OXOVANADIUM ALKOXIDES - STRUCTURE, REACTIVITY, AND V-51 NMR CHARACTERISTICS - CRYSTAL AND MOLECULAR-STRUCTURES OF VO(OCH2CH2CL)3 AND VOCL2(THF)2H2O

The vanadyl esters VO(OR)3 (R = Me, Et, Pr, iPr, sBu, tBu, CH2CH2F, CH2CH2Cl, CH2CCl3) have been prepared and their association properties in pentane investigated by 51V NMR. Limiting (low concentration) δ(51V) values depend on the bulk of R (highest 51V shielding for tBu). Shielding decreases with increasing concentration (more pronounced for small R groups), owing to the formation of oligomers, probably connected by μ-OR groups. The X-ray diffraction study of VO(OCH2CH2Cl)3 (space group [formula omitted]; a = 766.2 (2) pm, b = 907.5 (4) pm, c = 957.0 (2) pm, α = 82.08 (3)°, β = 66.90 (2)°, γ = 79.42 (3)°) reveals dimer association of molecules belonging to adjacent unit cells via long V-OR bonds (226.1 (2) pm), and a trigonal-bipyramidal geometry for each monomeric unit. From the reaction between VOCl3 and diols (glycol, 1,3-propanediol, 1,2-,2,3-,1,3-, and 1,4-butanediol), complexes are obtained that contain the {VOCl(OR)2} and {VOCl2OR} moieties and the alcohol coordinated in the monofunctional or bifunctional (chelating and bridging) mode. The 51V NMR spectrum of VOCl2OCH(Me)CH(Me)OH exhibits resolved 51V-35,37Cl coupling: J(51V-31Cl) = 100 Hz; 7(51V-37Cl) = 83 Hz. VvOC12(OCH2CH2CH2CH2OH) reacts with 1,4-butanediol to form VIVOCl2(THF)2(OH2) (space group C2/c; a = 1221.7 (5) pm, b = 1710.9 (7) pm, c = 922.3 (4) pm, β = 138.53 (22)°). In the presence of VOCl3, THF undergoes ether splitting, chlorination, and coordination to vanadium to yield VOCl2(OCH2C-H2CH2CH2Cl). © 1990, American Chemical Society. All rights reserved.