D. Braga et al., A VARIABLE-TEMPERATURE STUDY OF RU-3(CO)(12) IN THE SOLID-STATE AND THE GENERATION OF ALTERNATIVE CRYSTAL-STRUCTURES, Transition metal chemistry, 20(6), 1995, pp. 615-624
The molecular and crystal structure of Ru-3(CO)(12) has been reinvesti
gated on single-crystal X-ray diffraction data collected at 100 and 15
0 K. Thermal motion analysis on high-order diffraction data have been
used to characterize the motion about equilibrium positions of the mol
ecule as a whole and of groups of atoms. It has been shown that, while
the molecule undergoes an almost isotropic rigid-body librational and
translational motion, the three Ru(CO)(4) units undergo different lib
rational motions about the axes passing between each Ru atom and bisec
ting the opposite Ru-Ru bond. Packing potential energy calculations an
d computer graphics have been used to show that the most favoured pack
ing motion the experimental crystal is based on interlocking between t
etracarbonyl units formed by two pairs of CO ligands at right angles a
long a Ru-Ru edge. Starting from the structure of Ru-3(CO)(12), altern
ative crystal arrangements have been generated and compared with the e
xperimental crystal structure in terms of packing efficiency and cohes
ive energy.