6F5)3·CH3CN reveals its stability in the solid state up to 197 °C. With the temperature increase, the complex undergoes irreversible thermal decomposition with pentafluorobenzene formation.
Shcherbina, Nadezhda A.,Pomogaeva, Anna V.,Lisovenko, Anna S.,Kazakov, Igor V.,Gugin, Nikita Yu.,Khoroshilova, Olesya V.,Kondrat'ev, Yuri V.,Timoshkin, Alexey Y.
p. 873 - 881
(2020)
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A NEW METHOD OF 18F LABELLING AND INTERMEDIATE SALTS
Disclosed herein is a salt of formula I: where R1, X, n, R, R1, Y, m, p, q, Z and o are as defined herein. Also disclosed herein are methods of using said salts in chemical synthesis, such as to prepare compounds isotopically enriched in 18F for use in PET imaging, as well as methods to make the compounds of formula I.
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Page/Page column 37

(2021/06/26)

Lewis Acidic Boranes, Lewis Bases, and Equilibrium Constants: A Reliable Scaffold for a Quantitative Lewis Acidity/Basicity Scale
A quantitative Lewis acidity/basicity scale toward boron-centered Lewis acids has been developed based on a set of 90 experimental equilibrium constants for the reactions of triarylboranes with various O-, N-, S-, and P-centered Lewis bases in dichloromethane at 20 °C. Analysis with the linear free energy relationship log KB=LAB+LBB allows equilibrium constants, KB, to be calculated for any type of borane/Lewis base combination through the sum of two descriptors, one for Lewis acidity (LAB) and one for Lewis basicity (LBB). The resulting Lewis acidity/basicity scale is independent of fixed reference acids/bases and valid for various types of trivalent boron-centered Lewis acids. It is demonstrated that the newly developed Lewis acidity/basicity scale is easily extendable through linear relationships with quantum-chemically calculated or common physical–organic descriptors and known thermodynamic data (ΔH (Formula presented.)). Furthermore, this experimental platform can be utilized for the rational development of borane-catalyzed reactions.
Mayer, Robert J.,Hampel, Nathalie,Ofial, Armin R.
supporting information
p. 4070 - 4080
(2021/01/29)

Trimethylsilyl Pseudohalide Adducts of GaCl3 and B(C6F5)3
Me3Si?X (X=CN, N3, OCN, and SCN) was treated with the Lewis acids GaCl3 and B(C6F5)3 in toluene yielding the desired adducts Me3Si?X→GaCl3 and Me3Si?X→B(C6F5)3. All synthesized adducts were isolated and completely characterized including single crystal structure elucidations. The different structures, thermodynamics of formation and charge transfer effects are discussed on the basis of experimental and theoretical data.
Bl?sing, Kevin,Bresien, Jonas,Maurer, Steffen,Schulz, Axel,Villinger, Alexander
supporting information
p. 1913 - 1920
(2021/05/10)

Metal-Free Iodoperfluoroalkylation: Photocatalysis versus Frustrated Lewis Pair Catalysis
A comparison of two catalytic, metal-free iodoperfluoroalkylation protocols is presented. Frustrated Lewis pairs [ tBu 3P/B(C 6F 5) 3] or phosphines/phosphites under visible light irradiation efficiently mediate the functionalization of non-activated alkenes and alkynes. A comprehensive account of the corresponding substrate scopes as well as insights into the mechanistic details of both reaction pathways are provided.
Helmecke, Lucas,Spittler, Michael,Schmidt, Bernd M.,Czekelius, Constantin
supporting information
p. 123 - 134
(2020/09/02)

Frustrated Lewis-Pair-Meditated Selective Single Fluoride Substitution in Trifluoromethyl Groups
Single fluoride substitution in trifluoromethylarenes is an ongoing synthetic challenge that often leads to "over-reaction", where multiple fluorides are replaced. Development of this reaction would allow simple access to a vast range of difluoromethyl derivatives of current interest to pharmaceutical, agrochemistry, and materials sciences. Using a catalytic frustrated Lewis pair approach, we have developed a generic protocol that allows a single substitution of one fluoride in trifluoromethyl groups with neutral phosphine and pyridine bases. The resulting phosphonium and pyridinium salts can be further functionalized via nucleophilic substitution, photoredox coupling, and electrophilic transfer reactions allowing the generation of a vast array of difluoromethyl products.
Gupta, Richa,Jaiswal, Amit K.,Mandal, Dipendu,Young, Rowan D.
supporting information
p. 2572 - 2578
(2020/03/03)

Characterization of the Zwitterionic Intermediate in 1,1-Carboboration of Alkynes
The reaction of a Lewis acidic borane with an alkyne is a key step in a diverse range of main group transformations. Alkyne 1,1-carboboration, the Wrackmeyer reaction, is an archetypal transformation of this kind. 1,1-Carboboration has been proposed to proceed through a zwitterionic intermediate. We report the isolation and spectroscopic, structural and computational characterization of the zwitterionic intermediates generated by reaction of B(C6F5)3 with alkynes. The stepwise reactivity of the zwitterion provides new mechanistic insight for 1,1-carboboration and wider B(C6F5)3 catalysis. Making use of intramolecular stabilization by a ferrocene substituent, we have characterized the zwitterionic intermediate in the solid state and diverted reactivity towards alkyne cyclotrimerization.
Bismuto, Alessandro,Cowley, Michael J.,Duarte, Fernanda,Nichol, Gary S.,Thomas, Stephen P.
supporting information
p. 12731 - 12735
(2020/06/02)

