Nitrosyl and Selenonitrosyl Complexes

5 Nitrosyl and Selenonitrosyl Complexes - There is IR evidence for bridging nitrosyls in Cr[Cr(CN)5NO]o.5 and related species. vNO in (59) is at 1680 cm decreasing to 1653 cm on reduction to the neutral complex. One-electron reduction of [Mo(NO) HB(dmpz)3l 2 l,2-(HN)2C6H4 ] (vNO 1669 cm ) gives two vNO bands (1631, 1575 cm ) - showing that the reduced species is valence-trapped on the IR time-scale (despite being delocalised on the EPR time-scale). 

The bending mode, 5Fe-N-0 in the metastable state (MSi) of Na2[Fe(CN)s(NO)] shows a N/ N isotopic shift consistent with an Fe-O-N linkage.Ferric-NO and ferrous-CO complexes of cytochrome P450hor have been studied by resonance Raman spectroscopy. The effects of haem modification on bonding were followed from changes in vNO and vCO. The value of vNO for (ON)Fe(TPP) is very sensitive to intermolecular forces in the solid state.  

The redox potentials of mw5 -[Ru(NH3)4L(NO)] , where L is an N-heterocyclic ligand, shows a relationship with vNO such that the oxidising strength of coordinated NO increases with increasing L 7i-acidity. Assignments have been proposed for vNO in Ru(X)(NO)(Pc ) 1827 cm (X = I), 1856 cm (F). For X = ONO, nitrito modes are at 1501, 932 and 804 cm h The novel selenonitrosyl complex, TpOs(NSe)Cl2, where Tp = hydrotris(l-pyrazolyl)-borate, has vNSe at 945 cm compared to 1875 and 1205 cm for the NO and NS analogues respectively. 

The vNO band of nitrosylcobalamin is seen at 1652 cm consistent with bent Co-N-O bonding geometry. NO adsorbed on Co VSi02 forms Co (NO)2, with vNO at 1872 and 1804 cm k  

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