Chelate complexes containing the {Mo(NO)HB(3,5-Me2C3N2H)3} moiety and an example of a pyrazole substitution reaction involving the HB(3,5-Me2C3N2H)3 ligand

Hydrogen Bonding of CHCl3to Coordinated Nitric Oxide in a Binuclear Metallomacrocycle and the Crystal Structures ofanti-[Mo(NO){HB(3,5-Me2C3HN2)3}(2,7-O2C10H6)]2·2CHCl3·CH2Cl2,syn-[Mo(NO){HB(3,5-Me2C3HN2)3}(2,7-O2C10H6)]2·0.67CHCl3·2.7H2O, andsyn-[

“…807 V (Δ E p = 86 mV) ( E f vs SCE; internal standard Fc/Fc + , E f = 0.546, Δ E p = 76 mV). These reduction potentials lie on either side of the reduction potential of −0.74 V reported17a for [Mo(NO)(Tp*)(OPh) 2 ], and the separation (Δ E f ) of 174 mV between the first and second reduction potentials of syn- [Mo(NO)(Tp*)(2,7-O 2 C 10 H 6 )] 2 is slightly larger than that of 150 mV found 17b for the corresponding acyclic binuclear complex [{Mo(NO)(Tp*)Cl} 2 (2,7-O 2 C 10 H 6 )]. In contrast to this finding, the sucessive Δ E f values of 420 and 320 mV for the three reduction potentials of syn, syn- [Mo(NO)(Tp*)(1,4-O 2 C 6 H 4 )] 3 7d are slightly smaller than the value of 460 mV found in the binuclear acyclic complex [{Mo(NO)(Tp*)Cl} 2 (1,4-O 2 C 6 H 4 )] 17c…”

“…This might be expected since the Mo−S−C−C(aryl) torsion angles in [Mo(η 5 -C 5 H 5 )(NO)(SPh) 2 ] have been shown 17d to affect the energy of the LUMO of this complex. Furthermore, in [Mo(NO)(Tp*)(1,2-S 2 C 6 H 3 Me-3)] the reduction potential is shifted in the positive direction compared to [Mo(NO)(Tp*)(SPh) 2 ],17e again reflecting the effect of the Mo−S−C−C(aryl) torsion angles on the energy of the redox orbital. Thus it seems reasonable to assume that, where the geometric constraints imposed by forming the macrocyclic ring impinge on the Mo−O−C−C(aryl) torsion angles, the reduction potentials of the metallomacrocycle will be also be subject to geometric effects.…”

Evaluation of Molybdenum−Sulfur Interactions in Molybdoenzyme Model Complexes by Gas-Phase Photoelectron Spectroscopy. The “Electronic Buffer” Effect

“…Compounds. Samples of Tp*MoO(tdt) and Tp*Mo(NO)(tdt) were prepared by published procedures; , Tp*MoS(tdt) was kindly provided by Dr. C. G. Young of the University of Melbourne.…”

Recent advances in poly(pyrazolyl)borate (scorpionate) chemistry

“…This compound was reduced at a more anodic potential than the unchelated analog, Tp*MoNO(SPh)2. 141 The structure of the latter compound was determined by X-ray The electrochemistry of numerous Tp*Mo(NO)XY complexes has been studied in considerable detail. The common starting material itself, Tp*Mo(NO)l2, is reversibly reduced to a monoanion.…”