Phase-Transfer Catalysis via a Proton Sponge: A Bifunctional Role for Biscyclopropenimine.

The use of a bis(diisopropylamino)cyclopropenimine-substituted bis-protonated proton sponge as a bifunctional phase-transfer catalyst is reported. Experimental studies and DFT calculations suggest it operates simultaneously as a hydrogen bond donor and a phase-transfer catalyst, facilitating the movement of charged intermediates from the interface to the organic phase via favorable partitioning of hydrophilic/hydrophobic surface areas, resulting in high catalytic activity.

Synthesis, Theoretical Analysis, and Experimental pKa Determination of a Fluorescent, Nonsymmetric, In-Out Proton Sponge.

Herein, we report the synthesis and theoretical investigation of a nonsymmetric bis(diisopropylamino)cyclopropenimine (DAC)-functionalized proton sponge derivative, coined the "Janus" sponge. The reported sponge was isolated as a monoprotonated salt, though no intramolecular hydrogen bond was observed. Homodesmotic equations supported the absence of a N-HN intramolecular hydrogen bond and a relatively low freebase strain, while DFT calculations and X-ray crystallography revealed the presence of a hydrogen bond to the Cl(-) counterion.