without changing your settings we'll assume you are happy to receive all RSC cookies.
You can change your cookie settings by navigating to our Privacy and Cookies page and following the instructions. These instructions
are also obtainable from the privacy link at the bottom of any RSC page.
State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
; Fax: +86 592 2183047
; Tel: +86 592 2184531
Dalton Trans., 2013,42, 1627-1636
14 Jul 2012,
09 Oct 2012
First published online
11 Oct 2012
Substitutions of trans-Na(Him)[Mo2O4(ox)2(H2O)2]·H2O (1) and trans-(Him)2[Mo2O4(ox)2(H2O)2] (2) with imidazole result in the formation of the mixed-ligand molybdenum complexes cis-Na2[Mo2O4(ox)2(im)2]·4.5H2O (3), cis-K2[Mo2O4(ox)2(im)2]·3H2O (4), respectively (H2ox = oxalic acid; im = imidazole). Further reduction of cis-K2[Mo2O4(ox)2(im)2]·3H2O (4) gives a trinuclear molybdenum(IV) complex K(Him)[Mo3O4(ox)3(im)3]·3H2O (5), which contains an incomplete cubane cluster [MoIV3O4]4+. Two novel trinuclear mixed-valence imidazole compounds [Mo3O8(im)4](im)·H2O (6) and [Mo3O8(im)4]·H2O (7) were obtained by the reduction of (Him)4[Mo8O26(im)2] (8). Both 6 and 7 contain a novel MoVIO4(MoV2O4) center, where the [MoV2O4]2+ unit is linked by [MoVIO4]2− anion. The Mo–Mo bond distances in 1–7 decrease with the decrease of oxidation state of molybdenum. Solid and solution NMR spectra show that imidazole molybdenum compounds 6–8 fully dissociate in solution, where solvated imidazole and imidazolium groups in 6 and 8 could be served as internal references in their solid 13C NMR spectra. Furthermore, mixed-ligand molybdenum species 3 and 4 are stable in water. Stabilities of 3 and 4 in solution may be attributed to the strong coordination of bidentate oxalate and the formation of hydrogen bond. Dimers 2 and 4 display quasi-reversible redox process, while trimer 6 is irreversible. Bond valence calculations for 1–8 are consistent with their oxidation states of molybdenum atoms. Calculation of the oxidation state in recent structure of iron molybdenum cofactor [MoFe7S9C(R-homocit)] (FeMo-co) is 3.318.
Fetching data from CrossRef. This may take some time to load.