- Definition of an intramolecular Eu-to-Eu energy transfer within a discrete [Eu2L] complex in solution
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Ligand L, based on two do3a moieties linked by the methylene groups of 6,6'-dimethyl-2,2'-bipyridine, was synthesized and characterized. The addition of Ln salts to an aqueous solution of L (0.01 M Tris-HCl, pH 7.4) led to the successive formation of [LnL] and [Ln2L] complexes, as evidenced by UV/Vis and fluorescence titration experiments. Homodinuclear [Ln2L] complexes (Ln=Eu, Gd, Tb, Yb, and Lu) were prepared and characterized. The 1H and 13C NMR spectra of the Lu and Yb complexes in D2O solution (pD=7.0) showed C1 symmetry of these species in solution, pointing to two different chemical environments for the two lanthanide cations. The analysis of the chemical shifts of the Yb complex indicated that the two coordination sites present square antiprismatic (SAP) coordination environments around the metal ions. The spectroscopic properties of the [Tb2L] complex upon ligand excitation revealed conventional behavior with τH2O=2.05(1) ms and φH2O=51 %, except for the calculation of the hydration number obtained from the luminescent lifetimes in H2O and D2O, which pointed to a non-integer value of 0.6 water molecules per TbIII ion. In contrast, the Eu complex revealed surprising features such as: 1) the presence of two and up to five components in the 5D0→7F0 and 5D0→7F1 emission bands, respectively; 2) marked differences between the normalized spectra obtained in H2O and D2O solutions; and 3) unconventional temporal evolution of the luminescence intensity at certain wavelengths, the intensity profile first displaying a rising step before the occurrence of the expected decay. Additional spectroscopic experiments performed on [Gd 2-xEuxL] complexes (x=0.1 and 1.9) confirmed the presence of two distinct Eu sites with hydration numbers of 0 (site I) and 2 (site II), and showed that the unconventional temporal evolution of the emission intensity is the result of an unprecedented intramolecular Eu-to-Eu energy-transfer process. A mathematical model was developed to interpret the experimental data, leading to energy-transfer rates of 0.98 ms-1 for the transfer from the site with q=0 to that with q=2 and vice versa. Hartree-Fock (HF) and density functional theory (DFT) calculations performed at the B3LYP level were used to investigate the conformation of the complex in solution, and to estimate the intermetallic distance, which provided Foerster radii (R0) values of 8.1 A for the energy transfer from site I to site II, and 6.8 A for the reverse energy transfer. These results represent the first evidence of an intramolecular energy-transfer equilibrium between two identical lanthanide cations within a discrete molecular complex in solution. Copyright
- Nonat, Aline,Regueiro-Figueroa, Martin,Esteban-Gomez, David,De Blas, Andres,Rodriguez-Blas, Teresa,Platas-Iglesias, Carlos,Charbonniere, Loic J.
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- Determination of the absolute configuration and identity of chiral carboxylic acids using a Cu(II) complex of pyridine-benzimidazole-based ligand
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We report a new achiral Cu host [Cu(bmb-bpy)(H2O)(OTf) 2] (bmb-bpy = 6,6′-bis[((1-methylbenzimidazol-2-yl)thio)methyl] -2,2′-bipyridine) for the enantioselective and chemoselective recognition of chiral carboxylic acids. The binding of chiral carboxylic acids to [Cu(bmb-bpy)(H2O)(OTf)2] produced an exciton-coupled circular dichroism signal; the linear discriminant analysis allowed the assignment of the absolute configuration, enantiomeric excess, and identity of chiral carboxylic acids.
