G.M. de Lima

Structural and spectral studies of thiosemicarbazones derived from 2-acetylthiophene

Abstract The reaction of 2-acetylthiophene with thiosemicarbazide and 4-phenylthiosemicarbazide yielded 2-acetylthiophene thiosemicarbazone ( 1 ) and 2-acetylthiophene 4-phenylthiosemicarbazone ( 2 ). Both compounds were fully characterised by 1 H and 13 C{ 1 H}-NMR and infrared spectroscopies and showed satisfactory elemental analysis. The X-ray crystallographic studies can be summarised as follows: ( 1 ) triclinic, P -1, a =5.6515(3), b =10.1401(6), c=11.7910(7) A , α =105.4260(10)°, β =94.202(2)° and γ =90.234(2)°, V=649.42(6) A 3 and Z =2; ( 2 ) triclinic, P -1, a =9.0352(4), b =9.7898(4), c=12.1839(5) A , α =104.6820(10)°, β =102.8180(10)° and γ =108.28(10)°, V=935.08(7) A 3 and Z =4.

Synthesis, characterisation and molecular structure of Ru–Sn(II) containing derivatives

Abstract A series of new ruthenium-based derivatives were obtained by reactions of [Ru(η-C5H5)(PPh3)2Cl]. They are as follows: [Ru(η-C5H5)(PPh3)2SnF3] (1), [Ru(η-C5H5)(PPh3)2SnCl3] (2), [Ru(η-C5H5)(PPh3)2SnBr3] (3), [Ru(η-C5H5)(dppe)SnF3] (4), [Ru(η-C5H5)(dppe)SnCl3] (5), and [Ru(η-C5H5)(dppe)SnBr3] (6). Compounds 1–6 were studied by IR, NMR (1H, 13C, 31P and 119Sn) and 119Sn Mossbauer spectroscopies. In addition, 1, 2, 3 and 6 were structurally authenticated by X-ray crystallographic studies. Finally all the derivatives were tested as catalysts in the methanol to acetic acid conversion process, showing promising activities.

Pyrolysis of organotin compounds: A preparative method for nanometric tin dioxide powders

Nanometric tin dioxide powders were obtained by pyrolysis of organotin oxide based compounds such as Sn3O3Bu6 (1) and Sn4O6Bu4 (2) (Bu = n-butyl). The thermal behaviour of 1 and 2 was studied by thermogravimetric analysis (TG) and with simultaneous differential thermal analysis (DTA). Pyrolysis experiments were carried out in three different atmospheres (N2, air and O2) and the residual powders were characterised by X-ray diffraction (XRD) and the morphology was investigated by scanning electron microscopy (SEM). The XRD data showed the formation of pure SnO2 when the decomposition process was accomplished in air or O2, however, in N2, and for Sn4O6Bu4, the X-ray study indicated the formation of a mixture of SnO/SnO2. The micrographs revealed grains of 30–40 nm, approximately.

119Sn Mössbauer spectroscopic study of nanometric tin dioxide powders prepared by pyrolysis of organotin oxides

Abstract This paper reports the results of 119 Sn Mossbauer Spectroscopy of residues from the pyrolysis of Sn 3 O 3 Bu 6 ( 1 ) and Sn 4 O 6 Bu 4 ( 2 ) (Bu= n -butyl) in air, O 2 , and N 2 . The isomer shift and quadrupole splitting parameters of the samples allowed the identification of the tin oxidation states, as well as the number of non-equivalent coordinated tin sites. The result of the 119 Sn Mossbauer study correlates perfectly with those of X-ray electron probe microanalysis, scanning electron microscopy and X-ray powder diffraction for the formation of pure SnO 2 from the decomposition of ( 1 ) and ( 2 ) in air or O 2 . However, in N 2 , evidences suggest the formation of a mixture of SnO 2 and SnO.

Dibenzo-18-crown-6.

The asymmetric unit of the title compound, C20H24O6, contains two molecules that are identical within standard deviations concerning bond lengths and angles as well as their conformations. In the crystal structure, weak C—H⋯O interactions help to consolidate the packing.

