Mirror Symmetry Breaking in Helical Polysilanes: Preference between Left and Right of Chemical and Physical Origin

Abstract

Abstract:From elemental particles to human beings, matter is dissymmetric with respect to mirror symmetry. In 1860, Pasteur conjectured that biomolecular handednesshomochirality-may originate from certain inherent dissymmetric forces existing in the universe. Kipping, a pioneer of organosilicon chemistry, was interested in the handedness of sodium chlorate during his early research life. Since Kipping first synthesized several Si-Si bonded oligomers bearing phenyl groups, Si-Si bonded high polymers carrying various organic groups-polysilanes-can be prepared by sodium-mediated condensation of the corresponding organodichlorosilanes. Among these polysilanes, optically active helical polysilanes with enantiomeric pairs of organic side groups may be used for testing the mirror symmetry-breaking hypothesis by weak neutral current (WNC) origin in the realm of chemistry and material science. Several theoretical studies have predicted that WNC-existing chiral molecules with stereogenic centers and/or stereogenic bonds allow for distinguishing between image and mirror image molecules. Based on several amplification mechanisms, theorists claimed that minute differences, though still very subtle, may be detectable by precise spectroscopic and physicochemical measurements if proper chiral molecular pairs were employed. The present paper reports comprehensively an inequality between six pairs of helical polysilane high polymers, presumably, detectable by (chir)optical and achiral 29 Si-/ 13 C-NMR spectra, and viscometric measurements.

Achiral Polydialkylsilane Aggregates That Record Stirring Direction

“…www.chemasianj.org 6c atalyst and isolated by fractional precipitation from toluene solution with ethanol and/or methanol as the polar solvents. [6,31]…”

“…This stirring-induced chiral alignmenth as been also reported by Ts uda et al [30] Polysilanes with an arrow polydispersityi ndex (PDI) are usually isolated by fractional precipitation using n-propanol, ethanol, and methanol as poor solvents, successively. [6] Polysilanes with higherm olecular weights precipitate out first. If only methanol wereu sed as the poor solvent, polysilanes would precipitate immediately and the PDI would be broad.…”

“…16 10 4 ,P DI = 1.41), and poly(ndecyl-(S)-2-methylbutylsilane) (PSi*, M w = 7.37 10 4 ,P DI = 1.10) were prepared by Wurtz condensation from their corresponding dichlorosilane monomers with sodium in the presence of [18]crown- www.chemasianj.org 6c atalyst and isolated by fractional precipitation from toluene solution with ethanol and/or methanol as the polar solvents. [6,31] …”

“…[2] In addition to vortices, circularly polarized light, [3] natural light with ac ollinear static magnetic field, [4] crystallization and aggregation, [5] parity-violating weak neutral current, [6] and liquid/vapor solventc hirality [7] are possible origins of MSB in nature. Kaizu et al [8] andR ibó et al [2,9] have previously reported that electrostatic Ja ggregates of (4-sulfophenyl)porphyrin derivatives prepared in aqueous media by means of rotary stirring become optically active.…”

Supramolecular Chirality: Solvent Chirality Transfer in Molecular Chemistry and Polymer Chemistry

“…This non-mirror-image relation may be ascribed to some impurities, as claimed in several papers [68,71,73,117]. It may also infer other unknown reasons, such as an inherent mirror symmetry breaking at a global level upward, our universe scale [123,124] and macroscopic MPV effects [21,37,43,46,51,67,72,74]. The commercially available chiral alcohols shown above are very expensive compared to common chemicals.…”