- Zhao, Shuang,Ito, Shintaro,Ohba, Yoshihiro,Katagiri, Hiroshi
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Read Online
- Novel ruthenium complexes bearing bipyridine-based and N-heterocyclic carbene-supported pyridine (NCN) ligands: The influence of ligands on catalytic transfer hydrogenation of ketones
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Transfer hydrogenation (TH) is a powerful synthetic tool in the production of secondary alcohols from ketones by using a non-H2hydrogen source along with metal catalysts. Among homogeneous catalysts, Ru(ii) complexes are the most efficient catalysts. In our research, six novel ruthenium(ii) complexes bearing bipyridine-based ligands [Ru(L1)Cl2] (1), [Ru(L1)(PPh3)Cl]Cl (2) and [Ru(L2)Cl2] (3) and N-heterocyclic carbene-supported pyridine (NCN) ligands [RuCp(L3)]PF6(4), [RuCp*(L3)]PF6(5), and [Ru(p-cymene)(L3)Cl]PF6(6) (whereL1= 6,6′-bis(aminomethyl)-2,2′-bipyridine,L2= 6,6′-bis(dimethylaminomethyl)-2,2′-bipyridine andL3= 1,3-bis(2-methylpyridyl)imidazolium bromide) were synthesised and characterised by NMR spectroscopy, HRMS, and X-ray crystallography. The catalytic transfer hydrogenation of 28 ketones in 2-propanol at 80 °C in the presence of KOtBu (5 mol%) was demonstrated and the effect of ligands is highlighted. The results show that catalyst1exhibits improved TH efficiency compared to the commercially available Milstein catalyst and displays higher catalytic activity than2due to the steric effect from PPh3. From a combination of kinetic data and Eyring analysis, a zero-order dependence on the acetophenone substrate is observed, implying a rate-limiting hydride transfer step, leading to the proposed inner-sphere hydride transfer mechanism.
- Piyasaengthong, Akkharadet,Walton, James W.,Williams, Luke J.,Yufit, Dmitry S.
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p. 340 - 351
(2021/12/27)
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- Thermally induced transformation of a Cu4I4-based cluster to a Cu2I2-based cluster under mild conditions
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A reaction of 6,6′-bis((benzylthio)methyl)-2,2′-bipyridine (L) with CuI at room temperature led to one Cu4I4-based cluster, which could be thermally transformed to a Cu2I2-based one under mild conditions due to the formation of a Cu-S bond. Along with the structural transformation, remarkable changes in the color and luminescence have been triggered.
- Jiang, Cheng-Gang,Li, Bao,Meng, Xiao-Yu,Yuan, Yan-Fang,Zhang, Tianle,Zhou, Ke-Ke,Zhuang, Gui-Lin
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supporting information
p. 9016 - 9020
(2021/07/12)
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- Dynamic Helicates Self-Assembly from Homo- and Heterotopic Dynamic Covalent Ligand Strands
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The understanding and the application of reversible covalent reactions and coordination chemistry together with the proper design of the molecular frameworks, allow to achieve not only well-defined output architectures but also different grades of complex behavior. In this work, the dynamic nature of the helical systems offers an additional level of complexity by combining self-sorting on two levels: 1) the build-up of the ligand strand constituents from their components through dynamic covalent chemistry; 2) the assembly of the helicates from the ligands and the metal cations through dynamic metallo-supramolecular chemistry. The information encoded in the ligands constituent molecule was read differently (and accurately at the same time) by metal cations that varied in the coordination algorithms. It enabled the selective formation of a specific type of helicates from a wide library of helicates formed by the possible combination of subcomponents. Ligands containing dynamic tridentate and/or bidentate binding motifs in the same strand were studied to explore the helicates self-assembly with appropriate metal cations.
- Santoro, Antonio,Holub, Jan,Fik-Jaskó?ka, Marta A.,Vantomme, Ghislaine,Lehn, Jean-Marie
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p. 15664 - 15671
(2020/10/21)
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- Upconverted photosensitization of Tb visible emission by NIR Yb excitation in discrete supramolecular heteropolynuclear complexes
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Addition of Tb3+ salts to a solution of a (YbLD) complex in D2O resulted in the formation of [(YbLD)2Tbx] (x = 1 to 3) complexes that, upon NIR excitation at 980 nm, showed an unprecedented Yb to Tb upconversion sensitization phenomenon resulting in the observation of the typical green emission of Tb.
- Souri, Nabila,Tian, Pingping,Platas-Iglesias, Carlos,Wong, Ka-Leung,Nonat, Aline,Charbonnière, Lo?c J.
