Synthesis and structures of cyclic gold complexes containing diphosphine ligands and luminescent properties of the high nuclearity species

Abstract

A mixture of cyclic gold(I) complexes [Au(2)(μ-cis-dppen)(2)]X(2) (X = OTf 1, PF(6)3) and [Au(cis-dppen)(2)]X (X = OTf 2, PF(6)4) is obtained from the reaction of [Au(tht)(2)]X (tht = tetrahydrothiophene) with one equivalent of cis-dppen [dppen = 1,2-bis(diphenylphosphino)ethylene]. The analogous reaction with trans-dppen or dppa [dppa = bis(diphenylphosphino)acetylene] affords the cyclic trinuclear [Au(3)(μ-trans-dppen)(3)]X(3) (X = OTf 11, PF(6)12) and tetranuclear [Au(4)(μ-dppa)(4)]X(4) (X = OTf 13, PF(6)14, ClO(4)15) gold complexes, respectively. Recrystallization of 15 from CH(2)Cl(2)/MeOH yielded a crystal of the octanuclear gold cluster [Au(8)Cl(2)(μ-dppa)(4)](ClO(4))(2)16. Attempts to prepare dicationic binuclear gold(II) species from the reaction of a mixture of 3 and 4 with halogens gave a mixture of products, the components of which confirmed to be acyclic binuclear gold(I) [Au(2)X(2)(cis-dppen)] (X = I 5, Br 7) and cyclic mononuclear gold(III) [AuX(2)(cis-dppen)]PF(6) (X = I 6, Br 8) complexes. Complexes 11-14 reveal weak emission in butyronitrile glass at 77 K, but they are non-emissive at room temperature. Ab initio modelling was performed to determine the charge state of the gold atoms involved. Extensive structural comparisons were made to experimental data to benchmark these calculations and rationalize the conformations.

Diphosphine-bridged digold(I) compounds: Structural and computational studies on the aurophilic interaction in Au2Cl2(μ-bpcd) and Au2Cl2(μ-bmi)

“…29,30 The formal oxidation state of each gold atom is +1, and the coordination geometry about each Au(I) center is nearly linearly with angles of 173.72(6) ° and 172.69(6)° found for the P(1)-Au(1)-Cl(1) and P(2)-Au(2)-Cl(2) linkages, respectively. The mean Au-P bond distance of 2.232 Å is similar to those Au-P distances in the diphosphine-bridged compounds Au 2 Cl 2 (-bma), 5 Au 2 I 2 (-dppen), 31 and Au 2 Cl 2 (-dppbz). 32 The torsion angles for the P(1)-Au(1)-Au(2)-P(2) and…”

“…1 H NMR (CDCl 3 ):  3.18 (s, CH 2 ), 7.40 (t, 8H, meta aryl, J = 7.4 Hz), 7.52 (t, 4H, para aryl, J = 7.4 Hz), 7.64 (m, 8H, ortho aryl). 31…”

Phosphine-Coordinated Pure-Gold Clusters: Diverse Geometrical Structures and Unique Optical Properties/Responses

“…On the other hand, the core-to-exo distances are in the range 2.970 -3.072 Å, which are markedly longer than Au-Au distance in the bitetrahedral core (2.648 -2.872 Å). Other Au 6 +2Au type clusters (12 and 13) were reported recently [91,96], which show almost similar structural parameters (Table 4).…”

Influence of ancillary ligands on the photophysical properties of cyclometalated organoplatinum(ii) complexes

“…The composition of the molecular orbitals and theoretical absorption spectra were plotted using the Chemissian program. 22,23 The NBO analyses were carried out on the stationary points using the NBO 3.1 program 24 as implemented in the Gaussian 03 program suite.…”