316802-95-6Relevant academic research and scientific papers
A gold(I) mononuclear complex and its association into binuclear and cluster compounds by hydrogen bonding or metal ion coordination
Hao,Mansour,Lachicotte,Gysling,Eisenberg
, p. 5520 - 5529 (2008/10/08)
The mononuclear Au(I) complex, Au(Spy)(PPh2py) (1), has been synthesized and characterized structurally. The complex possesses the expected linear coordination geometry with a S-Au-P bond angle of 176.03(6)° and no evidence of aurophilic interactions between nearest neighbor Au(I) ions in the solid state. Protonation of the pendant pyridyl groups of 1 leads to the formation of the H-bonded dimer [{Au(SpyH)(PPh2py)}2](PF6)2 (2), which has also been structurally characterized. A linear coordination geometry at the Au(I) ions in 2 with a S-Au-P bond angle of 173.7(2)° is augmented by evidence of a strong aurophilic interaction with a Au···Au distance of 2.979(1) A. The pendant pyridyl groups of 1 have also been used to bind Cu(I) by reactions with [Cu(NCMe)4](PF6) and Cu(P(p-tolyl)3)2(NO3) leading to the formation of the heterobimetallic complexes [{AuCu-(μ-Spy)(μ-PPh2py)}2] (PF6)2 (3) and [AuCu(P(p-tolyl)3)2(μ-Spy) (μ-PPh2py)](NO3) (4), respectively. A structure determination of 3 reveals a tetranuclear complex composed of two AuCu(μ-Spy)(μ-PPh2py)+ units held together by bridging thiolate ligands. A strong metal-metal interaction is noted between the two different d10 ions with nearest Au-Cu distances averaging 2.6395 A. The S-Au-P bond angles in 3 deviate slightly from linearity due to the Au···Cu interactions, while the coordination geometries at Cu(I) are distorted tetrahedral consisting of the two pyridyl nitrogen atoms, a bridging thiolate sulfur, and the interacting Au(I) ion. While mononuclear complex 1 is only weakly emissive in the solid state and in fluid solution, complexes 2-4 show stronger photoluminescence in the solid state and rigid media at 77 K, and in fluid solution. The emission maxima for 2-4 in ambient temperature fluid solution are 470, 635, and 510 nm, respectively. A tentative assignment of the emitting state as a S(pπ) → Au LMCT transition is made on the basis of previous studies of Au(I) thiolate phosphine complexes. Shifts of λem result from the influence of H bonding or Cu(I) coordination on the filled thiolate orbital energy, or on the effect of metal-metal interaction on the Au(I) acceptor orbital energy. Crystal data for Au(Spy)(PPh2py) (1): triclinic, space group P1 (No. 2), with a = 8.3975(4) A, b = 11.0237(5) A, c = 12.4105(6) A, α = 98.6740(10)°, β = 105.3540(10)°, γ = 110.9620(10)°, V = 995.33(8) A3, Z = 2, R1 = 3.66% (I > 2σ(I)), wR2 = 9.04% (I > 2σ(I)) for 2617 unique reflections. Crystal data for [{Au(SpyH)(PPh2py)}2](PF6)2 (2): triclinic, space group P1 (No. 2), with a = 14.0284(3) A, b = 14.1093(3) A, c = 15.7027(2) A, α = 97.1870(10)°, β = 96.5310(10)°, γ = 117.1420(10)°, V = 2692.21(9) A3, Z = 2, R1 = 7.72% (I > 2σ(I)), wR2 = 15.34% (I > 2σ(I) for 5596 unique reflections. Crystal data for [{AuCu(μ-Spy)(μ-PPh2py)}2] (PF6)2 (3): monoclinic, space group P21/c (No. 14), with a = 19.6388(6) A, b = 16.3788(4) A, c = 17.2294(5) A, β = 91.48°, V = 5540.2(3) A3, Z = 4, R1 = 3.99% (I > 2σ(I)), wR2 = 8.38% (I > 2σ(I)) for 10597 unique reflections.
