Mononuclear copper(I) and binuclear silver(I) complexes of SPPh3 ligand: Synthesis, crystal structure, properties

Ferrocenyl Dithiophosphonate Ag(I) Complexes: Synthesis, Structures, Luminescence, and Electrocatalytic Water Splitting Tuned by Nuclearity and Ligands

The heterometallic [Ag(I)/Fe(II)] molecular electrocatalysts for hydrogen production were introduced here to recognize the mutual role of metallic nuclearity and ligand engineering. A series of ferrocenyl dithiophosphonate stabilized mononuclear [Ag(PPh3)2{S2PFc(OR)}] {where R=Me (1), Et (2), nPr (3), iPr (4), iAmyl (5); Fc=Fe (ɳ5-C5H4) (ɳ5-C5H5)} and dinuclear [Ag(PPh3){S2PFc(OR}]2 {where R=Et (2 a), and nPr (3 a)} complexes were synthesized and characterized by SCXRD, NMR (31P and 1H), ESI-MS, UV-Vis, and FT-IR spectroscopy. The comparative electrocatalytic HER behavior of 1-5 and 2 a-3 a showed effective current density of 1 mA/cm2 with overpotentials ranging from 772 to 991 mV, demonstrating the influence of extended and branched carbon chains in dithiophosphonates and metallic (mono-/di-) nuclearity, which correlates with documented tetra-nuclear [Ag4(S2PFc(OnPr)4], 6. DFT study suggests the coordinated (μ1-S) site of ligands is the reactivity center and the adsorption energy of intermediate [H*-SM] varies with the engineering of ligand and nuclearity. A catalytic mechanism using mononuclear (1) and di-nuclear (2 a) was proposed with the assistance of DFT. Each complex, being the first example of Ag(I) dithiophosphonates, exhibits intense photoluminescence with high quantum yields ranging from 33 % to 67 %. These results link the lower nuclearity structures to their physical and catalytic properties.

New cationic coinage metal complexes featuring silyl group functionalized phosphine: syntheses, structures and catalytic studies in alkyne-azide cycloaddition reactions

A series of coinage metal complexes bearing rarely explored ortho-silylated phosphine is reported. The treatment of diphenyl(2-(trimethylsilyl)phenyl)phosphine (1) with CuCl and [Cu(CH3CN)4]BF4 furnished the corresponding neutral [(1)CuCl]2 (2) and mono-cationic [(1)2Cu(CH3CN)]BF4 (3) complexes, respectively. The reactions of 1 with AgX (X = BF4-, NO3-) in 2 : 1 ratio furnished the corresponding mono cationic dicoordinate silver(I) complexes of the type [(1)2Ag]X (X = BF4- (4a), NO3- (4b)). The ortho-silylated phosphine ligand (1) was conveniently converted into the corresponding sulfide (5a) and selenide (5b) species, and their reactions with [Cu(CH3CN)4]BF4 yielded mono-cationic, homoleptic tris(silylphosphinochalcogenide)copper(I) complexes of the type [(5a/5b)3Cu]BF4 (6a/6b). The molecular structures of 2-4 and 6 were established by single-crystal X-ray diffraction analysis. The copper complexes 2, 3, and 6a were employed as catalysts in azide-alkyne cycloaddition reactions. Among these complexes, 3 was extensively used in the preparation of various mono- and bis-triazoles consisting of tolyl, benzyl, carbazolyl, and propargylic ether groups. Three sets of substituted triazole derivatives were achieved under mild conditions by employing copper(I) catalytic systems. The mechanistic studies indicated the formation of a heteroleptic copper(I) triazolide intermediate which was detected by high-resolution mass spectral analysis.