EFFECT OF SUBSTITUTING SULFUR FOR OXYGEN ON THE HETEROGENEOUS ELECTRON-TRANSFER KINETICS OF OXOMOLYBDENUM(V) HYDROTRIS(3,5-DIMETHYL-1-PYRAZOLYL)BORATE COMPLEXES
EFFECT OF SUBSTITUTING SULFUR FOR OXYGEN ON THE HETEROGENEOUS ELECTRON-TRANSFER KINETICS OF OXOMOLYBDENUM(V) HYDROTRIS(3,5-DIMETHYL-1-PYRAZOLYL)BORATE COMPLEXES
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DOI：
10.1016/0020-1693(94)04022-2
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发表时间：
1994-10-01
影响因子：
2.8
通讯作者：
SCHULTZ, FA
中科院分区：
文献类型：
--
作者：
OLSON, GM;SCHULTZ, FA
Heterogeneous electron transfer rate constants (k(s,h)) and formal potentials (E degrees') are measured for the one-electron reduction of a series of oxomolybdenum(V) complexes, HB(Me(2)pz)(3)MoO(L-L), where HB(Me(2)pz)(3)(-) = hydrotris(3,5-dimethyl-1-pyrazolyl)borate and L-L(2-) is a bidentate 1,2-disubstituted ethane or benzene ligand whose donor atoms can be either O or S. E degrees' shifts in the negative direction by about 1 V and k(s,h) decreases by about 1.5 orders of magnitude as S is replaced by O in the inner coordination sphere of these compounds. These observations are rationalized in terms of a hard acid-hard base interaction between the HB(Me(2)pz)(3)MoO2+ fragment and L-L(2-) which stabilizes the metal-ligand bond and increases the energy of the metal-centered redox orbital as the hard base character of the bidentate ligand increases. Electron transfer rate differences are believed to arise primarily from larger inner-shell contributions to the activation energy barrier for Mo-O versus Mo-S complexes, but contributions from differences in outer-shell energies and adiabaticities cannot be eliminated at this time.
