Solid-state structures of dinitrosyliron iodide and dinitrosylcobalt iodide: stereochemical consequences of strong metal-metal interactions in ligand-bridged complexes

The crystal and molecular structures of bis[bis(π-cyclopentadienyl)niobium(V)-bis-μ-methanethiolato]nickel(0) tetrafluoroborate dihydrate and bis-[bis-(π-cyclopentadienyl)molybdenum(IV)-bis-μ-methanethiolato]nickel(II) tetrafluoroborate

“…The Nb-Ni distance across the bridge is 2.771 A (mean). The dimensions of the NbS~Ni four-membered bridges are entirely consistent with the Dahl criteria for metal-metal bonding (Dahl, Gil & Feltham, 1969). The coordination at the metal atom is distorted tetrahedral with the point symmetry reduced from Tn to Dza by the opening of the internal (with respect to the NiS~Nb system) S-Ni-S angle to accommodate the short Nb-Ni contacts; the S(1)-Ni-S(3) and S(2)-Ni-S(4) planes make an angle of 89.3 ° with each other and the external S-Ni-S angles fall in the range 104.4-108.4 ° .…”

Synthesis and structure of 3,5-dimethylpyrazolyl iron and cobalt dinitrosyl dimers

“…Presumably these ions arise from M-M bonded species formed during fragmentation of the original dimeric species. It is instructive to compare these findings with the mass spectral data discussed earlier for halogen-and sulphur-bridged iron and cobalt dinitrosyl dimers (23,32).…”

“…The extent of the interaction, if any, between equivalent sets of ligands attached to different metal atoms in polynuclear complexes is difficult to predict (30). Such an interaction might be unexpected in the present complexes, however, particularly in the iron compound since the related complex [Fe(NO),I], displays but two vNo bands in its solution ir spectrum (23,31). In this iodide bridged compound a strong Fe-Fe interaction is indicated (23) and the two NO groups on each Fe atom are inequivalent in the same sense as those in the "pyrazolyl" bridged species [(N2CsH7)Fe(NO),],.…”

“…The solid state structures of dinitrosyl iron iodide and dinitrosyl cobalt iodide have been reported (23). The former structure consists of diamagnetic dimeric molecules in which the two Fe(NO), moieties are linked by bridging iodine atoms and also by a long For personal use only.…”

The crystal structures of bis(μ-ethoxycarbonylimido)-bis[(η-cyclopentadienyl)oxomolybdenum](Mo–Mo), (η5-C5H5)MoO(μ-NCOOC2H5)2OMo(η5-C5H5), and μ-ethoxycarbonylimido-μ-oxo-bis[(η-cyclopentadienyl)oxomolybdenum](Mo–Mo), (η5-C5H5)MoO(μ-NCOOC2H5)(μ-O)(η5-C5H5)OMo

“…Another difference between these new compounds and (VI), (VII) and ( (Tables 3 and 5), which are significantly smaller than would be expected in the absence of Mo--Mo bonds (Edelblut, Haymore & Wentworth, 1978;Dahl, de Gil & Feltham, 1969). They are smaller than 90 ° and, correspondingly, the N-Mo-N and N-Mo-O angles are larger (Tables 3 and 5).…”