Synthesis, crystal structure and characterization of a new layered gallium phosphite Ga(HPO3)F3·(trans-C6N2H16) with left- and right-handed helical chains

Abstract

A new 2D layered gallium phosphite Ga(HPO₃)F₃·(trans-C₆N₂H₁₆) 1, possessing left- and right-handed helical chains, has been solvothermally synthesized in the presence of 1,2-diaminocyclohexane (DACH) as a structure-directing agent. The inorganic framework of compound 1 consists of [Ga₂O₄F₆] dimers and HPO₃ groups. The dimers are linked up via HPO₃ groups to give rise to left- and right-handed helical chains along the b-axis, further these two types of helical chains are alternately connected, with [Ga₂O₄F₆] dimer units functioning as hinges to form a novel 2D layered network in the bc-plane. Interestingly, although a mixture of cis and trans isomers of DACH are used in the synthesis, only the trans isomer is found to direct the formation of compound 1. Moreover, the chirality of the racemic trans isomers of DACH can be transferred into the inorganic framework by hydrogen-bond. The crystal data are as follow: Ga(HPO₃)F₃·(trans-C₆N₂H₁₆); M = 322.91; Monoclinic; P2₁/c (14); a = 11.2635(5) Å; b = 9.8212(5) Å; c = 10.1458(3) Å; β = 102.981(2)°; Z = 4.