Crystal structures and luminescence properties of a D-A type CIEgen and its Zn(ii) complexes

A D-A type organic luminogen single crystal (CIE-C) and its two Zn(ii) complexes [Zn(CIE-P)(C₄H₄N₂)·CH₃OH] (1) and [Zn(CIE-P)(4,4′-bipy)·1.5CH₃OH] (2) (CIE-P = 2,3-bis(2,4-dihydroxybenzylideneamino)maleonitrile, C₄H₄N₂ = pyrazine, 4,4′-bipy = 4,4′-bipyridine) have been synthesised and studied. The single crystal X-ray diffraction analysis showed that the molecular structure of CIE-C is well planar and the good co-planarity is maintained in the 2D structure; 1 and 2 are all mononuclear complexes. The photoluminescence properties of CIE-C and its Zn(ii) complexes have been investigated in the solid state and solution. The novel crystallization-induced emission-enhancement (CIEE) behavior of CIE-C and unusual fluorescence selectivity for THF of 1 and 2 were found.