Thermodynamics and Kinetics of Reaction of (Oxo)(hydroxo)molybdenumtetraphenylporphyrin with Pyridine

Abstract

The reaction of meso-tetraphenylporphyrin with Mo(VI) oxide in boiling phenol resulted in a stable complex O=Mo(OH)TPP. Thermodynamics and kinetics of the reaction between (oxo)(hydroxo)molybdenumtetraphenyporphyrin with pyridine in toluene were studied by spectrophotometric method. This reaction was found to occur in three equilibrium elementary stages: replacement of OH− by Py (K1=9.1 × 103 l/mol, k1=5.25 s−1 mol−1 l), the formation of dication (dipyridine)(hydroxo)molybdenumtetraphenylporphyrin as a result of cleavage of a double bond Mo=O (K2=39.3 l/mol, k2=1.83 × 10−2 s-1 mol−1 l), and the formation of cationic complex[Mo(Py)3TPP]3+ · 3OH− (K3=1.0 l/mol, k3=1.19 × 10−3 s−1 mol−1 l).