20819-54-9

We report an NMR study on the binding of trimethylphosphine selenide (Se=PMe3) to cadmium oleate (Cd(OA)2) in CDCl3 and toluene-d8. At room temperature in CDCl3, Se=PMe3 binds to Cd(OA)2 in 1:1 ratio with a binding constant of 20 ± 3 as determined by NMR titration. The Cd-bound and free Se=PMe3 are in fast exchange on the NMR time scale at room temperature and gives only one 31P NMR peak. At ca. 190 K, three 31P NMR peaks were observed for a toluene-d8 solution of 1:1 mixture of Cd(OA)2 and Se=PMe3. These three peaks were tentatively assigned to free Se=PMe3 (9.0 ppm), 1:1 (19.5 ppm), and 2:1 complex between Se=PMe3 and Cd(OA)2 (18.8 ppm). (Chemical Equation Presented)

Diffusion-ordered spectroscopy (DOSY) was used to investigate the solution structure of cadmium carboxylate. The molecular weights of cadmium complexes highly depend on the solvent; the complexes are polymeric in toluene but break up in the presence of polar solvents or coordinating ligands.

We outline a reaction pathway for the cleavage of the P=Se bond in trialkylphosphine selenide during the synthesis of CdSe nanocrystals. The reaction between cadmium carboxylate and trimethylphosphine selenide in the presence of an alcohol produces alkoxytrimethylphosphonium (2). Control experiments and density functional theory calculations suggested that the cleavage of the P=Se bond is initiated by nucleophilic attack of carboxylate on a Cd2+-activated phosphine selenide to produce an acyloxytrialkylphosphonium intermediate (1), which is converted to 2 in the presence of an alcohol.

A series of silicon-constrained monodentate trialkylphosphines SMAPs bearing a Si substituent with diverse electronic natures were synthesized. DFT calculations and NMR measurements indicated that these compounds constitute a class of electronically tunab

The crystalline trilithium salt Li3[N3N] (N3N = [(Me3SiNCH2CH2)3N]3-) reacts with VCl4(DME) (DME = 1,2-dimethoxyethane) to give [N3N]VCl in 45% yield. The structure of [N3N]VCl, as determined by X-ray crystallography, is a distorted trigonal bipyramid with three equatorial silylamido groups and axial chloride and amine donor ligands. Reduction of [N3N]VCl with Na/Hg in pentane provides trigonal monopyramidal V[N3N] in >90% yield. V[N3N] deoxygenates propylene oxide, cis- or trans-2-butene oxide, pyridine N-oxide, nitrous oxide, or dimethyl sulfoxide to produce [N3N]V=O. Treatment of V[N3N] with either S8 or ethylene sulfide gives [N3N]V=S, while gray selenium reacts with V[N3N] to give black crystalline [N3N]V=Se. PMe3 abstracts selenium from [N3N]V=Se, forming Me3P=Se and regenerating V[N3N]. Elemental tellurium does not react with V[N3N], but when V[N3N] is treated with Me3P=Te in toluene under vacuum, [N3N] V=Te can be observed by NMR in solution. The chalcogenide complexes [N3N]V=X (X = O, S, Se, Te) were characterized by 51V NMR. Shifts ranged over 1600 ppm, with the more electronegative chalcogens producing greater upfield 51V chemical shifts. V[N3N] reacts with trimethylsilyl azide to give [N3N] V=NSiMe3. [N3N] V=NSiMe3 also could be prepared by reducing [N3N]VN3 with Na/Hg, followed by treatment with Me3SiCl. V[N3N] reacts with C5H5NNC6F5 to give rust-red [N3N]V=NC6F5 and with (trimethylsilyl)diazomethane to give [N3N]V=N-N=CH(SiMe3). [N3N]V=N(P-CH3C6H4) was prepared by adding a solution of Li3[N3N] to Cl3V=N(P-CH3C6H4) in ether. An NH group transfers from 2-methylaziridine to V[N3N], liberating propylene and forming yellow, crystalline [N3N]V=NH. [N3N]V=NH may be deprotonated and then silylated to give [N3N]V=NSiMe3. The structure of [N3N]V=NH was determined by X-ray crystallography. The imido hydrogen was located and refined; the V=N-H unit is nearly linear (173(6)°), and the V-Nimido bond length is 1.638(6) A?. The V-Namine bond length (2.241(6) A?) is comparable to that in [N3N]VCl (2.238(6) A?). The structure of [N3N]V=NH is compared and contrasted with the structures of [N3N]VCl and V[N3N′] (N3N′ = [(t-BuMe2SiNCH2CH2)3N] 3-).

