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Lash TD, Colby DA, Graham SR, Ferrence GM, Szczepura LF. Organometallic Chemistry of Azuliporphyrins: Synthesis, Spectroscopy, Electrochemistry, and Structural Characterization of Nickel(II), Palladium(II), and Platinum(II) Complexes of Azuliporphyrins. Inorg Chem 2003; 42:7326-38. [PMID: 14577805 DOI: 10.1021/ic030166b] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Four azuliporphyrins, two meso-unsubstituted and two meso-tetraaryl substituted, were investigated in the synthesis of novel organometallic compounds. The meso-unsubstituted or "etio" series azuliporphyrins 8 reacted with nickel(II) acetate, palladium(II) acetate, and platinum(II) chloride in DMF to give the corresponding chelates 14-16, where the metal cation lies within the macrocyclic cavity and binds to all three nitrogens and the internal carbon atom. The newly available meso-tetraarylazuliporphyrins 13 similarly afforded the corresponding nickel(II), palladium(II), and platinum(II) complexes, 17-19, respectively. The new organometallic complexes are stable nonpolar compounds and were fully characterized spectroscopically and by mass spectrometry. The UV-vis data indicate that these complexes, in common with the parent azuliporphyrin system 8, do not possess porphyrin-type aromaticity. However, electron donation from the azulene unit can give rise to dipolar resonance contributors that provide a degree of carbaporphyrin-type aromatic character. The platinum(II) azuliporphyrins 16 gave noteworthy proton NMR spectra where the meso-protons showed satellite peaks due to transannular coupling to platinum-195. The pyrrolic protons of the platinum(II) meso-tetraarylazuliporphyrin 19b also showed similar satellite peaks due to coupling from the platinum-195 isotope. The electrochemistry of free base tetraphenylazuliporphyrin 13a and the related nickel(II) and palladium(II) complexes was investigated using cyclic voltammetry, and these data indicate that metal coordination improves the reversibility of the ligand-based oxidations. Nickel(II) azuliporphyrin 14a and palladium(II) tetrakis(4-chlorophenyl)azuliporphyrin 18b were also structurally characterized by X-ray crystallography. The macrocyclic core of the palladium(II) complex 18b was significantly more planar than the nickel(II) derivative 14b, and this difference was attributed to the better size match between the azuliporphyrin cavity and the larger palladium(II) ion. The straightforward synthesis of metalloazuliporphyrins under mild conditions, and their interesting spectroscopic, electrochemical, and structural features, demonstrates that the azuliporphyrin system holds great promise as a platform for organometallic chemistry.
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Affiliation(s)
- Timothy D Lash
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, USA.
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Jiao W, Lash TD. Tert-butyl-substituted tripyrranes: insights into the steric and conformational factors that influence porphyrinoid ring formation in the "3 + 1" methodology. J Org Chem 2003; 68:3896-901. [PMID: 12737569 DOI: 10.1021/jo0207628] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The MacDonald "3 + 1" route for porphyrinoid synthesis involves the acid-catalyzed condensation of tripyrranes with monocyclic dialdehydes, followed by an oxidation step. In the present study, yields were found to be greatly diminished when tert-butyl substituents were introduced on to the tripyrrane unit. Analysis of the proton NMR spectra for the tripyrranes indicates that the preferred conformation in solution has been radically altered by the presence of these tert-butyl moieties. This appears to be the first time that the NMR properties of an intermediate in porphyrin or porphyrin analogue synthesis have been correlated to its effectiveness in macrocycle formation.
