- Facile Redox-Induced Aromatic–Antiaromatic Interconversion of a β-Tetracyano-21,23-Dithiaporphyrin under Ambient Conditions
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Facile redox-induced aromatic–antiaromatic interconversions were accomplished by using β-tetracyano-21,23-dithiaporphyrin (CN4S2Por). Introduced cyano groups not only increased the reduction potential of the porphyrin core but also stabilized the antiaromatic isophlorin (CN4S2Iph) by π conjugation. The reduction of CN4S2Por with hydrazine in polar solvents quantitatively affords CN4S2Iph, even under ambient conditions. CN4S2Iph retains a nearly planar conformation and exhibits considerable antiaromaticity. Aerobic oxidation of CN4S2Iph to CN4S2Por occurs in nonpolar solvents. This study was conducted to contribute to the understanding of the structure–antiaromaticity relationship.
- Honda, Yusuke,Nakajima, Kana,Ogawa, Takuji,Yamashita, Ken-ichi
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- Highly efficient synthesis of 21-thia-5,10,15,20-tetraarylporphyrins and 21,23-dithia-5,10,15,20-tetraarylporphyrins in presence of acidic ionic liquid catalyst
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The reaction of 2,5-bis-(α-arylhydroxymethyl)thiophenes with 5-aryldipyrromethanes in the presence of acidic ionic liquid gives 21-thia-5,10,15,20-tetraarylporphyrins in 30% yield whereas the reaction of 2,5-bis-(α-arylhydroxymethyl)thiophenes with 5,10-d
- Rawat, Amit Kumar,Bhattacharya, Soumee,Chauhan
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- One pot synthesis of core modified expanded porphyrins
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Reaction of various diols with pyrrole in TFA/CH2Cl2 leads to formation of core modified expanded porphyrins.
- Pushpan, Simi K.,Narayanan, Jeyaprakash S.,Srinivasan, Alagar,Mahajan, Sumeet,Chandrashekar, Tavarekere K.,Roy, Raja
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- Physicochemical Basis for the Creation of Liquid-Phase Sensor Materials Based on Tetraaryldithiaporphyrins
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Abstract: Basic properties of 5,10,15,20-tetraaryl-21-thia- and 5,10,15,20-tetraaryl-21,23-dithiaporphyrins in acetonitrile were examined spectrophotometrically. The geometry of the heteroporphyrins was optimized in the DFT approximation (hybrid functiona
- Ivanova, Yu. B.,Kiselev, A. N.,Pukhovskaya, S. G.,Syrbu, S. A.
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p. 231 - 240
(2022/03/18)
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- cis-Pyridyl core-modified porphyrins for the synthesis of cationic water-soluble porphyrins and unsymmetrical non-covalent porphyrin arrays
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Synthesis of a series of 21-thia and 21-oxoporphyrin building blocks containing two pyridyl functional groups at the meso positions in a cis fashion is reported. The building blocks were used to synthesize a series of cationic water-soluble 21-thia and 21-oxoporphyrins. An unsymmetrical non-covalent trimer containing two dissimilar porphyrin cores such as one N3S and two N4 porphyrins cores was also constructed using the pyridyl porphyrin building blocks reported here.
- Santra, Sangita,Kumaresan, Duraisamy,Agarwal, Neeraj,Ravikanth, Mangalampalli
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p. 2353 - 2362
(2007/10/03)
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- Synthesis of single strapped 21-thia tetraphenylporphyrin systems
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Synthesis and characterization of two single strapped 21-thia tetraphenylporphyrins have been reported. The two adjacent phenyls that are present at the meso position of 21-thia tetraphenylporphyrin are linked by either rigid aromatic group or flexible alkyl chain. Absorption and fluorescence studies indicated that the rigid aromatic group induced more nonplanarity in the porphyrin ring than flexible alkyl chain.
- Boobalan,Gupta, Iti,Ravikanth
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p. 1860 - 1863
(2007/10/03)
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- Synthesis of 21-thia and 21-oxaporphyrin building blocks and boron-dipyrrin appended systems
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A series of 21-thia and 21-oxaporphyrin building blocks bearing iodo-, ethynyl-and aldehyde functional groups were synthesized and characterized. These porphyrins are ideal building blocks for the construction of unsymmetrical porphyrin arrays containing
- Kumaresan,Agarwal, Neeraj,Gupta, Iti,Ravikanth
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p. 5347 - 5356
(2007/10/03)
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- Water-soluble, core-modified porphyrins as novel, longer-wavelength- absorbing sensitizers for photodynamic therapy
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Water-soluble, core-modified 5,10,15,20-tetrakis(4-sulfonatophenyl)- 21,23-dithiaporphyrin (1) and 5,10,15,20-tetrakis(4-sulfonatophenyl)-21,23- diselenaporphyrin (2) were prepared as the tetrasodium salts by the sulfonation of 5,10,15,20-tetraphenyl-21,2
- Stilts, Corey E.,Nelen, Marina I.,Hilmey, David G.,Davies, Sherry R.,Gollnick, Sandra O.,Oseroff, Allan R.,Gibson, Scott L.,Hilf, Russell,Detty, Michael R.
