Dipole moments, structure, and transannular interactions in silatranes containing planar fragments

Ishmaeva, E. A.; Timosheva, A. P.; Gazizova, A. A.; Чачков, Д. В.; Vereshchagina, Ya. A.; Катаев, В. Е.; Timosheva, Natalya V.

doi:10.1134/s1070363208070116

Cited by 7 publications

(8 citation statements)

References 7 publications

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“…An obvious approach to forcing the nitrogen to adopt the exo geometry is to make the cage rings sufficiently small that adopting the endo geometry induces unacceptable ring strain. Obvious candidates include what we term “silatanes”, as an extension of the commonplace “atrane” terminology. − Silatanes are molecules of formula XSi(OCR 2 ) 3 N, a [2,2,2] cage composed of six-membered rings (Figure ). One can view silatanes as structural analogues of [2,2,2]-bicyclooctane or DABCO, which exist solely as exo conformers.…”

Section: Resultsmentioning

confidence: 99%

Computational Study of Ways by Whichexo-Silatranes Might Be Prepared

2016

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exo-Silatranes involve cage structures where the nitrogen lone pair points away from the cage rather than into it. This distinguishes them from the well-established endo-silatranes. exo-Silatranes have not been observed experimentally, consistent with a significant benefit to silicon-nitrogen interactions inside the cages as suggested for endo-silatranes. Identifying examples of exo-silatranes would prove useful in understanding Si-N interactions, as they would represent the "no interaction" extreme of the spectrum. We have found four means by which exo-silatranes might be synthesized: (1) employing smaller cages; (2) employing constrained rings to stiffen the cage backbones; (3) employing steric interactions to enhance preference for the less crowded exo-geometry around nitrogen; (4) modifying the Lewis acidity and basicity of the silicon and nitrogen so significantly as to remove their desire to interact. The preference for exo geometries is established using the parameter Δ, representing the distance between the nitrogen atom and the least-squares plane containing the adjacent carbon atoms. In some cases, Δ values for exo-silatranes are greater than 0.3 Å. In others, they are near zero, indicating a nearly planar nitrogen atom. There are no obvious structural markers besides Δ that distinguish between exo- and endo-silatranes.

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Section: Resultsmentioning

confidence: 99%

Computational Study of Ways by Whichexo-Silatranes Might Be Prepared

2016

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“…Silatranes are novel biologically active compounds possessing a broad spectrum of biological effects , particularly in immune adjustment . Silatrane derivatives work through the immune system to enhance biological effects, such as immunoregulation, anti‐inflammation, and antitumor activity .…”

Section: Methodsmentioning

confidence: 99%

Design, Synthesis, and Biological Evaluation of γ‐Aminopropyl Silatrane–Acyclovir Hybrids with Immunomodulatory Effects

Song

Liu

et al. 2015

Chem Biol Drug Des

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Several derivatives of γ-aminopropyl silatrane containing acyclovir in their molecular structure were synthesized and evaluated for their immunomodulatory and antiviral activities. The structures of all these derivatives were confirmed by mass spectra, IR, and (1) H NMR. Based on WST-1 assay in vitro, these compounds could stimulate proliferation of splenic lymphocytes at certain concentrations. Furthermore, compound 3d could also potentiate the expression of IFN-γ, IL-2, CD4(+) , CD8(+) , and CD4(+) /CD8(+) in vivo. Our results show that these derivatives possess antiviral activity against herpes simplex viruses with a similar potency to acyclovir without a cellular immune response.

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“…The method of dipole moments is a high-precision instrument for the conformational analysis of polar compounds in solution, and it is successfully used in combination with other physical methods and quantum chemistry to study the fine features of the spatial and electronic structure of organic and organoelement compounds [52,54,56].…”

Section: Polarity Of Compounds 1-5 7 Andmentioning

confidence: 99%

Structure of Tris[2-(4-pyridyl)ethyl]phosphine, Tris[2-(2-pyridyl)ethyl]phosphine, and Their Chalcogenides in Solution: Dipole Moments, IR Spectroscopy, and DFT Study

Kuznetsova,

Chachkov,

Belogorlova

et al. 2023

Molecules

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Tris(hetaryl)substituted phosphines and their chalcogenides are promising polydentate ligands for the design of metal complexes. An experimental and theoretical conformational analysis of tris[2-(4-pyridyl)ethyl]phosphine, tris[2-(2-pyridyl)ethyl]phosphine, and their chalcogenides was carried out by the methods of dipole moments, IR spectroscopy and DFT B3PW91/6-311++G(df,p) calculations. In solution, these compounds exist as an equilibrium of mainly non-eclipsed (synclinal or antiperiplanar) forms with a predominance of a symmetrical conformer having a gauche-orientation of the Csp3–Csp3 bonds of pyridylethyl substituents relative to the P=X bond (X = lone pair, O, S, Se) and a gauche-orientation of the pyridyl rings relative to the zigzag ethylene bridges. Regardless of the presence and nature of the chalcogen atom (oxygen, sulfur, or selenium) in the studied molecules with many axes of internal rotation, steric factors—the different position of the nitrogen atoms in the pyridyl rings and the configuration of ethylene bridges—determine the realization and spatial structure of preferred conformers.

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Dipole moments, structure, and transannular interactions in silatranes containing planar fragments

Cited by 7 publications

References 7 publications

Computational Study of Ways by Whichexo-Silatranes Might Be Prepared

Computational Study of Ways by Whichexo-Silatranes Might Be Prepared

Design, Synthesis, and Biological Evaluation of γ‐Aminopropyl Silatrane–Acyclovir Hybrids with Immunomodulatory Effects

Structure of Tris[2-(4-pyridyl)ethyl]phosphine, Tris[2-(2-pyridyl)ethyl]phosphine, and Their Chalcogenides in Solution: Dipole Moments, IR Spectroscopy, and DFT Study

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