J. L. Brianso

Synthesis and vibrational spectra of[RSHgII]2+(ClO4)2 complexes. Crystal and molecular structure of bis(N-methylpiperidinium-4-thiolato)-mercury(II) perchlorate.

Abstract Hg(II) complexes have been prepared with γ-mercaptoamine ligands 1-methyl-4-mercaptopiperidine (4-MP), 1-methyl-3(mercaptomethyl)piperidine (3-MMP) and 1-methyl-2(2-mercaptoethyl)piperidine (2-MEP) with 1:1 and 1:2 metal to ligand ratios. Infrared and Raman spectra for all these compounds have been recorded and discussed. The spectral features agree with a linear SHgS structure and with the characteristic two-coordination of mercury in all the complexes. The structure of [Hg(4-MP)2](ClO4)2 has been determined by X-ray crystallography. The crystals are orthorhombic, space group C2221 (Z=4) in a unit cell of dimensions a= 13.161 (3) A, b= 6.589 (2) A and c= 24.740 (4) A. Solution of the structure by direct methods led to a final weighted R factor of 0.057 for 1339 independent reflections. The crystal structure consists of discrete [Hg(4-MP)2]2+ cations and ClO4− anions packed in layers paralell to the (100) plane.

Metal complexes of mercaptoamines—I. Synthesis and crystal and molecular structure of tetrakis (3-amino-1-propanethiolato) trinickel(II)chloride

Abstract The reaction of nickel(II)chloride with γ-mercapto-propylamine in ethanolic solution gives the complex [Ni 3 (MPA) 4 ]Cl 2 (MPA=NH 2 -(CH 2 ) 3 -S). The complexes [Ni 3 (MPA) 4 ]X 2 (X=Br, I, ClO 4 ) can be synthesized from the chloride complex by addition of the sodium salt in aqueous solution. The crystal structure consists of discrete divalent trinuclear cations and chloride anions. Each sulphur atom of the ligand acts as a bridge between two nickel atoms, and the nitrogen atoms complete the coordination around the terminal nickel atoms. The geometry around the metal atoms is square-planar. The electronic and IR spectra of the complexes [Ni 3 (MPA) 4 ]X 2 (X=Br, I, ClO 4 ) indicate that all these compounds are composed of the [Ni 3 (MPA) 4 ] 2+ and X − ions.

CF bond activation in polyfluorobenzothiolate compounds of Os(III). X-ray structures of [-2))(SC6F5)2(PMe2Ph)2], [Os(SC6F5)2(o-S2C6F4)(PMe2Ph)] and [Os(C6F5)2(o-S2C6F4)(PMe2Ph)2]

Abstract Thermolysis of [Os(SR) 3 (PMe 2 Ph) 2 ] (R=C 6 F 5 ( 1a ) or C 6 HF 4 -4 ( 1b )) in refluxing toluene affords [Os(SC 6 F 5 ) 2 ( o -S 2 C 6 F 4 )(PMe 2 Ph)] ( 2a ), [Os(SC 6 HF 4 ) 2 ( o -S 2 C 6 HF 3 )(PMe 2 Ph)] ( 2b ), and [Os(C 6 F 5 ) 2 ( o -S 2 C 6 F 4 )(PMe 2 Ph) 2 ] ( 3a ) through processes involving CF and CS bond cleavage as well as rearrangement of CS bonds. The single-crystal diffraction structures of 1a , 2a and 3a have been determined. In the solid state compound 1a shows a CF→Os interaction.

Synthesis and crystal and molecular structure of di-µ-(N-methylpiperidinium-4-thiolate)-bis[dichlorozinc(II)] monohydrate

The reaction of zinc chloride with 4-mercapto-N-methylpiperidinium chloride in aqueous solution gives the title complex. Crystals of the compound are monoclinic, space group P21/m, with a= 10.988(12), b= 13.086(12), c= 7.476(9)A, β= 91.99(1)°. With Z= 2, the calculated density is 1.71 g cm–3(measured density 1.69 g cm–3). Solution of the structure by direct methods led to a final weighted R factor of 0.072 for 2 028 independent reflections. The crystal structure of the zwitterionic complex consists of discrete dimeric molecules. Each sulphur atom of the ligand acts as a bridge between two zinc atoms. The crystallographic mirror plane passing through the zinc and chlorine atoms imposes a Cs symmetry on the molecule. The average Zn–Cl bond distance is 2.255(7)A, while the Zn–S bond distances average 2.371(11)A. The piperidine rings shows the usual ‘chair’ configuration. The dimeric molecules are bridged by a network of hydrogen bonds involving–NH groups and the chlorine atoms.

Notes. Synthesis, crystal and molecular structure of the compound dichlorobis[2-(phenylazo)phenyl–C1N2′]tin(IV)

The reaction of chloro[2-(phenylazo)phenyl]mercury(II) with metallic tin leads to dichlorobis[2-(phenylazo)phenyl]tin(IV) whose structure has been determined by X-ray diffraction. The tin atom is six-co-ordinated in a very distorted octahedral fashion with two cis chlorine and cis nitrogen atoms in the equatorial plane and two carbon atoms of the ortho-metallated phenyl groups considerably displaced from the trans axial position [C–Sn–C = 149.7(7)°].

