D. Braga et al., INTRAMOLECULAR AND INTERMOLECULAR BONDING IN CRYSTALLINE CLUSTERS OF THE TYPE (CPR)(3)M(3)(CO)(3)[M=CO,RH,IR, CP(R)=C5H5,C(5)ME(5),C(5)H(4)ME], Organometallics, 14(11), 1995, pp. 5350-5361
The relationship between molecular and crystal structures of (Cp(R))(3
)M(3)(CO)(3) clusters [M = Co, Rh, Ir; Cp(R) = C5H5, C(5)Me(5), C(5)H(
4)Me] has been investigated by a combined use of extended Huckel molec
ular orbital calculations, empirical atom-atom pairwise packing potent
ial energy calculations, and computer graphics. The indenyl derivative
(Ind)(3)Ir-3(mu(2)CO)(3) has also been investigated. The molecules pr
esent several isomers of similar energies, and the number of bridging
carbonyl groups decreases along the family cobalt, rhodium, iridium, a
s the metal-metal antibonding character of the orbitals populated in c
onsequence of their formation increases. Hydrogen-bonding networks of
the C-H- - -O type involving the carbonyl oxygen atoms have been detec
ted in all of these crystalline complexes. Facial and edge bridging CO
's are observed to form preferential interactions with respect to term
inal ligands. The intermolecular and intramolecular interactions in ea
ch case are discussed and compared in crystal isomers and polymorphs.