79152-75-3Relevant articles and documents
Pentacarbonylvanadates(I-) of mono- And oligodentate phosphines: Synthesis and IR and 31P and 51V NMR characterization
Ihmels, Klaus,Rehder, Dieter
, p. 1334 - 1340 (2008/10/08)
The complexes [Et4N][V(CO)5PR3] have been prepared by ligand exchange from [Et4N][V(CO)5Me2SO] (PR3 = PH2Cy, PHCy2, PCy3, PH3, PMe3, P(i-Bu)3, P(t-Bu)3, PPh3, P(OMe)3, P(OPh)3, PR2R′ (R′ = CH2CH2PPh2, CH2CH2PEt2, CH2CH2AsPh2, CH2CH2PPhCH2CH2PPh2, CH2CH2P(CH2CH2PPh2) 2)), [Et4N][V(CO)5THF] (P(NEt2)3, P(SiMe3)3), or [Et4N][V(CO)5NC5H5] ((P-t-Bu2)2Te) or by daylight induced reaction between [Et4N][V(CO)6] and Ph2P(CH2)3PPh(CH2) 3PPh2. They were characterized by their CO stretching frequencies, 51V NMR parameters (δ(51V) and 1J(51V-31P)), and, in the case of oligodentate phosphines, 31P NMR data of the uncoordinated P functions. The arphos ligand Ph2As(CH2)2PPh2 and the tri- and tetradentate phosphines are almost exclusively coordinated via the PPh2 group, while Et2P-(CH2)2PPh2 coordinates about equivalently via PEt2 and PPh2. The 51V-31P coupling constants increase in the order PH3, P(alkyl)3, PPh3 (around 210 Hz.) 2)3 (293) 3)3, P(OMe)3 (366) 3 (415), and δ(51V) ranges from -1806 ([V(CO)5P(NEt2)3]-) to -1928 ([V(CO)5P(OMe)3]-; ppm relative to VOCl3). The shift trends correlate with the integral ligand strength as quantified by Graham's σ and π parameters (with a predominance in π) and reflect, in accord with theory, electronic and steric effects imposed by the substituents R.