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Affiliation(s)
- Wenhua Jiao
- Department of Chemistry, Illinois State University, Normal 61790-4160, USA
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Liu D, Lash TD. Conjugated macrocycles related to the porphyrins. 25. Proton NMR spectroscopic evidence for a preferred [18]annulene substructure in carbaporphyrins from the magnitude of selected 4J(H,H) CH=C-CH3 coupling constants. J Org Chem 2003; 68:1755-61. [PMID: 12608788 DOI: 10.1021/jo020703u] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two new benzocarbaporphyrins with four or five alkyl substituents have been synthesized by the "3 + 1" MacDonald methodology. At lower temperatures, the proton NMR spectrum of the asymmetrically substituted carbaporphyrin 8 gave two NH resonances, while carbaporphyrin 9, which retains a plane of symmetry, gave only one resonance of this kind. As no additional peaks were seen for the remaining protons, these data strongly support the proposal that a single tautomer predominates in solution where the two NH protons flank the interior CH. Carbaporphyrin 8, which has a CH=CMe unit on the pyrrolic ring opposite the indene moiety, gave a long-range coupling constant of 4J(Me,H) = 1.3-1.4 Hz. On the other hand, the CH=CMe units of 9, which correspond to the pyrrole rings on each side of the carbocyclic moiety, gave 4J(Me,H) = 0.9-1.0 Hz. These values are in accord with those expected if the exterior carbon-carbon bonds of the pyrrole units next to the indene ring are part of a fully delocalized 18pi electron system, while the C=C bond of the remaining pyrrole ring retains substantial olefinic character.
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Affiliation(s)
- Dachun Liu
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, USA
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Liu D, Lash TD. Synthesis, spectroscopy and metallation of mixed carbaporphyrinoid systems. Chem Commun (Camb) 2002:2426-7. [PMID: 12430473 DOI: 10.1039/b206276n] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Modified tripyrranes incorporating furan and thiophene rings were found to condense with benzene, pyridine and indene dialdehydes to give a series of novel porphyrin analogues, including thia- and oxa-carbaporphyrins; the latter readily forms nickel(II) and palladium(II) organometallic complexes.
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Affiliation(s)
- Dachun Liu
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, USA
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Anand VG, Pushpan SK, Venkatraman S, Narayanan SJ, Dey A, Chandrashekar TK, Roy R, Joshi BS, Deepa S, Sastry GN. 30pi aromatic meso-substituted heptaphyrin isomers: syntheses, characterization, and spectroscopic studies. J Org Chem 2002; 67:6309-19. [PMID: 12201748 DOI: 10.1021/jo025788d] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The syntheses of new aromatic 30pi heptaphyrins either through a [5 + 2] or a [4 + 3] acid-catalyzed condensation and oxidative coupling reactions of easily available and air-stable precursors are reported. The methodology followed is not only simple and efficient but also allows synthesis of a range of heptaphyrins with different heteroatoms in the core. The oxidative coupling reactions of modified tripyrranes 11 and tetrapyrranes 12 were found to be dependent on the acid concentration used and as well as the substituents present on the meso position. The change of meso aryl substituents in 11 and 12 to meso mesityl substituents gave a new heptaphyrin 18. The structural characterization has been done with extensive 1H and 2D NMR studies. The heptaphyrins reported here show rich structural diversity when the connections of the heterocyclic rings are altered, and accordingly, one ring and two ring inversions have been observed. By a judicious choice of the precursors it has been possible to control the site of ring inversion either in the bithiophene unit or in the tripyrrane unit. Theoretical calculations performed on three different heptaphyrins, 4, 5, and 17, also reveal that the inverted structures are approximately 35-40 kJ lower in energy relative to the corresponding noninverted structures. Furthermore, one of the heptaphyrins 10c shows the presence of two conformers in solution in the ratio 1:2 and no interconversion between the conformers have been observed in the temperature range of 343-228 K. On protonation, the aromaticity and the ring inversions are retained and the deltadelta values vary in the range 10.07-20.59 ppm. The energies of the Soret maxima and the HOMO-LUMO gap vary linearly with the increase in pi electrons further justifying the aromatic nature of the heptaphyrins.
