Abstract
A family of seven silver(I)-perfluorocarboxylate-quinoxaline coordination polymers, [Ag(4) (O(2) CR(F) )(4) (quin)(4) ] 1-5 (R(F) =(CF(2) )(n-1) CF(3) )(4) , n=1 to 5); [Ag(4) (O(2) C(CF(2) )(2) CO(2) )(2) (quin)(4) ] 6; [Ag(4) (O(2) CC(6) F(5) )(4) (quin)(4) ] 7 (quin=quinoxaline), denoted by composition as 4 : 4 : 4 phases, was synthesised from reaction of the corresponding silver(I) perfluorocarboxylate with excess quinoxaline. Compounds 1-7 adopt a common 2D layered structure in which 1D silver-perfluorcarboxylate chains are crosslinked by ditopic quinoxaline ligands. Solid-state reaction upon heating, involving loss of one equivalent of quinoxaline, yielding new crystalline 4 : 4 : 3 phases [Ag(4) (O(2) C(CF(2) )(n-1) CF(3) )(4) (quin)(3) ](n) (8-10, n=1 to 3), was followed in situ by PXRD and TGA studies. Crystal structures were confirmed by direct syntheses and structure determination. The solid-state reaction converting 4 : 4 : 4 to 4 : 4 : 3 phase materials involves cleavage and formation of Ag-N and Ag-O bonds to enable the structural rearrangement. One of the 4 : 4 : 3 phase coordination polymers (10) shows the remarkably high dielectric constant in the low electric field frequency range.