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

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 Delta enantiomer. The counterion is an octupolar, te trahedral assembly of 2-chloro-4-nitrophenolate chromophores around a Zn2ion. A second harmonic generation signal equal to 5 x urea is observed. A c omplex having a slightly different stoichiometry, bis(2,2'-bipyridine)-bis( 2-chloro-4-nitrophenolate)Zn(II), crystallizes in the centrosymmetric space group P (1) over bar. The structure of bis(2-chloro-4-nitrophenolate)Zn(II ) pentahydrate, a precursor of 1 with P (1) over bar symmetry, is described .