Mo(W)/Cu/S Cluster-Based Supramolecular Arrays Assembled from Preformed Clusters [Et_4N]_4[WS_4Cu_4I_6] and [(n-Bu)_4N]_2[MoOS_3Cu_3X_3] (X = I,SCN) with Flexible Ditopic Ligands

摘要

In our working toward the rational design and synthesis of cluster-based suppramolecular architectures,a set of new [WS_4Cu_4]- or [MoOS_3Cu_3]-based supramolecular assemblies have been prepared from reactions of preformed cluster compounds [Et_4N]_4[WS_4Cu_4I_6] (1) and [(n-Bu)_4N]_2[MoOS_3Cu_3X_3] (2,X = I;3,X = SCN) with flexible ditopic ligands such as dipyridylsulfide (dps),dipyridyl disulfide (dpds),and their combinations with dicyanamide (dca) anion and 4,4'-bipy.The cluster precursor 1 reacted with dps or dpds and sodium dicyanamide (dca) in MeCN to produce [WS_4Cu_4I_2(dps)_3] centre dot 2MeCN (4 centre dot 2MeCN) and [WS_4Cu_4(dca)_2(dpds)_2] centre dot Et_2O centre dot 2MeCN (5 centre dot Et_2 O centre dot 2MeCN),respectively.On the other hand,treatment of 2 with dpds in DMF/MeCN afforded [MoOS_3Cu_3l(dpds)_2] centre dot 0.5DMF centre dot 2(MeCN)_(0.5) (6 centre dot 0.5DMF centre dot 2(MeCN)_(0.5)) while reaction of 3 with sodium dicyanamide (dca) and 4,4'-bipy in DMF/MeCN gave rise to [MoOS_3Cu_3(dca)(4,4'-bipy)_(1.5)] centre dot DMF centre dot MeCN (7 centre dot DMF centre dot MeCN).Compounds 4 centre dot 2MeCN,5 centre dot Et_2O centre dot 2MeCN,6 centre dot 0.5DMF centre dot 2(MeCN)_(0.5),and 7 centre dot DMF centre dot MeCN have been characterized by elemental analysis,IR spectroscopy,and single-crystal X-ray crystallography.Compound 4 contains a 2D layer array made of the saddle-shaped [WS_4Cu_4] cores interlinked by three pairs of Cu-dps-Cu bridges.Compound 5 has another 2D layer structure in which the [WS_4Cu_4] cores are held together by four pairs of Cu-dca-Cu and Cu-dpds-Cu bridges.Compound 6 displays a 1D spiral chain structure built of the nido-like [MoOS_3Cu_3] cores via two pairs of Cu-dpds-Cu bridges.Compound 7 consists of a 2D staircase network in which each [MoOS_3Cu_3(4,4'-bipy)]_2 dimeric unit interconnects with four other equivalent units by a pair of 4,4'-bipy ligands and two pairs of dca anions.The [WS_4Cu_4] core in 4 or 5 and the [MoS_3Cu_3] core in 7 show a planar 4-connecting node and a seesaw-shaped 4-connecting node,respectively,which are unprecedented in cluster-based supramolecular compounds.The successful assembly of 4-7 from the three cluster precursors 1-3 through flexible ditopic ligands provides new routes to the rational design and construction of complicated cluster-based supramolecular arrays.