Direct synthesis and characterization of Polyoxometallate organic fragments, bimetallic complexes and Chromium-based complexes for chemical catalysis

Abstract

This report contains the synthesis and characterization of Bimetallic, Chromium-based complexes and polyoxometallate organic fragments which can be used in heterogeneous catalysis. A series of new bimetallic complexes based on the [Fe(CN)6]3- building block have been described. The complexes have been found to be of the type [ML3][Fe(CN)6]2 where M=Cu, Co and L =ethylenediamine, aniline. Cyano-bridged {[Co(en)3]3[Fe(CN)6]2}, {[Cu(en)3]3[Fe(CN)6]} and Thiocyano-bridged {[Co(SCN)4][Cu (en)3]} bimetallic complexes were synthesized. Polyoxometallate organic fragments were synthesized and found to be of the type {Na1.5H4.5[(CH3)4N][Fe(CN)5NO](Se2W11O43)}.9H2O. Also some Chromium-based complexes were synthesized which include; potassium trioxalatochromate (iii), tris (ethylenediamine) chromium (iii) chloride, cis-and trans-potassium dioxalatodiaquachromate (iii). Characterization of complexes was done using UV-Visible spectroscopy and their spectra obtained, the spectrum of cis-potassium dioxalatodiaquachromate (iii) and potassium trioxalatochromate(iii) had two main peaks around 415nm and 575nm, tris(ethylenediamine) chromium(iii)chloride had main peaks at around 350nm and 457nm. The spectrum of {Na1.5H4.5[(CH3)4N][Fe(CN)5NO](Se2Mo11O43)} has one main peak at 580nm, the spectra of four of the Polyoxometallates which include; {Na1.5H4.5[(CH3)4N][Fe(CN)5NO](Se2CH3CO2O43)}, {Na1.5H4.5[(CH3)4N][Fe(CN)5NO](Se2As11O43)}, {Na1.5H4.5[(CH3)4N][Fe(CN)5NO](Se2Si11O43)}, {Na1.5H4.5[(CH3)4N][Fe(CN)5NO](Se2(HPO4)11O43)} showed only one peak at 380nm.