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Bhyrappa P, Sarangi UK. Effect of solvent on the electronic absorption spectral properties of mixed β-octasubstituted free base tetraphenylporphyrins. J PORPHYR PHTHALOCYA 2021. [DOI: 10.1142/s1088424621500371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A near planar macrocycle containing 2,3,12,13-tetraphenylethynyl-5,10,15,20-tetrakis-(4[Formula: see text]-[Formula: see text]-butylphenyl)porphyrin, H2T(4[Formula: see text]-[Formula: see text]-Bu Ph)P(PE)4 and a series of antipodally mixed substituted nonplanar porphyrins, 2,3,5,10,12,13,15,20-octaphenyl-7,8,17,18-tetra(2[Formula: see text]-thienyl/phenylethynyl, PE)porphyrin, H2OPP(2[Formula: see text]-Th/PE)4 and 2,3,12,13-tetramethyl-7,8,17,18-tetra(2[Formula: see text]-thienyl/PE)-5,10,15,20-tetraphenylporphyrin, H2TPP(CH[Formula: see text](2[Formula: see text]-Th/PE)4were examined by electronic absorption spectroscopy in twenty different solvents. The presence of push-pull substituents at the antipodal [Formula: see text]-pyrrole positions of the nonplanar macrocycle induces varying degrees of orthogonal dipole moments to the porphyrin ring. The influence of different solvents on the degree of nonplanarity and electronic nature of the macrocycle on their electronic absorption spectral properties were examined. Generally, free base porphyrins showed dramatic solvent dependent absorption spectral band shifts and follow the order: H2OPP(PE)4 > H2OPP(2[Formula: see text]-Th)[Formula: see text] H2TPP(CH[Formula: see text](2[Formula: see text]-Th)4 >[Formula: see text]H2TPP(CH[Formula: see text](PE)4 > H2T(4[Formula: see text]-[Formula: see text]Bu Ph)P(PE)4. Absorption spectral data in different solvents was analyzed using selected solvatochromic parameters, ([Formula: see text] – 1)/(2[Formula: see text] + 1), [Formula: see text] (30),[Formula: see text], and [Formula: see text]*. The enhanced red-shift of the absorption bands of the mixed substituted porphyrins in polar solvents was influenced by solvent-core (porphyrin) interaction and is reflected from the 1H NMR chemical shift of the core imino-hydrogens in polar solvents relative that observed in less polar solvents. The magnitude of the difference in chemical shift ([Formula: see text], ppm) of imino-hydrogens in DMSO-d6 relative to that in CDCl3 follow the order: H2TPP(CH[Formula: see text](2[Formula: see text]-Th)4 (1.37 ppm) > H2OPP(PE)4 (1.17 ppm) > H2TPP(CH[Formula: see text](PE)4 (0.57 ppm). The large red-shift in B and Q bands in polar solvents relative to apolar (or less polar) solvents has been possible due to the combined effect of the electronic nature of the macrocycle, its nonplanarity, and solvent-porphyrin core interactions.
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Affiliation(s)
- P. Bhyrappa
- Department of Chemistry, Indian Institute of Technology, Madras. Chennai 600 036, India
| | - U. K. Sarangi
- Department of Chemistry, Indian Institute of Technology, Madras. Chennai 600 036, India
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Yadav P, Sankar M, Ke X, Cong L, Kadish KM. Highly reducible π-extended copper corroles. Dalton Trans 2017; 46:10014-10022. [PMID: 28726883 DOI: 10.1039/c7dt01814b] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Di- and octa-phenylethynyl (PE) substituted π-extended copper corroles were synthesized and characterized as to their structural, electrochemical and spectroscopic properties. The addition of two or eight PE groups to the β-pyrrole positions of the corrole results in dramatic red shifts in the electronic absorption spectra and new reductions which are not seen for the parent compound lacking PE substituents. CuCor(PE)8 is reduced in four reversible one-electron transfer steps to give derivatives of [CuCor(PE)8]n- where n = 1, 2, 3 or 4. Variable temperature 1H NMR and EPR measurements were carried out and suggest that the octa- and di-PE substituted Cu-corroles can both be described as an antiferromagnetically coupled CuII corrole cation radical which is in equilibrium with a triplet state, possibly due to a lower singlet-triplet energy gap as compared to 1 and 2 at room temperature. The EPR spectra of one-electron oxidized and one electron reduced species exhibited the characteristics of Cu(ii) corroles. The products generated in the first two reductions of each π-extended corrole were characterized by thin-layer spectroelectrochemistry, thus providing new insights into how UV-vis spectra of highly reduced corroles vary as a function of the number of PE groups and overall charge on the molecule. The singly reduced and singly oxidized copper corroles were also chemically generated in CH3CN and shown to have UV-visible spectra almost identical to the spectra obtained by electroreduction or electrooxidation in PhCN or THF containing 0.1 M tetrabutylammonium perchlorate.
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Affiliation(s)
- Pinky Yadav
- Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247667, India.
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Higashino T, Ohashi Y, Imahori H. Synthesis of Partially meso-Free 2,3-Di(arylethynyl)porphyrins. CHEM LETT 2017. [DOI: 10.1246/cl.170350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Tomohiro Higashino
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510
| | - Yuta Ohashi
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510
| | - Hiroshi Imahori
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510
- Institute of Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501
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PUTTAIAH BHYRAPPA, VEERAPANDIAN VELKANNAN. Synthesis of antipodal β-trisubstituted meso-tetraphenylporphyrins and the crystal structure of hexaphenylporphinatozinc(II) bispyridinate complex. J CHEM SCI 2015. [DOI: 10.1007/s12039-015-0821-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kumar R, Yadav P, Rathi P, Sankar M. Synthesis, spectroscopic, electrochemical redox, solvatochromism and anion binding properties of β-tetra- and -octaphenylethynyl substituted meso-tetraphenylporphyrins. RSC Adv 2015. [DOI: 10.1039/c5ra15211a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
β-Phenylethynyl (PE) porphyrins exhibited unique photophysical properties and solvatochromic behavior due to ICT from the porphyrin core to PE moieties. Further, Zn(ii) porphyrins were utilized for anion sensing.
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Affiliation(s)
- Ravi Kumar
- Department of Chemistry
- Indian Institute of Technology Roorkee
- Roorkee - 247667
- India
| | - Pinky Yadav
- Department of Chemistry
- Indian Institute of Technology Roorkee
- Roorkee - 247667
- India
| | - Pinki Rathi
- Department of Chemistry
- Indian Institute of Technology Roorkee
- Roorkee - 247667
- India
| | - Muniappan Sankar
- Department of Chemistry
- Indian Institute of Technology Roorkee
- Roorkee - 247667
- India
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