Bis(pentafluorophenyl)phenothiazylborane-an intramolecular frustrated Lewis pair catalyst for stannane dehydrocoupling
We synthesized a novel Lewis acidic aminoborane containing a phenothiazyl substituent and demonstrated its potential to catalytically promote the dehydrocoupling of tin hydrides. The observed reactivity would imply a homolytic frustrated Lewis pair type mechanism, however computational analysis suggests a heterolytic mechanism for this reaction. This result represents one of the first frustrated Lewis pair systems to dehydrocouple stannanes in a heterolytic fashion.
Bentley, Jordan N.,Caputo, Christopher B.,Pradhan, Ekadashi,Zeng, Tao
supporting information
p. 16054 - 16058
(2020/12/03)

B(C6F5)3- And HB(C6F5)2-mediated transformations of isothiocyanates
This contribution reports on the reactivity of isothiocyanates towards the boranes B(C6F5)3and HB(C6F5)2. The reactions of alkyl-substituted isothiocyanates with B(C6F5)3were found to result in rearrangement reactions to yield stable thiocyanate-B(C6F5)3adducts. Treatment of isothiocyanates with HB(C6F5)2leads to 1,2-hydroboration and thus, B,N,C,S heterocycles are formed, which react further under non-inert conditions. Hydrolysis of the hydroboration products leads to a new access to thioformamides.
Fischer, Malte,Schmidtmann, Marc
supporting information
p. 6205 - 6208
(2020/06/22)

PHOTO LEWIS ACID GENERATOR
Provided is a compound capable of generating a Lewis acid in response to light unlike conventional photo acid generators. The compound comprises an anionic moiety having a central boron atom and a particular cationic moiety (for example, a cation having a HOMO-LUMO gap of 5.3 eV or less). The cationic moiety may, for example, have a skeleton selected from an N-substituted pyridinium skeleton, an N-substituted bipyridinium skeleton, an N-substituted quinolinium skeleton, and a pyrylium skeleton.
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(2020/03/09)

Preparation method of anhydrous tris (pentafluorophenyl) borane (by machine translation)
The raw materials are easily obtained, the production cost is reduced, the workload of post-treatment is reduced, the process operation is simple, the reaction time is effectively shortened, and the purity and the yield of the target product are improved. (by machine translation)
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Paragraph 0038; 0040; 0041; 0043; 0044; 0046; 0047; 0049

(2020/10/21)

Metal-Free Tandem Rearrangement/Lactonization: Access to 3,3-Disubstituted Benzofuran-2-(3H)-ones
A novel metal-free synthesis of 3,3-disubstituted benzofuran-2-(3H)-ones through reacting α-aryl-α-diazoacetates with triarylboranes is presented. Initially, triarylboranes were successfully investigated in α-arylations of α-diazoacetates, however in the presence of a heteroatom in the ortho position, the boron enolate intermediate undergoes an intramolecular rearrangement to form a quaternary center. The intermediate cyclizes to afford valuable 3,3-disubstituted benzofuranones in good yields.
Santi, Micol,Ould, Darren M. C.,Wenz, Jan,Soltani, Yashar,Melen, Rebecca L.,Wirth, Thomas
supporting information
p. 7861 - 7865
(2019/04/25)

Reactions of hydrazones and hydrazides with Lewis acidic boranes
The reaction of (diphenylmethylene)hydrazone or 1,4-bis-hydrazone-ylidene(phenylmethyl)benzene with Lewis acidic boranes B(2,4,6-F3C6H2)3 or B(3,4,5-F3C6H2)3 generates the Lewis acid-base adducts. Alternatively, when (9H-fluoren-9-ylidene)hydrazone is employed several products were isolated including 1,2-di(9H-fluoren-9-ylidene)hydrazone, the 2:1 borane adduct of NH2-NH2 and the 1-(diarylboraneyl)-2-(9H-fluoren-9-ylidene)hydrazone in which one ArH group has been eliminated. The benzhydrazide starting material also initially gives an adduct when reacted with Lewis acidic boranes which upon heating eliminates ArH generating a CON2B heterocycle.
Gazis, Theodore A.,Dasgupta, Ayan,Hill, Michael S.,Rawson, Jeremy M.,Wirth, Thomas,Melen, Rebecca L.
p. 12391 - 12395
(2019/08/26)

Interactions of C?F Bonds with Hydridoboranes: Reduction, Borylation and Friedel–Crafts Alkylation
The stoichiometric reactions of the alkylfluorides 1-fluoroadamantane (Ad-F), fluorocyclohexane (Cy-F), 1-fluoropentane (Pent-F) and benzyl fluorides with secondary boranes pinacolborane (HBpin), catecholborane (HBcat), 9-borabicyclo(3.3.1)nonane (9-BBN)
Bamford, Karlee L.,Chitnis, Saurabh S.,Qu, Zheng-wang,Stephan, Douglas W.
supporting information
p. 16014 - 16018
(2018/10/15)

Stoichiometric and Catalytic C?C and C?H Bond Formation with B(C6F5)3 via Cationic Intermediates
This work showcases a new catalytic cyclization reaction using a highly Lewis acidic borane with concomitant C?H or C?C bond formation. The activation of alkyne-containing substrates with B(C6F5)3 enabled the first catalytic intramolecular cyclizations of carboxylic acid substrates using this Lewis acid. In addition, intramolecular cyclizations of esters enable C?C bond formation as catalytic B(C6F5)3 can be used to effect formal 1,5-alkyl migrations from the ester functional groups to unsaturated carbon–carbon frameworks. This metal-free method was used for the catalytic formation of complex dihydropyrones and isocoumarins in very good yields under relatively mild conditions with excellent atom efficiency.
Soltani, Yashar,Wilkins, Lewis C.,Melen, Rebecca L.
supporting information
p. 11995 - 11999
(2017/09/20)

