The modification of bis(pyrazol-1-yl)methanes by chalcogen (S and Se) and their related reactions with organotin chloride and M(CO) 5THF (M = Mo and W)

Abstract

The modification of bis(pyrazol-1-yl)methane by sulfur or selenium on the methine carbon has been successfully carried out by the reaction of the bis(pyrazol-1-yl)methide anion, prepared in situ by the reaction of bis(pyrazol-1-yl)methane with n-BuLi, with elemental sulfur or selenium. These bis(pyrazol-1-yl)methylthiolate or selenolate anions reacted with Ph 2SnCl 2 to form new organotin derivatives CH(3,5-Me 2Pz) 2ESnPh 2Cl (Pz = pyrazol-1-yl, E = S ( 1) or Se ( 2)), which have been characterized by NMR, IR and elemental analysis. The molecular structure of 2 determined by X-ray structure analysis indicates that bis(3,5-dimethylpyrazol-1-yl)methylselenolate is a bidentate monoanionic κ 2-[N,Se] chelating ligand. The treatment of CH(3,5-Me 2Pz) 2ESnPh 2Cl with W(CO) 5THF resulted in the decomposition of ligands to yield pyrazole derivative of (3,5-Me 2PzH)W(CO) 5, while direct treatment of bis(pyrazol-1-yl)methylthiolate or selenolate anions with M(CO) 5THF (M = Mo or W) formed their tricarbonyl metal anions CH ( Pz ) 2 EM ( CO ) 3 - . Succedent reaction of these carbonyl metal anions with Ph 2SnCl 2 or Ph 3SnCl yielded heterobimetalic compounds CH(Pz) 2EM(CO) 3SnPh n Cl 3− n ( n = 2 or 3), which have also been characterized by 1H NMR, IR and elemental analysis. The structure of CH(3,4,5-Me 3Pz) 2SW(CO) 3SnPh 3 ( 8) has been confirmed by X-ray single crystal diffraction, showing that bis(3,4,5-trimethylpyrazol-1-yl)methylthiolate acts as a tridentate, monoanionic κ 3-[N,S,N] chelating ligand.