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p. 1456 - 1459
(2017/02/10)
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- Design and synthesis of new Ru-complexes as potential photo-sensitizers: Experimental and TD-DFT insights
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We report density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations on a novel organic ligand and a novel class of ruthenium complexes; cis-RuL2X2 with L = 2,2′-bipyridine-6,6′-bis ethyl ester phosphonate and phosphonic acid, X = Cl, CN or NCS. The calculations show that cis-configurations are more stable than the trans-counterparts. The DFT results have been used to help design such novel complexes for potential use as sensitizers. We demonstrate the opportunity to synthesize such complexes with high purity. The synthesis of these complexes relies on the preparation of the key intermediates cis-Ru(2,2′-bipyridine-6,6′-bisdiethyl ester phosphonate)Cl2. These complexes were characterized by 1H, 13C, and 31P NMR, elemental analysis and FTIR spectroscopy. The NCS complex shows the smallest optical band gap followed by the Cl and CN complexes, respectively, with the highest performance upon use as a sensitizer in dye-sensitized solar cells.
- Sharmoukh,Hassan, Walid M. I.,Gros, Philippe C.,Allam, Nageh K.
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p. 69647 - 69657
(2016/08/05)
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- Step by Step Assembly of Polynuclear Lanthanide Complexes with a Phosphonated Bipyridine Ligand
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The synthesis of the octadentate ligand L (LH8 = ((([2,2′-bipyridine]-6,6′-diylbis(methylene))bis(azanetriyl))tetrakis(methylene))tetrakis(phosphonic acid)) is reported. The coordination of L with various lanthanide cations was monitored by absorption and luminescence spectrophotometric titration experiments (Ln = Tb, Yb), potentiometry (Ln = La, Eu, Lu), and mass spectrometry (Ln = Tb). It was found that L forms very stable mononuclear (LnL) species in aqueous solutions (log K = 19.80(5), 19.5(2), and 19.56(5) for La, Eu, and Lu, respectively) with no particular trend along the series. Spectroscopic data showed the Ln cations to be enclosed in the cavity formed by the octadentate ligand, thereby shielding the metal from interactions with water molecules in the first coordination sphere. When more than one equivalent of cations is added, the formation of polynuclear [(LnL)2Lnx] complexes (x = 1-3) can be observed, the presence of which could be confirmed by electrospray and MALDI mass spectrometry experiments. DFT modeling of the mononuclear (LnL) complexes indicated that the coordination of the cation in the cavity of the ligand results in a very asymmetric charge distribution, with a region of small negative electrostatic potential on the hemisphere composed of the chromophoric bipyridyl moiety and an electron-rich domain at the opposite hemisphere around the four phosphonate functions. DFT further showed that this polarization is most likely at the origin of the strong interactions between the (LnL) complexes and the incoming additional cations, leading to the formation of the polynuclear species. 1H and 31P NMR were used to probe the possible exchange of the lanthanide complexed in the cavity of the ligand in D2O, revealing no detectable exchange after 4 weeks at 80 °C and neutral pD, therefore pointing out an excellent kinetic inertness.
- Souri, Nabila,Tian, Pingping,Lecointre, Alexandre,Lemaire, Zoé,Chafaa, Salah,Strub, Jean-Marc,Cianférani, Sarah,Elhabiri, Mourad,Platas-Iglesias, Carlos,Charbonnière, Lo?c J.
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p. 12962 - 12974
(2016/12/26)
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- Improved Halogenation of Methyl Aromatics and Methyl Heteroaromatics: Unexpected Reactivity of Tetrahalogeno-diphenylglycolurils
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1,3,4,6-Tetrachloro (TCDGU) and 1,3,4,6-tetrabromo-3α,6α-diphenylglycolurils smooth halogen oxidizers have been exploited in a new direction as reagents for free radical substitution toward some N-halosuccinimide nonreactive bis-heterocycles. An unexpected selectivity and reactivity were observed with methyl benzenes, methyl heterocycles, and methyl-bis-heterocycles of interest. A chemometric study has been performed to optimize five independent factors of the chlorination reaction with TCDGU. The predictive model was established either for the halogenation conversion and the ratio of monochlorination.
