Synthesis and Thermal Investigations of Eleven-Membered Ring Systems Containing One of the Heavier Group 14 Element Atoms Si, Ge, and Sn

Nadi Eleya; Clement Appiah; Enno Lork; Mathias Gogolin; Thorsten M Gesing; Tim Stauch; Anne Staubitz

doi:10.3390/molecules25020283

Synthesis and Thermal Investigations of Eleven-Membered Ring Systems Containing One of the Heavier Group 14 Element Atoms Si, Ge, and Sn

Molecules. 2020 Jan 10;25(2):283. doi: 10.3390/molecules25020283.

Authors

Nadi Eleya^{1

2}, Clement Appiah^{1

2}, Enno Lork³, Mathias Gogolin³, Thorsten M Gesing^{2

3}, Tim Stauch^{2

4}, Anne Staubitz^{1

2}

Affiliations

¹ Institute for Analytical and Organic Chemistry, University of Bremen, Leobener Straße 7, D-28359 Bremen, Germany.
² MAPEX Center for Materials and Processes, University of Bremen, Bibliothekstraße 1, D-28359 Bremen, Germany.
³ Institute of Inorganic Chemistry and Crystallography, University of Bremen, Leobener Straße 7, 28359 D-Bremen, Germany.
⁴ Institute for Physical and Theoretical Chemistry, University of Bremen, Leobener Str. 7, D-28359 Bremen, Germany.

Abstract

Unique eleven-membered rings containing silicon, germanium, and tin were synthesized in good yields by the reactions of the corresponding 1,2-bis((2-bromothiophen-3-yl)methoxy)benzenes with (C₆H₅)₂ECl₂ where E = Sn, Ge, Si. The Sn and Ge congeners were crystallized, but the conformers that these rings crystallized in, were quite different. As confirmed by Density Functional Theory (DFT) calculations, (C₂₈H₂₂O₂S₂Sn) assumes a unique crystal structure that leaves more room around the tetrel atom as compared to the crystal structure of the corresponding Ge compound. In the latter, the central cavity is quite open, whereas in the former, one of the methylene groups can fold inwards. Another consequence is the influence on the planes of the aromatic rings flanking the heterocycle. In the Ge case, the benzene ring is folded away from the central cavity, whereas in the Sn case, it is almost parallel to the imaginary axis through the center of the ring. Thermal analysis investigations (TGA and DSC methods) of these eleven-membered rings suggested the loss of a phenyl group in the first decomposition step. The decomposition temperature decreased from the Si containing heterocycle to Ge and was lowest for the Sn containing heterocycle.

Keywords: 11-membered rings; conformation; group 14 elements; tetrels.

MeSH terms

Crystallography, X-Ray
Germanium / chemistry*
Heterocyclic Compounds / chemical synthesis*
Heterocyclic Compounds / chemistry*
Models, Molecular*
Silicon / chemistry*
Tin / chemistry*

Substances

Heterocyclic Compounds
Germanium
Tin
Silicon

Abstract

MeSH terms

Substances

Grants and funding