Related Experiment Video
Updated: Aug 13, 2026

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
Excited-state energy-transfer dynamics of self-assembled imine-linked porphyrin dyads
Igor V Sazanovich1, Arumugham Balakumar, Kannan Muthukumaran
1Department of Chemistry, Washington University, St Louis, Missouri 63130-4899, USA.
Abstract:
Toward the development of new strategies for the synthesis of multiporphyrin arrays, we have prepared and characterized (electrochemistry and static/time-resolved optical spectroscopy) a series of dyads composed of a zinc porphyrin and a free base porphyrin joined via imine-based linkers. One dyad contains two zinc porphyrins. Imine formation occurs under gentle conditions without alteration of the porphyrin metalation state. Five imine linkers were investigated by combination of formyl, benzaldehyde, and salicylaldehyde groups with aniline and benzoic hydrazide groups. The imine-linked dyads are quite stable to routine handling. The excited-state energy-transfer rate from zinc to free base porphyrin ranges from (70 ps)(-)(1) to (13 ps)(-)(1) in toluene at room temperature depending on the linker employed. The energy-transfer yield is generally very high (>97%), with low yields of deleterious hole/electron transfer. Collectively, this work provides the foundation for the design of multiporphyrin arrays that self-assemble via stable imine linkages, have predictable electronic properties, and have comparable or even enhanced energy-transfer characteristics relative to those of other types of covalently linked systems.
Related Concept Videos
Energy Diagrams, Transition States, and Intermediates
Thermal and Photochemical Electrocyclic Reactions: Overview
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
Aldehydes and Ketones with Amines: Imine Formation Mechanism
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
Cycloaddition Reactions: MO Requirements for Photochemical Activation

