Distortions and Deformations of Metaled Meso-Substituted and Unsubstituted Porphyrins and Derivatives in Crystal Structures

Experimental crystallographic structural parameters of a range of metaled meso-substituted and unsubstituted porphyrins were reviewed to show how far the meso-substitution by any functional group and the insertion of metal in the porphyrins core macrocycle may affect the geometry. The analysis of twists and angles has shown two kinds of distortions: external [T(Cβ-Cα-Cmeso-Xn) and T(Cβ-Cα-Cmeso-Cα)] and internal [T(Nm-Cα-Cmeso-Xn) and T(Nn-Cα-Cmeso-Cα)] with averages of [+6°and –6°] and [–5°and +5°], respectively. In the meso-substituted case, the external and internal twists Cβ-Cα-Cmeso-X and N-Cα-Cmeso-X, respectively are oppositely orientated. Similar effect is observed in meso-unsubstituted of Cβ-Cα- Cmeso-H and N-Cα-Cmeso-H. However, the external distortions are more significant than internal. Considering the same order, the limit of distortions is [97°and 132°(–48°)] for external and [91°(–89°) and 52°] for internal. In the two cases, the substituents have opposite directions of distortions. The meso-substituted porphyrins have a high limit of twisting than usubstituted one, depending of the weight of substituents. The average of the bond angular deformations is 168°, almost planar. However, the limit of angular deformation is 94°.

Z-scheme photocatalyst based on porphyrin derivative decorated few-layer BiVO4 nanosheets for efficient visible-light-driven overall water splitting

It is highly desirable to simulate natural photosynthesis by using sunlight to drive the overall water splitting without using external bias and sacrificial agent.Herein,few-layer monoclinic BiVO4 nanosheets(BVNS)with a thickness of(∼)4.3 nm,exposed(010)facets and abundant oxygen vacancies are fabricated using graphene oxide dots as templating reagent.After decorating with asymmetric chromium porphyrin derivative bearing one benzoic acid and three phenyls as meso-position substituents(chromium-5-(4-carboxyphenyl)-10,15,20-triphenylporphrin,CrmTPP)and PtOx cocatalyst,the obtained two-dimensional(2D)hybrid nanocomposite(BVNS/CrmTPP/Pt)with an optimal component ratio delivers a robust overall water splitting performance with a relatively high apparent quantum yield(8.67%)at 400 nm monochromatic light.The ultrathin structure and widely distributed oxygen vacancies on the exposed(010)facets of BVNS not only endow strong and intimate contact with the decorated CrmTPP molecules to promote a two-step excitation Z-scheme charge transfer mechanism for preserving the high redox ability of the photogenerated charge carriers,but also alleviate their recombination,and thus causing the robust overall water splitting performance of the 2D hybrid nanocomposites.The present results provide a novel strategy to construct highly efficient artificial photosynthetic system for overall water splitting.

Nonlinear Optical Properties of Porphyrin Derivatives with Electron-donating or Electron-withdrawing Substituents

To investigate photoelectric properties of meso-extended porphyrin derivatives with electron-donating or elec- tron-withdrawing substituents, a series of functionalized porphyrin materials have been designed and synthesized by Suzuki coupling reaction. The meso-extended structures were fully characterized by IH NMR, IR spectroscopy and mass spectrometry. The photophysical properties of porphyrin derivatives were carefully examined by UV-Visible and fluorescence spectra, and the solvatochromic effect was observed and discussed. In particular, Z-scan technique was employed to characterize the third-order nonlinear optical （NLO） properties of the products such as nonlinear absorption and refraction, the third-order nonlinear refractive indexes （x（3）-value） of these porphyrin derivatives achieved 3.9 × 10-12 esu. In addition, the compounds could be self-assembled into highly organized morphologies through phase-exchange method. All the results indicated that the discotic materials have the potential for optoelec- tronic applications.

Effects of Donor and Acceptor on Optoelectronic Performance for Porphyrin Derivatives： Nonlinear Optical Properties and Dye-sensitized Solar Cells

Typical asymmetric donor-π-bridge-acceptor（D-π-A） zinc porphyrin dyes have been synthesized, and fur- ther modified by reacting the ethynyl groups of them with click reagent through a formal [2＋2] click reaction. The electronic interaction between the push and pull electronic groups and the click reaction process were investigated by UV-Vis absorption spectroscopy. The nonlinear optical（NLO） properties of the dyes were studied by the Z-scan tech- nique and clearly reverse saturable absorption to saturable absorption（RSA-SA） transition could be observed through click reaction of the dyes with TCNE. Furthermore, the photovoltaic properties of these porphyrin dyes were reaso- nably explained by the J-V curve fitting based on the equivalent-circuit model as well as the comparison between the absorption and incident-photon-to-current-conversion efficiency（IPCE） spectra. Besides, these dyes with different donors or acceptors could self-assembly into different microstructures by phase transfer methodology. Keywords Porphyrin derivative; Click chemistry; Optoelectronic performance; Nonlinear optical property; Dye-sensitized solar cell