Cyclic Trinuclear Gold(I) Clusters with N,N and Unusual C,C Mixed-Ligand Bridges.

Three crystalline trinuclear gold(I) clusters, [Au3f2y] (1), [Au3fy2] (2), and [Au3y3] (3), where f = N,N'-bis(2,6-dimethylphenyl)methanimidamidate and y = dimethylendiphenylphosphinate, exhibit bridges from the N,N-formamidinate and/or from the ylide anion ligand whose P-methylene groups chelate in an unusual fashion, where the chelate CPC unit is perpendicular to the trigonal plane of the metal atoms. Assemblies 1 and 2 are the first gold(I) trinuclear clusters featuring mixed-ligand bridges from different N,N and C,C donors; 3 is a previously unknown homoleptic ylide anion cyclic trinuclear assembly. Formamidinate bridges in 1 and 2 connect gold(I) atoms at aurophilic distances of 3.084(2) and 3.0543(4) Å, whereas an out-of-plane (perpendicular) P-ylide anion bite produces AuI-AuI distances of as large as 3.900(2) Å in 3. The crystal space groups for 1 and 2 are triclinic P1̅ and that for 3 is monoclinic P21/c, with Z = 2 for 1 and 2 and Z = 4 for 3. Compounds are synthesized under Schlenk conditions at -20 °C in toluene by reacting the proper ratios of the gold(I) formamidinate [Au2f2] with the phosphorus ylide [Hy] under basic conditions (KOH), followed by extraction with ether. This synthesis also produces a dinuclear cation, [Au2f(Hy)2]+, previously reported by our group. A neutral mixed-ligand dinuclear complex, [Au2fy], was not observed. Under UV light, 1 and 2 display a bright-green luminescence at room temperature and in frozen methyltetrahydrofuran solutions under liquid nitrogen, with microsecond lifetimes. All three complexes 1-3 are characterized by their X-ray crystal structures, 1H NMR, IR, UV-visible, and luminescence spectroscopies, and elemental analysis.

Multinuclear copper(I) and silver(I) amidinate complexes: synthesis, luminescence, and CS2 insertion reactivity.

Dinuclear Cu(I) and Ag(I) complexes, Cu2[(2,6-Me2C6H3N)2C(H)]2, 1, Ag2[(2,6-Me2C6H3N)2C(H)]2, 2, Cu2[2,6-(i)Pr2C6H3N)2C(H)]2, 3, and Ag2[(2,6-(i)Pr2C6H3N)2C(H)]2, 4, were synthesized from reactions of [Cu(NCCH3)4][PF6] with Na[(2,6-R2C6H3N)2C(H)] and AgO2CCH3 with [Et3NH][(2,6-R2C6H3N2C(H)], R = Me, (i)Pr. Carbon disulfide was observed to insert into the metal-nitrogen bonds of 1 to produce Cu4[CS2(2,6-Me2C6H3NC(H)═NC6H3Me2)]4, 5, with a Cu4S8 core, which represents a rare transformation of dinuclear to tetranuclear species. Insertion is also observed with 2 and CS2, with the product likely being polymeric, 6. With the (i)Pr-derivatives, CS2 insertion was also observed, albeit at much slower rate, with 3 and 4 producing hexanuclear clusters, M6[CS2(2,6-Me2C6H3NC(H)═NC6H3Me2)]6, M = Cu, 7; Ag, 8. Complexes 1 and 5 display green luminescence, a feature not shared by their Ag(I) analogs nor with 3. Notably, oxygen acts as a collisional quencher of the luminescence from 1 and 5 at a rate faster than most metal-based quenchometric O2 sensors. For example, we find that complex 1 can be rapidly and reversibly quenched by oxygen, presenting a nearly 6-fold drop in intensity upon switching from nitrogen to an aerated atmosphere. The results here provide a platform from which further group 11 amidinate reactivity can be explored.

Fine-tuning the luminescence and HOMO-LUMO energy levels in tetranuclear gold(I) fluorinated amidinate complexes.

