The complex (bpy)CdFe(CO)4 crystallizes from hot 1,2,4-trichlorobenzene as a trimer with the stoichiometry [(bpy)-CdFe(CO)4]3'3/4C6H3Cl3. The crystals belong to the tetragonal space group S41-P4 with eight six-membered metal-metal bonded rings and six solvent molecules in a unit cell of dimensions a = b= 29.049 (10), c = 13.241 (5) Å, V = 11 170 Å3. Full-matrix least-squares refinement yielded a final value of the conventional R index (on F) of 0.066 for 5643 reflections having Fo2 > 3σ(F02). The molecular structure consists of nearly planar rings of alternating cis-Fe(CO)4 and (bpy)Cd units. The ring is distorted from ideal D3h, to approximate C2 symmetry by compression along a C2 axis in the plane of the ring. All Fe-Cd distances are equal within experimental error [2.640 (7) Å], The Cd-Fe-Cd angles vary from 138.81 (15) to 148.40 (15)°, and the Fe-Cd-Fe angles from 94.78 (14) to 102.04 (16)°. The iron coordination geometry is significantly distorted from an octahedral one toward a tetrahedral one in which cadmium atoms cap two of the faces. There is evidence for a weak semibridging interaction between carbonyl carbon and cadmium atoms. The Cd-Fe bonding in [(bpy)CdFe(CO)4]3 appears to be more ionic than in [CdFe(CO)4]4. The trimeric compound dissociates in benzene solution.
ASJC Scopus subject areas
- Colloid and Surface Chemistry