A hydroboration route to geminal P/B frustrated Lewis pairs with a bulky secondary phosphane component and their reaction with carbon dioxide
The secondary aryl-P(H) phosphanyl substituted tert-butylacetylenes 7a,b (aryl: Mes or Mes?) undergo hydroboration with [HB(C6F5)2] to give the geminal vinylidene-bridged P/B Lewis pairs 8a,b. The treatment of 8a,b with benzonitrile, N-sulfinylaniline, and phenyl isothiocyanate, respectively, gives the addition products 12a,b, 13a,b, and 14 with proton transfer from the phosphorus to the more basic nitrogen site. The reaction of the FLPs 8a,b with carbon dioxide yields a doubly boron bonded addition product. The reaction of 8b with a conjugated ynone formally proceeded by trans-1,2-hydrophosphination of the alkyne at the geminal FLP framework to give the seven-membered heterocycle 21.
Jian, Zhongbao,Kehr, Gerald,Daniliuc, Constantin G.,Wibbeling, Birgit,Erker, Gerhard
supporting information
p. 11715 - 11721
(2017/09/18)

Perfluoroalkylation of Alkenes by Frustrated Lewis Pairs
The activation of perfluoroalkyl iodides by the frustrated Lewis pair tris(pentafluorophenyl)borane and tri-tert-butylphosphine is described. By abstraction of both a fluorine and an iodine atom, an iodophosphonium fluoroborate salt is formed. In the presence of alkenes the corresponding iodoperfluoroalkylation products are generated regioselectively. First mechanistic investigations support a radical mechanism.
Behrends, Ilona,B?hr, Susanne,Czekelius, Constantin
supporting information
p. 17177 - 17181
(2016/11/23)

Observation of zirconium allyl species formed during zirconocene-catalyzed propene polymerization and mechanistic insights
Oligomeric Cp2Zr+-allyl species were detected in reaction mixtures of either [Cp2ZrMe][MeB(C6F5)3] or [Cp2ZrMe][B(C6F5)4] with propylene by a combination of 1H NMR spectroscopy and electrospray ionization (tandem) mass spectrometry techniques. Conjointly, the data imply that formation of Cp2Zr+-allyl species occurs via (re)coordination of alkene (propylene and vinylidene end groups of unsaturated polymer chains, respectively) to Cp2Zr+R (R = CH3, H, polymeryl), followed by intramolecular proton transfer from Cγ to R and release of RH. Analysis of the olefinic region of the 1H NMR spectra of the reaction mixture obtained from [Cp2ZrMe][MeB(C6F5)3] and propylene reveals the presence of a triplet resonance at δ ～ 5.2, which was attributed to the unprecedented 3-propenyl end group. A plausible mechanism for the origin of the 3-propenyl end groups is discussed. Additionally, a mechanism for incorporation of stereodefects into stereoregular polymers is also discussed. The cationic Cp2Zr+-allyl intermediates formed during polymerization may contribute to catalyst deactivation.
Vatamanu, Mihaela
p. 112 - 120
(2015/09/28)

Synthesis, structures, and dynamic features of d0 zirconocene-allyl complexes
The reaction of [Cp2ZrMe][MeB(C6F5) 3] (1) with 2,4-dimethyl-1-pentene and 2,4-dimethyl-1-heptene, respectively, in C6D5Cl at 25 °C results in irreversible formation of the cationic Cp2Zr+-allyl complexes [Cp2Zr(η3-CH2C(CH 2R)CH2)]+ (2a, 3a) and [Cp2Zr(η 3-CH2C(Me)CHR)]+ (2b, 3b) (2a,b, R = CH(CH 3)2; 3a,b, R = CH(CH3)CH2CH 2CH3) and release of methane. The Cp2Zr +-allyl complexes were characterized with regard to their structures and rearrangement dynamics of their allyl ligands by NMR spectroscopy. Variable-temperature 1H NMR experiments show that the allyl ligands of complexes 2a,b and 3a,b are fluxional. The fluxional behavior in these complexes is mainly due to a mechanism that involves η3 to η1 isomerization, rotation of the allyl carbon-carbon π unit about the carbon-carbon σ bond, and reversion to the η3- allyl coordination mode, when both the allyl syn/anti hydrogen exchange and apparent Cp ligand exchange occur. The rotation of the C-C unit about the allyl carbon-carbon σ bond also results in a reversal of the η3-allyl coordination face relative to the Cp2Zr + moiety. A second mechanism which may account for the apparent Cp ligand exchange in the Cp2Zr+-allyl complexes under investigation consists of rotation of the η3-coordinated allyl ligand about the metal-allyl bond. The free energy of activation for the exchange processes, as estimated from the coalescence temperature of the two Cp ligands, is between 54 and 60 kJ/mol. Aside from the intramolecular allyl exchange processes described above, this study also shows that the η1- and η3-coordinated allyl forms of a particular Zr-allyl complex coexist in solution and that the equilibrium composition of these species is temperature dependent. The Cp2Zr+-allyl complexes described in this paper serve as models for similar cationic Cp 2Zr+-allyl intermediates implicated in zirconocene-catalyzed alkene polymerization reactions.
Vatamanu, Mihaela
p. 3683 - 3694
(2014/08/18)

