Inorganic Chemistry, Vol.45, No.24, 9858-9863, 2006
Electron deficient carbon-titanium triple bonds: Formation of triplet XC divided by TiX3 methylidyne complexes
Laser- ablated titanium atoms react with CX4 ( X) F and Cl) to produce triplet state XC, divided by TiX3 complexes trapped in an argon matrix. Products are identified by their infrared spectra and comparison to theoretically predicted vibrations. Density functional theory calculations converge to C 3 v symmetry structures for these lowest-energy products. The two unpaired electrons in the carbon 2p orbitals are shared with empty titanium d orbitals leading to degenerate singly occupied pi molecular orbitals and an electron-deficient triple bond between the carbon and titanium centers, on the basis of DFT bonding analysis and spin density calculations. The carbon - titanium distances are near typical CdTi double bond lengths, and the C - X bonds in the resulting products are shorter than in the CX4 precursors. It appears that X lone- pair conjugation contributes to the C - X bond strength and somewhat to the C - Ti bond, and Cl does better in this regard than F.