Synthesis and structure of an organometallic coordination polymer based on copper benzoate

Abstract

A new organometallic coordination polymer [Cu(benz)2(dioxane)]‧dioxane (1) has been synthesized by solvothermal method (in DMSO/1,4-dioxane solution) with the use of reaction between diacetylenedibenzoic acid, copper(II) nitrate, and benzoic acid. The main structural details and experimental parameters: C20H22CuO7, М 437.91; space group – P4/ncc, a = b = 14.4008(1) Å, c = 19.3459(3) Å, α = β = γ = 90°, V = 4012.01(8) Å3, F (000) = 1816.0, absorption coefficient μ = 1.876 мм–1, crystal size 0.12 × 0.11 × 0.09 mm, reflection index intervals -16 ≤ h ≤ 14, -13 ≤ k ≤ 18, -24 ≤ l ≤ 21, total reflections 10916, independent reflections 2096, Rint = 0.0269, residual electron density 0.32/-0.31 e/Å3. The cell consists of one benzoate anion, two independent copper cations, and two molecules of 1,4-dioxane. Four bridging benzoate ions bond two copper cations, with coordination number equaling six and an octahedron as the corresponding coordination polyhedron. The C–O bonds in the benzoate anion are very close in length, namely, 1.252 and 1.253 Å, indicating a high degree of mixing between single and double bonds in the carboxyl group. Two types of 1,4-dioxane molecules are present in the structure: the first ones are coordinated to the metal and the second ones are enclosed in the structure cavities. The coordinated bridging dioxane molecules link the Cu2(benz)4 clusters into 1D chains using both oxygen atoms of dioxane. These chains in the structure are arranged parallel to each other with cavities formed between them, in which free molecules of 1,4-dioxane are located. The presence of these pores makes it possible to consider compound 1 as an organometallic coordination polymer.