- Moretti, Florian,Poisson, Guillaume,Marsura, Alain
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p. 173 - 183
(2016/05/19)
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- Template synthesis and spectral characterization of new Lead(II)-Schiff base macrocyclic complexes incorporating phenanthroline and/or bipyridine units
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Lead(II) complexes of Schiff-bases containing phenanthroline and/or bipyridine units were synthesized by the template reaction between new diamine compound, 6,6'-bis(2-aminophenoxymethyl)-2,2'-bipyridine and 2,2-bipyridine-6,6-dicarboxaldehyde or 1,10-phenanthroline- 2,9-dicarboxaldehyde in the presence of metal ions. These complexes, [PbL1]( ClO4)2and [PbL2](NO3)2, were characterized and investigated by using; MALDI-TOF and Q-TOF-MS spectroscopy, FTIR, UV/Visible spectroscopy, 1H NMR, Elemental analyses (CHN), magnetic susceptibility and molar conductivity measurements.
- Beynek,Tan,Beynek
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p. 4141 - 4144
(2015/12/23)
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- Template synthesis, characterization, and antimicrobial activity of a new lead (II) Schiff base complex
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A novel lead (II) complex of Schiff base containing three bipyridine units was synthesized by the template reaction between a new amine compound, 6-methyl-6′-(2-aminophenoxymethyl)-2,2′-bipyridine, and 2,2′-bipyridine-6,6′-dicarboxaldehyde in the presence of a Pb(II) perchlorate ion. The new amino compound and Schiff base complex, [PbL](ClO4)2·2H2O, were characterized by using matrix-assisted laser desorption/ionization with time-of-flight mass spectroscopy, FAR FT-IR, UV/visible spectroscopy, 1H NMR, elemental analyses (CHN), and molar conductivity measurements. Then the synthesized complex was screened in vitro for its antibacterial and antifungal activities against three Gram-negative and two Gram-positive bacteria and also against Candida albicans as a fungus by the microdilution broth method as a minimal inhibitory concentration. [PbL](ClO4)2·2H2O exhibits moderate activity on Staphylococcus aureus and Listeria monocytogenes when compared with standard drug and also shows moderate antifungal activity on the fungus Candida albicans.
- Beynek, Nesrin,Tan, Nurcihan,Beynek, Hayrettin
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p. 145 - 150
(2015/12/09)
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- An efficient route to pyridine and 2,2'-bipyridine macrocycles incorporating a triethylenetetraminetetraacetic acid core as ligand for lanthanide ions
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Two novel macrocyclic chelators L1 and L2 incorporating an intracyclic pyridine or 2,2'-bipyridine unit and a triethylenetetraminetetraacetic acid core (TTTA) were synthesized with the aim of forming lanthanide complexes suitable as
- Bechara, Ghassan,Leygue, Nadine,Galaup, Chantal,Mestre, Béatrice,Picard, Claude
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experimental part
p. 6522 - 6525
(2011/02/24)
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- Synthesis and characterization of new binaphthyl-linked phenanthroline-, bipyridine-, or pyridine-derived ligands, and the study of their cytotoxic activity
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In the present work, we describe the synthesis and characterization of five new versatile acyclic or macrocyclic ligands containing binaphthyl-linked pyridine, bipyridine, or phenanthroline groups in their framework (see Schemes 1-4). The structures of the ligands were elucidated on the basis of elemental analyses, IR, 1H-NMR, 13C-NMR, and FAB mass spectra. The cytotoxicity of these compounds was tested in vitro by using the tetrazolium salt reduction (MTT) assay on A549 (human lung carcinoma epithelial like) cells. All of the tested compounds induced time- and concentration-dependent cytotoxic effect.
