The development of new classes of designer anions has opened up the potential to generate novel architectures by self-assembly. However, each new class of anion requires exploration of its structure-property relationships to understand their practical use as synthons for large-scale assemblies. We do this here with organo-trifluoroborate anions, RBF3–, that bear different substituents. We investigate how the hybridization (sp3, sp2, sp) of the a-carbon atom on the substituent affects their binding to cyanostar macrocycles as 2:1 complesxes. For this purpose, a set of anions was designed and composed of phenylethyl-BF3– (sp3), phenylethylene-BF3– (sp2), and phenylethynyl-BF3– (sp). Electrostatic potential maps suggest that the order of affinity is phenylethyl-BF3– (sp3) &gt; phenylethylene-BF3– (sp2) &gt; phenylethynyl-BF3– (sp). However, the experimental result shows the affinity order is inverted. In addition, the use of a phenyl group creates a steric block that simultaneously lower the symmetry of the anionic guest. Surprisingly, the 1H-NMR splitting pattern of phenylethynyl-BF3– resolves both the handedness of the macrocycles when they come together as a dimer as well as their inward or outward location on the non-symmetric rod. This resolution suggests that the ethynyl triple bond contributes to the molecular recognition unit. More complex architectures will be designed and presented based on this idea.

Hybridization affects the binding affinity and isomer resolution of cyanostar complexes with organo-trifluoroborate anions

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.