Second harmonic generation of η5-monocyclopentadienyl ruthenium p-benzonitrile derivatives by Kurtz powder technique. Crystal and molecular structure determinations of [Ru(η5-C5H5)((+)-DIOP)(p-NCC6H4NO2)][X], X=PF6−, CF3SO3− and [Ru(η5-C5H5)((+)-DIOP)(NCC

A new series of salts [RuCp(PP)(p-NC(CHCH)nC6H4R)][X] (PP=((+)-DIOP, DPPE; n=0, 1; R=CH3, Br, OCH3, NH2, N(CH3)2, C6H5 and NO2; X=PF6−, CF3SO3−) were synthesised and the second harmonic generation (SHG) efficiencies were measured by Kurtz powder technique in order to better understand the relationship between structural features and solid state packing with SHG properties. A structural study of [RuCp((+)-DIOP)(p-NCC6H4NO2)][X], X=PF6−, CF3SO3− by X-ray diffraction showed crystallisation on accentric groups. The PF6− salt crystallised in a triclinic space group P1 showing perfect parallel alignment of the molecular dipoles. The CF3SO3− salt crystallised in a monoclinic space group P21 and shows an angle of 73.8° between the molecular dipoles in the unit cell. Complex [RuCp((+)-DIOP)(p-NCCH3)][PF6], studied for comparison, crystallises in the C2221 space group and shows eight molecules per unit cell randomly orientated. Comparison of the RuN and NC distances between the three compounds are in agreement with metal–nitrile bonding suggested by the spectroscopic data.