3RD-ORDER NONLINEAR-OPTICAL PROPERTIES OF GROUP-4 METALLOCENES

The third order nonlinear optical (NLO) coefficients (gamma) of Ti, Zr, and Hf metallocene halides, acetylides and alkenylzirconocene compounds were measured with a third harmonic generation technique with a fundamental laser frequency of 1908 nm. Metallocene halide compounds have gamma of less than 5 x 10(-36) esu. Titanocene bisphenyl-acetylide has the largest gamma (92 x 10(-36) esu) of the metallocene acetylide compounds. The gamma of the metallocene acetylide complexes are significantly larger than the sum of the free organic acetylene and the metallocene halide compounds. Cp(2)Zr(Cl)CH=CH-1,4-phenyl-CH=CH(CI)ZrCp(2) has the largest gamma (154 x 10(-36) esu) of any of the group 4 metallocene compounds studied. The origin of this optical nonlinearity is most likely due to a conjugated 71 system; which involves the pi-metal bonding network and like symmetry orbitals of the vinyl and acetylide ligands.