Addition of ynamines to the tungsten η1-vinylidene complexes (η5-C5H5)(NO)(CO)W=C=C(H)R

With the aim of synthesis of chiral-at-metal complexes with NLO properties, the reaction of ynamines 2a,b with the eta(1)-vinylidene complexes (eta(1)-C5H5)(CO)(NO)W=C=(H)R (R = C6H5 (1), C(CH3)(3) (6), H (8)) was investigated. It has been shown that the substituent R on the eta(1)-vinylidene complex determines the outcome of the reaction. Whereas the reaction of 2a,b with complex 1 gave rise to the expected cyclobutenylidene complexes 4a,b and 5a,b, the reaction of ynamines with complexes 6 yielded the aminocarbene complexes 7a,b and the reaction of eta(1)-vinylidene complexes 8 gave rise to a mixture of compounds 9 and 10. The mechanism of formation of these complexes was investigated. Single-crystal X-ray diffraction data of 4a, 7a, and 9 are reported. Complex 4a is composed of a strong electron-donating and accepting group conjugated via double bonds of a cyclobutenylidene unit. Hence, the first hyperpolarizability beta was determined by hyper-Rayleigh scattering measurements with a stimulating laser beam at lambda = 1500 nm. A first hyperpolarizability of beta = 105 x 10(-30) esu was determined.