Coordination Chemistry of Silver(I) with the Nitrogen-Bridged Ligands (C₆H₅)₂PN(H)P(C₆H₅)₂ and (C₆H₅)₂PN(CH₃)P(C₆H₅)₂:  The Effect of Alkylating the Nitrogen Bridge on Ligand Bridging versus Chelating Behavior

Abstract

The coordination chemistry of silver(I) with the nitrogen-bridged ligands (C(6)H(5))(2)PN(R)P(C(6)H(5))(2) [R = H (dppa); R = CH(3) (dppma)] has been investigated by (31)P NMR and electrospray mass spectrometry (ESMS). Species observed by (31)P 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)(+). (C(6)H(5))(2)PN(CH(3))P(C(6)H(5))(2) showed a strong tendency to chelate, while (C(6)H(5))(2)PN(H)P(C(6)H(5))(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)[(C(6)H(5))(2)PN(H)P(C(6)H(5))(2)](3))(BF(4))(2) has been determined. Bond distances include Ag-Ag = 2.812(1) A, Ag(1)-P(av) = 2.492(3) A, and Ag(2)-P(av) = 2.509(3) A. The compound crystallizes in the monoclinic space group Cc at 294 K, with a = 18.102(4)(o), Z = 4, V = 7261(3) A(3), R = 0.0503, and R(W) = 0.0670.

Coordination complexes of silver(I) with tertiary phosphine and related ligands

“…Polymeric structure of AgI with PPh 2 AsCH 2 AsPh 2 [156]. L 2 = PPh 2 NPPh 2 [194]. In addition a different structural type for the 3:2 L 2 :Ag stoichiometry was described for the long chain phosphine PPh 2 (CH 2 CH 2 O) 2 CH 2 CH 2 PPh 2 [166], two AgL 2 units being linked by the third phosphine.…”

Rhodium(I), Palladium(II) and Platinum(II) Coordination Chemistry of the Short‐Bite Chiral Ligands (Sc)‐N,N‐Bis(diphenylphosphanyl)‐sec‐butylamine, (Ra,Ra)‐N,N‐Bis(binaphthylphosphonito)phenylamine and (Ra,Sc)‐N‐(Diphenylphosphanyl)‐N‐(binaphthylphosphonito)‐sec‐butylamine

“…Literature reports indicate that the presence of an alkyl or aryl group on the nitrogen atom favours the formation of a four-membered strained ring when the ligand coordinates to a metal centre. [8] Reactions with Rhodium(i), Palladium(ii) and Platinum(ii) Substrates…”

Rhodium(I) carbonyl complexes of mono selenium functionalized bis(diphenylphosphino)methane and bis(diphenylphosphino)amine chelating ligands and their catalytic carbonylation activity

“…Metal complexes of functionalized phosphines particularly potential chelating ligands like phosphine-phosphine monochalcogenides with different backbones have attracted much attention in the recent time because of their structural novelty, reactivity and catalytic activity [1][2][3][4][5][6][7][8][9][10][11][12]. Presence of two different types of donor sites makes the chemistry of these ligands more fascinating as they can coordinate to the metal center in bidentate or monodentate way [13,14].…”