Tetranuclear gold(I) fluorinated amidinate complexes have been synthesized and their photophysical properties and structures described. DFT calculations were carried out to illustrate how a minor change in the ligand resulted in a loss of emission in the perfluorophenyl amidinate complex compared with nonfluorinated phenyl amidinate complexes reported previously. The fluorinated complexes reported here [Au(ArN)(2)C(H)](4) (1, Ar = 4-FC(6)H(4); 2, 3,5-F(2)C(6)H(3); 3, 2,4,6-F(3)C(6)H(2); 4, 2,3,5,6-F(4)C(6)H) emit in the blue-green region at 470, 1, 478, 2, 508, 3, and 450 nm, 4, by excitation at ca. 375 nm at room temperature with nanosecond lifetimes. The emissions observed at 77 K in the solid state show structured emission for complexes 1 and 2, with a vibrational spacing of ca. 1200 and 1500 cm(-1), corresponding to the vibrational modes of the amidinate ligand. The pentafluorophenyl derivative 5, Ar = C(6)F(5,) shows no photoluminescence in the solid state nor in the solution. This result is different from results in which the pentafluorophenyl group is attached to a phenylpyridine ligand in an Ir(III) complex and other organics. This quenching appears to be related to a nonradiative de-excitation process caused by the ππ*-πσ* crossover in the excited state of the pentafluorophenyl amidinate ligand. With increasing numbers of fluorine atoms, there is a progressive decrease in the contribution of the amidinate ligands to the corresponding HOMO orbital. There also is a slight decrease in the ligand contribution to the LUMO with increased numbers of fluorine atoms and an exchange of the character of the orbitals of the gold centers.

A copper(I) homocubane collapses to a tetracapped tetrahedron upon hydride insertion.

The hydrido copper(I) and silver(I) clusters incorporating 1,1-dicyanoethylene-2,2-dithiolate (i-MNT) ligands are presented in this paper. Reactions of M(I) (M = Cu, Ag) salts, [Bu(4)N](2)[S(2)CC(CN)(2)], with the anion sources ([Bu(4)N][BH(4)] for H(-), [Bu(4)N][BD(4)] for D(-)) in an 8:6:1 molar ratio in THF produce octanuclear penta-anionic Cu(I)/Ag(I) clusters, [Bu(4)N](5)[M(8)(X){S(2)CC(CN)(2)}(6)] (M = Cu, X = H, 1(H); X = D, 1(D); M = Ag, X = H, 2(H); X = D, 2(D)). They can also be produced from the stoichiometric reaction of M(8)(i-MNT)(6)(4-) with the ammonium borohydride. All four compounds have been fully characterized spectroscopically ((1)H and (13)C NMR, IR, UV-vis) and by elemental analyses. The deuteride-encapsulated Cu(8)/Ag(8) clusters of 1(D) and 2(D) are also characterized by (2)H NMR. X-ray crystal structures of 1(H) and 2(H) reveal a hydride-centered tetracapped tetrahedral Cu(8)/Ag(8) core, which is inscribed within an S(12) icosahedron formed by six i-MNT ligands, each in a tetrametallic-tetraconnective (µ(2), µ(2)) bonding mode. The encapsulated hydride in 2(H) is unequivocally characterized by both (1)H and (109)Ag NMR spectroscopies, and the results strongly suggest that the hydride is coupled to eight magnetically equivalent silver nuclei on the NMR time scale. Therefore, a fast interchange between the vertex and capping silver atoms in solution gives a plausible explanation for the perceived structural differences between the Ag(8) geometry deduced from the X-ray structure and the NMR spectra.

Synthesis and structure of a dinuclear gold(II) complex with terminal fluoride ligands.

The potential for reductive elimination of fluorine from dinuclear gold(II) for catalysis has prompted our efforts to synthesize a dinuclear gold(II) fluoride complex. This has been achieved with bis(2,6-dimethylphenyl)formamidinate bridging ligands. In order to obtain this product, it was necessary first to synthesize the corresponding dinuclear gold(II) nitrate, which reacts readily with KF in a metathesis reaction. The nitrate complex and fluoride complexes have been structurally characterized. The Au-Au distance in the dinuclear fluoride, 2.595 Å, is longer than the distance found in the analogous chloride complex, 2.567 Å. This result is consistent with the presence of a fluoride "π electron effect" on the filled Au 5d orbitals. The Raman spectrum shows an Au-Au stretch at 206 cm(-1), which agrees with Woodruff's rules and the density functional theory computational model used for modeling the complex.

