Multidimensional Cyanide‐Bridged Heterometallic FeII–CuI and Homometallic CuI Coordination Polymers from Solvothermal Reactions Involving either K3[Fe(CN)6] or KCN as the Source of Cyanide Anions

Abstract

AbstractThe reaction between K3[Fe(CN)6], CuCl2·2H2O and 1,10‐phenanthroline (phen) under hydrothermal conditions gives rise to the formation of the 3D cyanide‐bridged heterometallic FeII–CuI complex [Fe(CN)4(phen)2Cu2] (1). Its 3D network structure is constructed from two types of fused cyanide‐bridged 10‐ and 14‐metal‐membered centrosymmetric rings (Fe2Cu8 and Fe2Cu12), which are defined by the general sequences {(CuI)4‐FeII‐(CuI)4‐FeII} and {(CuI)6‐FeII‐(CuI)6‐FeII}, respectively. The copper(I) and iron(II) atoms exhibit distorted triangular planar and distorted octahedral coordination environments, respectively. Complex 1 is the first example of a 3D cyanide‐bridged bimetallic complex prepared by hydrothermal methods. The use of methanol as solvent, KCN as source of cyanide anions and 2,2',6,6'‐bipyrimidine as the bridging ligand results in the isolation of the 2D homometallic copper(I) complex [Cu2(CN)2(bpym)]·H2O (2). Its structure consists of neutral 2D (6,3) honeycomb layers in the ab plane made of fused Cu6(CN)4(bpym)2 rings, in which the copper(I) atoms exhibit a distorted tetrahedral geometry. The layers are interdigitated in such a way that the bpym ligands lie above and below the ring cavities of neighbouring networks, with an ABCD repeat sequence of layers. Water molecules are located in the free space between the A/D and B/C layers. Under the same conditions as used for 1, but with 4‐methyl‐2,2',6,6'‐bipyrimidine 2‐oxide instead of phen, the 3D complex [Cu2(CN)2(mbpym] (3) was obtained (mbpym = 4‐methyl‐2,2',6,6'‐bipyrimidine). During the reaction the oxygen atom of the N‐oxide group is eliminated and the novel ligand mpym formed. Its structure consists of distorted tetrahedral copper(I) atoms connected by cyanide and mpym bridging ligands to give rise to a 3D chiral network. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)