Assembly of [(η⁵-C₅Me₅)MoS₃Cu₃]-Supported One-Dimensional Chains with Single, Double, Triple, and Quadruple Strands

The construction of a new set of [(η5-C5Me5)MoS3Cu3]-based supramolecular compounds with different one-dimensional (1D) arrays from two preformed clusters [PPh4][(η5-C5Me5)MoS3(CuX)3] (X = Br (1a), NCS (1b)) with 1,2-bis(4-pyridyl)ethane (bpe) and 1,3-bis(4-pyridyl)propane (bpp) is presented. Reactions of 1a with bpe in different molar ratios afforded {[{(η5-C5Me5)MoS3Cu3}2(μ-bpe)3.5Br4]·MeCN}n (2), {[{(η5-C5Me5)MoS3Cu3}2(μ-bpe)3Br4]·Sol}n (3a: Sol = DMSO·3MeCN; 3b: Sol = 2aniline·3MeCN), {[{(η5-C5Me5)MoS3Cu3}2(μ-bpe)3(bpe)Br4]·0.35DMF}n (4), and {[{(η5-C5Me5)MoS3Cu3}2(μ-bpe)2(μ-Br)(μ3-Br)Br2]·DMF·MeCN}n (5). On the other hand, treatment of 1a or 1b with bpp produced [(η5-C5Me5)MoS3Cu3(μ-bpp)(μ-Br)Br]n (6) and {[{(η5-C5Me5)MoS3Cu3}2(μ-bpp)3(μ-NCS)2(NCS)](NCS)}n (7). Compounds 2−7 have been characterized by elemental analysis, UV−vis spectroscopy, IR spectroscopy, 1H NMR, and X-ray analysis. In 2, each [(η5-C5Me5)MoS3Cu3] core serves as an angular two-connecting node to link other equivalent cores by single and double bpe bridges to form a 1D “Great Wall”-like chain. In 3a and 3b, the [(η5-C5Me5)MoS3Cu3] cores are linked alternatively by single and double bpe bridges to give a 1D zigzag chain. In 4, six cluster cores (two as a two-connecting node and four as a three-connecting node) are connected by four single bpe and two double bpe bridges to form a cyclohexane-shaped repeating unit, which is further fused with other units to generate a 1D double-stranded chain. Compound 5 has a simple 1D zigzag chain consisting of the cluster cores linked by single bpe bridges. In 6, the cluster cores are linked by single bpp bridges to give a 1D helical chain, which further holds two symmetry-related chains through C−H···Br hydrogen-bonding interactions, thereby forming a 1D H-bonded triple-stranded chain. Compound 7 has a rare 1D quadruple chain, in which the [(η5-C5Me5)MoS3Cu3] cores work as planar four- and five-connecting nodes to interconnect other equivalent cores through single bpp bridges and single and double thiocyanate bridges. In addition, the third-order nonlinear optical properties of 1a, 2, 3a, and 4−7 in aniline were also investigated by using the Z-scan technique with a 4.5 ns pulse laser at 532 nm.