Silver coordination chemistry of a new versatile "Janus"-type N2,O2-bichelating donor, formation of an unprecedented supramolecular network of binuclear silver building blocks containing a five-coordinate β-diketonate, and isolation of unexpected silver-tin-silversilver heterotrimetallic complexes from silver metathesis reactions

Synthetic, spectroscopic, and single-crystal X-ray studies are reported for several complexes of silver(I) with the N2,O2-bichelating Qpy ligand (HQpy = 1-(2-pyridyl)-3-methyl-4-trifluoroacetylpyrazol-5-one). Direct interaction between HQpy and AgNO3 in methanol, in the presence of NaOCH3, affords derivative Ag(Qpy), showing a polynuclear structure composed of dinuclear building blocks with two different Ag environments and two Qpy donors differently connected. By adding neutral ligands such as PR3 (R = Ph, Cy, C6H4-o-CH3, C6H4-p-F, Bui) to Ag(Qpy), dinuclear Ag(Qpy)(PR3) derivatives have been isolated, containing bridging N2,O-exotridentate Qpy donors spanning a pair of AgPR3 moieties. Reaction of Ag(Qpy)(PPh3) with excess PPh3 produces the mononuclear Ag(Qpy)(PPh3)2 containing N2-chelate Qpy. Ag(Qpy) interacts with 1,2-bis(diphenylphosphino)ethane (dppe) yielding the derivative Ag(Qpy)(dppe), having a polynuclear structure in the solid state which is seemingly disrupted in solution, with the formation of two new species, a mononuclear neutral compound and a dinuclear ionic one. By the interaction of Ag(Qpy) with nitrogen donors L (L = imidazole (imH), 1-methylimidazole (Meim), 1-methyl-2-mercaptoimidazole (Hmimt), 1,10-phenanthroline (phen)), mononuclear species Ag(Qpy)(L) have been obtained, where Qpy is coordinated to silver in N2-chelating mode. Ag(Qpy)(PPh3)2 reacts with SnRCl3 (R = Ph, Bun) affording heterotrimetallic [{(Ph3P)2AgCl}2SnRCl3] derivatives.