Charge-Assisted Hydrogen-Bonding Enables Quantitative Multicomponent Self-Assembly in Strongly Polar Environments

Abstract

Multicomponent discrete assemblies, composed of a defined number of molecular building blocks, represent valuable supramolecular constructs with broad functional potential. Their formation relies on cooperativity, on one hand, and on directional noncovalent interactions, on the other. Many of these interactions have a marked electrostatic component, like H-bonding, and cannot survive in strongly competing polar solvents. A notable exception is the coordination bond, which offers enough strength and selectivity to enable assembly in such polar environments. In this work, we introduce a unique, versatile alternative based on amidinium–carboxylate salt bridges. Concretely, a [2+4] hexacomponent assembly, comprising 2 cofacial tetracarboxylate porphyrins linked through 4 diamidine spacers that exhibits remarkably high kinetic and thermodynamic stability is quantitatively formed in DMSO-rich environments, as a result of the charge-assisted hydrogen-bonding interactions employed and the strong chelate cooperativities attained.