Hydridotris(3,5-dimethylpyrazolyl)borate Tungsten Alkyne Complexes for Nonlinear Optics

Abstract

Deprotonation of the propargyl site of racemic or enantiomerically pure Tp′(CO)IW-(C 6 H 5 CtCCH 3 ) (Tp′) hydridotris(3,5-dimethylpyrazolyl)borate) yields an η 2 -allenyl anion which has been reacted with a series of aldehydes and ketones possessing electron-donating substituents. Elimination under either acidic or basic conditions generates chiral trans conjugated enynes. Characterization has been accomplished by NMR, IR, UV-vis, and elemental analysis. Additionally, X-ray diffraction has been used to structurally characterize racemic Tp′(CO)IW(C 6 H 5 CtCCHdC(CH 3 )C 5 H 4 FeC 5 H 5 ). The structural analysis reveals a centrosymmetric space group (P1 h); cell dimensions of a ) 10.690(5) Å, b ) 13.360(7) Å, c ) 15.392(7) Å, R ) 92.57(6)°, β ) 101.70(5)°, and γ ) 100.97(4)°; Z ) 2 molecules/unit cell; and R w ) 4.7% and R ) 3.9%. Second harmonic generation of the enynes has been measured by the Kurtz powder technique.