Dynamic Covalent Metathesis in the CC/CN Exchange between Knoevenagel Compounds and Imines

Fast and reversible dynamic covalent CC/CN exchange takes place without catalyst in nonpolar solvents between barbiturate-derived Knoevenagel (Kn) compounds and imines. A detailed study of the reaction indicates that it proceeds by an associative organo-metathesis mechanism involving the formation of a four-membered ring azetidine intermediate by addition of the imine CN group to the CC bond of the Kn compound. This intermediate could be generated cleanly and stabilized at low temperature by condensation of the <i>o,p</i>-dinitrophenyl Kn derivative with the cyclic imine 1-azacyclohexene. It was characterized by extensive NMR and mass spectrometric studies. The process described represents a genuine dynamic covalent organo-metathesis through a four-membered ring adduct as intermediate. It paves the way for the exploration of a wide set of dynamic systems involving (strongly) polarized CC bonds and various imines, extending also into covalent dynamic polymers and polymolecular assemblies

Dynamic Covalent Metathesis in the CC/CN Exchange between Knoevenagel Compounds and Imines

Fast and reversible dynamic covalent CC/CN exchange takes place without catalyst in nonpolar solvents between barbiturate-derived Knoevenagel (Kn) compounds and imines. A detailed study of the reaction indicates that it proceeds by an associative organo-metathesis mechanism involving the formation of a four-membered ring azetidine intermediate by addition of the imine CN group to the CC bond of the Kn compound. This intermediate could be generated cleanly and stabilized at low temperature by condensation of the <i>o,p</i>-dinitrophenyl Kn derivative with the cyclic imine 1-azacyclohexene. It was characterized by extensive NMR and mass spectrometric studies. The process described represents a genuine dynamic covalent organo-metathesis through a four-membered ring adduct as intermediate. It paves the way for the exploration of a wide set of dynamic systems involving (strongly) polarized CC bonds and various imines, extending also into covalent dynamic polymers and polymolecular assemblies

Dynamic Covalent Metathesis in the CC/CN Exchange between Knoevenagel Compounds and Imines

Fast and reversible dynamic covalent CC/CN exchange takes place without catalyst in nonpolar solvents between barbiturate-derived Knoevenagel (Kn) compounds and imines. A detailed study of the reaction indicates that it proceeds by an associative organo-metathesis mechanism involving the formation of a four-membered ring azetidine intermediate by addition of the imine CN group to the CC bond of the Kn compound. This intermediate could be generated cleanly and stabilized at low temperature by condensation of the <i>o,p</i>-dinitrophenyl Kn derivative with the cyclic imine 1-azacyclohexene. It was characterized by extensive NMR and mass spectrometric studies. The process described represents a genuine dynamic covalent organo-metathesis through a four-membered ring adduct as intermediate. It paves the way for the exploration of a wide set of dynamic systems involving (strongly) polarized CC bonds and various imines, extending also into covalent dynamic polymers and polymolecular assemblies

Presentation1_Multicolor emission based on a N, N′—Disubstituted dihydrodibenzo [a, c] phenazine crown ether macrocycle.PDF

Dynamic fluorophore 9,14-diphenyl-9,14-dihydrodibenzo[a,c]phenazine (DPAC) affords a new platform to produce diverse emission outputs. In this paper, a novel DPAC-containing crown ether macrocycle D-6 is synthesized and characterized. Host-guest interactions of D-6 with different ammonium guests produced a variety of fluorescence with hypsochromic shifts up to 130 nm, which are found to be affected by choice of solvent or guest and host/guest stoichiometry. Formation of supramolecular complexes were confirmed by UV-vis titration, 1H NMR and HRMS spectroscopy.</p