20644-87-5Relevant articles and documents
Suslick, Kenneth S.,Johnson, Robert E.
, p. 6856 - 6858 (1984)
Synthesis and structures of vanadium(II) alkynide complexes: [(LiTMEDA)2V(μ-C≡CPh)4(TMEDA)] and V(C≡CR)2(TMEDA)2 (R = Ph, tBu; TMEDA = N,N,N′,N′-tetramethylethylenediamine)
Kawaguchi, Hiroyuki,Tatsumi, Kazuyuki
, p. 4294 - 4299 (2008/10/09)
The V(II) tetrakis- and bis(alkynide) complexes, [(LiTMEDA)2V(μ-C≡CPh)4 (TMEDA)] (1) and V(C≡CPh)2(TMEDA)2 (2) have been synthesized from the reaction between VCl3(THF)3 and LiC≡CPh in THF in the presence of TMEDA (=N,N,N′,N′-tetramethylethylenediamine). In the case of the analogous VCl3(THF)3/LiC≡CtBu/TMEDA reaction system, only the bis(alkynide) complex V(C≡CtBu)2 (TMEDA)2 (3) was isolable. Reduction of vanadium occurred during these reactions, and use of a divalent vanadium chloride, VCl2(TMEDA)2, instead of VCl3(THF)3 was found to give 1-3 in higher yields. Complex 1 crystallizes in the monoclinic space group P21/c with Z = 4 in a unit cell of dimensions a = 15.761(4) A?, b = 14.325(4) A?, c = 22.614(9) A?, and β = 98.38(4)°. Crystals of 2 are orthorhombic, space group Cmcm, with a = 10.045(5) A?, b = 22.379(7) A?, c = 12.306(4) A?, and Z = 4. Crystals of 3 are triclinic, space group P1, with a = 9.402(2) A?, b = 9.833(2) A?, c = 8.907(2) A?, and Z = 1. Reactions of these alkynide complexes with electrophiles such as Me3SiCl, MeI, PhNCO, CO2, and CO were examined.
Steric effects in the oxidative-addition reactions of gaseous V(CO)5-
Buckner, Steven W.,VanOrden, Steven L.
, p. 1093 - 1097 (2008/10/08)
Some gas-phase reactions of the 16-electron complex V(CO)5- are reported. The reactions of V(CO)5-, generated by dissociative electron capture from V(CO)6, were performed in a Fourier transform ion cyclotron resonance mass spectrometer. V(CO)5- reacts with V(CO)6 to generate V(CO)6- and V2(CO)9-. V(CO)4-, also generated by dissociative electron capture from V(CO)6, reacts with V(CO)6 to generate V2(CO)7- and V2(CO)8-. These results contrast with condensed-phase photolysis studies of V(CO)6-. The reaction of V(CO)5- with CH3OH generates V(CO)4CH2O-. Labeling studies indicate a 1,2-dehydrogenation with retention of the incoming C-O group. V(CO)5- is unreactive with larger alcohols (C2-C4). this difference in reactivity is ascribed to a steric effect in the reaction intermediate. A positive second derivative in a plot of the decay kinetics for V(CO)5- consumed in the V(CO)5-/CH3OH reaction indicates the process is endothermic or there is an energy barrier along the reaction coordinate. These results also indicate internal excitation drives the dehydrogenation reaction.