Structural aspects of molybdenum(IV), molybdenum(V) and molybdenum(VI) complexes

The Coordination and Bioinorganic Chemistry of Molybdenum

The flash photolysis of the mono and di-thiocyanate complexes of μ-oxo bis(oxo-molybdenum(V)) (Mo2O4(NCS)x(H2O)6−x(2−x)+ where x = 1, 2) has been studied in the system composed of perchloric acid solutions of Mo2O4(H2O)62+ in the presence of excess thiocyanate.



Irradiation with light in the wavelength range 250–340 nm induced the formation of three reaction intermediates identified as μ-oxo-bis (oxo-molybdenum(V)) species: Mo2O3(H2O)84+ (A), Mo2O3(NCS) (H2O)73+ (B), and Mo2O3(NCS)2(H2O)62+ (C). A rapid equilibria between the transient species is established before they decay following a first order kinetics. Intermediate A is the only species effective in promoting the observed decay leading to the end products Mo(VI) and H2.



The relative absorption spectrum of species A, B, and C are reported, as well as the measured stability constants for the formation of B and C in the temperature range 20–45°C. An overall mechanism is proposed.

The flash photolysis of di-μ-oxo-bis(oxo-molybdate(V)) acid aqueous solutions in the presence of excess thiocyanate

Electrochemical reduction of a binuclear dioxo-bridged molybdenum(V) complex with ethylenediaminetetraacetate*

The crystal and electronic structures of several novel dimeric di-μ-oxo, di-μ-oxo-μ-carboxylato and μ-oxo-oxomolybdates(V) coordinated to O and N donors are presented and discussed in detail. The local symmetries of donor atoms linked to the molybdenum atoms are the highest known. A more detailed discussion of the influence of electronic interactions on the overall symmetry and structure of the dimers is therefore possible. In both μ-oxo bridged dimers the terminal molybdenyl oxygen atoms were found trans to each other whereas in two di-μ-oxo-μ-carboxylato bridged oxomolybdenum(V) dimers a new type of “cis-equivalent” distortion was found in the MoO2Mo rings.

The electronic, crystal and molecular structures of novel dimeric μ-oxo, di-μ-oxo and di-μ-oxo-μ-carboxylato bridged oxodimolybdates(V)

Results of SCCC MO calculations for the dimeric oxygen double-bridged [Mo2O4Cl4(H2O)2]2−ion are reported. On the basis of these results the previously reported spectra and magnetic properties may be explained. The strong direct molybdenum — molybdenum interaction in the Mo2O
 4
 2+
 core was proved to exist.

Bogusława Jeźowska-Trzebiatowska

Papers

The electronic structure of the oxygen double-bridged μμ′-dioxo-bis(oxodichloroaquo)dimolybdate (V)-ion by SCCC MO method