| W/Cu/S clusters have been extensively investigated because of their structure diversity and broad application prospects in industrial catalysis and optical materials. In our previous works, a series of oligomeric and polymeric W/Cu/S cluster-supported supramolecular compounds have been assembled by the reactions of some preformed clusters with various inorganic or organic linkers. In most of these reactions, the cluster core frameworks are retained. However, there are several exceptions in which the original cluster core frameworks are rearranged. In this thesis, we report the employment of a cluster core degradation or expansion reaction to assemble new Mo(W)/Cu/S cluster-based oligomers and polymers. Two items are focused on: (1) assembly and third-order NLO properties of dimeric and polymeric W/Cu/S clusters via degradation or expansion of the cluster core in [Et4N]4[WS4Cu4I6];(2) assembly of new clusters containing butterfly-shaped [WS4Cu3] core.The reactions of a precursor cluster [Et4N]4[WS4Cu4I6] (1) with two equiv. of 1,1' -(1,4-butanediyl)bis(3,5-dimethyl-pyrazole) (bbd) or 1,3,5-tris(3,5-dimethyl-pyrazolyl-ylmethyl)-2,4,6-trimethylbenzene (tdtb) in MeCN/DMF gave rise to the two dimeric clusters, [WS4Cu3I(μ-bbd)]2 (2)(double nido-shaped) and [{WS4Cu3(tdtb)}2(μ-I)2]·2DM F (3·2DMF) (double butterfly-shaped), respectively. Solvothermal reactions of 1 with two equiv. of bbd in MeCN/DMF at 90℃for 24 h resulted in the formation of the dimeric cluster [EuN]6[{WS4Cu5(μ-I)2I4}2(μ-bbd)] (4) (double double half-open cubane-like), while those of 1 with two equiv. of 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6 -trimethylbenzene (titb) in DMF at 120℃afforded the polymeric cluster {[WS4Cu2(tit b)]·0.5H2O}n (5) which has a linear core. During these reactions, the cluster cores of 2,3 and 5 were obtained via degration of the cluster core in 1, while the formation of the cluster core in 4 could be ascribed to the expansion of the cluster core in 1. Investigated by using Z-scan techniques at 532 nm, 2 and 4 exhibited good third-order NLO performances in MeCN. These results showed that the third-order optical non-linearities of 2 and 4 were enhanced relative to those of 1. Their third-order nonlinear optical susceptibility X and second-order hyperpolarizabilityγvalues were measured to be 6.00×10-12 esu and 1.58×10-29 esu (2), 3.70×10-12 esu and 1.35×10-29 esu (4), respectively.In addition, it was found that when some weakly acidic species existed in the same system, only a monomeric species [WS4Cu3I(tdtb)]·3(MeCN)0.5 (6·3(MeCN)0.5) (butterfly-shaped) was obtianed. We also explored severl effects (e.g. ligands, coordination atoms, molar ratios of components, types of precursor cluster and solvents) on the assembly of new cluster species containing a [WS4Cu3] core. Three new clusters [WS4Cu3I(dmpm)2] (7),[{WS4Cu3(tdtb)}2(μ-Cl)2]·DMF·2MeCN (8·DMF·2MeCN)),and [{WS4Cu3(tdtb)}2(μ-Br)2]·DMF·MeCN (9·DMF·MeCN)) were isolated. Compounds 6-9 were all characterized by IR,elemental analysis and their structures were determined by X-ray analysis. The results revealed that the assembly of those containing the butterfly-shaped [WS4Cu3] core may be preferred if the W/Cu/S precursors react with pyrazolyl-based linkers that possess large steric effects and good chelating ability in weakly acidic or neutral MeCN/CHCl3(or DMF) solvent systems. |
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