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Lash TD, Hayes MJ, Spence JD, Muckey MA, Ferrence GM, Szczepura LF. Conjugated macrocycles related to the porphyrins. 21. Synthesis, spectroscopy, electrochemistry, and structural characterization of carbaporphyrins. J Org Chem 2002; 67:4860-74. [PMID: 12098299 DOI: 10.1021/jo020267b] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The "3 + 1" variant of the MacDonald condensation has been shown to be an excellent methodology for synthesizing carbaporphyrins. In particular, 1,3-indenedicarbaldehyde condenses with tripyrranes in the presence of TFA to give, following oxidation with DDQ, a series of benzocarbaporphyrins in excellent yields. Triformylcyclopentadienes also afford carbaporphyrin products, albeit in low yields ranging from 5 to 8%. These hybrid bridged annulene structures have porphyrin-like electronic absorption spectra with strong Soret bands near 420 nm and a series of Q-bands through the visible region. The proton NMR spectrum confirms the presence of a strong diamagnetic ring current, and the meso-protons show up at 10 ppm, while the internal CH is shielded to approximately -7 ppm. Carbaporphyrins undergo reversible protonation with TFA. Initial addition of acid affords a monocation, although mixtures of protonated species are observed in the presence of moderate concentrations of TFA. However, in the presence of 50% TFA a C-protonated dication is generated. The dications relocate the pi-delocalization pathway through the benzo moiety of benzocarbaporphyrins, and these therefore represent bridged benzo[18]annulenes, although they nevertheless retain powerful macrocyclic ring currents. Carbaporphyrins with fused acenaphthylene and phenanthrene rings have been prepared, and the former demonstrated significantly larger bathochromic shifts in UV-vis spectroscopy that parallel previous observations for acenaphthoporphyrins. A diphenyl-substituted benzocarbaporphyrin 19b was also characterized by X-ray crystallography, and these data show that the macrocycle is reasonably planar although the indene subunit is tilted out of the mean macrocyclic plane by 15.5 degrees. The structural data indicates that the preferred tautomer in the solid state has the two NH's flanking the pyrrolene unit in agreement with previous spectroscopic and theoretical studies. Cyclic voltammetry for carbaporphyrin 19a was more complex than for true porphyrins, showing five anodic waves and two quasi-reversible reductive couples.
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Affiliation(s)
- Timothy D Lash
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, USA.
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Affiliation(s)
- A K Burrell
- Institute of Fundamental Sciences-Chemistry, Massey University, Private Bag 11-222, Palmerston North, New Zealand
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Lash TD, Werner TM, Thompson ML, Manley JM. Porphyrins with exocyclic rings. 16. Synthesis and spectroscopic characterization of fluoranthoporphyrins, a new class of highly conjugated porphyrin chromophores. J Org Chem 2001; 66:3152-9. [PMID: 11325282 DOI: 10.1021/jo010066s] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Porphyrins with fused aromatic rings are under detailed investigation due to their unique spectroscopic properties. To gain more insights into the effects due to ring annealation on the porphyrin chromophore, a series of fluoranthoporphyrins have been synthesized. Reaction of 3-nitrofluoranthene with isocyanoacetate esters in the presence of a phosphazene base afforded good yields of the fluorantho[2,3-c]pyrrole esters 8. Cleavage of the ester moiety with KOH in ethylene glycol afforded the parent heterocycle 9, and this condensed with 2 equiv of acetoxymethylpyrroles 10 in refluxing acetic acid-2-propanol to afford tripyrranes 11. Following cleavage of the tert-butyl ester protective groups with TFA, "3 + 1" condensation with pyrrole dialdehyde 12 gave the fluoranthoporphyrins 13 in good overall yields. In addition, reaction of tripyrrane 11 with acenaphthopyrrole dialdehyde 16 gave the mixed acenaphthofluoranthoporphyrin 17 in excellent yields. A difluoranthoporphyrin 18 was also prepared via a "2 + 2" MacDonald condensation. Reaction of fluoranthopyrrole 8a with dimethoxymethane in the presence of p-toluenesulfonic acid gave the symmetrical dipyrrylmethane 19, and following ester saponification, this was condensed with a dipyrrylmethane dialdehyde to afford the adj-difluoranthoporphyrin 18. The UV--vis spectra for these fluoranthoporphyrins gave a series of three broadened absorptions in the Soret band region, although the Q-bands were little effected by ring fusion. The nickel(II), copper(II), and zinc chelates were more unusual, showing strong absorptions near 600 nm. Difluoranthoporphyrin 18 showed many of the same spectroscopic features, although the presence of two ring fusions gave rise to an increase in the spectroscopic shifts. The mixed system 17 gave spectra that showed larger red shifts due to the acenaphthylene unit combined with the features due to the fluoranthene rings. This work further demonstrates the utility of aromatic ring fusion in altering the properties of porphyrinoid systems.
