Martin Reichelt

catena-Poly[[di-tert-butyl­tin(IV)]-μ-oxalato]

The title compound, [Sn(C4H9)2(C2O4)]n, an unexpected side product in the reaction of di-tert-butyltin(IV) oxide with nitric acid, represents the first diorganotin(IV) oxalate to be structurally characterized. The SnIV atom of the one-dimensional coordination polymer is located on a mirror plane and is coordinated by two chelating oxalate ions with two rather different Sn—O bond lengths of 2.150 (1) and 2.425 (1) Å, and two t-butyl groups with Sn—C bond lengths of 2.186 (2) and 2.190 (2) Å. The coordination polyhedron around the SnIV atom is a distorted tetragonal disphenoid. The centrosymmetric oxalate ion also has an asymmetric coordination geometry, as reflected by the two slightly different C—O bond lengths of 1.242 (2) and 1.269 (2) Å. The chains of the polymer propagate along the b-axis direction. Only van der Waals interactions are observed between the chains.

Methyl­phospho­nic acid, CH3PO(OH)2

The asymmetric unit of the title compound, CH5O3P, contains two independent molecules with nearly identical bond lengths and angles. In the crystal, each of the molecules acts as acceptor (P=O) and donor (P—OH) of four hydrogen bonds to three adjacent molecules, resulting in the formation of two different bilayers (one for each molecule) stacked perpendicular to the a axis in the crystal.

Diacetatodi-tert-butyltin(IV)

The title compound, [Sn(C4H9)2(CH3COO)2], was synthesized in order to study the influence of large organic groups on the molecular structure of diorganotin diacetates. The title compound exhibits the same structure type as other diorganotin(IV) diacetates characterized by an unsymmetrical bidentate bonding mode of the two acetate groups to tin. The influence of the t-butyl groups on this molecular structure is expressed in two significant differences: tin—carbon bond lengths are much more longer than in the other diacetates, as are the additional interactions of the acetate groups with the tin atom. Intermolecular interactions are restricted to C—H⋯O ones similar to those in the other diacetates, giving rise to a chain-like arrangement of the molecules with the tin atoms and acetate groups in the propagation plane.

Hexa-μ2-acetato-hexa-n-butyl­hexa-μ3-oxido-tin(IV) toluene monosolvate

The title compound, [Sn6(C4H9)6(CH3COO)6O6]·C7H8, has one half-toluene molecule and one half-organotin molecule in the asymmetric unit. The latter is situated about an inversion centre and belongs to the class of hexameric monoorganooxotin carboxylates with a hexagonal prismatic or ‘drum-like’ motif of the central tin–oxygen core. Two Sn3O3 rings in a flat-chair conformation are linked via six Sn—O bonds and six bridging acetate groups. All Sn atoms have approximate octahedral coordination geometry. The Sn—O bonds which are trans to the alkyl group are significantly shorter than the others. One butyl group is disordered over two different sites, with occupancies of 0.9:0.1. Very large atomic displacement parameters of the toluene molecule indicate an unresolvable disorder about the twofold axis.

(E)-4-(2,3-Dihydro-1,3-benzothia­zol-2-yl­idene)-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one

In the title compound, C17H13N3OS, the dihedral angle between the ring systems is 2.22 (5)°. The N—H grouping participates in both intra- and intermolecular N—H⋯O hydrogen bonds, the latter leading to dimers related by a twofold rotation axis.

Redetermination of the crystal structure of di­methyl­bis­[2,4-penta­nedionato(1−)-κ2O2,O4]tin(IV)

The current redetermination confirms the previous structure report, but with considerably higher precision and accuracy.

Crystal structure of the coordination compound of triiodidomethyltin(IV) with 2,2′-bi­pyridine, MeSnI3·bipy

The title complex is one of the few structurally characterized coordination compounds of an organotin(IV) trihalide with 2,2′-biypridine. Its distorted octahedral geometry shows a meridional arrangement of the I atoms and the methyl group is in-plane with the five-membered chelate ring. Directional intermolecular interactions are restricted to weak I⋯H van der Waals contacts.

Crystal structure of a one-dimensional coordination polymer of tin(IV) bromide with 1,4-di-thiane.

The title compound, [SnBr4(C4H8S2)] {systematic name: catena-poly[[tetrabromidotin(IV)]-μ-1,4-dithiane-κ2 S:S′]}, represents the first 1,4-dithiane complex with tin as coordination centre. The asymmetric unit consist of half a formula unit with the tin(IV) atom at the centre of symmetry at 0,0,1/2 (Wyckoff symbol b) and a centrosymmetric 1,4-dithiane molecule with the centre of symmetry in 1/2,0,1 (Wyckoff symbol c). The tin(IV) atom is coordinated in a distorted octahedral manner by the four bromine atoms and two sulfur atoms of two 1,4-dithiane molecules in a trans-position. Sn—Br [mean value: 2.561 (5) Å] and Sn—S distances [2.6546 (6) Å] are in the typical range for octahedrally coordinated tin(IV) atoms and the dithiane molecule adopts a chair conformation. The one-dimensional polymeric chains propagate along the [101] direction with weak intermolecular Br⋯Br [3.5724 (4) Å] between parallel chains and weak Br⋯H interactions [2.944–2.993 Å] within the chains.

Crystal structure of catena-poly[[aquadi-n-propyl­tin(IV)]-μ-oxalato]

The SnIV atom in the title compound shows a slightly distorted pentagonal–bipyramidal SnC2O5 coordination with the C atoms of the aliphatic chain in the axial positions.

New polymorphs of tiphenyltin(IV) halides

Triphenyltin(IV) halides, Ph3SnHal with Hal = Cl, Br, and I, are white, low melting solids soluble in many indifferent organic solvents like chloroform or toluene. In these solutions as well as in solid they consist of isolated, tetrahedral molecules which intermolecular interactions restricted to van-der Waals ones. These molecules are characterized through the three aromatic phenyl rings attached at a certain pitch angle around the shaft of the tin-halide bond giving them a propeller-like shape accompanied by molecular chirality as the normal vectors of the blades can be oriented clock-wise or anti-clock-wise with respect to the tin-halide bond. In the past, a lot of different polymorphs of triphenyltin(IV) halides with up to 24 molecules in the unit cell have been described, all crystallizing in centrosymmetric space groups, implying that both chiral molecules are present. From a structural point of view there are still several questions of general interest: (i) how are both enantiomers distributed in these polymorphs, (ii) how are the molecular dipole moments arranged, and (iii) how are the different polymorphs related to each other. During various studies on the syntheses and reactivity of triphenyltin(IV) halides we found four additional polymorphs, which constitute new structure types in case of δ-Ph3SnI (Z = 8, monoclinic, P21/c), and ε-Ph3SnI (Z = 12, monoclinic, P21/c) or complete the already existing α-Ph3SnCl structure type (Z = 24, rhomboedric, R-3) in case of β-Ph3SnBr and ζ-Ph3SnI. Analysing the new and already known polymorphs with respect to the three questions mentioned above points out (i) the influence of crystal symmetry elements (screw axes and glide planes) as well as (ii) the importance of the formation of supramolecular dimers composed of both enantiomers with an antiparallel orientation of the two molecular dipole moments, on the different structure types formed and their relation among each other.