Organic Chemistry

What’s in an Atom? a Comparison of Carbon and Silicon-Centered Amidinium···carboxylate Frameworks

Abstract

Despite their apparent similarity, framework materials based on tetraphenylmethane and tetraphenylsilane building blocks often have quite different structures and topologies. Herein, we describe a new silicon tetraamidinium compound and use it to prepare crystalline hydrogen bonded frameworks with carboxylate anions in water. The silicon-containing frameworks are compared with those prepared from the analogous carbon tetraamidinium: when biphenyldicarboxylate or tetrakis(4-carboxyphenyl)methane anions were used similar channel-containing networks are observed for both the silicon and carbon tetraamidinium. When terephthalate or bicarbonate anions were used, different products form. Insights into possible reasons for the different products are provided by a survey of the Cambridge Structural Database and quantum chemical calculations, both of which indicate that, contrary to expectations, tetraphenylsilane derivatives have less geometrical flexibility than tetraphenylmethane derivatives, i.e. they are less able to distort away from ideal tetrahedral bond angles.

Content

Thumbnail image of Boer et al chemrxiv manuscript.pdf

Supplementary material

Thumbnail image of Boer et al ToC.png
Boer et al ToC
Thumbnail image of Boer et al SI.pdf
Boer et al SI