Anionic Gold(I) Complexes—Twelve‐ and Ten‐Vertex Monocarba‐closo‐borate Anions with Carbon–Gold σ Bonds

Abstract

The anionic gold(I) complexes [1-(Ph(3)PAu)-closo-1-CB(11)H(11)](-) (1), [1-(Ph(3)PAu)-closo-1-CB(9)H(9)](-) (2), and [2-(Ph(3)PAu)-closo-2-CB(9)H(9)](-) (3) with gold-carbon 2c-2e sigma bonds have been prepared from [AuCl(PPh(3))] and the respective carba-closo-borate dianion. The anions have been isolated as their Cs(+) salts and the corresponding [Et(4)N](+) salts were obtained by salt metathesis reactions. The salt Cs-3 isomerizes in the solid state and in solution at elevated temperatures to Cs-2 with DeltaH(iso)=(-75+/-5) kJ mol(-1) (solid state) and DeltaH( not equal)=(118+/-10) kJ mol(-1) (solution). The compounds were characterized by vibrational and multi-NMR spectroscopies, mass spectrometry, elemental analysis, and differential scanning calorimetry. The crystal structures of [Et(4)N]-1, [Et(4)N]-2, and [Et(4)N]-3 were determined. The bonding parameters, NMR chemical shifts, and the isomerization enthalpy of Cs-3 to Cs-2 are compared to theoretical data.

Germa‐closo‐dodecaborate: An Ambident and Flexible Coordinating Ligand

“…Red crystals of the acetonitrile adduct 1 could be obtained after several days by carefully layering a solution of an equimolar mixture of FeBr 2 and triphos in acetonitrile with a solution of one equivalent [Bu 3 MeN] 2 [GeB 11 H 11 ] in the same amount of acetonitrile. The zwitterionic complex crystallizes in the orthorhombic space group P2 1 2 1 2 1 with four molecules of acetonitrile in the asymmetric unit.…”

“…ac.uk/data_request/cif. 3 -{Ru(triphos)}-GeB 11 H 11 ] (4): A suspension of 2 (0.05 mmol, 50 mg) in acetone (30 mL) was heated under reflux for several days. The reaction mixture turned yellow and the unreacted starting material was filtered off the yellow solution.…”

“…Elemental analyses were performed by the Institut für Anorganische Chemie Universität Tübingen with a Vario EL analyzer and a Vario MICRO EL analyzer. The starting material [Ru 2 (μ-Cl) 3 (triphos) 2 ]Cl was synthesized by the published method. [19] [Bu 3 MeN] 2 [GeB 11 H 11 ] was synthesized by a modified protocol of the work of Todd et al [20] All further chemicals used were purchased commercially and were not further purified.…”

“…Whereas the carbon-containing borate cluster is known to behave as a weakly coordinating anion in the protonated form [CB 11 H 12 ] -, [2] the deprotonated cluster [CB 11 H 11 ] 2-and the higher homologues [EB 11 H 11 ] 2-(E = Ge, Sn) serve as versatile ligands in coordination chemistry. [3,4] It has been shown that the dianions [SnB 11 H 11 ] 2-and [GeB 11 H 11 ] 2-act as σ and π donors with a strong trans influence; they readily undergo substitution of halides to form stable complexes containing metal-germanium and metal-tin bonds, respectively. [5][6][7][8] These heteroborates can be regarded as a strong-donating germylene or stannylene.…”

Carba‐closo‐dodecaborate Anions with Cluster Carbon–Phosphorous Bonds

“…[3] Especially for the cluster carbon atom the selective functionalization is well developed and a number of different substituents have been introduced. [1,[4][5][6] This includes the synthesis of derivatives with different substituents at the boron atoms, e.g. [1-R-closo-1-CB 11 X 11 ] -(R = functional group; X = H, Hal, alkyl), [5,[7][8][9][10][11][12][13][14][15][16][17] as well.…”