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Updated: Jun 16, 2026

Effect of Microwave Synthesis Conditions on the Structure of Nickel Hydroxide Nanosheets
Published on: August 18, 2023
Synthesis, spectral, structural, second-order nonlinear optical properties and theoretical studies on new
Alexander Trujillo1, Mauricio Fuentealba, David Carrillo
1Laboratorio de Química Inorgánica, Instituto de Química, Pontificia Universidad Católica de Valparaíso, Campus Curauma, Avenida Parque Sur 330, Valparaíso, Chile.
Abstract:
The synthesis, spectroscopic and structural characterization, linear and nonlinear optical properties, as well as the electrochemical behavior of a series of robust neutral binuclear M[Fc-C(O)CH=C(CH(3))N-X-N=CH-(2-O,5-R-C(6)H(3))] (M = Ni (4), Cu (5), X = o-C(6)H(4), R = H; M = Ni (9), X = CH(2)CH(2), R = OH), and their corresponding ionic trinuclear [M{Fc-C(O)CH=C(CH(3))N-X-N=CH-(eta(6)-2-O,5-R-C(6)H(3))RuCp*}][PF(6)] (6, 7, 10), M[ONNO]-type unsymmetrical Salophen and salen complexes featuring ferrocenyl (Fc) donor and the mixed sandwich acceptor [Cp*Ru(eta(6)- salicylidene)](+) as a push-pull moiety are reported in this paper (Fc = CpFe(eta(5)-C(5)H(4)); Cp = eta(5)-C(5)H(5); Cp* = eta(5)-C(5)Me(5)). The single-crystal X-ray structure of the bimetallic iron-nickel derivative 4 indicates a bowed structure of the unsymmetrical Schiff base skeleton. The Ni(II) ion is tetracoordinated in a square planar environment, with two nitrogen atoms and two oxygen atoms as donors. The new metalloligand [Fc-C(O)CH=C(CH(3))N(H)CH(2)CH(2)N=CH-(2,5-(OH)(2)C(6)H(3))] (8) obtained from the Schiff base condensation of 2,5-dihydroxobenzaldehyde with the half-unit precursor, Fc-C(O)CH=C(CH(3))N(H)CH(2)CH(2)NH(2) (2), is reported with its crystal structure showing partial delocalization of the heteroconjugated [O-C-C-C-N] frameworks with a dihedral angle between the respective planes of 60.76 degrees. Second order nonlinear optical (NLO) measurements were achieved using the Harmonic Light Scattering technique to probe the role of the M[ONNO] chromophores and of the pi-complexation of the salicylidene ring in the nonlinearity. All the complexes exhibit a second-order nonlinear response increasing with the nuclearity, the hyperpolarizability (beta) value of the trinuclear complex 10 being 1.5 time larger than that of the metalloligand 8 (beta = 155 x 10(-30) esu). A rationalization of the structural, electronic, and redox properties of the title compounds is provided, based on a theoretical investigation at the density functional theory (DFT) level. Their UV-visible spectra has been assigned with the help of time-dependent (TD) DFT calculations. They are dominated by LMCT, MLCT, and pi-pi* transitions.
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