Related Experiment Video
Updated: Jun 9, 2026

Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions
Published on: October 5, 2019
Cobaltacarborane-phthalocyanine conjugates: Syntheses and photophysical properties
Hairong Li1, Frank R Fronczek, M Graça H Vicente
1Department of Chemistry, Louisiana State University, 433 Choppin Hall, Baton Rouge, LA 70803, USA.
None:
Syntheses of two new cobaltacarborane-phthalocyanine conjugates, one anionic (Pc 6) and one zwitterionic (Pc 7), were accomplished via cyclotetramerization of the corresponding cobaltacarborane-substituted phthalonitriles (4 or 5) with excess phthalonitrile in quinoline. X-ray structures of two phthalonitrile precursors (2 and 3) were obtained and are discussed, and the absorption and emission properties of the two cobaltacarborane-phthalocyanine conjugates in several solvents were investigated. The anionic conjugate 6 exists mainly as a monomer in polar organic solvents and has fluorescence quantum yields in the region 0.2-0.3. The zwitterionic conjugate 7 aggregates in solution and displays lower quantum yields ~0.1 in organic solvents.
Related Concept Videos
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
UV–Vis Spectroscopy of Conjugated Systems
One of the factors influencing λmax is the extent of conjugation in the...
Thermal and Photochemical Electrocyclic Reactions: Overview
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
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.

