The coordination chemistry of silver(l) with the nitrogen-bridged ligands (C6H5)(2)PN(R)P(C6H5)(2) [R = H (dppa); R = CH3 (dppma)] has been investigated by P-31 NMR and electrospray mass spectrometry (ESMS). Species observed by P-31 NMR include Ag-2(mu-dppa)(2+), Ag-2(mu-dppa)(2)(2+), Ag-2(mu-dppa)(3)(2+), Ag-2(mu-dppma)(2+), Ag-2(mu-dppma)(2)(2+), and Ag-(eta(2)-dppma)(2)(+), Species observed by ESMS at low cone voltages were Ag-2(dppa)(2)(2+), Ag-2(dppa)(3)(2+), Ag-2(dppma)(2)(2+), and Ag(dppma)(2)(+). (C6H5)(2)PN(CH3)P(C6H5)(2) showed a strong tendency to chelate, while (C6H5)(2)PN(H)P(C6H5)(2) preferred to bridge. Differences in the bridging versus chelating behavior of the ligands are assigned to the Thorpe-Ingold effect, where the methyl group on nitrogen sterically interacts with the phenyl groups on phosphorus. The crystal structure of the three-coordinate dinuclear silver(I) complex {Ag-2[(C6H5)(2)PN(H)P(C6H5)(2)](3)}(BF4)(2) has been determined. Bond distances include Ag-Ag = 2.812(1) Angstrom, Ag(1)-P(av) = 2,492(3) Angstrom, and Ag(2)-P(av) 2.509-(3) Angstrom . The compound crystallizes in the monoclinic space group Cc at 294 K, with a = 18.102(4)degrees, Z = 4, V 7261(3) Angstrom(3), R = 0.0503, and R-W = 0.0670.