Propeller-Like Chirality of Methyl-Tris (2,6-diisopropylphenoxy)Silylsulfide

Abstract

Two new methylsilylsulfides are synthesized. Propeller-like chirality is described for triaryloxysilanethiol and its methyl derivative. S-methylation of the silanethiol lowers the overall symmetry of the unit cell.

Variable-temperature X-ray diffraction study of structural parameters of NH---S hydrogen bonds in triethylammonium and pyridinium silanethiolates

“…In TDST-TEA both hydrogenbonded molecules, i.e. silanethiolate and protonated amine, exhibit helical chirality (Herman et al, 2016). It is interesting to observe that whereas both helical enantiomers of TDST are found in crystals, they are accompanied by only one helical form of triethylamine.…”

RM1 Semiempirical Model: Chemistry, Pharmaceutical Research, Molecular Biology and Materials Science

“…Energetic properties of species formed during chemical reactions are widely employed by organic chemists to build energy surfaces. 110,111,114,115,137 By building energy surfaces, for example with structural, and thermodynamic data of species formed during the reaction, it is possible to carry out studies on the nature of the reaction pathways. The energy surfaces can result in the identification of the species most likely to occur from a thermodynamic perspective.…”

“…Articles that reported the use of RM1 method for the prediction of energetic properties of conformer species of organic compounds, and to build an energy surface appeared. 110,111,114,115,137 In these studies, the RM1 method was used to predict the energetic properties of the transition states and intermediate systems, with their respective probabilities of formation for the following cases: conformational equilibria of six enantiomeric pairs of chiral α,α,α',α'-tetraaryl-2,2-disubstituted 1,3-dioxolane-4,5-dimethanol (TADDOL-s); 137 possible polymers formed during the electropolymerization of 3-hydroxyphenylacetic acid; 110 elucidation of factors that govern the selectivity of the sequence of reactions to synthesize homoallylhomocrotylamine compounds; 111 chirality of methyltris(2,6-diisopropylphenoxy)silylsulfide; 115 and possible conformational structures of the polymers formed during the electropolymerization of 3-hydroxyphenylacetic acid. 110 In surface energy studies, it is frequent to come up with transition states that are characterized by structures of either maximum energy or that can be characterized as saddle points in the potential energy surface, as described by Herman et al 115 These authors justified their choice by RM1 in transition state investigations, as can be read: "The characterization of even a simple reaction potential surface may result in location of more than one transition state structure, and is likely to require many more individual calculations than are necessary to obtain equilibrium geometries for either reactant or product.…”

“…For this reason, the semi-empirical RM1 method of estimation of transition state energy has been chosen…". 115 Propositions of transition states and intermediate and transient compounds are very important in studies of photochemical reactions that can be initialized, for example, by electronic excitation of precursors due to external effects, such as light irradiation, which lead to photon absorption processes. This phenomenon results in excited species leading to the formation of electron isomers as is the case of transition states.…”

Synthesis and characterization of mononuclear Zn(ii), Co(ii) and Ni(ii) complexes containing a sterically demanding silanethiolate ligand derived from tris(2,6-diisopropylphenoxy)silanethiol

“…† The difference results from the helical chirality of the TDST anion described elsewhere. 16 First, there are two helical enantiomers of the TDST ligand present in the crystals of 3 and 4, thus the crystals may be considered as racemic mixtures with regard to the TDST ligand. Second, when molecules of 3 and 4 with the TDST ligand of the same helicity are overlaid, it may be seen that they exhibit torsions O6-Zn1-S1-Si1 of similar values but reverse signs: 117.4(1)°and −110.2(2)°r espectively (see Fig.…”