Comparative Lewis acidity in fluoroarylboranes: B(o-HC6F 4)3, B(p-HC6F4)3, and B(C6F5)3
The Lewis acidic fluoroarylborane B(o-HC6F4) 3 (2) was prepared and its Lewis acid strength assessed in comparison to the known, related boranes B(C6F5)3 (1) and B(p-HC6F4/
Morgan, Matthew M.,Marwitz, Adam J. V.,Piers, Warren E.,Parvez, Masood
p. 317 - 322
(2013/02/25)

A photo Lewis acid generator (PhLAG): Controlled photorelease of B(C 6F5)3
A molecule that releases the strong organometallic Lewis acid B(C 6F5)3 upon irradiation with 254 nm light has been developed. This photo Lewis acid generator (PhLAG) now enables the photocontrolled initiation of several reactions catalyzed by this important Lewis acid. Herein is described the synthesis of the triphenylsulfonium salt of a carbamato borate based on a carbazole function, its establishment as a PhLAG, and the application of the photorelease of B(C6F5) 3 to the fabrication of thin films of a polysiloxane material.
Khalimon, Andrey Y.,Piers, Warren E.,Blackwell, James M.,Michalak, David J.,Parvez, Masood
p. 9601 - 9604
(2012/07/14)

Silylium-arene adducts: An experimental and theoretical study
The solvent-coordinated [Me3Si·arene][B(C 6F5)4] salts (arene = benzene, toluene, ethylbenzene, n-propylbenzene, isopropylbenzene, o-xylene, m-xylene, p-xylene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene) are prepared and fully characterized. As an interesting decomposition product the formation of bissilylated fluoronium ion [Me3Si-F-SiMe 3]+ was observed and even cocrystallized with [Me 3Si·arene][B(C6F5)4] (arene = benzene and toluene). Investigation of the degradation of [Me 3Si·arene][B(C6F5)4] reveals the formation of fluoronium salt [Me3Si-F-SiMe3][B(C 6F5)4], B(C6F5) 3, and a reactive "C6F4" species which could be trapped with CS2. Upon addition of CS2, the formation of a formal S-heterocyclic carbene adduct, C6F 4CS2-B(C6F5)3, was observed. The structure and bonding of substituted [Me3Si· arene][B(C6F5)4] with arene = R nC6H6-n (R = H, Me, Et, Pr, and Bu; n = 0-6) is discussed on the basis of experimental and theoretical data. X-ray data of [Me3Si·arene][B(C6F5)4] salts reveal nonplanar arene species with significant cation...anion interactions. As shown by different theoretical approaches (charge transfer, partial charges, trimethylsilyl affinity values) stabilizing inductive effects occur; however, the magnitude of such effects differs depending on the degree of substitution and the substitution pattern.
Ibad, Muhammad Farooq,Langer, Peter,Schulz, Axel,Villinger, Alexander
supporting information; experimental part
p. 21016 - 21027
(2012/03/07)

PROCESS FOR PRODUCING METHANOL
The present invention relates to a novel process for the production of methanol. The process comprises the heterolytic cleavage of hydrogen by a frustrated Lewis pair comprising a Lewis acid and a Lewis base; and the hydrogenation of CO2 with the heterolytically cleaved hydrogen to form methanol.
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Page/Page column 19-20

(2011/05/05)

Synthesis of pentafluorophenyl silver by means of lewis acid catalysis: Structure of silver solvent complexes
The synthesis and structure of lithium, and silver tetrakis(pentafluorophenyl)borate salts have been studied in different solvents ranging from polar (CH2Cl2, diethyl ether) to nonpolar (toluene, pentane). While Li[B(C6F5)4]is stable in all studied, solvents and crystallizes with four ether molecules from ether and with two toluene molecules from toluene, the silver salt, is only stable when the Ag+ ion is strongly coordinated such as in [Ag(toluene) 3][B(C6F5)4] or [Ag(Et 2O)3][B(C6F5)4]. Li weakly coordinating solvents such as CH2Cl2 Ag[B(C 6F5)4] decomposes, yielding AgC 6F5 and B(C6F5)3. The overall process of the AgC6F5 synthesis starting from B(C6F5)3 and LiC6F5 can formally be regarded as a B(C6F5)3-catalyzed reaction. The salt [Ag(toluene)3][B(C6F5)4] presents an easily accessible, ether-free, stable silver salt of the [B(C 6F5)4]-anion. All compounds have been fully characterized.
Kuprat, Marcus,Lehmann, Mathias,Schulz, Axel,Villinger, Alexander
p. 1421 - 1427
(2010/05/01)

Chelate restrained boron cations for intermolecular electrophilic arene borylation
Highly electrophilic boron species that borylate arenes are generated by halide abstraction from CatBX (Cat = catecholato, C6H 4O22-, X = Cl or Br) by [Et3Si] [CbBr6] (CbBr6 = [closo-1-H-CB11H 5Br6]-). A transient [CatB][CbBr6] related species reacts as a synthetic equivalent of [CatB]+ in intermolecular electrophilic borylation, with reactions proceeding rapidly at 25 °C. The [CatB]+ moiety was shown to be strongly Lewis acidic on the basis of 1H and 31P{1H} NMR spectroscopy of the crotonaldehyde and triethylphosphine oxide adducts, respectively. Catalytic quantities of [Et3Si][CbBr6] and CatBX were effective for the high-yielding borylation of arenes by CatBH in a highly atom efficient cycle with H2 the only byproduct. Successful catalysis was dependent on the robust [CbBr6]- anion and the use of electrophile-resistant borane sources
Del Grosso, Alessandro,Pritchard, Robin G.,Muryn, Chris A.,Ingleson, Michael J.
p. 241 - 249
(2010/04/04)

