H. H. Murray

The synthesis and crystal structure of a novel gold(I)–pyrazolate hexamer containing an 18-membered inorganic ring

The reaction of ClAuPPh3 with sodium 3,5-diphenylpyrazolate in tetrahydrofuran with added AgOCOPh yields hexakis(µ-3,5-diphenylpyrazolato-N,N′)-hexagold(I)(1), a compound with a novel 18-membered twisted ring and a fused-edge bi-tetrahedral grouping of gold atoms, as determined crystallographically.

Heterobimetallic pyrazolato complexes: The syntheses and crystal structures of cis-(PPh3)2ClPtII(3,5-Ph2pz), cis-(PPh3)2BrPtII(μ-3,5-Ph2pz)CuICl, cis-(PPh3)2ClPtII(μ-3,5-Ph2pz)AgICl and cis-(PPh3)2BrPtII(μ-3,5-Ph2-4-Br-pz)AuIBr (pz=pyrazolato anion)

Abstract The mononuclear complex cis-(PPh3)2ClPt(3,5-Ph2pz), is formed from the reaction of cis-(PPh3)2PtCl2 and Na[3,5- Ph2pz]. This metalloligand can form adducts with all three Group 11 MI halides. Three such heterobimetallic complexes, Pt/Cu, Pt/Ag and Pt/Au, as well as the Pt starting material, have been characterized by single crystal X-ray analysis. A rational synthesis for all complexes is given by cis-(PPh3)2ClPt(3,5-Ph2pz)·Et2O (1): C55H51ClN2OP2Pt, monoclinic, P21/n (No. 14), a=11.120(2), b=24.438(6), c=18.125(3) A, β=99.50(1)°, V= 4858(2) A3, Z=4, R= 0.061. For cis-(PPh3)2BrPt(μ-3,5-Ph2pz)CuCl·Et2O (2): C55H51BrClCuN2P2Pt, orthorhombic, Pc21n (No. 33), a=10.721(3), b=15.757(4), c=30.263(8) A, V=5112(2) A3, Z=4, R=0.051. For cis-(PPh3)2- ClPt(μ-3,5-Ph2pz)AgCl·Et2O (3): C55H51AgCl2N2OP2Pt, monoclinic, P21/c (No. 14), a=21.948(4), b=11.946(3), c=36.733(5) A, β=96.76(1)°, V=9564(1) A3, Z=8, R=0.063. For cis-(PPh3)2BrPt(μ-3,5-Ph2-4-Br-pz)- AuBr·2thf (4): C59H57AuBr3N2O2P2Pt, triclinic, P 1 (No. 2), a=10.456(2),b =12.301(3), c=24.058(5) A, α= 77.66(2)°, β=89.18(2)°, γ=67.42(2)°, V=2783(1) A3, Z=2, R=0.060. The structures of the heterobimetallic units are bridged by single 3,5-diphenylpyrazolato ligands. The Pt···MI distances average 3.37 A.

A vibrational study by Raman spectroscopy of some dinuclear gold ylide complexes

Abstract A vibrational study of the dinuclear gold ylide complexes [Au(CH2)2PPh2]2 and [Au(CH2)2PPh2]2X2 (X = Cl, Br or I) has been undertaken by Raman spectroscopy. The non-bonding AuAu interaction in the AuI dimer, [Au(CH2)2PPh2)2, at 64 cm−1 shifts to higher wavenumber in the single-bonded AuII halogen complexes, with bands at 162, 132 and 103 cm−1 for X = Cl, Br and I, respectively, being assigned to ν(AuAu). The Au-X vibration was also identified. The general trends in AuAu and Au-X stretching vibrations with changing halogen are compared with those for other dinuclear metal-metal bonded complexes, with a metal-metal bond order of one, and with those for mononuclear gold-halogen complexes.

