A new octupolar material for quadratic nonlinear optics: tris(2,2′-bipyridyl)Zn(ii) tetrakis(2-chloro-4-nitrophenolate)Zn(ii)

Abstract

Tris(2,2′-bipyridine)Zn(II) tetrakis(2-chloro-4-nitrophenolate)Zn(II), [Zn(bpy)3][Zn(CNP)4] 1, is a new octupolar material for quadratic nonlinear optics. 1, a chiral metal–organic complex, crystallizes in space group C2. Refinement of the Flack parameter supports the description of the [Zn(bpy)3]2+ cation as the Δ enantiomer. The counterion is an octupolar, tetrahedral assembly of 2-chloro-4-nitrophenolate chromophores around a Zn2+ ion. A second harmonic generation signal equal to 5 × urea is observed. A complex having a slightly different stoichiometry, bis(2,2′-bipyridine)-bis(2-chloro-4-nitrophenolate)Zn(II), crystallizes in the centrosymmetric space group P. The structure of bis(2-chloro-4-nitrophenolate)Zn(II) pentahydrate, a precursor of 1 with P symmetry, is described.