Formation of new organometallic W/Cu/S clusters from reactions of [{(η5-C5Me5)WS3}3Cu7(MeCN)9](PF6)4 with donor ligands. Crystal structures and optical limiting properties of [(η5-C5Me5)WS3Cu3(Py)6](PF6)2, [(η5-C5Me5)WS3Cu3Br(PPh3)3](PF6), and [(η5-C5Me5)

Treatment of a preformed cluster {(η5-C5Me5)WS3}3Cu7(MeCN)9](PF6)4 (1) in MeCN with excess pyridine afforded a tetranuclear cationic cluster [(η5-C5Me5)WS3Cu3(Py)6](PF6)2 (2). On the other hand, reactions of 1 with excess PPh3 under the presence of LiBr gave rise to the other tetranuclear cationic cubane-type cluster [(η5-C5Me5)WS3Cu3Br(PPh3)3](PF6) (3) while analogous reactions of 1 with dppm and LiCl followed by addition of excess pyridine generated an intriguing pentanuclear cationic cluster [(η5-C5Me5)WS3Cu4(Py)Cl(dppm)2](PF6)2 (4). Compounds 2–4 were fully characterized by spectroscopy and X-ray crystallography. The cluster dication of 2 adopts an incomplete WS3Cu3 cubane-like structure while the cluster cation of 3 contains a WS3Cu3Br cubane-like structure. The structure of the cluster dication of 4 consists of an unique WS3Cu4Cl framework in which an open cubane-like WS3Cu3Cl fragment and a Cu(dppm)2 fragment are connected by one Cu–Cl bond and two Cu–dppm–Cu bridges. The optical limiting (OL) properties of the MeCN solutions of 1–4 were investigated with 7-ns laser pulses at 532 nm.