[1] Univ Milan, Dipartimento Chim Inorgan Metallorgan & Analit L, I-20133 Milan, Italy
[2] CNR, ISTM, I-20133 Milan, Italy
[3] Univ Milan, Dipartimento Chim Strutturale & Stereochim Inorga, I-20133 Milan, Italy
[4] Univ Bern, Dept Chem & Biochem, CH-3012 Bern, Switzerland