Synthesis and Catalytic Use of Gold(I) Complexes Containing a Hemilabile Phosphanylferrocene Nitrile Donor

Abstract

Removal of the chloride ligand from [AuCl(1-κP)] (2) containing a P-monodentate 1'-(diphenylphosphanyl)-1-cyanoferrocene ligand (1), by using silver(I) salts affords cationic complexes of the type [Au(1)]X, which exist either as cyclic dimers [Au(1)]2 X2 (3 a, X=SbF6 ; 3 c, X=NTf2 ) or linear coordination polymers [Au(1)]n Xn (3 a', X=SbF6 ; 3 b', X=ClO4 ), depending on anion X and the isolation procedure. As demonstrated for 3 a', the polymers can be readily cleaved by the addition of donors, such as Cl(-) , tetrahydrothiophene (tht) or 1, giving rise to the parent compound 2, [Au(tht)(1-κP)][SbF6 ] (5 a) or [Au(1-κP)2 ][SbF6 ] (4 a), respectively, of which the last two compounds can also be prepared by stepwise replacement of tht in [Au(1-κP)2 ][SbF6 ]. The particular combination of a firmly coordinated (phosphane) and a dissociable (nitrile) donor moieties renders complexes 3/3' attractive for catalysis because they can serve as shelf-stable precursors of coordinatively unsaturated Au(I) fragments, analogous to those that result from the widely used [Au(PR3 )(RCN)]X catalysts. The catalytic properties of the Au-1 complexes were evaluated in model annulation reactions, such as the synthesis of 2,3-dimethylfuran from (Z)-3-methylpent-2-en-4-yn-1-ol and oxidative cyclisation of alkynes with nitriles to produce 2,5-disubstituted 1,3-oxazoles. Of the compounds tested (2, 3 a', 3 b', 3 a, 4 a and 5 a), the best results were consistently achieved with dimer 3 c, which has good solubility in organic solvents and only one firmly bound donor at the gold atom. This compound was advantageously used in the key steps of annuloline and rosefuran syntheses.

Adjustable coordination of a hybrid phosphine–phosphine oxide ligand in luminescent Cu, Ag and Au complexes

“…Yield 73 mg, 81%. 31 General procedure of AgXP 3 (X = Cl, Br, I) complexes (14)(15)(16) AgPF 6 (25.3 mg, 0.1 mmol) was dissolved in acetone (5 ml) and a solution of the corresponding tetrabutyl ammonium halide NBu 4 X (0.1 mmol) in dichloromethane (10 ml) was added. The suspension was stirred for 10 min in the absence of light.…”

“…AgClP 3 (14). Colorless crystalline material (57.2 mg, 74% (16). Colorless crystalline material (73.7 mg, 85.0%).…”

“…2,3,10,11 The corresponding P-N (phosphine-amine/oxazoline/nitrile) and P-O (phosphineether/phosphine oxide) complexes of Ni, Pd, Co, Au, and Cu demonstrate impressive catalytic activity in many industrially important reactions, e.g. olefin oligo-and polymerization (including ring opening metathesis polymerization), 12 amination, 13,14 hydrogenation, 15 annulation, 16 hydroformylation, 17 allylation, 18 Suzuki 3,19 and Heck 20 coupling.…”

Group 11 Metal Complexes with Unsymmetrical Bifunctional Ferrocene Ligands

“…These functionalized ferrocene derivatives and their metal complexes represent an important topic of research in many fields such as organic synthesis, catalysis, asymmetric catalysis, materials chemistry, and in medicine as antimalarial or antitumor agents. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In particular, ferrocenyl phosphines have been studied thoroughly, as represented by the well-known 1,1′-bis(diphenylphosphino)ferrocene (dppf ). [1] Some of us have described the formation of several amidephosphines containing ferrocene units, studied their coordination chemistry, [17,18] and also showed that some gold and silver complexes are active as antitumor agents.…”

Catalytic ring-closing reactions of gold compounds containing bis(phosphino)ferrocene ligands

“…The catalytic ring closing of (Z)-3-methylpent-2-en-4-yn-1-ol was examined using 1ʹ-(diphenylphosphino)-1-cyanoferrocene gold chloride [(C5H4CN)Fe(C5H4PPh2AuCl)] as the catalyst. [20] Ring closing was accomplished in 65% conversion when [(C5H4CN)Fe(C5H4PPh2AuCl)] was used as the catalyst and rose to >97% when the chloride ligand of [(C5H4CN)Fe(C5H4PPh2AuCl)] was abstracted with a silver salt.…”