- Beynek, Nesrin,Ulucam, Gueherguel,Benkli, Kadriye,Koparal, Ayse Tansu
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scheme or table
p. 2089 - 2096
(2009/02/08)
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- Structure and DNA cleavage properties of two copper(ii) complexes of the pyridine-pyrazole-containing ligands mbpzbpy and Hmpzbpya
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The DNA-cleavage properties of the two copper(ii) complexes, [Cu(mbpzbpy)Br2](H2O)2.5 (1) and [Cu(mpzbpya)Cl](CH3OH) (2), obtained from the ligands 6,6′-bis(3,5-dimethyl-N-pyrazolmethyl)-2,2′-bipyridine) (mbpzbpy) and 6′-(3,5-dimethyl-N-pyrazolmethyl)-2,2′-bipyridine-6-carboxylic acid) (Hmpzbpya), respectively, are reported. Upon coordination to Cu II chloride in methanol, one arm of the ligand mbpzbpy is hydrolyzed to form mpzbpya. Under the same experimental conditions, the reaction of mbpzbpy with CuBr2 does not lead to ligand hydrolysis. The ligand mpzbpya is coordinated to a copper(ii) ion generating a CuN3OCl chromophore, resulting in a distorted square-pyramidal environment, whereas with the N 4 mbpzbpy ligand, the CuII ion is four-coordinated in a distorted square planar geometry. Both complexes promote the oxidative DNA cleavage of X174 phage DNA in the absence of reductant. The oxidative nature of the DNA cleavage reaction has been confirmed by religation and cell-transformation experiments. Studies using standard radical scavengers suggest the involvement of hydroxyl radicals in the oxidative cleavage of DNA. Although both compounds do convert form I (supercoiled) DNA to form II (nicked, relaxed form), only complex 1 is able to produce small amounts of form III (linearized DNA). This observation may be explained either by the attack of the copper(ii) complexes to only one single strand of DNA, or by a single cleavage event. Statistical analysis of relative DNA quantities present after the treatment with both copper(ii) complexes supports a random mode of DNA cleavage. This journal is The Royal Society of Chemistry.
- Maheswari, Palanisamy Uma,Lappalainen, Kristian,Sfregola, Michael,Barends, Sharief,Gamez, Patrick,Turpeinen, Urho,Mutikainen, Ilpo,Van Wezel, Gilles P.,Reedijk, Jan
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p. 3676 - 3683
(2008/02/12)
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- Imidazolium ionic liquid-grafted 2,2′-bipyridine - A novel ligand for the recyclable copper-catalyzed selective oxidation of alcohols in ionic liquid [bmim][PF6]
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A novel imidazolium ionic liquid-grafted 2,2′-bipyridine ligand has been prepared and successfully employed in the copper-catalyzed selective oxidation of alcohols to the corresponding carbonyl compounds in ionic liquid [bmim] [PF6] under mild conditions, and the catalytic ionic liquid solution can be recovered and reused without significant loss of catalytic efficiency. Copyright
- Wu, Xue-E.,Ma, Li,Ding, Meng-Xian,Gao, Lian-Xun
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p. 312 - 313
(2007/10/03)
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- Time-resolved luminescence in aqueous solution - New europium labels derived from macro(bi)cyclic ligands with aminocarboxylic units
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A new family of macro(bi)cyclic ligands has been designed and synthesized, with the goal of developing lanthanide labels suitable for time-resolved luminescence-based biological applications. They are constructed from diamide (3) or tetralactam (4) complexing moieties associated with an intracyclic 2,2′-bipyridine chromophore and two exocyclic carboxylic groups. The luminescence properties of their Eu3+ complexes were studied in aqueous solution. In this medium, noticeable enhancements in the lifetime and quantum yield were observed, in comparison with those of other bipyridine-based ligands considered interesting as luminescent labels. The effects of coordinated water molecules, LMCT states, and ligand triplet state energy on the nonradiative deactivation processes to the ground state were examined. According to these results and in view of the stability of these complexes in aqueous solutions, the [Eu(3)]+ complex may be considered as a promising luminescent bioprobe.
- Galaup, Chantal,Carrie, Marie-Christine,Tisnes, Pierre,Picard, Claude
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p. 2165 - 2175
(2007/10/03)
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- Bipyridine building blocks for self-organization systems: First complete NMR-spectroscopic investigation of 6,6′-disubstituted 2,2′-bipyridines obtained via N-oxidation route and related reactions
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One- and two-dimensional NMR-spectroscopic data of eight 6,6′disubstituted 2,2′-bipyridines, prepared by the N-oxidation route, were used to confirm their structures. These key compounds in supramolecular construction lead to the characterization of larger oligo(bipyridine) building blocks. Furthermore some related reactions are described which lead to unsymmetrically functionalized bipyridines or can be used for the purification of bishydroxy compounds.
