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A ternary silver-mercury-pyridyltellurolate – [Ag4Hg(μ-TeoPy-κTe)3(μ3-TeoPy-κTe)2(μ-TeoPy-κN,Te)(PPh3)2] (1) – was obtained by the reaction of Ag(PPh3)NO3 and Hg(OAc)2 with a solution of LiTeoPy (oPy = 2-pyridyl, Ph = phenyl). In a similar fashion, the cluster [Cu4(μ3-TePh)3Cl(phen)3]⋅0.5C2H6O (2) was obtained when CuCl and 1,10-phenanthroline (phen) reacted with a solution of NaTePh. The alkali-metal aryltellurolate solutions were generated in situ from the reduction of the appropriate diarylditellane with LiBH4 (for 1) or NaBH4 (for 2). Single crystal X-ray diffraction studies were performed, and molecular structures were discussed in detail. Density Functional Theory (DFT) calculations were carried out to better understand the nature of the central moiety connectivity among the metals and the tellurium atoms.

The topological properties of the electron density, ρ(r), and the electron localization function (ELF) are used to study the ground state properties of [M4(µ-EO3)2(µ4-EO3)2(bipy)4] (M = Mn, Fe, Co, Ni, Cu, Zn (d5–10) and E = Se,Te) compounds. The Quantum Theory of Atoms in Molecules was employed, through the use of the Density Functional Theory, to analyze the topological parameters of the M - O and M – N interactions. The results indicate that these interactions are in the transition region (II) between shared to closed-shell (Espinosa et al., 2002). The interactions E–O are in the border region between shared-shell (III) and the intermediate region (II) with dative covalent character. The ELF was used to complete the understanding of the electronic distribution. The topological parameters of the electronic density are then used to elucidate the correlation between the optimized geometries of the coordination spheres of the transition metal atoms and the electronic configurations of these transition metals and the chalcogen atoms.

In this article we describe the synthesis and characterization of [PhTe(tu)2][PhTeI4] and [MesTe(tu)][PhTeX4] (tu = thiourea, X = Br, I), containing multivalent tellurium species. During the syntheses of the compounds, the formation of different species, such as [PhTe(tu)I] or [I(tu)2][PhTeI4] was found, which were isolated and characterized. Thiourea was used in order to explore the relevance of Te···S bonds in the solid state structures of the products compared to related compounds with Te···X and X···X bonds in their molecular structures. Different types of chalcogen-chalcogen, chalcogen-halogen and halogen-halogen interactions are described by the combination of crystallographic data and computational methods. The nature of these interactions was evaluated by the noncovalent interaction index (NCI), and quantum theory of atoms in molecules (QTAIM) analyses.

The compounds [Pd2I2{Te((2,6-OCH3)2C6H3)}2(PCy3)2] (1), [Pd2I2{Te((2,6-OCH3)2C6H3)}2(PR2R')2]∙2CH3CN (2), [Pd2{Te((2,6-OCH3)2C6H3)}2(phen)2][Hg2Br6(phen)2] (3), [Pd2Cl2(TePh2)2(TePh)2] ∙ DMF (4), [Pd2(SePh)2(2,2′-bipy)2][HgBr4]∙2DMF (5), [Pd2(SePh)2-(phen)2][HgI4]∙5DMF (6), [Pd2{Te((2,6-OCH3)2C6H3)}2(phen)2][Hg2I6]-[Hg((2,6-OCH3)2C6H3)2] (7) containing [Pd2(µ-ER)2] core (E = Se, Te; R = aryl) were synthesized and characterized by IR spectroscopy, elemental analysis and X-ray crystallography. Intermolecular metallophilic interactions were evaluated through crystallographic studies combined with Density Functional Theory calculations. The structural stability of 4–7 were investigated taking in account the interactions E⋯E, Pd⋯Pd and Pd⋯Hg between [Pd2(µ-ER)2] cores.