Halide and nitrite recognizing hexanuclear metallacycle copper(II) pyrazolates.

Halide-centered hexanuclear, anionic copper(II) pyrazolate complexes [trans-Cu(6)((3,5-CF(3))(2)pz)(6)(OH)(6)X](-), X = Cl, Br, I are isolated in a good yield from the redox reaction of the trinuclear copper(I) pyrazolate complex [µ-Cu(3)((3,5-CF(3))(2)pz)(3)] with a halide source such as PPh(3)AuCl or [Bu(4)N]X, X = Cl, Br, or I, in air. X-ray structures of the anion-centered hexanuclear complexes show that the six copper atoms are bridged by bis(3,5-trifluoromethyl)pyrazolate and hydroxyl ligands above and below the six copper atom plane. The anions are located at the center of the cavity and weakly bound to the six copper atoms in a µ(6)-arrangement, Cu-X = ~3.1 Å. A nitrite-centered hexanuclear copper(II) pyrazolate complex [trans-Cu(6)((3,5-CF(3))(2)pz)(6)(OH)(6)(NO(2))](-) was obtained when a solution of [PPN]NO(2) in CH(3)CN was added dropwise to the trinuclear copper(I) pyrazolate complex [µ-Cu(3)((3,5-CF(3))(2)pz)(3)] dissolved in CH(3)CN, in air. Blue crystals are produced by slow evaporation of the acetonitrile solvent. The X-ray structure of [PPN][trans-Cu(6)((3,5-CF(3))(2)pz)(6)(OH)(6)(NO(2))] complex shows the nitrite anion sits in the hexanuclear cavity and is perpendicular to the copper plane with a O-N-O angle of 118.3(7)°. The (19)F and (1)H NMR of the pyrazolate ring atoms are sensitive to the anion present in the ring. Anion exchange of the NO(2)(-) by Cl(-) can be observed easily by (1)H NMR.

Mono and tetranuclear gold(I) complexes of tris(1-benzylimidazole-2-yl)phosphine.

The reaction of tris(1-benzylimidazole-2-yl)phosphine, (Bzim)(3)P, 1, with Ph(3)AsAuCl in 1:1 stoichiometric ratio produced (Bzim)(3)PAuCl, 2. The reaction of (Bzim)(3)PAuCl with NaAuCl(4) in 1:1 stoichiometry in dichloromethane gives an orange-yellow crystalline tetranuclear gold(I) cluster [{mu-N,N'-(Bzim)(3)PAuCl}(2)Au(2)][AuCl(2)][AuCl(4)], 3. Complex 4, [{mu-N,N'-(Bzim)(3)PAuCl}(2)Au(2)][AuCl(2)](2) is formed when the reaction stoichiometry of (Bzim)(3)PAuCl and AuCl(4)(-) is 2:1. The crystal structure of 3 shows the formation of a 12-membered macrocycle with Au...Au distances of approximately 3.0 A. The structures of (Bzim)(3)PAuCl and 3 show Au...H-C interactions ranging from 2.57 to 2.95 A. Complex 2 crystallizes in the monoclinic space group P2(1)/n (Z = 4), a = 9.1927(5), b = 13.528(2), c = 22.995(2) A, and beta = 94.537(5)(o). Complex 3 crystallizes in the monoclinic space group P2(1)/c (Z = 4), a = 13.785(4), b = 21.426(6), c = 25.203(8) A, and beta = 96.51(6)degrees.

A short, unsupported CuI...CuI interaction, 2.65 A, in a dinuclear guanidine chloride complex.

