Bruna Bovio

Reactions of C-imidazolyllithium derivatives with Group Ib compounds: Tris[μ-(1-alkylimidazolato-N3,C2)]tri-gold(I) and -silver(I). Crystal structure of bis(1-benzylimidazolin-2-yliden)gold(I) chloride

Abstract Upon reaction of LMX (M  Au, X  Cl, L  PPh3 or Me2S; M  Ag, X  NO3, L  Me2S) with 1-R-2-lithiumimidazole the lithium is replaced by a noble metal to give the species (1-R-2-M-imidazole)n (M  Au, R  methyl or benzyl, n = 3; M  Ag, R = benzyl). From Me2SCuBr the compound bis(1-R-imidazol-2-yl) was obtained (R = methyl or benzyl). The unexpected formation during work up of [Au( CN(CH 2 Ph)CHCHN H)2]Cl, a carbene derivative, was confirmed by an X-ray crystal structural study which showed the presence of two independent molecules where CAuC is 175.2(4) or 176.6(4)°, average AuC is 2.027(7) A, and there is an Au ··· Au interaction at 3.2630(5) A.

X-ray crystal structure of tris[μ-3,5-bis(trifluoromethyl)pyrazolato-N,N′]trigold(I), a compound containing an inorganic nine-membered ring

Abstract In the AuNNAuNNAuN non-planar ring the three linearly coordinated gold atoms are 3.344-3.355(2) A apart while a separation of at least 3.998(2) A between metals belonging to different trimers rules out any intermolecular interaction, such as that found in the related [AuC(OEt)=NC 6− H 4 Me] 3 compound. The unusual distances inside the planar pyrazolato rings and the very short AuN distances (1.93(1), average) may be taken as evidence for a π-interaction between the gold atoms and the attached pyrazolato rings.

Organotin derivatives of 4-acyl-5-pyrazolones. Crystal structure of trans-di(t-butyl)bis(1-phenyl-3-methyl-4-benzoyl-pyrazolon-5-ato)tin(IV)

Abstract Stable, six-coordinated Q 2 SnRX compounds have been prepared where QH is 1-phenyl-3-methyl-4-R′C(O)-pyrazol-5-one (R′ = Me, Ph) X = Cl or R, and R = Cl, Me, Et, i-Pr, n- and t-Bu, vinyl, benzyl or phenyl. They are not fluxional when X = Cl or Ph or X = R = t-Bu. The 119 Sn NMR chemical shift is a function of the number of chloride groups. Owing to crowding of the ligands, in the title molecule the CSnC axis is bent (150.0(5)°) and the SnC bonds and two of the four SnO bonds are long; 2.20(1) for the SnC, 2.381(7) and 2.461(6) vs. 2.145(5) and 2.135(6) A for SnO.

Reaction of platinum(II) derivatives with bis(pyrazolyl)propane. Cleavage of a C(sp3)-N bond in a bis(pyrazolyl)alkane promoted by platinum(II) derivatives. Crystal structure of cis-Pt(pzH)2CL2 (pzH = pyrazole)

The reactions of bis(pyrazolyl)propane (CH3)2C(pz)2, (pzH = pyrazole), with PtCl2, (RCN)2PtCl2 and K2[PtCl4 have been investigated, and the results compared with those described previously for the corresponding palladium(II) derivatives. In contrast with the behaviour of the palladium analogues, the platinum derivatives promote the rupture of the ligand: simple adducts of pyrazole, cis- or trans-Pt(pzH)2Cl2, or species containing the ligand [HNC(R)pz], formally arising from the insertion of a nitrile into the NH bond of pyrazole, are obtained. For comparison, the reaction of the platinum derivatives with pyrazole itself has been investigated under various conditions. The crystal structure of cis-Pt(pzH)2Cl2 has been determined by X-ray diffraction: monoclinic, space group C2/c, a 9.180(1), b 15.084(1), c 15.1445(9) A, β 101.536(7)°, Z - 8, R = 0.039, Rw = 0.040 for 2125 observed reflections.

Tin(IV) and organotin(IV) complexes containing the anion of some substituted-3-methyl-4-acyl-5-pyrazolones. Crystal structure of dimethylbis(1-phenyl-3-methyl-4-benzoyl pyrazolon-5-ato)tin(IV)

Abstract Six-coordinate [(Q) 2 SnRX] compounds, where QH is 1-R′-3-methyl-4-R″C(O)-5-pyrazolone (QpH: R′= p -NO 2 C 6 H 4 , R″= C 6 H 5 ; Q M H: R′= CH 3 , R″ = C 6 H 5 ; Q F H: R′= C 6 H 5 , R″ = CF 3 ), X = Cl or R, R = Cl or CH 3 , have been prepared and characterized by analyses, spectral (IR, 1 H-, 13 C- and 119 Sn-NMR data) and conductivity measurements. The crystal structure of [(Q′) 2 Sn(CH 3 ) 2 ] (Q′H is 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone) was also determined: the sterically demanding ligand gives rise to severe distortion of the six-coordinate [(Q′) 2 Sn(CH 3 ) 2 ] compound, similar to that noted in [(Q′) 2 Sn(t-C 4 H 9 ) 2 ] and I(Q′) 2 Sn(n-C 4 H 9 ) 2 ]. The CSnC axis is bent (153.3(3)°) and two of the four SnO bonds are exceptionally long (2.337(4) and 2.412(4) A) whereas the other two SnO bonds are normal (2.104(3) and 2.103(4), A).

