Structure of Compounds Containing Metal-Carbon a Bonds

STRUCTURE OF COMPOUNDS CONTAINING METAL-CARBON a BONDS 

In general, M-C distances in transition metal complexes vary in the 190-240 pm range. Greater distances are encountered in the case of alkyl compounds of the lanthanides and the actinides. For a given metal the bond distance decreases according to the series  

Coordination numbers change from 2 to 8. Complexes of elements of groups 4-7 possessing compositions MR4, MR5, and MR have tetrahedral (often considerably distorted), trigonal-bipyramidal, and octahedral structures, respectively. 

Li[Lu(2, 6-Me2C6H3)4]4THF [AU2Cl2 (CH2)2PEt2 2] [Mo2(CH2SiMe3)6] [Re2(/z-CSiMe3)2(CH2SiMe3)4]  

The IR spectra of methyl complexes exhibit the types of bands shown in display (4.31). Other alkyl compounds show characteristic bands for both CH3 and CH2 groups. 

---