The reaction of CuCl with the neutral guanidine Hhpp ligand (1,3,4,6,7,8-hexahydropyrimido[1,2-a]pyrimidine) yields two crystalline polymorphs of the neutral dimer, bis(1,3,4,6,7,8-hexahydropyrimido[1,2-a]pyrimidine) dichloro-di-copper(I) with the shortest distance known for a bridging unsupported copper(I)-copper(I) interaction.

A monomeric gold(I) carbanion complex with an uncoordinated thioether: [2-(methylsulfanyl)phenyl](triphenylphosphine)gold(I).

The title compound, [Au(C7H7S)(C18H15P)], is conformationally chiral and crystallizes from benzene-hexane as individually enantiopure crystals. This mononuclear compound has the Au(I) atom linearly bound to a triphenylphosphine P atom and to a phenyl C atom of a 2-(methylsulfanyl)phenyl group. The angle at the Au(I) atom is 175.9 (2) degrees. The linear ligand coordination about the Au(I) atom has geometric parameters inside the remarkably narrow range found for gold complexes bound by a phosphine ligand and by the ortho-C atom of a substituted phenyl group. This is the first example of gold(I) attached to a methylsulfanyl aromatic carbanion.

The neutral cluster amminehexa-mu(2)-chlorido-mu(4)-oxido-tris(1,4,6-triazabicyclo[3.3.0]oct-4-ene)tetracopper(II).

The title compound, [Cu(4)Cl(6)O(C(5)H(9)N(3))(3)(NH(3))], is a neutral conformationally chiral cluster which crystallizes under the conditions described in this paper as a racemic conglomerate. It contains four Cu(II) atoms in a tetrahedral coordination with a central O atom lying on a crystallographic threefold axis. Six chloride anions bridge the four Cu(II) atoms. Three Cu(II) atoms are bound by an N atom of a monodentate 1,4,6-triazabicyclo[3.3.0]oct-4-ene (Htbo) ligand and the remaining Cu(II) atom is bound by a terminal ammine ligand. The geometry at each copper center is trigonal bipyramidal, produced by the bound N atom of Htbo or ammonia, the O atom in the axial position, and three chloride ions in the equatorial plane. The chloride anions form an octahedron about the oxygen center. The copper-ammonia bond lies along the crystallographic threefold axis, along which the molecules are packed in a polar head-to-tail fashion.

Vapochromic behavior of {Ag2(Et2O)2[Au(C6F5)2]2}n with volatile organic compounds.

The vapochromic behaviors of {Ag2L2[Au(C6F5)2]2}n (L = Et2O (1), Me2CO (2), THF (3), CH3CN (4)) were studied. {Ag2L2[Au(C6F5)2]2}n (L = Et2O (1)) was synthesized by the reaction of [Bu4N][Au(C6F5)2] with AgOClO3 in 1:1 molar ratio in CH2Cl2/Et2O (1:2). 1 was used as starting material with THF to form {Ag2L2[Au(C6F5)2]2}n (L = THF (3)). 3 crystallizes in the monoclinic space group C2/c and consists of tetranuclear units linked together via aurophilic contacts resulting in the formation of a 1D polymer that runs parallel to the crystallographic z axis. The gold(I) atoms are linearly coordinated to two pentafluorophenyl groups and display additional Au...Ag close contacts within the tetranuclear units with distances of 2.7582(3) and 2.7709(3) A. Each silver(I) center is bonded to the two oxygen atoms of the THF molecules with a Ag-O bond distance of 2.307(3) A. TGA analysis showed that 1 loses two molecules of the coordinated solvent per molecular unit (1st one: 75-100 degrees, second one: 150-175 degrees C), whereas 2, 3, and 4 lose both volatile organic compounds (VOCs) and fluorinated ligands in a less well defined manner. Each complex loses both the fluorinated ligands and the VOCs by a temperature of about 325 degrees C to give a 1:1 gold/silver product. X-ray powder diffraction studies confirm that the reaction of vapors of VOCs with 1 in the solid state produce complete substitution of the ether molecules by the new VOC. The VOCs are replaced in the order CH3CN > Me2CO > THF > Et2O, with the ether being the easiest to replace. {Ag2(Et2O)2[Au(C6F5)2]2}n and {Ag2(THF)2[Au(C6F5)2]2} n both luminesce at room temperature and at 77 K in the solid state. Emission maxima are independent of the excitation wavelength used below about 500 nm. Emission maxima are obtained at 585 nm (ether) and 544 nm (THF) at room temperature and at 605 nm (ether) and 567 nm (THF) at 77 K.