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Affiliation(s)
- T D Lash
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, USA.
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Richter DT, Lash TD. Conjugated macrocycles related to the porphyrins. Part 18: Synthesis and spectroscopic characterization of electron-rich benzi- and oxybenziporphyrins: influence of steric and electronic factors on porphyrinoid aromaticity. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00256-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
A novel 5,10,15,20-tetraaryl-21-selenaporphyrin isomer with an inverted pyrrole ring, i.e., 5,10,15, 20-tetraaryl-2-aza-21-carba-22-selenaporphyrin (SeC-TArPH) has been produced by a [3 + 1] condensation of 2, 5-bis(phenylhydroxymethyl)selenophene and 5,10-ditolyltripyrrin. The reaction yielded 5,20-diphenyl-10,15-bis(p-tolyl)-21-selenaporphyrin Se-DPDTPH (19%) and its isomer with an inverted pyrrole ring, i.e., 5,10-diphenyl-15,20-bis(p-tolyl)-2-aza-21-carba-22-selenaporphyrin, SeC-DPDTPH (1%). Mechanistically the synthesis of SeC-DPDTPH requires one beta-condensation at the pyrrole moiety of 5, 10-ditolyltripyrrin instead of the stereotypical alpha-condensation. The identity of inverted selenaporphyrin has been confirmed by high-resolution mass spectrometry and (1)H NMR spectroscopy. A saddle distortion mode for the inverted selenaporphyrin macrocycle SeC-DPDTPH has been determined by X-ray crystallography. NMR spectra are consistent with the existence of tautomeric equilibria that involve three tautomeric species of the neutral form of SeC-DPDTPH. The preference for the tautomer with the labile proton located at the peripheral N(2) nitrogen atom has been detected in pyridine-d(5) solution. The density functional theory (DFT) has been applied to determine the molecular and electronic structure of three tautomers of 2-aza-21-carba-22-selenaporphyrin: 2-N, 23-N, 24-NH, 2-N, 23-NH, 24-N, and 2-NH, 23-N, 24-N formally created from SeC-DPDTPH by a replacement of phenyl and tolyl groups with hydrogen. The total energies calculated using the B3LYP/6-311G//B3LYP/6-311G approach, demonstrate that relative stability of postulated tautomers decreases in the order 2-N, 23-NH, 24-N > 2-N, 23-N, 24-NH > 2-NH, 23-N, 24-N. The small energy differences between tautomeric species suggests their simultaneous presence in equilibrium.