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p. 2403 - 2410
(2007/10/03)
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- Novel core-modified expanded porphyrins with meso-Ary1 substituents: Synthesis, spectral and structural characterization
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The synthesis, spectral and structural characterization of meso-aryl sapphyrins and rubyrins containing heteroatoms such as S, O, Se in addition to pyrrole nitrogens are reported. The synthesis of the desired expanded porphyrins has been achieved using a
- Narayanan, Seenichamy Jeyaprakash,Sridevi, Bashyam,Chandrashekar, Tavarekere K.,Vij, Ashwani,Roy, Raja
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p. 9053 - 9068
(2007/10/03)
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- meso-Aryl sapphyrins with heteroatoms; synthesis, characterization, spectral and electrochemical properties
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The synthesis, characterization and spectral properties of six new meso-aryl core modified sapphyrins are described. An efficient approach involving an acid catalyzed condensation of bithiophene diol 1 and modified tripyrranes 2a-2e allows preparation of the desired meso-aryl sapphyrins in 16-36% yield. The product distribution and the isolated yield were found to be dependent on the nature of the acid catalyst (Lewis acid or protic acid) and its concentration. Protic acid catalyst exclusively gave the expected sapphyrins while two additional products, an 18π tetraphenylporphyrin and a 26π modified rubyrin, were isolated under Lewis acid catalysis. An analysis of proton NMR and absorption spectral data suggests that in free base sapphyrins, the heterocyclic ring opposite to the bithiophene unit is inverted as in N-5 meso-aryl sapphyrin and the degree of inversion is dependent on the nature of the heterocyclic ring. The energy optimized structure calculated from the semi-empirical method substantiates such a conclusion. Protonation of sapphyrins generates respective mono- and dications and the heterocyclic ring retains an inverted structure in contrast to normal N-5 sapphyrins. The triplet excited lifetimes for free base and protonated derivatives are similar both under argon saturated and air equilibrated conditions, indicating that the triplet state quenching by oxygen is minimal. Cyclic voltammetric studies reveal easier reductions and harder oxidations relative to meso-aryl porphyrins and the Δredox observed for 3d suggests significant reduction of the HOMO-LUMO energy gap consistent with the large red shift observed for the Soret band.
- Srinivasan, Alagar,Pushpan, Simi K.,Kumar, Murugaeson Ravi,Mahajan, Sumeet,Chandrashekar, Tavarekere K.,Roy, Raja,Ramamurthy
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p. 961 - 968
(2007/10/03)
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- Characterisation of new 26,28-diheterosapphyrins: 5,10,15,20-tetraphenyl-26,28-dioxasapphyrin and 5,10,15,20-tetraphenyl-26,28-dithiasapphyrin
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5,10,15,20-Tetraphenyl-26,28-dioxasapphyrin (O2TPSH) and 5,10,15,20-tetraphenyl-26,28-dithiasapphyrin (S2TPSH), heteroanalogues of 5,10,15,20-tetraphenylsapphyrin (TPSH3) have been synthesized by condensation of the respective precursors, namely 2,5-bis(arylhydroxymethy)furan or bis(arylhydroxymethyl)thiophene and pyrrole. 26,28-Dioxasapphyrin presents an unusual skeleton with an inverted pyrrole ring lying opposite to the bipyrrolic unit at each protonation stage. In contrast, the planar arrangement of the macrocycle has been determined for 26,28-dithiasapphyrin. The tautomeric equilibrium of S2TPSH which involves the exchange of a proton between N-25 and N-29 has been found to be slow on the 1H NMR timescale below 213 K. Activation parameters of tautomerization were determined by the line shape analysis: ΔH? = 47.2 ± 1.1 kJ mol-1, ΔS? = 19.9 ± 5.5 J K-1 (ΔH? = 10.9 ± 0.3 kcal mol-1, ΔS? = 4.6 ± 1.4 cal K-1).
- Rachlewicz, Krystyna,Sprutta, Natasza,Chmielewski, Piotr J.,Latos-Grazynski, Lechoslaw
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p. 969 - 975
(2007/10/03)
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- Synthesis of meso-substituted core modified expanded porphyrins; Effect of acid catalysts on the cyclization
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[3 + 2] condensation between modified tripyrromethane and bithiophene or bifurandiol leads to the formation of 18π, 22π, 26π macrocycles trader Lewis acid conditions while only 22π macrocycle is formed under protic acid conditions.
- Srinivasan, Alagar,Mahajan, Sumeet,Pushpan, Simi K.,Ravikumar, Murugaeson,Chandrashekar, Tavarekere K.
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p. 1961 - 1964
(2007/10/03)
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