Dinuclear and tetranuclear gold-nitrogen complexes. Solvent influences on oxidation and nuclearity of gold guanidinate derivatives.

The sodium salt of the Hhpp ligand, Hhpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine, a 6,6 bicyclic, guanidine system, reacts with (THT)AuCl (THT = tetrahydrothiophene) in THF or CH2Cl2 to form the Au(II) complex, [Au2(hpp)2Cl2]. The Au(II) complex forms either by oxidation with solvents such as CH2Cl2 or disproportionation of Au(I) with concomitant Au(0) formation. The reaction in ethanol gives the colorless tetranuclear Au(I) complex, [Au4(hpp)4]. The tbo ligand, Htbo = 1,4,6-triazabicyclo[3.3.0]oct-4-ene a bicyclic 5,5 guanidine system, behaved differently from the hpp ligand, and only the colorless tetranuclear gold complex, [Au4(tbo)4], formed in THF, CH2Cl2, or ethanol. The X-ray structure of the oxidized species, [Au2(hpp)2Cl2], shows a Au(II)-Au(II) distance of 2.4752(9) A, the shortest gold-gold bond reported prior to the characterization here of the [(PhCOO)6Au4(hpp)2Ag2], Au(II)-Au(II) = 2.4473(19) A. A preliminary description of the formation of this material, obtained by reacting [Au2(hpp)2Cl2] with Ag(OOCPh), is included in this paper. The four Au(I) atoms in the tetranuclear complexes are arranged in a parallelogram with Au-Au distances ranging from 2.8975(5)-2.9392(6) A in [Au4(hpp)4] and 3.1139(12)-3.2220(13) A in [Au4(tbo)4]. density functional theory (DFT) and MP2 calculations on [Au2(hpp)2Cl2] find that the highest occupied molecular orbital (HOMO) is predominately hpp and chlorine-based with some Au-Au delta* character. The lowest unoccupied molecular orbital (LUMO) has metal-to-ligand (M-L) and metal-to-metal (M-M) sigma* character (approximately 50% hpp/chlorine, and 50% gold). DFT calculations on [Au4(hpp)4] show that the HOMO and HOMO-1 are each a mixture of metal-metal antibonding character and metal-ligand antibonding character and that the LUMO is predominately metal based s character (85% Au and 15% hpp).

Oxidative addition of small molecules to a dinuclear Au(I) amidinate complex, Au2[(2,6-Me2Ph)2N2CH]2. Syntheses and characterization of Au(II) amidinate complexes including one which possesses Au(II)-oxygen bonds.