31P and 125Te NMR data of trialkylphosphane tellurides are compared.The deviation of the shifts for Me3PTe and t-But3PTe from those of other phosphane tellurides is interpreted in terms of high s-character of the P-Te bond originating from the phosphorus

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Bis(1,5-cyclooctanediylboryl) selenide (C8H14B)2Se (1) is obtained quantitatively from bis(9-borabicyclononane) (9-BBN)2 and elemental selenium in mesitylene at 150 deg C accompanied by evolution of hydrogen.Bis(1,5-cyclooctanediylboryl) diselenide (C8H14BSe)2 (2) is prepared efficiently from 1 with selenium in mesitylene at 120 deg C. 9-(Hydroseleno)-9-BBN (1H) together with 9-(phenylamino)-9-BBN (3) is easily obtained from 1 and aniline. - γ-Picoline (γPic) reacts with 1 to give the 2:1 addition compound γPic2-1, trimethylphosphane (TMP) with 1 forms the 1:1 addition compound TMP-1.Selenide 1 reacts spontaneously at room temperature with trialkoxyboranes B(OR)3 or with ClnAl(C2H5)3-n compounds exchanging the substituents. - The 1:1 addition compounds γPic-1H, TMP-1H, and Q-1H, are prepared from 1H with γPic, TMP, and quinuclidin (Q), respectively. - 1, 1H, and 2 undergo Se/O exchange reactions with organic and other oxygenated compounds and add to certain CC triple bonds.Pure Fe2Se3 is prepared quantitatively from 1 and Fe2O3. - Key Words: Boryl selenides, 1,5-cyclooctanediyl- / 9-Borabicyclononane, 9-hydroseleno- / Selenidation reagents / Lewis base - organoboron selenium compounds / Borane exchange reactions

Low-valent trimethylphosphine cobalt compounds are oxidized by tellurium, selenium, or sulfur to give the title compounds.Several high-yield syntheses are described.The crystal and molecular structures of (Me3P)3CoX2Co(PMe3)3 (1: X = Te, 2: X = Se, 3: X = S) have been determined by single crystal X-ray diffraction.Complex 1 crystallizes in the monoclinic space group P21/n: a = 933.8(6) pm, b = 1488.3(6) pm, c = 1257.9(6) pm, β = 92.82(6) deg, Z = 2.Complex 2 crystallizes in the triclinic space group P, a = 1785.6(7) pm, b = 1599.7(7) pm, c = 928.9(5) pm, α = 87.8(1) deg, β = 85.2(1) deg, γ = 73.3(1) deg, Z = 3.Complex 3 crystallizes in the monoclinic space group P21/c: a = 952.6(5) pm, b = 1868.7(8) pm, c = 1893.1(8) pm, β = 90.19(6) deg, Z = 4.All three structures contain centrosymmetric molecules with planar Co2X2 rings.In solution dissociation of phosphine ligands occurs followed by slow decomposition to produce 2 among other products. 1 reacts with carbon monoxide to afford a ditelluride 2Te2, but no corresponding derivatives of 2 or 3 were obtained. - Keywords: Di-μ-Sulfido, Di-μ-Selenido, Di-μ-Tellurido Dicobalt Complexes, Synthesis, Structure

A low-temperature ESR study of electron-capture phosphoranyl radicals in X-irradiated single crystals of trialkylphosphine sulfides and selenides (R3PX: X=S, Se; R=CH3, C2H5, C6H11) is presented.The principal values and direction cosines of the g tensors