Synthesis and Optical Features of Axially and Peripherally Substituted Subporphyrins. A Paradigmatic Example of Charge Transfer versus Exciplex States.

We report here the synthesis of two novel subporphyrins (SubPs), in which the macrocycle has been functionalized at its () or axial () position with tetracyanobuta-1,3-diene (TCBD)-aniline. In-depth spectroscopic, spectrometric, and electrochemical analyses were carried out with both of them, whose molecular structures were determined by single-crystal X-ray diffraction studies. In the case of , its and enantiomers were separable by chiral HPLC and presented a fairly good configurational stability at room temperature, which enabled determining the activation parameters for the thermally induced racemization.

Subphthalocyanine-tetracyanobuta-1,3-diene-aniline conjugates: stereoisomerism and photophysical properties.

Two subphthalocyanines (SubPcs) decorated at their peripheral (SubPc ) or peripheral and axial (SubPc ) positions with tetracyanobuta-1,3-diene (TCBD)-aniline moieties have been prepared as novel electron donor-acceptor (D-A) conjugates. In and , the multiple functionalization of -symmetric SubPcs by TCBD moieties, each of them having a chiral axis, results in the formation of several stereoisomers. Variable temperature H-NMR studies in chlorinated solvents suggest that these latter species, which are detected at low temperatures, rapidly interconvert - on the NMR timescale - into each other at room temperature.

Synergy of light harvesting and energy transfer as well as short-range charge shift reactions in multicomponent conjugates.

We report herein on the design, the synthesis, and the characterization of a panchromatic, charge stabilizing electron donor-acceptor conjugate: (BBPA)-ZnPor-ZnPc-SubPc 1. Each component, that is, bis(biphenyl)phenylamine (BBPA), Zn(ii) porphyrin (ZnPor), Zn(ii) phthalocyanine ZnPc, and subphthalocyanine (SubPc), has been carefully chosen and modified to enable a cascade of energy and charge transfer processes. On one hand, ZnPor, has been functionalized with three electron-donating BBPA as primary and secondary electron donors and to stabilize the final charge-separated state, and, on the other hand, a perfluorinated SubPc has been selected as ultimate electron acceptor.

Screening Supramolecular Interactions between Carbon Nanodots and Porphyrins.

We present an in-depth investigation regarding the electron-accepting nature of pressure-synthesized carbon nanodots (pCNDs) in combination with porphyrins as excited-state electron donors. To this end, electrostatic attractions involving negative charges, which are present on the pCND surface, are essential to govern the hybrid assembly, on one hand, and charge separation, on the other hand.

Subphthalocyanines Axially Substituted with a Tetracyanobuta-1,3-diene-Aniline Moiety: Synthesis, Structure, and Physicochemical Properties.

A 1,1,4,4-tetracyanobuta-1,3-diene (TCBD)-aniline moiety has been introduced, for the first time, at the axial position of two subphthalocyanines (SubPcs) peripherally substituted with hydrogen (HSubPc) or fluorine atoms (FSubPc). Single-crystal X-ray analysis of both SubPc-TCBD-aniline systems showed that each conjugate is a racemic mixture of two atropisomers resulting from the almost orthogonal geometry adopted by the axial TCBD unit, which were separated by chiral high-performance liquid chromatography. Remarkably, the single-crystal X-ray structure of one atropisomer of each SubPc-TCBD-aniline conjugate has been solved, allowing to unambiguously assign the atropisomers' absolute configuration, something, to the best of our knowledge, unprecedented in TCBD-based conjugates.