Reversible metal-free carbon dioxide binding by frustrated lewis pairs
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Moemming, Cornelia M.,Kehr, Gerald,Froehlich, Roland,Grimme, Stefan,Erker, Gerhard,Otten, Edwin,Stephan, Douglas W.
p. 6643 - 6646
(2009/12/26)

Experimental and theoretical treatment of hydrogen splitting and storage in boron-nitrogen systems
Hydrogen gas serves as a reducing agent and hydrogen atom source in numerous industrially important chemical processes and also has a great potential as a clean power source for fuel cells. In this respect, the reversible storage of hydrogen and the development of new metal-free hydrogenation catalysts are important tasks. Here, we review the recent literature, primarily on cases where the split H2 forms an N-H?H-B dihydrogen bond. In these systems dihydrogen interaction was found to be the key actor in the hydrogen liberating process. Accordingly, the intramolecular ansa-aminoboranes (where B and N atoms are situated within each other's range) can reversibly activate hydrogen. Moreover, the theoretical studies of the hydrogen splitting by bulky Lewis acid-Lewis base systems are discussed.
Sumerin, Victor,Schulz, Felix,Nieger, Martin,Atsumi, Michiko,Wang, Cong,Leskel?, Markku,Pyykk?, Pekka,Repo, Timo,Rieger, Bernhard
p. 2654 - 2660
(2009/12/09)

Pentamethylcyclopentadienylmethyltitanium silsesquioxanes and their zwitterionic complexes with tris(pentafluorophenyl)borane
Reaction of [(η5-C5Me5)TiMe 3] with [(c-C5H9)7Si 8O12(OH)] (SIPOSS) or [(c-C5H9) 7Si7O9(OSiMe3)(OH)2)] (DIPOSS') affords stoichiometrically the half-sandwich titanium-disiloxy-methyl complexes [(η5-C5Me5){(c-C5H 9)7Si8O12O)2TiMe] (1) and [(η5-C5Me5){(c-C5H 9)7Si7O9(OSiMe3)O 2)TiMe] (2), respectively. Compound 2 consists of the two stereoisomers possessing the (η5-C5Me5) ligand and OSiMe3 group in syn- (2a) and anti-position (2b). The more abundant 2a (2a/2b ≈2:1) was isolated by fractional crystallization. Compounds 1 and 2a reacted rapidly with B(C6F5) 3 to give zwitterionic complexes [(η5-C 5Me5){(c-C5H9)7Si 8O12O}2Ti](+)[(μ-Me)B(C 6F5)3](-) (3) and syn-[(η5C5Me5){(c-C5H 9)7Si7O9(OSiMe3)O 2}Ti]{+)[(μ-Me)B(C6F5) 3](-) (4a), respectively. Infrared spectra proved that 3 and 4a were thermally stable in the solid state and the structure of 4a was determined by X-ray single-crystal analysis. In contrast, 1H, 13C and 19F NMR spectra of 3 in toluene C 7D8 revealed that it was completely dissociated into initial components at 25 °C; however, the features of 3 were dominating already at -35 °C. On the other hand, 4a was dissociated only slightly at 25 °C. Stable ionic complexes 7 and 8 were prepared by reacting [PhNHMe 2]+[B(C6F5)4] - with 1 and 2, respectively. Both 7 and 8 contained the molecule PhNMe2 coordinated to the titanium cation and 8 consisted of the syn- and anti-isomers 8a and 8b in abundances found for 2a/2b. Analogous reaction of 1 and 2 with [Ph3C]+[B(C6F5) 4]- afforded impure ionic complexes 9 and 10. When dissolved in the presence of PhNMe2, the amine coordinated to the titanium cations, thus reproducing complexes 7 and 8a/8b, identified by 1H NMR spectra. All compounds 1-10 were inactive in polymerization of styrene to syndiotactic polymer. A low activity was achieved by adding of 2 equiv of AlMe3 to 3 or 4.
Varga, Vojtech,Pinkas, Jiri,Cisarova, Ivana,Horacek, Michal,Mach, Karel
p. 6944 - 6956
(2010/04/04)

