Reaction of AgBr with TabHPF6 (TabH = 4-(trimethylammonio)benzenethiol) readily produces a unique one-dimensional coordination polymer [(TabH)(AgBr2)]n (1), consisting of anionic chains [AgBr2]nn– with hydrogen bonds to TabH+ cations. By examining its electrical resistance and stability upon exposure to ammonia and seven common organic amines in water under ambient conditions, compound 1 is found to exhibit good stability and reproducibly high sensitivity toward these analytes at low concentrations. Especially, it can selectively detect NH3 in water with the detection limit as low as 0.05 ppm. This chemiresistive sensing system has the potential for highly efficient monitoring of ammonia and amines responsible for water pollution, eutrophication, food contamination, and industrial hazards.

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.Three new W/Cu/S clusters [(η5-C5Me5)WS3Cu3(Py)6](PF6)2, [(η5-C5Me5)WS3Cu3Br(PPh3)3](PF6), and [(η5-C5Me5)WS3Cu4(Py)Cl(dppm)2](PF6)2 were prepared from reactions of [{(η5-C5Me5)WS3}3Cu7(MeCN)9](PF6)4 with pyridine, PPh3 and dppm. The structures of the three compounds were characterized by X-ray crystallography and their optical limiting properties in solution were studied.