T. Subrahmanyan

Bio: T. Subrahmanyan is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Crystal structure & X-ray crystallography. The author has an hindex of 3, co-authored 3 publications receiving 17 citations.

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

Abstract: 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.

On the Importance of σ–Hole Interactions in Crystal Structures

Abstract: Elements from groups 14–18 and periods 3–6 commonly behave as Lewis acids, which are involved in directional noncovalent interactions (NCI) with electron-rich species (lone pair donors), π systems (aromatic rings, triple and double bonds) as well as nonnucleophilic anions (BF4−, PF6−, ClO4−, etc.). Moreover, elements of groups 15 to 17 are also able to act as Lewis bases (from one to three available lone pairs, respectively), thus presenting a dual character. These emerging NCIs where the main group element behaves as Lewis base, belong to the σ–hole family of interactions. Particularly (i) tetrel bonding for elements belonging to group 14, (ii) pnictogen bonding for group 15, (iii) chalcogen bonding for group 16, (iv) halogen bonding for group 17, and (v) noble gas bondings for group 18. In general, σ–hole interactions exhibit different features when moving along the same group (offering larger and more positive σ–holes) or the same row (presenting a different number of available σ–holes and directionality) of the periodic table. This is illustrated in this review by using several examples retrieved from the Cambridge Structural Database (CSD), especially focused on σ–hole interactions, complemented with molecular electrostatic potential surfaces of model systems.

Structure and reactivity of [{Te(NMe2)2}∞]; application to the preparation of metalloorganic tellurium(II) compounds

Abstract: Condensation of the highly reactive complex [{Te(NMe2)2}∞]1, prepared by the reaction of TeCl4 and Li[NMe2](1 : 4 equivalents), with various organic acids has been used as a route to tellurium(II) metalloorganic complexes. The crystal structures of 1 and of Te(SCPh3)22, formed by the reaction of 1 with Ph3CSH(1 : 2 equivalents), have been determined.

A facile synthesis of potassium selenocarboxylates and their oxidation with XeF2 to diacyl diselenides: An X‐ray structural analysis of di(4‐methoxybenzoyl) diselenide

Abstract: Several potassium selenocarboxylates were synthesized in moderate to good yields by the direct reaction of acyl chlorides with potassium selenide. The potassium salts were readily oxidized with XeF2 to give diacyl diselenides in quantitative yields. The structure of di(4-methoxybenzoyl) diselenide was established by X-ray diffraction analysis. Intramolecular interactions between the carbonyl oxygen and the selenium that is connected to the opposite carbonyl group were observed. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 373–379, 1999