Synthesis and structure of coordination polymer compounds of AgReO4 and AgPF6 with piperazine

Abstract

Coordination polymers [Ag(C4H10N2)]ReO4 (I) and [Ag(C4H10N2)]PF6 (II) (C4H10N2 is piperazine, Ppz) were synthesized and their structures were determined. Crystals of compound I are monoclinic, space group P21/c, a = 6.207(1) A, b = 12.533(1) A, c = 11.386(1) A, β = 93.41(1)°, V = 884.2(2) A3, ρcalc = 3.337 g/cm3, Z = 4. Crystals of II are monoclinic, space group C2/m, a = 8.723(1) A, b = 9.083(1) A, c = 5.797(1) A, β = 95.07(1)°, V = 457.5(1) A3, ρcalc = 2.548 g/cm3, Z = 2. Structure I contains polymer chains [Ag(Ppz)]∞+. The silver atom is linked with two nitrogen atoms of the adjacent Ppz ligands to form a nearly linear fragment; the Ag-Nav distance is 2.173 A, and the NAgN angle is 169.4(3)°. The chains are linked with each other by weak interactions Ag…O(ReO4) (2.643(8) A) and N-H…O hydrogen bonds. The structure of compound II also contains cationic polymer chains [Ag(Ppz)]∞+. The Ag+ ion is located in the inversion center and has a linear coordination (Ag-N distance is 2.171(9) A). The central P atom of the octahedral fluorophos-phate ion is also located in the inversion center; the anion is slightly distorted and has no contacts with silver ions at a distance <3.4 A.