BENZODIHYDROFURANS IN THE RESINOUS EXUDATE FROM DIPLOSTEPHIUM CINEREUM

Del exudado resinoso de Diplostephium cinereum, se han aislado dos benzodihidrofuranos. Sus estructuras fueron determinadas por espectroscopia de alta resolucion como: 13-(2-metilpropanoiloxi)toxol (2) y 13[(R)-3-hidroxi-3-fenilpropanoiloxi]toxol (3)

Thermodynamic, crystallographic and solvent extraction properties of cobalt(II), nickel(II) and copper(II) complexes of ethylenediamine- N,N,N′,N′-tetraacetanilide

Abstract Complexes of ethylenediamine-N,N,N′,N′-tetraacetanilide (edtan, C34H36N6O14) with cobalt(II), nickel(II) and copper(II) in the solid state and in solution are reported for the first time. Thermodynamic data (stability constant, and derived Gibbs energy, enthalpy and entropy changes)for the 1 : 1 complexation of edtan with the metal ions at 298.15 K in water-saturated butan-1-ol gave the selectivity sequence log10Ks; Ni2+, 4.56±0.02; Cu2+, 4.41±0.01; Co2+, 4.18±0.04 as found from microcalorimetric titration studies. The entropies suggested that the structure of the 1 : 1 complex with copper(II) contains fewer chelate rings than those for nickel(II) and cobalt(II) (δcS0 : Cu-21.4, Co 5.7, Ni 3.9 J mol−1K−1). Solid complexes of the metal ions with edtan and perchlorate as the counter anion were prepared. For each, a complex with a 1 : 1 metal: edtan stoichiometry with non-coordinated perchlorate was isolated. The X-ray structure of [Cu(edtan)(H2O)][ClO4]2·1.5H2O (1) revealed a six-coordinate Cu centre with edtan acting as pentadentate ligand (2N, 3O) with the coordination sphere completed by an oxygen atom from water. In striking contrast to the Cu complex, the Co centre in [Co(edtan)(H2O)][ClO4]2·H2O·0.5C2H5OH (2) is seven-coordinate with hexadentate edtan (2N, 4O) and one coordinated water molecule. There is thus an excellent confirmation of the results obtained from the microcalometric study in that edtan forms four chelate rings to Cu but five to Co in the solid state. The ability of the ligand to extract metal ions from water to the water-saturated butan-1-ol phase was assessed from distribution data as a function of the aqueous phase hydrogen ion concentration and of the ligand concentration in the organic phase. The data showed that Cu2+ is selectively extracted over a wide range of aqeous phase hydrogen ion concentrations.

The arsenate ion as an intra- and inter-molecular bridging ligand: Crystal structure and spectroscopic studies of the tetrakis(Hydrogen arsenato)dimolybdenum(III) ion

SummaryDimolybdenum tetraacetate Mo2 (OAc)4 reacts with concentrated solutions of arsenic acid in air to form [Mo2(HAsO4)4]2− and some related ions which can be isolated with caesium or pyridinium cations: Cs2[Mo2(HAsO4)4]3 H2O (1), (C5NH6)3[Mo2(HAsO4)Cl] (2), (C5NH6)3 [Mo2(HAsO4)4Br] (3) and (C5NH6)2[Mo2(HAsO4)4]2H2O (4). The four compounds are stable indefinitely in air at room temperature. The last compound has been fully characterized structurally. It crystallizes in the space group P21/a witha = 11.057(2)Å,b = 10.720(2)Å,c = 10.303(4)Å, β = 91.56(3)°, V = 1220.8(6)Å3 and Z = 2. Interestingly, the overall structure can be described in terms of molybdenum-containing layers stacked in the c direction, in which arsenato ligands equatorially coordinating the Mo26+ unit play the role of an axial ligand for the next closest unit. The [Mo2(HAsO4)4]2− ion has a paddlewheel structure very similar to that of [Mo2(HPO4)4]2− and [Mo2(SO4)4]4−, 3−. The length of the Mo-Mo triple bond of (4) is 2.265(1)Å. Comparing the HPO42− and HAsO42− complexes, the electronic spectra have been found to be very similar, but the Raman spectra show a noticeable decrease of frequency from phosphato to arsenato-complexes for the Mo-Mo stretching modes. This decrease may come from a mechanical coupling between HAsO42− deformation modes and ν(Mo-Mo) and ν(Mo-O) vibrations, but is more likely due to a weakening of the Mo-Mo bond strained by the bridging ligand.

Synthesis, characterisation and X-ray diffraction studies of new lower rim calix[4]arene derivatives containing mixed donor atoms

New lower rim p-tert-butylcalix[4]arene derivatives containing tetrathiophene functional groups as well as derivatives with two different pendant arms alternately arranged, one of which is in all cases a methylsulfanyl substituent whilst the other is either a tertiary amine (aliphatic of alicyclic) or a methylthiophene or an amide substituent, have been synthesised and characterised by 1H and 13C NMR spectroscopy in chloroform at 298 K. The use of phase transfer catalysis in the synthesis of calixarene derivatives is discussed. X-Ray diffraction studies of 5,11,17,23-tetrakis-(1,1-dimethylethyl)-25,26,27,28-tetrakis-[2-(thienyl)methoxy]calix[4]arene 1a and 5,11,17,23-tetrakis-(1,1-dimethylethyl)-25,27-bis[(2-methylsulfanyl)ethoxy]-26,28-bis[2-(diethylamino)ethoxy]calix[4]arene 2b are reported.