Crystal structures and spectroscopic studies of the mononuclear complex [AgBr(PPh₃)₂] and binuclear [Ag₂X₂(PPh₃)₄]·2CHCl₃(X = Cl or Br)

Abstract

The structures of the silver([) complexes [AgBr(PPh,),] and [Ag,X2(PPh,),]*2CHCI, (X = CI or Br) have been determined by single-crystal X-ray diffraction. The complex [AgBr( PPh,),] crystallizes in the monoclinic space group C2/c and contains discrete monomeric [AgBr( PPh,),] units with essentially trigonal-planar AgBrP, co-ordination, and a crystallographic two-fold axis of symmetry coincident with

Silver Phosphanes Partnered with Carborane Monoanions: Synthesis, Structures and Use as Highly Active Lewis Acid Catalysts in a Hetero-Diels–Alder Reaction

“…These changes in the NMR spectrum on cooling are consonant with the presence of two different complexes in solution at low temperature, which interconvert at ambient temperature. The species that reveals the larger AgP coupling constant has a value very similar to that reported for twocoordinate [Ag(PPh 3 ) 2 ][BF 4 ] (J(AgP) 530 Hz), [14] while the alternative species has a coupling constant intermediate between the three-coordinate [Ag(PPh 3 ) 2 Br] (J(AgP) 385 Hz) [15] and four-coordinate [Ag(PPh 3 ) 4 ][PF 6 ] (J( 107 AgP) 224 Hz) [13] silver phosphane complexes. On the basis of these observations, we tentatively suggest that, at low temperature an approximate 1:1 mixture consisting of the twocoordinate, ion-pair separated, species [Ag(PPh 3 ) 2 ][CB 11 11 H 12 ] was seen in the low-temperature 31 P{ 1 H} NMR spectrum.…”

“…However, similar to 1, the packing diagram ( Figure 6) reveals a long interaction (3.4901(5) ä) between Ag(1) and Br(11)' on a symmetry related cage in the lattice; this bromine atom approaches Ag(1) approximately trans to Br(12) (Br(12) À Ag(1) À Br(11)' 157. 15 (1)8). Although this distance is long, the coordination motif around the silver suggests that it is significant in the solid state.…”

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

“…Addition of pyridine to this tetramer resulted in the formation of dimeric [{AgI(PCy 3 )} 2 Py] with bridging iodides and an unusual bridging pyridine in a 'crevice' co-ordination mode, weakly co-ordinated to both silver atoms [18] (Table 1). [48]. In contrast, the structure of the unsolvated 1:2 AgCl:PPh 3 complex reveals the presence of dimers, [Ag 2 Cl 2 (PPh 3 ) 4 ], containing bridging chloride and terminal PPh 3 ligands [46].…”

Di-μ-bromido-tris(triphenylphosphine)-1κP,2κ2P-disilver(I) tetrahydrofuran 0.85-solvate

“…Since the first tertiary phosphine silver (I) complexes of the type [AgXL n ] (L is tertiary phosphine; n is 1-4; X is a coordinating or noncoordinating anion) were prepared in 1937 by Mann et al (1937), many complexes have been obtained by the reaction of triphenylphosphine with an appropriate silver (I) salt (Whitcomb & Rajeswaram, 2006;Whitcomb & Roger, 1996;Teo et al, 1976;Bowmaker et al, 1993;Olmstead et al, 2004;Zhang et al, 2003;Lobana et al, 2008;Cingolani et al, 2003).…”

“…For general background on triphenylphosphinesilver(I) complexes, see: Whitcomb & Rajeswaram (2006); Whitcomb & Roger (1996); Mann et al (1937); Teo & Calabrese (1976); Bowmaker et al (1993); Olmstead et al (2004); Zhang et al (2003); Lobana et al (2008); Cingolani et al (2003). For the sensitization of photothermographic materials by coordination polymers formed by the reaction of triphenylphosphine with silver(I) salts, see : Freedman (1994).…”