Synthesis and x-ray crystallographic characterization of the gold(II) ylide dimers [Au(CH2)2PPh2] 2(CH2CN)Br and [Au(CH2)2PPh2] 2(CH2C(O)Ph)Br. Unusually stable functionalized alkyl halide adducts

The reaction of bromoacetonitrile and [Au(CH 2 ) 2 PPh 2 ] 2 , 1 , in benzene gives [Au(CH 2 ) 2 PPh 2 ] 2 (CH 2 CN)Br, 2 , in near quantitative yield. Bromoacetophenone reacts with 1 in dichloromethane to give [Au(CH 2 ) 2 PPh 2 ] 2 (CH 2 C(O)Ph)Br, 3 , in high yield. These gold(II) functionalized alkyl halide adducts are very stable. Their structural, physical and chemical properties are compared with [Au(CH 2 ) 2 PPh 2 ] 2 (Me)Br, 4 . For 2, C 30 H 30 Au 2 BrP 2 N, triclinic, P ; a = 11.030(3), b = 16.016(4), c = 10.3639(2) A, α = 92.310(20), β = 107.950(18), γ = 106.730(19)°, V = 1651.4(7)A 3 with Z = 2. The structure refined to R = 0.040, R w = 0.040 for 3195 reflections with I ⩾ 3.0σ( I ). For 3, C 36 H 35 Au 2 BrP 2 O, monoclinic, Pc ; a = 13.684(4), b = 9.667(15), c = 25.765(3) A, β = 100.95(16)°; V = 3346(1) A 3 with Z = 4. The structure refined to R = 0.049, R w = 0.045 for 2852 reflections with I ⩾ 3.0σ( I ). Both compounds have AuAu singte bonds. In solution each shows a much lower tendency to reductively eliminate alkyl halide than the non-functionalized alkyl adduct.

Syntheses and characterizations of tin complexes of methylenediphenylphosphinate ligands: the crystal structures of [Ph4−xSn(CH2P(S)Ph2)x] (x = 1–4) and [Ph2SnCl(CH2P(O)Ph2)]2

Abstract Reactions between methylenediphenylphosphinate anions [CH2P(E)Ph2]− (E = S,O) and appropriate chlorophenyltin(IV) compounds in tetrahydrofuran afforded the organotin compounds [Ph4−xSn(CH2P(S)Ph2)x], (x = 1–4), 1–4 and [Ph2SnCl(CH2P(O)Ph2)]2, 5. All compounds have been characterized structurally, 1–4 as 4-coordinate monometallic species and 5 as a bimetallic 8-membered metallacycle which is 5-coordinate at each metal atom.

The reactivity of bromoform with [Au(CH2)2PPh2]2. The completion of the halomethane series CHyX4−y (y=3,2,1,0; X=Cl, Br, I) and reactivity with [Au(CH2)2PPh2]2

The reaction of [Au(CH2)2PPh2]2 with excess CHBr3 in benzene initially gives [Au(CH2)2PPh2]2− (CHBr2)Br. This observation establishes that halomethanes, CHyX4−y (y=3,2,1,0; X=Cl, Br, I), react with [Au(CH2)2PPh2]2 to initially give Au(II) adducts of the general form [Au(CH2)2PPh2]2−(CHyX3−y)X (y=3,2,1,0) via oxidative addition across the carbon-halogen bond. The order of reactivity inversely follows the order of carbon-halogen bond dissociation energies of haloalkanes. Methyl chloride is the only halomethane of the series that does not give a Au(II) adduct under similar reaction conditions.

Symmetrical Ring Cleavage of the Gold(I) Phosphorus Ylide Dimer [Au(CH2)2PPh2]2 by Hydrogen Halides in Toluene

Abstract The reaction of the cyclic, 8-membered gold(I) ylide dimer, bis [μ-(dimethylenediphenylphosphoranyl-C,C)]-digold(I), [Au(CH2)2PPh2]2, with two moles of HX (X = Cl, Br) in toluene yields the symmetric cleavage product halo(methylmethylenediphenylphosphoranyl)-gold(I), XAuCH2PPh2- (CH3), as the only isolable gold containing product. Further addition of HX affords a dimethyldiphenylphosphonium dihaloaurate(I) salt.