Reactions of (tertiary phosphine)gold(I) substituted imidazoles or pyrazolones with acidic reagents: protonation, zole displacement, and adduct formation. Crystal structure determination of the adduct 1-methyl-2-(cyclohexylphosphinegoldthiolato)imidazole · 2benzimidazole

Abstract Imidazole (QH) or pyrazolone (Q′H2) in QAuL or (LAu)2Q′ (where L is a tertiary phosphine) is displaced by some acidic reagents HZ, where HZ = terminal acetylene, imide, thiol, dithio acid, or HI, to give ZAuL. If Z− is not a soft ligand an adduct between the ragents is obtained, and this is formulated as a protonated species, e.g. [LAuQH]+Z− (HZ = picric acid). In other cases the adduct is LAuZ · HQ (rather than LAuQ · HZ or a protonated species), in which the displaced QH is hydrogen-bonded to the product, as shown by the crystal structure of the adduct 1-methyl-2(cyclohexylphosphinegoldthiolato)imidazole sd 2benzimidazole. In this species gold(I) is two-coordinated (PAuS 172.0(1)), with AuP and AuS 2.292(3) and 2.331(3) A, respectively; the first benzimidazole is hydrogen-bonded to N(3) of the imidazole, and the second benzimidazole to the N(3) of the first, the inter-diazole N⋯HN distance being 2.81 and 2.86(1) A, respectively.

Reactions of symmetric C-imidazolylgold(I) leading to Au1 carbene complexes or mixed valence or AuIII imidazolyl derivatives. Crystal structure of [1-benzyl-3-(carboethoxy)imidazolin-2-yliden]chlorogold(I)

Reaction of trimeric 1-benzyl-2-gold(I)-imidazole, Au3im3 (im  [μ-(N1-benzyl)imidazolato-N3,C2]) with XY reagents gives either gold(I) mononuclear carbene derivatives, XAuCNRCHCHNY (Y−X = Et-I or EtO(O)CCl) or trinuclear mixed valence or gold(III) compounds. The gold(III) complexes, [(X)(Y)Au]3im3, are formed by addition of X–Y (benzoyl or p-tosyl chloride) or by reaction with thionyl chloride. With iodine and with Me3SiI, Au3im3I2 and Au3im3I4, respectively, are formed. The crystal structure of ClAuCN(CH2Ph)CHCHNCOOEt has been determined.

A 197Au mössbauer study of reaction products of trimeric 1-benzyl-2-gold(I)-imidazole leading to AuI carbene or AuI imidazoline complexes and trinuclear AuIII imidazolyl derivatives. X-Ray crystal structure of [{(μ-1-benzylimidazolato-N3,C2)Au}3I2]

Reactions of the trinuclear [Au3Rim3] compound (Rim = [μ-1-benzylimidazolato-N3,C2] with several reagents capable of oxidative addition have been investigated by 197Au Mossbauer spectroscopy. The reaction products are either AuI carbene mononuclear and binuclear complexes or trinuclear AuIII and mixed-valence compounds. The X-ray crystal structure of the mixed-valence complex [AuIIIAuI2Rim3I2] has been determined. Two two-coordinate AuI centres show average AuC and AuN distances of 2.02(3) and 2.04(2) A and average CAuN angles of 175.0(1.2)°, whereas the four-coordinate AuIII centre gives AuC and AuN 1.96(4) and 1.91(3) A with the CAuN angle 170.5(1.6)°, and AuI average distances 2.598(3) A, with an IAuI angle 175.8(1)°. The AuAu intramolecular distances [Au(1) ⋯ Au(2) 3.432(3), Au(1) ⋯ Au(3) 3.508(3), Au(2) ⋯ Au(3) 3.464(3) A] indicate a weak metal-metal interaction.

Synthesis and characterization of copper(I) derivatives with N-donor ligands—III. Hydridotris (1H-pyrazol-1-yl)borate. The X-ray crystal structure of [HB-(μ-pz)3-Cu(PPh3)]

Abstract (Triarylphosphine)copper(I) derivatives containing anionic tris(1 H -pyrazol-1-yl)borato have been prepared from (Ar 3 P) 2 CuNO 3 and KTp, KTp ∗ , KTp Me and KTp ∗Cl and characterized through IR and 1 H, 13 C and 31 P NMR spectra. The complexes contain tetrahedral Cu I and a tridentate ligand. The X-ray single crystal analysis of the (PPh 3 )CuTp complex is reported. Four-coordinate Cu 1 is present in a distorted tetrahedral configuration owing to the bulky PPh 3 and Tp groups: NCuN angles range from 88.4(2) to 91.8(2)°; NCuP angles range from 120.6(2) to 127.3(1)°. The CuN distances are 2.081(5), 2.065(5) and 2.083(5) A and the CuP distance is 2.153(2) A.

Reactions of trimeric 1-benzyl-2-gold(I)imidazole leading to AuI carbene complexes. Crystal structure of [1-benzyl-3-benzoyl-imidazolin-2-yliden]chlorogold(I)☆

Abstract The crystal structure determination of a compound previously described as tris-[{μ-(N1-benzyl)imidazolato-N3,C2}(chloro)benzoylgold(III)], which turned out to be a gold(I) mononuclear carbene derivative, has led to a reconsideration of the reactions of [Au3 (im3 = μ-(N1-benzyl)imidazolato-N3,C2) with reagents X–Y. The mononuclear or trinuclear nature of other Au imidazolyl derivatives is discussed and the compounds obtained by reaction with X–Y = ClCOOEt, IEt or Cl-p-tosyl and chlorobenzoyl appear to be mononuclear, whereas those obtained by reaction with Me3SiI, SOCl2 or I2 appear to be trinuclear mixed valence or gold(III) compounds.