- Schubert, Ulrich S.,Newkome, George R.,Go?ldel, Andreas,Pemp, Alexander,Kersten, Jo?rg L.,Eisenbach, Claus D.
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p. 2141 - 2148
(2007/10/03)
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- Synthesis and characterization of some new bipyridyl-based multidentate ligands and their CuI complexes
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Four new 2,2′-bipyridyl-based ligands: 6,6′-bis(methylthiomorpholine)-2,2′-bipyridine (L1), 4,4′-dimethyl-6,6′-bis(methylthiomorpholine)-2,2′-bipyridine (L2), 6,6′-bis(methylpiperidine) -2,2′-bipyridine (L3) and 4,4′-dimethyl-6,6′-bis(methylpiperidine)-2,2′-bipyridine (L4), and dimeric CuI complexes of the ligands L1 and L2 have been synthetized. The X-ray crystal structures of the ligands L1 and L2 and the L1-CuI complex have been determined. Complexation of these ligands with other metals produced mainly compounds having very low solubilities. Acta Chemica Scandinavica 1997.
- Laitinen, Riitta H.,Csoban, Katalin,Pursiainen, Jouni,Huuskonen, Juhani,Rissanen, Kari
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p. 462 - 469
(2007/10/03)
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- Enantioselektive Synthese von Helicaten auf Bipyridin-Kupfer(I)-Basis durch den Templateffekt eines chiralen Sekundaerstrukturelements: Uebertragung von stereochemischer Information im Nanometerbereich
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Keywords: Chiralitaet; Helices; Kupferverbindungen; Selbstorganisation
- Woods, Craig R.,Benaglia, Maurizio,Cozzi, Franco,Siegel, Jay S.
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p. 1977 - 1980
(2007/10/03)
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- Rare earth macrocyclic complexes and use thereof for reduction of disturbances in an assay using fluorescence
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The invention relates to macrocyclic rare earth complexes which consist of at least one rare earth salt complexed by a macrocyclic compound of formula (I): STR1 in which: the bivalent radicals A, B, C and D, which are identical or different, are hydrocarbon chains optionally containing one or more heteroatoms, at least one of said radicals containing at least one molecular unit or essentially consisting of a molecular unit possessing a triplet energy greater than the energy of the emission level of the complexed rare earth ion, at least one of said radicals consisting of a substituted or unsubstituted nitrogen-containing heterocyclic system in which at least one of the nitrogen atoms carries an oxy group, and it being possible for one of the radicals C or D not to exist; and X1 and X2, which are identical or different, are hydrogen or a hydrocarbon chain (CH2)n optionally interrupted by 1 or more heteroatoms, n being an integer from 1 to 10, with the proviso that if the radicals A and/or B are a nitrogen-containing heterocyclic system in which at least one of the nitrogen atoms carries an oxy group, the radicals C and/or D are selected from biquinolines, biisoquinolines, bipyridines, terpyridines, coumarins, bipyrazines, bipyrimidines and pyridines, and to their use for reducing the perturbations in a fluorescent assay.
