Synthesis and spectroscopic characterization (IR, 1H and 31P NMR, electrospray ionization mass) of mono-, di-, tetra- and poly-meric complexes of silver(I) with diphosphine ligands: X-ray crystal structures of AgNO2:(Ph2PCH2PPh2) (1:1)2, AgNO2:(Ph2P(CH2)3PPh2) (1:1)2, AgNO2:(Ph2PCH=CHPPh2) (2:1)2 and AgNO2:{p-tolyl)2P(C10H6)2P(p-tolyl)2} (1:1).

Adducts of diphosphine ligands R2P(R′)nPR2 (dppm: R=Ph, R′=CH2, n=1; dppe: R=Ph, R′=CH2, n=2; dppp: R=Ph, R′= CH2, n=3; dppb: R=Ph, R′= CH2, n=4; dppf: R=Ph, R′=ferrocenyl, n=1; dppet: R=Ph, R′=CHCH, n=1; dcpm: R=cy, R′=CH2, n=1; S-Binap: R=Ph, R′= (S)-(+)-1,1-binaphthyl, n=1, n=2; (R-Tol-Binap: R=p-tolyl; R′=(R)-(+)-1,1-binaphthyl, n=1; (S,S-Diop: R=Ph, R′=(4S,5S-(+)-O-isopropylidene-2-3-dihydroxybutane, n=1) with silver(I) nitrite have been synthesized and characterized both in solution (1H, 31P NMR, ESI MS) and in the solid state (IR, single crystal X-ray structure analysis, 31P NMR). The topologies of the structures in the solid state were found to depend on the nature of the diphosphine and in some cases also on the stoichiometric ratio AgNO2:R2P(R′)nPR2. The adducts AgNO2:dppm (1:1)2 and AgNO2:dppp (1:1)2 are dimers, the role of dppm and dppp being to bridge two silver centers with each nitrite O,O′-chelating. The adduct AgNO2:dppet (2:1)2 is tetranuclear, derivative of the chair form, the bidentate ligands bridging central and peripheral silver centers, the nitrite being coordinated through both oxygens, the first unidentate, the second bridging bidentate. R-Tol-Binap forms a mononuclear 1:1 adduct, with the nitrite an O,O′-chelate.