The synthesis of the o-phenylene-bridged ditin species o-C 6 H 4 (SnXMe 2 ) 2 (2, X ) Cl; 4, X ) F) and o-C 6 H 4 (SnCl 2 Me) 2 (3) is reported and the crystal structures of [o-C 6 H 4 (SnClMe 2 ) 2 ‚ Cl] -[(Ph 3 N) 2 P] + (5) and [o-C 6 H 4 (SnClMe 2 ) 2 ‚F] -[K‚C 20 H 24 O 6 ] + (7) are described. Variabletemperature 119 Sn and 19 F NMR studies indicate that 2 and 4 act as bidentate Lewis acids toward chloride and fluoride ions exclusively forming the stable anionic 1:1 complexes 5, 7, and [o-C 6 H 4 (SnFMe 2 ) 2 ‚F] -[Et 4 N] + ( 8). No formation of dianionic 1:2 adducts was observed even with excess of halide ions. The affinity of 2 toward fluoride is greater than toward chloride. Reaction of 2 with HMPA gives the neutral complex o-C 6 H 4 (SnClMe 2 ) 2 ‚(Me 2 N) 3 PO (10), the crystal structure of which is also described.

The homoleptic 1:1 Lewis pair (LP) complex [MesTe(TeMes2)]O3SCF3 (1) featuring the cation [MesTe(TeMes2)](+) (1a) was obtained by the reaction of Mes2Te with HO3SCF3. The reaction of 1 with Ph3E (E = P, As, Sb, Bi) proceeded with substitution of Mes2Te and provided the heteroleptic 1:1 LP complexes [MesTe(EPh3)]O3SCF3 (2, E = P; 3, E = As) and [MesTe(SbPh3)][Ph2Sb(O3SCF3)2] (4) featuring the cations [MesTe(EPh3)](+) (2a, E = P; 3a, E = As; 4a, E = Sb) and the anion [Ph2Sb(O3SCF3)2](-) (4b). In the reaction with Ph3Bi, the crude product contained the cation [MesTe(BiPh3)](+) (5a) and the anion [Ph2Bi(O3SCF3)2](-) (5b); however, the heteroleptic 1:1 LP complex [MesTe(BiPh3)][Ph2Bi(O3SCF3)2] (5) could not be isolated because of its limited stability. Instead, fractional crystallization furnished a large amount of Ph2BiO3SCF3 (6), which was also obtained by the reaction of Ph3Bi with HO3SCF3. The formation of the anions 4b and 5b involves a phenyl group migration from Ph3E (E = Sb, Bi) to the MesTe(+) cation and afforded MesTePh as the byproduct, which was identified in the mother liquor. The heteroleptic 1:1 LP complexes 2-4 were also obtained by the one-pot reaction of Mes2Te, Ph3E (E = P, As, Sb) and HO3SCF3. Compounds 1-4 and 6 were investigated by single-crystal X-ray diffraction. The molecular structures of 1a-4a were used for density functional theory calculations at the B3PW91/TZ level of theory and studied using natural bond order (NBO) analyses as well as real-space bonding descriptors derived from an atoms-in-molecules (AIM) analysis of the theoretically obtained electron density. Additionally, the electron localizability indicator (ELI-D) and the delocalization index are derived from the corresponding pair density.

Structural investigations, i.e. solid-state (X-ray), solution ( 1 H NMR) and gas-phase (theoretical), on molecules with the general formula MeOC(LS)N(H)C 6 H 4 -4-Y: Y 5 H (1), NO 2 (2), C(LO)Me (3), Cl (4) have shown a general preference for the adoption of an E-conformation about the central C-N bond. Such a conformation allows for the formation of a dimeric hydrogen-bonded { … H-N-CLS} 2 synthon as the building block. In the cases of 1-3, additional C-H … O interactions give rise to the formation of tapes of varying topology. A theoretical analysis shows that the preference for the E-conformation is about the same as the crystal packing stabilisation energy and consistent with this, the compound with Y 5 C(LO)OMe, (5), adopts a Z-conformation in the solid-state that facilitates the formation of N-H … O, C-H … O and C-H … S interactions, leading to a layer structure. Global crystal packing considerations are shown to be imperative in dictating the conformational form of molecules 1-5.

Si NMR spectroscopy, IR spectroscopy and electrospray mass spectrometry, and in the case of 4 and 6 also by X-ray diffraction. The key feature of the crystal structures is the incorporation of tert-butoxy groups into the hydrogen bonding. The results obtained are discussed in relation to the sol±gel process.

The stoichiometrically controlled chlorination of the diarylditelluride (8-Me(2) NC(10) H(6) Te)(2) with SO(2) Cl(2) afforded the aryltellurinyl chloride 8-Me(2) NC(10) H(6) TeCl (1) and the aryltellurium trichloride 8-Me(2) NC(10) H(6) TeCl(3) (2). Alternatively, 1 was obtained by the reaction of the aryltellurenyl diethyldithiacarbamate 8-Me(2) NC(10) H(6) Te(S(2) CNEt(2) ) with hydrochloric acid. The base hydrolysis of 2 provided the novel telluroxanes (8-Me(2) NC(10) H(6) Te)(2) OCl(4) (3), (8-Me(2) NC(10) H(6) Te)(6) O(5) Cl(8) (4), (8-Me(2) NC(10) H(6) Te)(6) O(8) Cl(2) (5), [(8-Me(2) NC(10) H(6) Te)(2) O(3) ](n) (6) and (8-Me(2) NC(10) H(6) Te)(6) O(8) (OH)(2) (7) depending on the reaction conditions applied. The reaction of 7 with ClTe(OiPr)(3) in the presence of water gave rise to the telluroxane (8-Me(2) NC(10) H(6) Te)(6) Te(2) O(12) Cl(2) (8). The crystal and molecular structures of 1-3 and 5-8 were determined by X-ray crystallography. The telluroxane clusters and polymers 6-8 hold potential as model compounds for alkali tellurite glasses (M(2) O)(x) (TeO(2) )(1-x) (M=Li, Na, K) for which no precise structural data are available.

Structural data (X-ray and solution and solid-state 119 Sn NMR) show that skew-trapezoidalbipyramidal diorganotin compounds of 2-quinaldate are invariably monomeric, owing to the steric bulk of the carboxylate ligand. In contrast, most of the analogous compounds of 2-picolinate (2-pic) can increase their coordination number by polymerization or the incorporation of solvent in their coordination sphere in the solid state. The exceptional compound is tBu 2 Sn(2-pic) 2 (3), for which no increase in coordination number is apparent, a result that is correlated with the bulky tert-butyl groups. Thus, judicious choice of tin or ligand substituents can be exploited to dictate coordination number and/or the degree of supramolecular aggregation in the investigated systems.

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The characterization of the previously reported diorganotellurium oxides R 2 TeO (R ) Ph (1) and p-MeOC 6 H 4 (2)) was revisited by osmometric molecular weight determinations, 125 Te NMR spectroscopy, and electrospray spectrometry (ESMS) in solution and by 125 Te MAS NMR spectroscopy in the solid state. The single-crystal X-ray structure of 2 revealed a polymeric arrangement that features a zigzag configured Te-O backbone without any secondary Te‚‚‚O interactions. In solution 1 and 2 exist predominantly as monomers but appear to be in equilibrium with higher oligomers to a minor extent.