| Autor: |
Landrini M; Department of Chemistry, Biology and Biotechnology, University of Perugia and CIRCC, Via Elce di Sotto 8, 06123 Perugia, Italy., Patel R; School of Chemistry, University of East Anglia, Norwich Research Park, NR4 7TJ Norwich, U.K., Tyrrell-Thrower J; School of Chemistry, University of East Anglia, Norwich Research Park, NR4 7TJ Norwich, U.K., Macchioni A; Department of Chemistry, Biology and Biotechnology, University of Perugia and CIRCC, Via Elce di Sotto 8, 06123 Perugia, Italy., Hughes DL; School of Chemistry, University of East Anglia, Norwich Research Park, NR4 7TJ Norwich, U.K., Tensi L; Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy., Hrobárik P; Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Ilkovičova 6, SK-84215 Bratislava, Slovakia., Rocchigiani L; Department of Chemistry, Biology and Biotechnology, University of Perugia and CIRCC, Via Elce di Sotto 8, 06123 Perugia, Italy.; School of Chemistry, University of East Anglia, Norwich Research Park, NR4 7TJ Norwich, U.K. |
| Abstrakt: |
A diverse family of heterobimetallic bridging hydride adducts of the type [LAu(μ-H) 2 MCp 2 ][X] (L = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene, IPr; 1,3-bis(1-adamantyl)imidazole-2-ylidene, IAd; 1,3-bis(2,6-di- iso -propylphenyl)-5,5-dimethyl-4,6-diketopyrimidinyl-2-ylidene, Dipp DAC; triphenylphosphine, PPh 3 ; 2-di- tert -butylphosphino-2',4',6'-triisopropylbiphenyl, t Bu XPhos; X = SbF 6 - , BF 4 - or TfO - ) was synthesized by reacting group VI metallocene dihydrides Cp 2 MH 2 (Cp = cyclopentadienyl anion; M = Mo, W) with cationic gold(I) complexes [LAu(NCMe)][X]. Trimetallic [L'Au 2 (μ-H) 2 WCp 2 ][X] 2 and tetrametallic [L'Au 2 {(μ-H) 2 WCp 2 } 2 ] [X] 2 complexes (L' = rac -2,2'-bis(diphenylphosphino)-1,1'-binaphthalene or bis(diphenylphosphinomethane)) were obtained by reacting digold [L'{Au(NCMe)} 2 ][X] 2 with Cp 2 WH 2 in a 1:1 and a 1:2 stoichiometry. Accessing such a broad structural diversity allowed us to pinpoint roles played by the ancillary ligands and group VI metals on the bonding properties of this family of bridging hydrides. In particular, a clear effect of the ligand on the interaction energy and electronic structure was observed, with important implications on photolytic reactivity. UV or visible light irradiation, indeed, leads to the selective cleavage of the heterobimetallic Au(μ-H) 2 M arrangement and formation of molecular gold hydrides. The photolysis was found to be chromoselective (wavelength-dependent), which can be ascribed to different charge redistributions upon excitation to the first (Kasha's reactivity) and higher (anti-Kasha's reactivity) excited states. |
