Flavio Bonati

Organotin(IV) N,N-disubstituted dithiocarbamates

Compounds with general formulas R3Sn(SSCNR′2 (REt, Ph, R′) or R2Sn(SSCNR′2)2 (Rhalogen, Et, Ph; R′Et, Ph) were prepared and their physical data are reported and discussed. In X2SN(SSCNEt2)2 an octahedral cis coordination of the tin atom is shown to be present with a chelated dithiocarbamato moiety. A similar labile type of coordination seems to exist in solution for the corresponding organotin derivatives. In the case R3Sn(SSCNR′2), no sure evidence was found for or against the chelation of the dithiocarbamate moiety. A discussion as to what physical measurements actually serve as convincing criteria of structure and chelation in dithiocarbamates is presented.

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.

New isocyanide complexes of platinum(II)

New platinum compounds, of formula [Pt(CNR)4][PtCl4] and cis-Pt(CNR)2Cl2, with R = cyclohexyl, p-tolyl, and p-anisyl, have been prepared and characterized. Reaction with stannous chloride yield trans-[(RNC)2Pt(SnCl3)2] and reaction with methanol gives the “carbene” complexes cis-[(RNHCOCH3)(RNC)PtCl2].

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.

Carbonylrhodium(I) derivatives of 3,5-dimethyl- and 3,5-bis(trifluoromethyl)pyrazole

Abstract Binuclear pyrazolato-bridged complexes such as [(OC) 2 Rh(μ-pyrazolato- N,N ′] 2 , I or II, were obtained in alkaline solution from (OC) 4

Organotin(IV) polypyrazolylborates. III, Tris(3,5-dimethylpyrazolyl)borates

Abstract The compounds RnSnX3-nQ where R = Me, Et, Bu or Ph; X = Cl or Br: n = 0, 1, or 2 and Q is the sterically demanding title ligand have been shown to be stable and non-fluxional and to contain six-coordinated tin(IV) and the tridentate ligand Q.

Bis(carbene) complexes of gold(I) and gold (III)

The preparation of [(carbene)2Au]+ClO4−, [(carbene)Au(C6H11NC)]+ClO4− and of [(carbene)2AuI2]+ClO4− is reported.