The reactivity of [Au(CH2)2PPh2]2(1) with CCl4. The oxidative addition of CCl4 to a dimeric gold ylide complex to give AuII and AuIII CCl3 adducts. The X-ray crystal structure of [Au(CH2)2PPh2]2Cl2, [Au(CH2)2PPh2]2(CCl3)Cl, and [Au(CH2)2PPh2]2(CCl3)Cl3

Prolonged reaction of [Au(CH2)2PPh2]2(1) with CCl4 gives [Au(CH2)2PPh2]2Cl2(2), [Au(CH2)2PPh2]2(CCl3)Cl (3) being formed initially, and the reaction of (1) with tetrahydrofuran-CCl4(1 : 5) gives [Au(CH2)2PPh2]2(CCl3)Cl3(4), an example of a new class of dimeric gold(III)–alkyl halide complex; the X-ray crystal structures of (2), (3), and (4) are described.

Addition of halogens to [{Au(CH2)2PPh2}2RX] complexes. The structures of cis,trans-[{Au(CH2)2PPh2}2(CH2CF3)Br3] and trans,trans-[{Au(CH2)2PPh2}2(CHCl2)Br2Cl]

The syntheses and X-ray structures of the dinuclear gold(III) phosphorus ylide complexes cis,trans-[{Au(CH2)2PPh2}2(CH2CF3)Br3] and trans,trans-[{Au(CH2)2PPh2}2(CHCl2)Br2Cl] are reported. In CDCl3, cis,trans-[{Au(CH2)2PPh2}2(CH2CF3)Br3] is stable towards isomerisation after 4 d at 25°C. The cis,trans and trans,trans complexes are obtained from the oxidative addition of Br2 to the gold(II) alkyl halide complex [{Au(CH2)2PPh2}2(CH2CF3)I] and the reaction of [{Au(CH2)2PPh2}2] with an excess of CHCl2Br, respectively. Crystallographic data: cis,trans-[{Au(CH2)2PPh2}2(CH2CF3)Br3]·(C2H5)2O, triclinic, space group P(no. 2), a= 10.995(3), b= 13.056(3), c= 15.028(3)Aα= 93.35(2), β= 105.45(2), γ= 109.43(2)°, Z= 2, R= 0.058, R′= 0.058 for 2 782 unique reflections with |F0|2 > 3σ(|F0|2); trans,trans-[{Au-(CH2)2PPh2}2(CHCl2)Br2Cl] triclinic, space group P(no. 2), a= 11.716(4), b= 14.634(4), c= 9.619(3)A, α= 94.44(3), β= 96.26(3), γ= 83.41(3)°, Z= 2, R= 0.081, R′= 0.086 for 2 254 reflections with |F0|2 > 3σ(|F0|2). Both complexes contain four-co-ordinate gold atoms in the +3 oxidation state with an approximate square-planar arrangement of the bridging lignds. The metal atoms are separated by non-binding distances of 3.103(1) and 3.070(9)A respectively.

Characterization of the gold(II) dimer [Au(CH2)2PPh2]2(CH2Cl)Br: structural evidence suggesting the formation of a carbene intermediate preceeding A-frame (bridging methylene) formation

[Au(CH2)2PPH2]2, (1), reacts with neat CH2ClBr to give [Au(CH2)2PPH2]2(CH2Cl)Br, (2), and the X-ray structure of (2), shows a close contact between one Au centre and the Cl of the co-ordinated CH2Cl [2.895(16)Ă]; this interaction is consistent with the observed further oxidative addition of the CH2Cl to form the bridging methylene A-frame complex, and suggests that a carbene intermediate may be involved.