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- Unusual Stabilities of 6,6'-Bis(aminomethyl)-2,2'-bipyridyl Chelates of Transition-metal Ions and Crystal Structures of the Ligand and its Copper(II) and Nickel(II) Complexes
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An improved four-step synthesis of the tetradentate compound 6,6'-bis(aminomethyl)-2,2'-bipyridyl (badp) has been developed and the crystal structure of its dihydrochloride monohydrate determined: space group C2/c, a = 11.991(2), b = 5.703(1), c = 22.109(3) Angstroem, β = 97.17(1) deg and Z = 4.The complexes of copper(II) and nickel(II) with badp have also been synthesized and structurally characterized.The metal ion in Br2 is five-co-ordinated and the complex crystallizes in the monoclinic P21/c space group with a = 11.508(3), b = 9.584(3), c = 14.362(30 Angstroem, β = 107.93(2) deg and Z = 4.The complex Br contains six-co-ordinated Ni(II) and crystallizes in the monoclinic P21/c space group with a = 11.387(3), b = 9.417(2), c = 14.317(5) Angstroem, β = 106.21(2) deg and Z = 4.The stepwise stability constants of the 1 : 1 ligand to metal complexes of badp with divalent transition-metal ions have been determined in KCl as supporting electrolyte (0.100 mol dm-3) at 25.0 deg C: log KML = / for the Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes is 8.94, 10.16, 11.87, 15.05 and 10.02 respectively.Iron(II) and cobalt(II) also formed 2 : 1 complexes with badp.The unusually low stabilities of the transition-metal complexes are considered due to the low basicity of the ligand and to the unfavourable spacing of its donor groups as indicated by the structures of the complexes of Ni(II) and Cu(II).
- Wang, Zheng,Reibenspies, Joseph,Motekaitis, Ramunas J.,Martell, Arthur E.
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p. 1511 - 1518
(2007/10/02)
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- Wiitig-Synthesis and X-ray Structure of a 26-Membered Macrocycle Containing two Bipyridine Units
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Wittig-type macrocyclization of bipyridinedicarbaldehyde 5 with bis(phosphonium bromide) 6 leads to the new bipyridinophanes 7, 8.The X-ray structural analysis of 8 reveals a steptype conformation, which according to 1H-NMR results is also present in solution.
- Voegtle, Fritz,Hochberg, Robert,Kochendoerfer, Frank,Windscheif, Paul-Michael,Volkmann, Martin,Jansen, Martin
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p. 2181 - 2185
(2007/10/02)
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- Macrocyclic Inclusion Complexes. Synthesis, X-ray Structural Analysis, and Formation of Mono- and Dinuclear Transition-Metal Complexes of Dipyridino Crown Ethers
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The synthesis of crown ether derivatives containing the dipyridino subunit is described.Direct nucleophilic displacement by the glycolates of di-, tri-, tetra-, penta-, and hexaethylene glycol on 6,6'-bis(chloromethyl)-2,2'-dipyridine resulted in an extensive series of macrocycles; the addition of Co(II), Cu(II), Zn(II), and Pd(II) salts to the 1:1- and 2:2-macrocycles generated the corresponding complexes.X-ray crystallography confirmed the structure of the 2:2-macrocycle derived from diethylene glycol as well as the related unsymmetrical derivative arising from glycol fragmentation.The ligands were fully characterized by 1H NMR spectroscopy, and a europium shift study was conducted on a representative 1:1-macrocycle in order to establish the preferred site of complexation.
- Newkome, George R.,Kiefer, Garry E.,Kohli, Dalip K.,Xia, Yuan-Jiao,Fronczek, Frank R.,Baker, Gregory R.
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p. 5105 - 5110
(2007/10/02)
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- Photoactive Cryptands Synthesis of the Sodium Cryptates of Macrobicyclic Ligands Containing Bipyridine and Phenanthroline Groups
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The NaBr cryptates of five macrobicyclic ligands containing bipyridine (bpy) and phenanthroline (phen) groups, i.e. of 1 2 3 4 and 5, have been prepared. 1, 2, 4 and 5 have been obtained in high yield by condensation of bis(bromomethyl)bipyridine 6 or -phenanthroline 9 with the corresponding macrocyclic diamines in presence of Na2CO3.Direct access to the NaBr complexes of the symmetrical cryptands 1 and 3 was achieved by a one-step macrobicyclisation procedure.The metal-ion complexes of ligands 1-5 have the attractive feature of combining the cation inclusion nature of cryptates with the photoactivity of bipyridine and phenanthroline groups; they may thus be expected to possess a variety of interesting physical and chemical properties.
- Rodriguez-Ubis, Juan-Carlos,Alpha, Beatrice,Plancherel, Dominique,Lehn, Jean-Marie
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p. 2264 - 2269
(2007/10/02)
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