The dinuclear Au(I) amidinate complex Au2(2,6-Me2Ph-form)2 (1) is isolated in quantitative yield by the reaction of (THT)AuCl and the potassium salt of 2,6-Me2Ph-form in a 1:1 stoichiometric ratio. Various reagents such as Cl2, Br2, I2, CH3I, and benzoyl peroxide add to the dinuclear Au(I)amidinate complex Au2(2,6-Me2Ph-form)2 to form oxidative-addition Au(II) metal-metal-bonded complexes 2, 3, 4, 5, and 6. The Au(II) amidinate complexes are stable as solids at room temperature. The structures of the dinuclear Au2(2,6-Me2Ph-form)2 and the Au(II) oxidative-addition products Au2(2,6-Me2Ph-form)2X2, X=Cl, Br, I, are reported. Crystalline products with an equal amount of oxidized and unoxidized complexes in the same unit cell, [Au2(2,6-Me2Ph-form)2X2][Au2(2,6-Me2Ph-form)2], X=Cl, 2m, or Br, 3m, are isolated and their structures are presented. The structure of [Au2(2,6-Me2Ph-form)2X2][Au2(2,6-Me2Ph-form)2], X=Cl has a Au(II)-Au(II) distance slightly longer, 0.05A, than that observed in the fully oxidized product Au2(2,6-Me2-form)2Cl2, 2. The gold-gold distance in the dinuclear complex decreases upon oxidative addition with halogens from 2.7 to 2.5 A, similar to observations made with the Au(I) dithiolates and ylides. The oxidative addition of benzoyl peroxide leads to the isolation of the first stable dinuclear Au(II) nitrogen complex possessing Au-O bonds, Au2(2,6-Me2Ph-form)2(PhCOO)2, 6, with the shortest Au-Au distance known for Au(II) amidinate complexes, 2.48 A. The structure consists of unidentate benzoate units linked through oxygen to the Au(II) centers. The replacement of the bromide in 3 by chloride, and the benzoate groups in 6 by chloride or bromide also occurs readily. The unit cell dimensions are, for 1, a=7.354(6) A, b=9.661(7) A, c=11.421(10) A, alpha=81.74(5) degrees, beta=71.23(5) degrees, and gamma=86.07(9) degrees (space group P, Z=1), for 2.1.5C6H12, a=11.012(2) A, b=18.464(4) A, c=19.467(4) A, alpha=90 degrees, beta=94.86(3) degrees, and gamma=90 degrees (space group P21/c, Z=4), for 2m.ClCH2CH2Cl, a=16.597(3) A, b=10.606(2) A, c=19.809(3) A, alpha=90 degrees, beta=94.155(6) degrees, and gamma=90 degrees (space group P21/n, Z=2), for 3m, a=16.967(3) A, b=10.783(2) A, c=20.060(4) A, alpha=90 degrees, beta=93.77(3) degrees, and gamma=90 degrees (space group P21/n, Z=2), for 4.THF, a=8.0611(12) A, b=10.956(16) A, c=11.352(17) A, alpha=84.815(2) degrees, beta=78.352(2) degrees, and gamma=88.577(2) degrees (space group P, Z=1), for 5, a=16.688 A, b=10.672(4) A, c=19.953(7) A, alpha=90.00 (6) degrees, beta=94.565(7) degrees, and gamma=90.00 degrees (space group P21/n, Z=4), for 6.0.5C7H8, a=11.160(3) A, b=12.112(3) A, c=12.364(3) A, alpha=115.168(4) degrees, beta=161.112(4) degrees, and gamma=106.253(5) degrees (space group P, Z=1).

Self-assembly of a high-nuclearity chloride-centered copper(II) cluster. Structure and magnetic properties of [Au(PPh3)2][trans-Cu6(micro-OH)6[micro-(3,5-CF3)2pz]6Cl].

A chloride-centered hexanuclear copper(II) pyrazolate [Au(PPh3)2][trans-Cu6(micro-OH)6[micro-(3,5-CF3)2pz]6Cl] is isolated from the reaction of the trinuclear copper(I) pyrazolate [Cu3[micro-(CF3)2pz]3] with PPh3AuCl and Ph3P in moist air. The six copper atoms are bridged by pyrazolate and hydroxyl ligands, above and below the copper plane. The chloride anion exists at the center of the planar cavity formed by the copper atoms with Cu-Cl distances of 3.02-3.13 A. The magnetic susceptibility measurements show a strong antiferromagnetic coupling between the copper centers with an estimated exchange constant of J approximately 650 cm-1.

Syntheses of mixed-ligand tetranuclear gold(I)-nitrogen clusters by ligand exchange reactions with the dinuclear gold(I) formamidinate complex Au(2)(2,6-Me2Ph-form)2.

