Magnetic behavior of odd- and even-electron metal carbonyl clusters: the case study of [Co(8)Pt(4)C(2)(CO)(24)](n-) (n = 1, 2) carbide cluster.

The reaction of Co(6)C(CO)(15) with 2 equiv of PtCl(2)(Et(2)S)(2) affords the new heterobimetallic Co(8)Pt(4)C(2)(CO)(24), 1, carbonyl cluster. 1 undergoes reversible chemical and electrochemical oxidation and reduction processes disclosing a complete series of 1 (n = 1-4) clusters. The mono- and dianion of 1 have been isolated as their tetra-substituted ammonium salts and fully characterized by means of IR, (13)C NMR, ESI-MS, and X-ray crystallography. Variable-temperature (VT) solid-state EPR studies on pure crystalline samples indicate that both 1 and 1 are paramagnetic, due to a doublet state of the latter and a triplet state of 1. This conclusion is supported by SQUID measurements on the same crystalline sample of 1. The present study indisputably demonstrates that even-electron transition metal carbonyl clusters (TMCC) can be magnetic.