Structural variations and spectroscopic properties of luminescent mono- and multinuclear silver(I) and copper(I) complexes bearing phosphine and cyanide ligands

Reaction of equimolar amounts of AgCN and PCY3 gave the polymer [(CY3P)Ag(NCAgCN)]infinity (1), whereas employment of excess PCY3 yielded the discrete compound (CY3P)(2)Ag(NCAgCN] (2). Reacting bis(dicyclohexylphosphino)methane (dcpm) with AgCN in 1:1 and 1:2 molar ratios gave two crystalline forms, namely [Ag-2(mu-dcpm)(2)][Ag(CN)(2)](2).(CH3OH)2 (3a.(CH3OH)(2)) and [Ag-2(mu-dcpm)(2)}[Ag(CN)(2)}(2) (3b), respectively. The similar reaction of CuCN with PCY3 afforded the polymeric compound [{(Cy3P)CU(CN)}(3)](infinity) (4), whereas treatment of CuCN with dcpm gave [CU2(mu-dcpm)(2)(CN)(2)] (5). Employment of diphosphine ligands with longer -(CH2)(n-)), spacers, such as 1,2-bis-(dicyclohexylphosphino)ethane (dcpe, n = 2) and 1,3-bis(diphenylphosphino)propane (dppp, n = 3), in reactions with [Cu(CH3CN)(4)]PF6 and KCN afforded the macrocylic compounds [{Cu(dcpe)12(CN)(mu-dcpe)]PF6 (6(PF6)) and [{Cu(dppp)13(CN)2(mu-dppp)]PF6 (7(PF6)), respectively. The hexanuclear complex [Cu(CN)(PCY3)16 (8) was obtained by reacting CuCN with PCY3 in the presence of sodium pyridine-2-thiolate. The UV-vis absorption spectrum of 1 in acetonitrile displays a weak shoulder at 245 nm (c = 350 dm(3) Mol(-1) cm(-1)). For 3a, 3b, and 5, the intense absorption bands at,lambda(max) = 257-276 nm with 6 values of (1.73-1.80) x 104 d m(3) mol(-1) cm-1 are assigned to [nda* - (n + 1)psigma] transitions. Complexes 3a and 3b emit at lambda(max) = 365 nm in CH3CN (quantum yield similar to6 x 10(-3), lifetime similar to0.2 us). The solid-state emission of 5 lambda(max), = 470 and 488 nrn at 298 and 77 K) is red-shifted in energy from that of 4 (),m, = 401 and 405 nm at 298 and 77 K, respectively). In 77 K MeOH/EtOH (1:4) glassy solution, complexes 4-8 display intense emission with) lambda(max) at 382-416 nm, which is assigned to the [3d - (4s, 4p)] triplet excited state.