Organic molecules induced crystal transformation from a two dimensional coordination polymer to chain-like structures

Abstract

Using exo-7-oxabicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic acid (H₂2L), three Mn(II) complexes formulated as [Mn(L)(H₂O)]·H₂O (1), [Mn₂(L)₂(H₂O)₄]·(C₆H₆O)·5H₂O (2) and [Mn(L)(H₂O)₂]·0.5(C₆H₆O₂) (3) have been synthesized and structurally characterized by single-crystal X-ray diffractions. Complex 1 shows a uninodal 3-connected 2D layer with 6³-hcb topology. In complexes 2 and 3, similar alternating left-handed and right-handed helical chains are observed. Complex 1 is transformed into complexes 2 and 3 upon the attack of phenol and hydroquinone, respectively. The centrosymmetric complex 1 is transformed into the acentric complex 2, which is induced by the acentric phenol molecule. L exhibits similar exo-configuration and different coordination modes in the three complexes. Due to the unsymmetrical coordination environments of two carboxylate groups, achiral L possesses four chiral carbon atoms in the three Mn(II) complexes. The three complexes show different photoluminescence properties.