Ligand reactivity, substituent effects and solvent interactions in the spectra and structure of some oxovanadium(V) chelates with Schiff bases. Proof for dimeric species

Synthesis and characterization of oxovanadium(IV), vanadium(IV) and oxovanadium(V) complexes of tetradentate Schiff bases. Attempted preparation of vanadium-carbon bonded compounds through desilylation

“…Similar reactions of [VO(salpnol)Cl] (6) or [VO(ohacpnol)Cl] (7) with p-Me 3 SiC 6 H 4 SiMe 3 or p-Me 3 SiCH 2 C 6 H 4 CH 2 SiMe 3 yielded organo derivatives of oxovanadium(V) bridged by -C 6 H 4 -or -CH 2 C 6 H 4 CH 2 -(Scheme 1).…”

“…These lower (C¼N) values suggest stronger V-N bonding in the complexes. Despite complications due to the appearance of several bands in the infrared spectra of the ligands in the region 500-300 cm À1 , the presence of (V-Cl) in (2), (4), (6) and (8) can be identified around 360 cm À1 by careful comparison of the IR spectra of the free ligand and metal complexes. On the other hand, complexes 13-16 exhibit a peak at 320 cm À1 , which may be assigned to (V-Cl) stretching.…”

“…The biological importance of vanadium compounds in different oxidation states is many faceted [1][2][3][4][5][6][7][8]. Vanadium complexes are also of major concern because of their adverse effect on hydroprocessing catalysts used in the refining of crude oil [9,10].…”

“…Vanadium complexes are also of major concern because of their adverse effect on hydroprocessing catalysts used in the refining of crude oil [9,10]. The revelation that coordination complexes of vanadium in different oxidation states can play a vital role in nitrogen activation and nitrogen fixation and many other biologically important reactions [1][2][3][4][5][6][7][8][11][12][13][14] has stimulated interest in the synthesis, characterization, stereochemistry and reactivity of its coordination compounds that contain diazo-, hydrazido-and imine-group because they can provide information on the mechanism of metalloenzymatic reduction of dinitrogen and are capable of confining metal atoms and controlling their properties and functionality [14].…”

Synthesis, spectral and structural studies of oxovanadium(IV/V) complexes derived from 2-hydroxyacetophenone-3-hydroxy-2-naphthoylhydrazone: polymorphs of oxovanadium(V) complex [VOL(OCH3)]

“…The complexes 2 and 3 display bands at 1468 and 687; 1462 and 681 cm -1 indicate the coordination of bipyridine and phenanthroline. In addition, the compounds exhibit a strong band in the 956-993 cm -1 region due to the terminal V=O stretching [19][20][21]. The electronic spectra of the complexes in DMF solution are presented in the Table 5.…”