m-Terphenylaluminum and -gallium compounds: Synthesis and conversion into low-coordinate organogallium cations
The reaction of two or 3 equiv. of m-terphenyllithium with MCl3 or AlH3·NMe3 (M = Al, Ga) affords the bis(terphenyl)-aluminum and -gallium chloride compounds [{2,6-(4-tBuC 6H4)2C6H3} 2GaCl] (1), [{2,6-(3,5-Me2C6H3) 2C6H3}2GaCl] (2), [{2,6-(4-tBuC 6H4)2C6H3}3Ga] (3), [(2,6-Mes2C6H3)2AlCl] (5), and [(2,6-Mes2C6H3)2AlH] (7; Mes = 2,4,6-Me 3C6H2). While the gallium compounds can be obtained at room temperature, heating is required for the aluminum derivatives. The dibutyl compounds [(2,6-Mes2C6H3)GaBu 2] (8) and [(2,6-Dipp2C6H3)GaBu 2] (9; Dipp = 2,6-iPr2C6H3) have also been synthesized by the reaction of m-terphenyllithium with ClGaBu 2. A metathesis reaction of 2 with Li[Al{OCH(CF3) 2}4] gives the ionic species [(2,6-Mes2C 6H3)2Ga]+[Li[Al-[OCH(CF 3)2]4}2]- (11). The cationic butyl(terphenyl)gallium compounds [(2,6-Mes2C6H 3)GaBu]+ ([13]+) and [(2,6-Dipp 2C6H3)GaBu]+ ([14]+) have been prepared by butanide abstraction with the trityl salts of the weakly coordinating anions [B(C6F5)4]-, [CHB11Br6Me5]-, and [CHB 11Cl11]-. These ionic species are stable at room temperature for days or weeks, although their combinations with the borate anion [B-(C6F5)4]- suffer from C6F5 migration, which is slow at room temperature and faster at elevated temperatures. The compound [14]+[CHB 11Cl11]- is stable at 70°C for at least 23 h. Addition of 1-octene to a solution of [14]+[CHB 11Cl11]_ in C6D6 results in olefin exchange and formation of the octyl species [(2,6-Dipp 2C6H3)Ga(octyl)]+ ([17] +), and a slow alkylation of the solvent to afford various octylbenzenes. Hydrolysis of 8 and [13]+[CHB11Br 6Me5]- gives the compounds [{(2,6-Mes 2C6H3)GaBu(μ-OH)}2] (10) and [(BuGa)4(μ-OH)6]2+[CHBnBr6Me 5]-2 (16). All compounds have been characterized by 1H and 13C{1H} NMR spectroscopy and mass spectrometry, and compounds 3, 5, 7, 10, and 16·4.5C6H6 have also been characterized by single-crystal X-ray crystallography. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Young, Jackie D.,Khan, Masood A.,Powell, Douglas R.,Wehmschulte, Rudolf J.
p. 1671 - 1681
(2008/02/06)

Olefin polymerization catalyst system
This invention relates to a catalyst precursor compound comprising a tridentate phenoxy-amide-amine group bound to a group 3 to 12 metal or lanthanide metal. In particular, this invention relates to a catalyst precursor compound represented by the formula: wherein: M is a group 3 to group 12 transition metal or lanthanide metal, provided however N1 is not part of a pyridine ring when M is a group 8, 9, or 10 metal; Q is oxygen or sulfur; N is nitrogen; N1 is nitrogen; R1, is a hydrogen, a hydrocarbyl, a substituted hydrocarbyl, a halocarbyl, a substituted halocarbyl, a heteroatom or heteroatom containing group; R2 and R3 are independently, a hydrogen, a halogen, a hydrocarbyl, a substituted hydrocarbyl, a halocarbyl, or a substituted halocarbyl, a heteroatom or heteratom containing group and R2 and R3 together may form a multidentate ligand, such as a bidentate dianionic ligand; R4 is hydrogen, a hydrocarbyl, a substituted hydrocarbyl, a halocarbyl, a substituted halocarbyl, a heteroatom or heteroatom containing group; R5 is a hydrogen, a hydrocarbyl, a substituted hydrocarbyl, a halocarbyl, a substituted halocarbyl, a heteroatom or heteroatom containing group; R6, R7, and R8 are, independently, a hydrogen, a hydrocarbyl, a substituted hydrocarbyl, a halocarbyl, a substituted halocarbyl, a heteroatom or heteroatom containing group, and any two of R1, R6, R7, and R8 may form a fused ring system; each Ris, independently, hydrogen, a hydrocarbyl, a substituted hydrocarbyl, a halocarbyl, a substituted halocarbyl group, or a heteroatom or heteroatom containing group; R10 is a hydrocarbyl, a substituted hydrocarbyl, a halocarbyl, a substituted halocarbyl group, or a heteroatom or heteroatom containing group; where any two adjacent R groups may form a ring structure.
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(2008/06/13)

Process for preparing a tetrakis(fluoroaryl) borate derivative
A fluoroaryl magnesium derivative expressed by General Formula (1): where each of R1-R5represents a hydrogen atom, a fluorine atom, a hydrocarbon group, or an alkoxy group while at least one of R1-R5representing a fluorine atom, and Xa represents a chlorine atom, a bromine atom, or an iodine atom; and boron halide expressed by General Formula (2): BXb3??(2) ?where Xb represents a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, are reacted with each other in a solvent (a) containing diethyl ether and/or tetrahydrofuran, after which the resulting reaction solution is added to a solvent (b) having a higher boiling point than diethyl ether and/or tetrahydrofuran while diethyl ether and/or tetrahydrofuran are distilled out. Consequently, it has become possible to obtain a (fluoroaryl)borane compound expressed by General Formula (3): ?where each of R1-R5, and Xb, represents the same as above, and n represents 2 or 3, from which magnesium halide produced as a by-product is separated and removed, selectively in a simple manner at a low cost.
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Page column 25-28; 29

(2008/06/13)

