Conformational and structural studies of meso monosubstituted metalloporphyrins—Edge-on molecular interactions of porphyrins in crystals

Senge, Ma­thias O.; Flanagan, Keith J.; Ryan, Aoife A.; Ryppa, Claudia; Donath, Mandy; Twamley, Brendan

doi:10.1016/j.tet.2015.11.008

Cited by 8 publications

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References 33 publications

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“…Herein, we report a photophysical and computational study of a set of zinc porphyrins bearing 0–4 meso -phenyl substituents (Chart ). The constructs include the zinc chelates of porphine ( ZnP-0 ), the monophenylporphyrin ( ZnP-1 ), − the cis -diphenylporphyrin ( ZnP-2c ), , the trans -diphenylporphyrin ( ZnP-2t ), − the triphenylporphyrin ( ZnP-3 ), ,− and tetraphenylporphyrin ( ZnP-4 = ZnTPP ) . The synthetic chemistry of this series of compounds has been reviewed. ,− The current studies of the zinc chelates were motivated by an earlier study from our groups of the six free base analogues of the meso -phenyl-substituted porphyrins ( H 2 P-0 – H 2 P-4 ; Chart ).…”

Section: Introductionmentioning

confidence: 99%

Photophysical Properties and Electronic Structure of Zinc(II) Porphyrins Bearing 0–4 meso-Phenyl Substituents: Zinc Porphine to Zinc Tetraphenylporphyrin (ZnTPP)

et al. 2020

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Six zinc(II) porphyrins bearing 0–4 meso-phenyl substituents have been examined spectroscopically and theoretically. Comparisons with previously examined free base analogues afford a deep understanding of the electronic and photophysical effects of systematic addition of phenyl groups in porphyrins containing a central zinc(II) ion versus two hydrogen atoms. Trends in the wavelengths and relative intensities of the absorption bands are generally consistent with predictions from time-dependent density functional theory calculations and simulations from Gouterman’s four-orbital model. These trends derive from a preferential effect of the meso-phenyl groups to raise the energy of the highest occupied molecular orbital. The calculations reveal additional insights, such as a progressive increase in oscillator strength in the violet-red (B-Q) absorption manifold with increasing number of phenyls. Progressive addition of 0–4 phenyl substituents to the zinc porphyrins in O2-free toluene engenders a reduction in the measured lifetime of the lowest singlet excited state (2.5–2.1 ns), an increase in the S1 → S0 fluorescence yield (0.022–0.030), a decrease in the yield of S1 → T1 intersystem crossing (0.93–0.88), and an increase in the yield of S1 → S0 internal conversion (0.048–0.090). The derived rate constants for S1 decay reveal significant differences in the photophysical properties of the zinc chelates versus free base forms. The unexpected finding of a larger rate constant for internal conversion for zinc chelates versus free bases is particularly exemplary. Collectively, the findings afford fundamental insights into the photophysical properties and electronic structure of meso-phenylporphyrins, which are widely used as benchmarks for tetrapyrrole-based architectures in solar energy and life sciences research.

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Section: Introductionmentioning

confidence: 99%

Photophysical Properties and Electronic Structure of Zinc(II) Porphyrins Bearing 0–4 meso-Phenyl Substituents: Zinc Porphine to Zinc Tetraphenylporphyrin (ZnTPP)

et al. 2020

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“…3 The diverse application of these chemically similar compounds has long been prescribed to the macrocycle conformation within their specific protein structure. There are several ways to induce nonplanarity in a porphyrin; [4][5] the introduction of sterically demanding groups, metalation, [6][7][8][9][10][11] axial ligands, [12][13] reducing the porphyrin system, 14 alteration of the conjugated system, 14 N-substitution to the inner core nitrogen atoms, 15 cation radical formation, 16 "strapping" the macrocycle via covalent linkage, 17 or heteroatom substitution of the inner core nitrogen atoms. 18 For this publication, we have focused on increasing the steric hinderance through peripheral overcrowding of the porphyrin macrocycle.…”

