87884-07-9Relevant academic research and scientific papers
Ligation of phosphorus ligands to silver (I). 1. Coordination of one to four P(NR2)3 ligands and the structure of a nonlinear two-coordinate complex
Socol,Jacobson,Verkade
, p. 88 - 94 (2008/10/08)
The ligation properties of three aminophosphine ligands, P(NMe2)3 (1), P(NMeCH2)3CMe (2), and P(NCH2CH2)3 (3), toward Ag(I) have been investigated. Reaction of 1 with silver salts yields the isolable ionic complexes [Ag(1)2]BPh4 and [Ag(1)3]BPh4 and neutral complexes of the type Ag(1)2X (X = Cl, Br, I, CN). Reaction of excess 2 with AgBF4 also resulted in the formation of an ionic three-coordinate complex. The substantial steric requirement of 1 and 2 appears to preclude the formation of stable four-coordinate complexes. In contrast, the smaller ligand 3 readily forms isolable four-coordinate complexes of the type [Ag(3)4]X, where X = BF4, Cl, I. Addition of three successive molar equivalents of 2 or 3 to solutions of AgBF4 at -95°C allowed observation of [AgL2,3]BF4 in their 31P NMR spectra. Evidence is presented suggesting that the 1:1 complexes are better formulated as weak or nonconducting [Ag(L)BF4] species. On the other hand, addition of 1 to solutions of AgBF4 at -95°C allowed observation of [Ag(1)1-4]BF4 in the 31P NMR spectra. Addition of a fourth equivalent of 1 or 2 to the corresponding three-coordinate cations gave NMR results consistent with ligand exchange as did addition of ligand to [Ag(1)2X] (X = Cl, CN, NO3), but addition of a fourth equivalent of 3 to [Ag(3)3]BF4 gave [Ag(3)4]BF4. At room temperature these complexes appear to undergo rapid ligand exchange. X-ray crystallographic studies of [Ag(1)2]BPh4 reveal a monoclinic space group P21/c with a = 11.975 (3) A?, b = 17.325 (3) A?, c = 20.079 (5) A?, and β = 107.08 (3)°. Both ligands were found to be in an approximate Cs configuration with a Ag-P distance of 2.394 (3) A? and P-Ag-P angle of 167°.