A comparative study of base-free arylcopper reagents for the transfer of aryl groups to boron halides
A comparative study on the reactivity and selectivity of arylcopper species in reactions with boron halides was performed. Mesitylcopper reacts with BX3 (X=Cl, Br) in toluene at low temperature under highly selective formation of the monosubstituted boranes MesBX2. The dimesitylboranes Mes2BX are gradually formed with a twofold excess of the organocopper reagent at elevated temperature. In contrast, pentafluorophenylcopper shows a tendency for formation of B(C6F5) 3 in reactions with BX3 irrespective of the stoichiometry used, suggesting a strong impact of electronic factors on the selectivity of the aryl transfer reaction. New procedures for the synthesis of the pentafluorophenylboron halides C6 F5BX2 (X=Cl: 57%; X=Br: 62%) and of tris(pentafluorophenyl)borane (80%) and related mixed-substituted triarylboranes from the base-free isolable pentafluorophenylcopper precursor have been developed.
Sundararaman, Anand,J?kle, Frieder
p. 134 - 142
(2007/10/03)

Synthesis, structural characterization and reactivity of the amino borane 1-(NPh2)-2-[B(C6F5) 2]C6H4
The bright red title compound 1 was synthesized from (2-lithiophenyl) diphenylamine and bis(pentafluorophenyl)boron chloride. Its reactions with small acids like H2O and HCl proceeded easily giving zwitterionic compounds. For 1 and its water adduct 2 the crystal structures were determined, the latter featuring an ammonium borate structure containing a short intramolecular hydrogen bond bridge. Treatment of 1 with Jutzi's acid, [H(OEt2)2] [B(C6F5)4], did not result in protonation of the nitrogen, but reaction of 1 with LiH in the presence of 12-crown-4, led to the isolation of the aminoborate [1-(Ph2N)-2-{B(H)(C6F5)2} C6H4][Li(12-crown-4)] (3). Borohydride 3 reacted with Jutzi's acid to regenerate 1 and liberate hydrogen.
Roesler, Roland,Piers, Warren E.,Parvez, Masood
p. 218 - 222
(2007/10/03)

Reaction of vinyl chloride with group 4 metal olefin polymerization catalysts
The reactions of three types of group 4 metal olefin polymerization catalysts, (C5R5)2ZrX2/activator, (C5Me5)TiX3/MAO (MAO = methylalumoxane), and (C5Me4SiMe2NtBu) MX2/activator (M = Ti, Zr), with vinyl chloride (VC) and VC/propylene mixtures have been investigated. Two general pathways are observed: (i) radical polymerization of VC initiated by radicals derived from the catalyst and (ii) net 1,2 VC insertion into LnMR+ species followed by β-Cl elimination, rac-(EBI)ZrMe(μ-Me)B(C6F5)3. (EBI = 1,2-ethylenebis-(indenyl)) reacts with 2 equiv of VC to yield oligopropylene, rac-(EBI)ZrCl2, and B(C6F5)3. This reaction proceeds by net 1,2 VC insertion into rac-(EBI)ZrMe+ followed by fast β-Cl elimination to yield [rac-(EBI)- ZrCl][MeB(C6F5)3] and propylene. Methylation of rac-(EBI)ZrCl+ by MeB(C6F5)3- enables a second VC insertion/β-Cl elimination to occur. The evolved propylene is oligomerized by rac-(EBI)ZrR+ as it is formed. At high Al/Zr ratios, rac-(EBI)ZrMe2/MAO catalytically converts VC to oligopropylene by 1,2 VC insertion into rac-(EBI)ZrMe+, β-Cl elimination, and realkylation of rac-(EBI)ZrCl+ by MAO; this process is stoichiometric in Al-Me groups. The evolved propylene is oligomerized by rac-(EBI)ZrR+. Oligopropylene end group analysis shows that the predominant chain transfer mechanism is VC insertion/β-Cl elimination/realkylation. In the presence of trace levels of O2, rac-(EBI)ZrMe2/MAO polymerizes VC to poly(vinyl chloride) (PVC) by a radical mechanism initiated by radicals generated by autoxidation of Zr-R and/or Al-R species. Cp*TiX3/MAO (Cp* = C5Me5; X = OMe, Cl) initiates radical polymerization of VC in CH2Cl2 solvent at low Al/Ti ratios under anaerobic conditions; in this case, the source of initiating radicals is unknown. Radical VC polymerization can be identified by the presence of terminal and internal allylic chloride units and other radical defects in the PVC which arise from the characteristic chemistry of PCH2CHCl? macroradicals. However, this test must be used with caution, since the defect units can be consumed by postpolymerization reactions with MAO. (C5Me4SiMe2NtBu) MMe2/[Ph3C]][B(C6F5)4] catalysts (M = Ti, Zr) react with VC by net 1,2 insertion/β-Cl elimination, yielding [(C5Me4SiMe2NtBu) MCl][B(C6F5)4] species which can be trapped as (C5Me4SiMe2NtBu)MCI2 by addition of a chloride source. The reaction of rac-(EBI)ZrMe2/MAO or [(C5Me4- SiMe2NtBu)ZrMe][B(C6 F5)4] with propylene/VC mixtures yields polypropylene containing both allylic and vinylidene unsaturated chain ends rather than strictly vinylidene chain ends, as observed in propylene homopolymerization. These results show that the VC insertion of LnM(CH2CHMe)nR+ species is also followed by β-Cl elimination, which terminates chain growth and precludes propylene/VC copolymerization. Termination of chain growth by β-Cl elimination is the most significant obstacle to metal-catalyzed insertion polymerization/copolymerization of VC.
Stockland Jr., Robert A.,Foley, Stephen R.,Jordan, Richard F.
p. 796 - 809
(2007/10/03)