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Ono N, Ito S, Ochi N, Murashima T, Uno H. A New Synthesis of Benzoporphyrins Using 4,7-Dihydro-4,7-ethano-2H-isoindole as an Isoindole Equivalent. HETEROCYCLES 2000. [DOI: 10.3987/com-99-s50] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Lash TD, Richter DT, Shiner CM. Conjugated Macrocycles Related to the Porphyrins. Part 16.1 Synthesis of Hexa- and Heptaalkyl-Substituted Inverted or N-Confused Porphyrins by the “3 + 1” Methodology. J Org Chem 1999. [DOI: 10.1021/jo991019r] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Timothy D. Lash
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, and Department of Chemistry, Michigan State University, East Lansing, Michigan 48824
| | - Daniel T. Richter
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, and Department of Chemistry, Michigan State University, East Lansing, Michigan 48824
| | - Craig M. Shiner
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, and Department of Chemistry, Michigan State University, East Lansing, Michigan 48824
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Oxidation with dilute aqueous ferric chloride solutions greatly improves yields in the ‘4+1’ synthesis of sapphyrins. Tetrahedron Lett 1999. [DOI: 10.1016/s0040-4039(99)01352-0] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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118
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Warrener RN, Schultz AC, Johnston MR, Gunter MJ. New Porphyrin 4π-Cycloaddition Reagents and Their Use in the Preparation of Porphyrin-(Rigid Spacer)- 1,10-Phenanthrolines in Which Geometric “Tuning” of the Chromophores Is a Feature. J Org Chem 1999. [DOI: 10.1021/jo982487o] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ronald N. Warrener
- Centre for Molecular Architecture, Central Queensland University, Rockhampton, Queensland, 4702, Australia
| | - Austin C. Schultz
- Centre for Molecular Architecture, Central Queensland University, Rockhampton, Queensland, 4702, Australia
| | - Martin R. Johnston
- Centre for Molecular Architecture, Central Queensland University, Rockhampton, Queensland, 4702, Australia
| | - Maxwell J. Gunter
- Department of Chemistry, University of New England, Armidale, New South Wales, 2351, Australia
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Kozyrev AN, Alderfer JL, Dougherty TJ, Pandey RK. Synthese von Mono- und Di(oxopyri)porphyrinen durch Ringerweiterung mit Diazomethan. Angew Chem Int Ed Engl 1999. [DOI: 10.1002/(sici)1521-3757(19990115)111:1/2<169::aid-ange169>3.0.co;2-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Lash TD, Chaney ST, Richter DT. Conjugated Macrocycles Related to the Porphyrins. 12.1 Oxybenzi- and Oxypyriporphyrins: Aromaticity and Conjugation in Highly Modified Porphyrinoid Structures. J Org Chem 1998. [DOI: 10.1021/jo981872a] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Timothy D. Lash
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160
| | - Sun T. Chaney
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160
| | - Daniel T. Richter
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160
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Synthesis of deoxophylloerythroetioporphyrin (DPEP) and three ring homologs by an improved b-bilene methodology. Tetrahedron Lett 1998. [DOI: 10.1016/s0040-4039(98)01960-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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122
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Lash TD, Chandrasekar P, Osuma AT, Chaney ST, Spence JD. Porphyrins with Exocyclic Rings. 13.1 Synthesis and Spectroscopic Characterization of Highly Modified Porphyrin Chromophores with Fused Acenaphthylene and Benzothiadiazole Rings. J Org Chem 1998. [DOI: 10.1021/jo9815655] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Timothy D. Lash
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160
| | - Pushpa Chandrasekar
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160
| | - Augustine T. Osuma
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160
| | - Sun T. Chaney
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160
| | - John D. Spence
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160
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Lash TD, Richter DT. Synthesis of the First Expanded Carbaporphyrinoid by the “4 + 1” Approach. J Am Chem Soc 1998. [DOI: 10.1021/ja981887q] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Timothy D. Lash
- Department of Chemistry Illinois State University Normal, Illinois 61790-4160
| | - Daniel T. Richter
- Department of Chemistry Illinois State University Normal, Illinois 61790-4160
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Lash TD, Chaney ST. Azuliporphyrin: Grenzfall eines aromatischen, porphyrinoiden Makrocyclus. Angew Chem Int Ed Engl 1997. [DOI: 10.1002/ange.19971090809] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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127
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Synthesis of novel porphyrin chromophores from nitroarenes: Further applications of the Barton-Zard pyrrole condensation. Tetrahedron Lett 1997. [DOI: 10.1016/s0040-4039(97)00287-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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