Syntheses, crystal structures, and NLO properties of new chiral inorganic chromophores for second-harmonic generation

A new chiral ligand (H2L) based on the condensation of diaminocyclohexane and 4-(diethylamino)salicylaldehyde is reported along with its nickel(II) and manganese(III) complexes. These compounds all crystallize in noncentrosymmetric space groups. Crystal data are as follows. For the ligand(C28H40N4O2): monoclinic, I2, a = 15.487(2) Angstrom, b = 8.1988(6) Angstrom, c = 20.958(3) Angstrom, beta = 95.92(1)degrees, Z = 4. For the (NiL)-L-II complex: monoclinic, P2(1), a = 8.613(2) Angstrom, b = 21.714(4) Angstrom, c = 15.870(4) Angstrom, beta = 91.02(2)degrees, Z = 4. For the (MnLCl)-L-III complex: orthorhombic, P2(1)2(1)2(1), a = 7.233(2) Angstrom, b = 15.159(3) Angstrom, c = 25.591(7) Angstrom, Z = 4. The manganese derivative exhibits an efficiency 8 times that of urea in second-harmonic generation at 1.9 mu m. INDO/SCI-SOS quantum-chemical calculations predict a sizable molecular nonlinear response and an enhancement of the nonlinearity after metal complexation.