Synthesis, characterization, and biocide activity of new dithiocarbamate-based complexes of In(III), Ga(III), and Bi(III) – Part III

In this work, we describe the syntheses, characterization, and antifungal activity of [In{S2CNR(R1)}3] (1), [Ga{S2CNR(R1)}3] (2), [Bi{S2CNR(R1)}3] (3), [In{S2CNR(R2)}3] (4), [Ga{S2CNR(R2)}3] (5), and [Bi{S2CNR(R2)}3] (6) {R = Me; R1 = CH2CH(OMe)2; and R2 = 2-methyl-1,3-dioxolane}. All complexes have been characterized using infrared and 1H and 13C spectroscopy, and the structures of 1, 3, 4, and 6 have been authenticated by X-ray diffraction. The In(III)–dithiocarbamate bonding scheme depicts a distorted octahedral with asymmetric In(III)–S bonds and S–In–S angles. A pentagonal bipyramid is observed for the corresponding Bi(III) complexes with intermolecular Bi–S associations through the lone pair of electrons. The antifungal activities of 1–6 have been screened against Aspergillus niger, Aspergillus parasiticus, and Penicillium citrinum, and the results have been compared with those of nystatin and miconazole nitrate, as control drugs. Graphical Abstract

Bis(2-{[2,8-bis­(trifluoro­meth­yl)quinolin-4-yl](hydr­oxy)meth­yl}piperidin-1-ium) tetra­chloridodiphenyl­stannate(IV)

In the title salt, (C17H17F6N2O)2[Sn(C6H5)2Cl4], the complete anion is generated by crystallograaphic inversion symmetry, giving a trans-SnC2Cl4 octahedral coordination geometry for the metal atom. In the cation, the quinoline residue is almost normal to the other atoms, so that the ion has an L-shaped conformation [the C—C—C—C torsion angle linking the fused-ring systems is 100.9 (7)°]; the six-membered piperidin-1-ium ring has a chair conformation. An intramolecular N—H⋯O interaction occurs. In the crystal, N—H⋯Cl and O—H⋯Cl hydrogen bonds link the components into a supramolecular chain propagating along the a axis. C—H⋯Cl interactions are also present.

5-{[(E)-2-(4-Iodo-phen-yl)hydrazinyl-idene]meth-yl}thio-phene-2-carbaldehyde.

The title compound, C12H9IN2OS, has an overall U-shape, with a dihedral angle of 21.4 (3)° between the thiophene and benzene rings. In the crystal, supramolecular chains mediated by N—H⋯O hydrogen bonds are formed along the b-axis direction.

fac-(2-Amido­ethyl-κ2C1,O)aqua­tri­chlorido­tin(IV) 1,4,7,10,13,16-hexa­oxacyclo­octa­decane (2/1)

The asymmetric unit of the title compound, [Sn(C3H6NO)Cl3(H2O)]2·C12H24O6, comprises a six-coordinate tin complex and a 18-crown-6 molecule, the latter disposed about a centre of inversion. The tin atom is coordinated by three Cl atoms, that define a facial arrangement, a chelating C-,O- ligand, and a water molecule. The resulting CCl3O2 donor set defines a distorted octahedral geometry. The tin-bound aqua ligand forms O—H⋯O hydrogen bonds to the centrosymmetric 18-crown-6 molecule, resulting in a tri-molecular aggregate. These assemble into a supramolecular chain along the a axis being connected by N—H⋯O hydrogen bonds.

Bis[2-(ethoxy-carbonyl-amino)ethan-aminium] hexa-bromidostannate.

In the title salt, (C5H13N2O2)2[SnBr6], the Sn atom (site symmetry ) exists in a slightly distorted octahedral geometry. The cation is non-planar as the terminal CH2NH3 + residue lies below the plane defined by the remaining non-H atoms. In the crystal, cations associate via N—H⋯O hydrogen bonds involving the ammonium and carbonyl residues, forming a 14-membered {⋯HNC2NCO}2 synthon. The cations and anions are arranged in alternating layers arranged along the a-axis direction, the major association between them being N—H⋯Br contacts.