A survey of tellurium-centered secondary-bonding supramolecular synthons

Synthesis and characterisation of mercaptoimidazole, mercaptopyrimidine and mercaptopyridine complexes of platinum(II) and platinum(III). The crystal and molecular structures of tetra(2-mercaptobenzimidazole)- and tetra(2-mercaptoimidazole)platinum(II) chloride

This review summarizes the data for over five hundred and fifty six-, seven- and eight-coordinate Cu(II) coordination compounds. The six-coordinate derivatives are mostly distorted tetragonal (elongation along a single C 4 axis). The seven-coordinate derivatives are only penta-gonal-bipyramidal with different degrees of distortion and the eight-coordinate complexes are dodecahedral. The most common ligands are O- and N-donors. There is a trend for the Cu-L distance to increase with covalent radius of the coordinated atom and also increasing coordination number. In general, Cu(II) compounds “prefer” a monoclinic class and are blue or green. Several relationships were found and discussed. The data are compared and discussed with those of four- and five-coordinate Cu(II) compounds.

Copper(ii) coordination compounds: classification and analysis of crystallographic and structural data ii. mononuclear-, hexa-, hepta-and octacoordinate compounds

The 3 centre-4 electrons (3c-4e) and the donor/acceptor or charge-transfer models for the description of the chemical bond in linear three-body systems, such as I3– and related electron-rich (22 shell electrons) systems, are comparatively discussed on the grounds of structural data from a search of the Cambridge Structural Database (CSD). Both models account for a total bond order of 1 in these systems, and while the former fits better symmetric systems, the latter describes better strongly asymmetric situations. The 3c-4e MO scheme shows that any linear system formed by three aligned closed-shell species (24 shell electrons overall) has reason to exist provided that two electrons are removed from it to afford a 22 shell electrons three-body system: all combinations of three closed-shell halides and/or chalcogenides are considered here. A survey of the literature shows that most of these three-body systems exist. With some exceptions, their structural features vary continuously from the symmetric situation showing two equal bonds to very asymmetric situations in which one bond approaches to the value corresponding to a single bond and the second one to the sum of the van der Waals radii of the involved atoms. This indicates that the potential energy surface of these three-body systems is fairly flat, and that the chemical surrounding of the chalcogen/halogen atoms can play an important role in freezing different structural situations; this is well documented for the I3– anion. The existence of correlations between the two bond distances and more importantly the linearity observed for all these systems, independently on the degree of their asymmetry, support the state of hypervalency of the central atom.

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The nature of the chemical bond in linear three-body systems: from i3- to mixed chalcogen/halogen and trichalcogen moieties.

Near-IR absorption due to supramolecular electronic interaction in an extended 3D hydrogen-bonding network material: synthesis, crystal structure and properties of [4,4′-H2bpy][Cu(mnt)2] ☆

The crystal and molecular structure of the title compound, C16H24CuN6S4, is reported. The crystals are monoclinic: space groupP21/c,Z=4,a=13.230(3),b=11.518(9),c=16.269(6) A,β=95.07(2)°. The structure was solved by the heavy-atom method, and refined by full-matrix least squares toR=0.059 for 1907 unique diffractometer data. The anions have approximately 222 (D2) symmetry, with an angle of 41.14(1)° between the normals to planes of the ligands. The amino atoms of the cations have an approximate tetrahedral configuration. The anions are well separated from each other, the closest Cu-Cu distance being 7.811 (2) A. The anionic units can be considered as being stacked alongb in columns. The metal atoms are not collinear along the stack axis, but form a kind of kinked chain.

Crystal and molecular structure of bis(tetramethyl-ammonium)bis(maleonitriledithiolato)cuprate(II). Structure of C16H24CuN6S4

The synthesis, properties, and structural characterization of the title compound, C14H10O2S2Te, are reported. The crystals are monoclinic, space groupC2/c (No. 15) witha=24.369(6),b=4.333(2),c=14.569(3) A, andβ=109.56(2)°,V=1449.57 A3,M=402, andD

 x
 =1.843 g cm−3 forZ=4. The structure was solved by the heavy-atom method and refined by full-matrix least squares toR=0.029 andR

 w
 =0.027 for 772 diffractometer data. Crystal structure analysis and IR spectroscopic study indicate that the tellurium is covalently bonded to sulfur. There are weak secondary interactions between tellurium and oxygen which complete an S2O2 coordination around tellurium.

M. Seshasayee

Papers

Crystal and molecular structure of bis(tetramethyl-ammonium)bis(maleonitriledithiolato)cuprate(II). Structure of C16H24CuN6S4

Synthesis, properties, and molecular structure of bis(thiobenzoato-S)tellurium(II), C14H10O2S2Te(II)

Synthesis, properties and crystal structure of bis(thiobenzoato-s) selenium(II)

Synthesis and structure of tetrakis(phenylenethiourea)tellurium(II) chloride dihydrochloride, C28H26N8S4Cl4Te