Construction of [CunIn]-based coordination polymers via flexible benzimidazolyl-based ligands

Four new [CunIn]-based coordination polymers, [{ Cu4(µ3-I)4(mbbm)2}·2DMF]n (1), [(CuI)2(mbbm)2]n (2), [{Cu2(µ-I)2-(ebbm)2}·2MeCN]n (3), and [Cu2(µ-I)2(prbbm)2]n (4), were prepared from solvothermal reactions of CuI with three flexible ligands [(bzim)(CH2)n(bzim)] (bzim = benzimidazole; n = 1, mbbm; n = 2, ebbm; n = 3, prbbm). These compounds were characterized by elemental analysis, IR and X-ray crystallography. 1 consists of cubanelike [Cu4(µ3-I)4] fragments that link the neighboring ones via mbbm bridges to form a 1D ladder-type chain. 2 contains mononuclear [CuI] fragments that are bridged by mbbm ligands to yield a 1D zigzag chain. 3 or 4 contains a [Cu2(µ-I)2] dimeric fragment, which works as a four-connecting node to link its four equivalent ones to form a 2D (4,4) network (3) or acts as a two-connecting node to connect its two equivalent ones via two pairs of prbbm bridges to form a 1D double chain (4). The photoluminescent properties of 1–4 in the solid state at ambient temperature were investigated.