Handling method of (fluoroaryl) borane compound and preparing method of hydrocarbon solution
A mixture of bis- and tris(fluoroaryl)borane compounds expressed by General Formula (1) below is handled in the form of a slurry made with a hydrocarbon solvent: where each of R1, R2, R3, R4 and R5 independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group, or an alkoxy group provided that at least one of R1-R5 represents a fluorine atom, X represents a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and wherein n represents 2 for the bis(fluoroaryl)borane compounds and 3 for the tris(fluoroaryl)borane compounds. Then, a hydrocarbon solution of the (fluoroaryl)borane compounds having a concentration of the tris(fluoroaryl)borane compounds in a range between 1 wt % and 1 wt % is prepared by dissolving the slurry into a hydrocarbon solvent in a virtually air-tight vessel. Consequently, it has become possible to provide a method of handling the tris(fluoroaryl)borane compounds in an industrially and economically advantageous manner, and a method of preparing the hydrocarbon solution of the tris(fluoroaryl)borane compounds readily and quickly without lowering the purity.
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(2008/06/13)

Transition metal compound, catalyst for addition polymerization, and process for producing addition polymer
A transition metal compound (A) of the formula (1), a catalyst for addition polymerization obtained by bringing the transitionmetal compound to contact with (B) and/or (C) below, and a process for producing an addition polymer with the catalyst: wherein, M represents a titanium atom, zirconium atom or hafnium atom in the +3 formal oxide condition; A represents a multidentate mono-anionic ligand; R1 represents an alkyl group, aralkyl group, aryl group or substituted silyl group; E represents an oxygen atom or sulfur atom; each of two Xs independently represents a hydrogen atom, halogen atom, alkyl group, aralkyl group, aryl group, substituted silyl group, alkoxy group, aralkyloxy group, aryloxy group or di-substituted amino group, and two Xs may bond mutually to form a ring; D represents a neutral ligand coordinated on M; and n represents an integer of from 0 to 2.), (B)Organic aluminum compound and/or aluminoxane, (C)Specific boron compound.
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(2008/06/13)

Metal complex containing one or more silsesquioxane ligands
Metal complex containing one or more silsesquioxane ligands, having the formula Zy(MAxBq)b??(I), wherein Z is a silsesquioxane according to the formula R7-lSi7O12YD1+l??(II), M is a metal from groups 3-6 of the Periodic System of the Elements and the lanthanides, A is a monoanionic ligand bound to the metal, B is a ?-bound ligand, y represents the number of silsesquioxane ligands and is 1-10, b represents the number of metal groups and is 1-20, q is 0, 1 or 2, x is the number of substituents A bound to the metal; the value of x depends on the metal used and is equal to the valency of the metal minus 1, 2, 3 or 4, R is a substituent bound to Si, Y is an atom from group 13 or 14 of the Periodic System of the Elements, D is a group, directly bound to Y or Si with one atom from group 15 or 16 of the Periodic System of the Elements and l determines the amount of substituents R and atoms D and is equal to 0, 1, 2 or 3.
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(2008/06/13)

New perfluoroarylborane activators for single-site olefin polymerization. Acidity and cocatalytic properties of a "superacidic" perfluorodiboraanthracene
The synthesis, Lewis acid properties, and single-site olefin polymerization characteristics of catalyst systems utilizing the binuclear organo-Lewis acid cocatalyst 9, 10-bis(pentafluorophenyl)-9, 10-diboraoctafluoroanthracene, C12F8B2(C6F5)2 (8b), are reported. X-ray diffraction analysis of 8b reveals a nearly planar C12F8B2 core with -C6F5 rings rotated 75° out of the plane, hindering π communication between the pendant -C6F5 substituents and the C12F8B2 core, and thereby enhancing Lewis acidity at the boron centers. Competition equilibration experiments with 8b, B(C6F5)3, and acetonitrile over a wide temperature range demonstrate that 8b is a stronger Lewis acid than B(C6F5)3 by ΔH = +1.4(2) kcal/mol and ΔS = -5.3(1) eu. The diffraction-derived molecular structure of 8b←NCCH3 reveals substantial skeletal reorganization only at the coordinated boron center. When it is paired with dimethyl organo-group 4 catalyst precursors, 8b affords extremely efficient single-site olefin polymerization systems in both laboratory and large-scale reactors. In all cases, 8b forms polymerization systems with higher activities than those utilizing B(C6F5)3 as the cocatalyst.
Metz, Matthew V.,Schwartz, David J.,Stern, Charlotte L.,Marks, Tobin J.,Nickias, Peter N.
p. 4159 - 4168
(2008/10/08)

Method for manufacturing fluoroaryl magnesium halide
In order to provide a method of safely, efficiently, and industrially manufacturing fluoroaryl magnesium halide containing no impurities, such as coloring components, by a relatively gradual reaction compared with the conventional reactions, and a method of readily and efficiently manufacturing a highly-pure fluoroaryl borane derivative, fluoroaryl magnesium halide expressed by General Formula (1): where each of R1-R5independently represents H, F, a hydrocarbon group, or an alkoxy group, provided that at least three of R1-R5are fluorine atoms, and Xarepresents Cl, Br, or I; is manufactured by reacting, in a solvent containing a chain ether solvent, hydrocarbon magnesium halide expressed by General Formula (2): R6MgXa??(2) where R6represents a hydrocarbon group, and Xarepresents Cl, Br, or I; with fluoroaryl halide expressed by General Formula (3): where each of R1-R5independently represents H, F, a hydrocarbon group, or an alkoxy group, provided that at least three of R1-R5are fluorine atoms and Xbrepresents Br or I.
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(2008/06/13)