Syntheses, structures and properties of copper(I) co-ordination polymers with bridging phenazine: construction of one- and two-dimensional structures with π–π stacking of phenazine

Abstract

Four novel copper(I) phenazine (phz) compounds, [{Cu(phz)(NO₃)}_∞]1, [{Cu(acr)₂(NO₃)}₂(phz)(H₂O)]2(acr = acridine), [{Cu₂(phz)(PFO₃)}_∞]3 and [{[Cu(phz)(MeCN)]₂(C₁₆H₁₀)(PF₆)₂}_∞]4(C₁₆H₁₀= pyrene) have been synthesized and their molecular structures and packing have been determined by single-crystal X-ray diffraction methods. The copper atoms in 1 are bridged by phz forming an infinite one-dimensional zigzag chain. These bridging phz molecules have a π–π interaction between neighbouring chains forming an infinite columnar stack of phz molecules. The monomer complex, 2, has an infinite columnar stack of metal-free phz and metal-co-ordinated acr. Copper(I) atoms in 3 are bridged by phz and PFO₃^2– alternately. The resulting one-dimensional chains are connected through a tetradentate, asymmetric PFO₃^2– bridge, with π–π interaction between the phz molecules forming an infinite two-dimensional sheet structure. The backbone of compound 4 is almost the same as in 1 except that a pyrene molecule is intercalated into every other phz stack in a one-dimensional chain. The electrical conductivity of compound 3 and [{[Cu(phz)(MeCN)]₂(C₁₆H₁₀)(PF₆)₂I_1.3}_∞]5, obtained by iodine doping of compound 4 were 1 × 10^–7.6 and 1 × 10^–4.7 S cm^–1, respectively. The electronic absorption bands of compounds 1, 3 and 4 which appeared around 700 nm are characteristic of copper(I) co-ordination polymers with bridging phz.