Design and Synthesis of Polytopic Metalloligands Based on Fluoroaryl Gold(I) Organometallic Compounds

• Published in: Organometallics 2011-06, Vol.30 (12), p.3419-3429
• Main Authors: Ferrer, Montserrat, Gutiérrez, Albert, Mounir, Mounia, Rodríguez, Laura, Rossell, Oriol, Font-Bardia, Mercè, Gómez-Sal, Pilar, Martín, Avelino, Solans, Xavier
• Format: Article
• Language: English
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om200318c

New neutral and anionic fluoroaryl gold(I) complexes featuring terminal pyridine rings were prepared following different strategies. The homoleptic anionic compounds NBu4[Au(C5F4N)2] (1) and NBu4[Au(C6F4py)2] (2) were obtained by reacting [AuCl(tht)] (tht = tetrahydrothiophene) with the organolithium derivatives of BrC5F4N and BrC6F4py, respectively. This route required the previous synthesis of the new fluorinated compound BrC6F4py, which was produced by a Stille cross-coupling between (4-pyridyl)trimethylstannane and 1,4-dibromotetrafluorobenzene. The neutral phosphane compounds [Au(C6F4N)(PPh3)] (3) and [Au(C6F4py)(PPh3)] (4) were obtained by treatment of [AuCl(PPh3)] with the organolithium reagents LiC6F4N and LiC6F4py, respectively. However, this synthetic strategy failed for organogold compounds containing a polyphosphane ligand. Consequently, an alternative synthetic procedure, based on displacement reactions of the weakly coordinated tht ligand from [Au(C6F4py)(tht)] by the appropriate polyphosphane, was undertaken. Thus, the following complexes were isolated and characterized: [(AuC6F4py)2(μ2-diphosphane)] [diphosphane = bis(diphenylphosphanyl)methane (dppm) (9), 2,2-bis(diphenylphosphanyl)propane (dppip) (10), 1,2-bis(diphenylphosphanyl)ethane (dppe) (11), trans-1,2-bis(diphenylphosphanyl)ethylene (dppet) (12), 1,2-bis(diphenylphosphanyl)acetylene (dppa) (13), 1,3-bis(diphenylphosphanyl)propane (dppp) (14), 1,4-bis(diphenylphosphanyl)butane (dppb) (15), 4,4′-bis(diphenylphosphanyl)-1,1′-biphenyl (dppdph) (16)], [(AuC6F4py)3(μ3-triphosphane)] [triphosphane = 1,1,1-tris(diphenylphosphanylmethyl)ethane (triphos) (17), 1,3,5-tris(diphenylphosphanyl)benzene (triphosph) (18)], and [(AuC6F4py)4(μ4-tetraphosphane)] [tetraphosphane = tetra(diphenylphosphanyl)methane (tetraphos) (19), 1,2,3,5-tetra(diphenylphosphanyl)benzene (tetraphosph) (20)]. Coordination reaction assays of compounds 1, 2, 3, and 4 with [M(diphosphane)(H2O)2](OTf)2 (M = Pd, Pt) were performed in order to test their potential as building blocks in the self-assembly of discrete species. The crystal structures of compounds BrC6F4py, 1, 4, 17, and 19 were determined. Extensive noncovalent interations, particularly fluorine interactions such as C–F···πF, C–F···H, and F···F, have been found to influence the molecular packing of these species.