The reaction of the sterically crowded dinuclear gold(I) amidinate complex Au2(2,6-Me2Ph-form)2, 1, with the less bulky bidentate nitrogen ligands results in the formation of tetranuclear gold(I) complexes. When the less bulky amidinate, K(4-MePh-form), A, was reacted with 1 in a 1:1 stoichiometric ratio, crystals containing equal amounts of the tetranuclear and dinuclear gold(I) aryl formamidinates, Au4(4-MePh-form)4 and Au2(2,6-Me2Ph-form)2, where 2,6-Me2Ph-form = B, were found in the same unit cell, 2 x 2THF: space group P, a = 10.794(11) A, b = 14.392(15) A, c = 25.75(3) A, alpha = 82.564(17) degrees, beta = 85.443(18) degrees, gamma = 82.614(19) degrees. The reaction of K(4-MePh-form), A, and 1 in a 1:2 ratio (excess) produced the tetranuclear complex only, 3. The potassium salt of the exchanged bulky ligand, K(2,6-Me2Ph-form), formed as a byproduct. The reaction of the dinuclear gold(I) complex Au2(2,6-Me2Ph-form)2 with the 3,5-diphenylpyrazolate salt, K(3,5-Ph2pz), resulted in the formation of two tetranuclear mixed-ligand complexes, Au4(3,5-Ph2pz)2(2,6-Me2Ph-form)2 x 2THF, 4 x 2THF (space group P21/c, a = 11.5747(19) A, b = 25.497(4) A, c = 21.221(3) A, beta = 96.979(3) degrees) and Au4(3,5-Ph2pz)3(2,6-Me2Ph-form) x THF, 5 x THF (space group P21/c, a = 23.058(5) A, b = 14.314(3) A, c = 18.528(4) A, beta = 90.94(3) degrees. The block crystals from the tetranuclear complex, 4 x 2THF, contain mixed ligands with each pyrazolate ring facing an amidinate ring. The tetranuclear mixed ligand complex, 5 x THF, was isolated as needles with ligands alternating above and below the Au4 plane. The two tetranuclear mixed-ligand complexes emit at 490 and 530 nm, respectively, under UV excitation.

Gold(I) and silver(I) mixed-metal trinuclear complexes: dimeric products from the reaction of gold(I) carbeniates or benzylimidazolates with silver(I) 3,5-diphenylpyrazolate.

Trinuclear mixed-metal gold-silver compounds are obtained by the reaction of gold(I) carbeniate [Au(mu-C(OEt)=NC6H4-p-CH3)]3, TR(carb), or gold(I) imidazolate [Au-mu-C,N-1-benzyl-2-imidazolate]3, TR(bzim), with silver(I) pyrazolate [Ag(mu-3,5-Ph2pz)]3. The crystalline products are mixed-ligand, mixed-metal dimeric products [Au(carb)Ag2(mu-3,5-Ph2pz)2], [Au2(carb)2Ag(mu-3,5-Ph2pz)].CH2Cl2, [Au(bzim)2Ag2(mu-3,5-Ph2pz)], and [Au2(bzim)2Ag(mu-3,5-Ph2pz)]. They have been characterized by elemental analysis and 1H NMR and mass spectrometry. The X-ray structure of [Au(carb)Ag2(mu-3,5-Ph2pz)2] shows it to be a dimer with two Ag...Au contacts between the trinuclear units of 3.083(2) and 3.310(2) A and with average intramolecular Ag...Ag and Au...Ag distances of approximately 3.3 and 3.2 A, respectively. The structure of [Au2(carb)2Ag(mu-3,5-Ph2pz)].CH2Cl2 is a dimer with one intermolecular Au...Au attraction of 3.3354(10) A and a short Ag...Au distance of approximately 3.42 A and intramolecular Ag...Au and Au...Au contacts of approximately 3.2 and approximately 3.3 A, respectively. Packing diagrams of both complexes show that the dimeric units are independent, similar to their parent molecules. The dimers of trinuclear [Au(carb)Ag2(mu-3,5-Ph2pz)2] and [Au2(carb)2Ag(mu-3,5-Ph2pz)].CH2Cl2 crystallize in the triclinic space group P (Z = 2), a = 9.688(3) A, b = 15.542(4) A, c = 23.689(6) A, alpha = 82.560(5) degrees , beta = 87.887(6) degrees , gamma = 78.060(5) degrees , and the orthorhombic space group Pca2(1) (Z = 4), a = 29.644(4) A, b = 7.4582(10) A, c = 30.473(4) A, respectively. The structure of [Au(bzim)Ag2(mu-3,5-Ph2pz)2] is a dimer with two metallophilic Ag...Au interactions of 3.14 A. The complex crystallizes in the monoclinic space group C2/c (Z = 4), a = 26.368(5) A, b = 15.672(3) A, c = 17.010(3) A, beta = 102.206(3) degrees .

