Sulfido complexes hydrogen activation

In some cases the oxidative addition reaction has been observed to proceed further with the elimination of dihydrogen and the consequent formation of a stable sulfido complex, in a way the reverse reaction of the activation of hydrogen by Cp 2Ti=S described in the preceding section. For instance, the Zr(n) complex Cp 2Zr(CO)2 reacts with excess HjS in the presence of pyridine to yield the corresponding bis(hydrosulfido) derivative Cp Zr(SH),. This reaction takes place via an initial oxidative addition of HjS to yield Cp Zr(H)(SH) followed by hydrogen elimination in the presence of pyridine to form a terminal sulfido complex Cp Zr(S)(py) the latter undergoes a second oxidative addition of H2S to finally produce the bis(hydrosulfido) complex, as shown in Eq. 5.14 [2]. 

Hydrogen activation on complexes containing sulfido or disulfide ligands... 

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