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Investigating the Impact of Conformational Molecular Engineering on the Crystal Packing of Cavity Forming Porphyrins

2019

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Herein we report the synthesis of 5,10,15,20-tetraaryl-(X)-substituted-2, 3,7,8,12,13,17, and a structural investigation of their solid-state properties via small molecule X-ray diffraction. A series of halogen (fluorine to iodine), nitrogenous (azido, cyano), alkyl (TMS-acetylene and acetylene) and chained (benzyloxy) porphyrins were chosen as the initial target molecules. Following this, a selection of tetravalent metal complexes [Cu(II), Ni(II) and Pd(II)] based on these porphyrins were synthesized to allow for an investigation of the effects of metal complexes on the structural properties of these highly substituted porphyrins. The size of the halogen atom affects the potential of intermolecular interactions and the resulting crystal packing in these 4-halo-OETArXP complexes. The fluorine series have an equal preference for alkyl or aryl Flanagan, K. J.; Twamley, B.; Senge, M. O. (2019): Investigating the Impact of Conformational Molecular Engineering on the Crystal Packing of Cavity Forming Porphyrins. Inorganic Chemistry 58, 15769-15787. doi: 10.1021/acs.inorgchem.9b01963groups (ortho-hydrogen), the chlorine series favoring interactions between the alkyl groups, and the bromine appears to favor the aryl (ortho-and meta-hydrogens). This results in an extensive cupping pattern in the unit cell. For the 2,6-halo-OETArXP it was established that the change in position alters the types of the intermolecular contacts towards face-to-edge or face-to-face interactions and altering the packing patterns observed. Within the 4-benzyloxy-OETArXP series the meso-substituent favors interacting with the core of the porphyrin macrocycle. The 4-cyano-OETArXP is a suitable hydrogen-bond acceptor and resulted in an interesting Z-shape network. Additionally, it was highlighted that solvent effects play a much larger role in crystal packing than intermolecular/intramolecular interaction or metal(II) center substitution. This is accompanied by a study using both the azide-and acetylene-OETArXPs as a base molecule to allow for a quick one-step reaction for the generation of a variety of functional groups. Using a copper(I)-catalyzed azide-alkyne cycloaddition reaction we were able to append hydrogen bonding functionalities to the OETArXPs framework in high yields. The crystals packing of this work shows the potential to create selective and functional receptor sites based on free base porphyrins. However, in so far of analytical measurements indicate, the design such free base porphyrin through crystal engineering has not yet been realized. The variety of porphyrin packing arrangements herein indicates the need for further studies.

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“…In the case of compounds 3 and VC11 , the NMR spectra could not be recorded due to the paramagnetic character of Cu 2+ . [ 47 ] Thermogravimetric analysis (TGA) shows good thermal stability for VC11 , with a weight loss of 5% at 370 °C (Figure S8, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Ambipolar Behavior of a Cu(II)–Porphyrin Derivative in Ternary Organic Solar Cells

et al. 2023

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Conformational and structural studies of meso monosubstituted metalloporphyrins—Edge-on molecular interactions of porphyrins in crystals

Cited by 8 publications

References 33 publications

Photophysical Properties and Electronic Structure of Zinc(II) Porphyrins Bearing 0–4 meso-Phenyl Substituents: Zinc Porphine to Zinc Tetraphenylporphyrin (ZnTPP)

Photophysical Properties and Electronic Structure of Zinc(II) Porphyrins Bearing 0–4 meso-Phenyl Substituents: Zinc Porphine to Zinc Tetraphenylporphyrin (ZnTPP)

Investigating the Impact of Conformational Molecular Engineering on the Crystal Packing of Cavity Forming Porphyrins

Ambipolar Behavior of a Cu(II)–Porphyrin Derivative in Ternary Organic Solar Cells

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