Spectroscopic investigation of the structure of a novel zerovalent cobalt nitrosyl in zeolite matrices

Abstract

Cobalt (II) hexahydrate introduced in synthetic zeolites by conventional ion-exchange was shown to give up readily five of its water molecules upon evacuation at room temperature. Subsequently the cobalt ion was coordinated by three lattice oxide ions from the zeolite lattice and by a single water molecule so as to acquire a slightly distorted tetrahedral symmetry. This tetrahedral Co^II species readily reacted at room temperature with nitric oxide to yield a zerovalent paramagnetic cobalt dinitrosyl within the zeolite framework. The complex was identified on the basis of its i.r., u.v. and e.p.r. spectra as a C_2h distorted octahedral complex with a d_x²–y² ground state with a coordination sphere made up of three lattice oxide ions [possibly O(4) ions], a water molecule and two NO ligands which transferred their odd electrons to the cobalt d orbitals.