Coordination polymers of d~(10) metals and N,N'-bis(3-pyridine-carboxamide)-1,2-ethane

摘要

The ligands N,N'-bis(3-pyridine-carboxamide)-1,2-ethane (L) was designed to form coordination polymers capable of assembling into 2-D network via complementary amide hydrogen bonds. The reactions of L with AgX (X = ClO_4~-, CF_3SO_3~- or NO_3~-), Zn(ClO_4)_2(centre dot)6H_2O and Cd(ClO_4)_2(centre dot)6H_2O produced coordination polymers 1-5, the structures of which were characterized by single crystal X-ray diffraction. The polymer {[AgL][ClO_4]_(infinity) crystallized in two polymorphs 1A and 1B which consisted of coordination polymers {[AgL]~+}_(infinity) in sine-wave and zigzag conformations, respectively. In addition, the X-ray crystal structures of {[AgL][CF_3SO_3]}_(infinity) (2) and {[AgL][NO_3](H_2O)_(1.25)}_(infinity) (3) showed coordination polymers in zigzag conformation similar to that of 1B. The polymers in compounds 1, 2 and 3 aggregate via complementary amide hydrogen bonds, forming corrugated sheets in the solid state. Furthermore, the compound trans-{[ZnL_2(H_2O)_2][ClO_4]_2(centre dot)(H_2O)_2(centre dot)CH_3CN}_(infinity) (4) was shows to be an infinite chain of [Zn_2L_2]metallacycles. The stacking of the Zn polymer leads to the formation of a channel-like structure. The coordination polymer {[CdL(H_2O)][ClO_4]_2}_(infinity) (5) shows zigzag chains which are linked through hydrogen bonds between the anion, amide groups and coordinated water molecules. In contrast to its isomer L, the ligand N,N'-bis(3-pyridine-carboxamide)-1,2-ethane (L~1) formed segregated Ag(1) coordination polymer (6) in which the Ag ion is four coordinate.