Mercury(II) cyanide coordination polymer with dinuclear gold(I) amidinate. Structure of the 2-D [Au2(2,6-Me2-formamidinate)2].2Hg(CN)2.2THF complex.

The dinuclear gold(I) amidinate complex [Au(2)(Me(2)-form)(2)], 1, (Me(2)-form = 2,6-Me(2)-formamidinate) reacts with Hg(CN)(2) to form a 2D structure, 1.2Hg(CN)(2).2THF. Each gold center interacts with two Hg(CN)(2) molecules. The Au...Au distance increases from 2.7 Angstroms in the starting dinuclear complex to 2.9 Angstroms in the adduct. The gold centers are connected to four nitrogen atoms with Au-N distances in the range 2.13-2.51 Angstroms. The cyanide stretch is shifted from 2192 cm(-1) in the Hg(CN)(2) to 2147 cm(-1) in the adduct.

External heavy-atom effect of gold in a supramolecular acid-base pi stack.

The nucleophilic trinuclear Au(I) ring complex Au3(p-tolN=COEt)3, 1, forms a sandwich adduct with the organic Lewis acid octafluoronaphthalene, C10F8. The 1.C10F8 adduct has a supramolecular structure consisting of columnar interleaved 1 ratio 1 stacks in which the Au3(p-tolN=COEt)3 pi-base molecules alternate with the octafluoronaphthalene pi-acid molecules with distances between the centroid of octafluoronaphthalene to the centroid of 1 of 3.458 and 3.509 A. The stacking with octafluoronaphthalene completely quenches the blue photoluminescence of Au3 (p-tolN=COEt)3, which is related to inter-ring Au-Au bonding, and leads to the appearance of a bright yellow emission band observed at room temperature. The structured profile, the energy, and the lifetime indicate that the yellow emission of the 1.C10F(8) adduct is due to monomer phosphorescence of the octafluoronaphthalene. The 3.5 ms lifetime of the yellow emission of 1.C10F8 is two orders of magnitude shorter than the lifetime of the octafluoronaphthalene phosphorescence, thus indicating a strong gold heavy-atom effect. The diffuse-reflectance spectrum of the solid adduct shows new absorptions that are red-shifted from the absorptions of the monomeric organic and inorganic components alone, indicating charge transfer. Luminescence excitation spectra suggest that these new absorptions represent the major excitation route that leads to the yellow luminescence of 1.C10F8, which is different from the conventional heavy-atom effect in which the phosphorescence route entails simply the enhancement of the S1-T1 intersystem crossing of the organic compound.

Mixed-metal triangular trinuclear complexes: dimers of gold-silver mixed-metal complexes from gold(I) carbeniates and silver(I) 3,5-diphenylpyrazolates.

Dimers of trinuclear mixed gold-silver compounds are obtained by the reaction of a gold(I) carbeniate, [Au(mu-C(OEt)=NC6H4-p-CH3)]3, with a silver(I) pyrazolate, [Ag(mu-3,5-Ph2pz)]3. The crystalline products are the mixed-metal species Au(carb)Ag2(mu-3,5-Ph2pz)2 and Au2(carb)2Ag(mu-3,5-Ph2pz)CCH2Cl2.

Novel metallamacrocyclic gold(I) thiolate cluster complex: structure and luminescence of [Au9(mu-dppm)4(mu-p-tc)6](PF6)3.

The structure of a novel metallamacrocyclic phosphine gold(I) thiolate cluster, [Au9(mu-dppm)4(mu-p-tc)6](PF6)3, where dppm = bis(diphenylphosphine)methane and p-tc = p-thiocresolate, is reported and shows AuAu attractions of approximately 3.0 A and gold(I) atoms linked to thiolate and phosphine ligands in distorted trigonal and nearly linear geometries.