LCAO MO SCFπ-electron calculations on the magnetic circular dichroism of porphin, protoporphyrin, and porphyrin a

Kaito, Akira; Nozawa, Tsunenori; Yamamoto, Takao; Hatano, Masahiro; Orii, Yutaka

doi:10.1016/0009-2614(77)85142-7

Cited by 46 publications

(15 citation statements)

References 26 publications

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“…Unlike the other derivatives, the 1,2-DNTAiBCs (8-10, Figure 10, right-hand side) show marked differences in their Q-band positions depending on the species. Since the MCD signal that corresponds to the longest Q-band is the Faraday B term, the other coupled Qband, which must have the opposite MCD sign, [19,20] should appear in a higher energy region. Figure 11 shows the results of the band-deconvolution analysis of 8.…”

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confidence: 99%

Synthesis, Spectroscopic, and Electrochemical Studies of 1,2‐Naphthalene‐Ring‐Fused Tetraazachlorins, ‐bacteriochlorins, and ‐isobacteriochlorins: The Separation and Characterization of Structural Isomers

Макарова

Fukuda

Luk’yanets

et al. 2005

Chemistry A European J

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1,2-Naphthalene-ring-expanded tetraazachlorins (TACs), tetraazabacteriochlorins (TABCs), and tetraazaisobacteriochlorins (TAiBCs) have been synthesized. Procedures for the synthesis of the starting materials, that is, derivatives of 1,2-naphthalenedicarboxylic acid, have been reinvestigated and improved. Nine possible derivatives, including four, two, and three structural isomers of TACs, TABCs, and TAiBCs, respectively, were separated by using thin-layer chromatography (TLC) or high-performance liquid chromatography (HPLC), and the structure of each isomer was determined by (1)H NMR spectroscopy combined with the NOE technique. The formation ratio of each isomer was rationalized in terms of the intramolecular steric repulsion effect, which was predicted by geometry optimizations at the DFT level. The derived compounds were characterized by using IR, electronic, and magnetic circular dichroism (MCD) spectroscopy, and by electrochemical methods. Frequency calculations at the DFT level correctly reproduced the experimental IR spectra and, in particular, distinguished between the three isomers of the TAiBCs. In the electronic absorption and MCD spectra of the TAC and TABC species, the Q-band splits into two intense components similarly to the 2,3-naphthalene-fused derivatives described in our preceding paper, although no significant spectral differences were observed from species to species. On the other hand, the spectra of the TAiBCs showed moderate differences depending on the structure of the isomer. The spectroscopic properties as well as the electrochemical behavior of these chlorins resemble those of the corresponding benzene-fused derivatives rather than the 2,3-naphthalene-fused derivatives. Molecular-orbital and configuration-interaction calculations within the framework of the ZINDO/S method were helpful in the discussions of the above observations.

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confidence: 99%

Synthesis, Spectroscopic, and Electrochemical Studies of 1,2‐Naphthalene‐Ring‐Fused Tetraazachlorins, ‐bacteriochlorins, and ‐isobacteriochlorins: The Separation and Characterization of Structural Isomers

Макарова

Fukuda

Luk’yanets

et al. 2005

Chemistry A European J

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“…Therefore, the pattern observed for 3 is more likely assigned as pseudo Faraday A terms, which can be observed when a molecule exhibits low sym- 1.460(5) C(2)ÀC (7) 1.387(6) metry but the excited states are nearly degenerate, that is, when two Faraday B terms lie close in energy. [15] Calculated absorption spectra: Transition energies and oscillator strengths were calculated for the optimized structures of 2, 3, and 4 by the time-dependent DFT (TD-DFT) method by using the B3LYP/6-31G(d) combination of hybrid functional and basis sets. The TD-DFT calculations predict two transitions with oscillator strengths greater than 0.1 in the Q-band region for all of the compounds, which mainly comprise transitions from the HOMO to LUMO and LUMO+1 ( Table 2) and reveal that the absorption spectra of 2-4 can be described using Goutermans four-orbital model as a theoretical framework.…”

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confidence: 99%

Azaphenalene Phthalocyanines: Phthalocyanine Analogues with Six‐Membered‐Ring Units Instead of Five‐Membered‐Ring Units

Shimizu

Zhu

Kobayashi

2010

Chemistry A European J

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Mixed-condensation reaction of 1,8-naphthalenedicarbonitrile and a 4,5-disubstituted phthalonitrile provided a series of phthalocyanine (Pc) analogues with azaphenalene (AP) moieties in place of the isoindole moieties. Monosubstituted species, APPc, and the two structural isomers of disubstituted species, adj-AP(2)Pc and opp-AP(2)Pc, were successfully isolated by gel-permeation chromatography on HPLC apparatus. Their structures were elucidated by (1)H NMR spectroscopy and X-ray crystallographic analysis. Replacement of the isoindole moieties with azaphenalene moieties created six-membered-ring units in the core and caused distortion of the molecular structures. The Q-band absorption shifted to the red upon an increase in the number of azaphenalene units; the shape of the absorption spectra depended on the molecular symmetries. APPc and opp-AP(2)Pc showed a large splitting of the Q band, whereas adj-AP(2)Pc exhibited a single broad Q band. These changes in the absorption spectra, as well as the unique electronic structures, are discussed in detail, based on magnetic circular dichroism spectra, electrochemical measurements, and density functional theory calculations.

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“…Because the molecular symmetries of these SubPcs are lower than C 3 ,all of the MCD spectra in the Q-band region consist of as uperimposition of Faraday B terms with aminus-to-plus sequence on ascending energy,which resulted in pseudo Faraday A terms,except for VV. [16,17] Owing to the splitting of the Qband, VV exhibited clear B terms at 608 and 585 nm. In contrast to the dependence of the absorption spectral morphologies on the manner of bridging of the two SubPc units in the case of the dimers, both of the monomer species, exo and endo,exhibited similar absorption and MCD spectra with respect to those of regular SubPcs,although the Qband was slightly shifted to the red by approximately 15 nm (Figure 3d,e).…”

Section: Methodsmentioning

confidence: 99%

Cyclophanes Containing Bowl‐Shaped Aromatic Chromophores: Three Isomers of anti‐[2.2](1,4)Subphthalocyaninophane

2015

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The connection of bowl-shaped aromatic boron subphthalocyanines with anti-[2.2]paracyclophane resulted in the first observation of electronic communication between convex and concave surfaces. Three isomers of anti-[2.2](1,4)subphthalocyaninophane, described as concave-concave (CC), convex-concave (CV), and convex-convex (VV) according to the orientation of the subphthalocyanine units, were synthesized and characterized by various spectroscopic techniques, including (1) H NMR, electronic absorption, fluorescence, and magnetic circular dichroism spectroscopy and X-ray crystallography, together with molecular-orbital calculations. On going from the CC system to CV and further to VV, the Q band broadened and finally split as a result of through-space expansion of the conjugated systems, which were also reproduced theoretically.

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LCAO MO SCFπ-electron calculations on the magnetic circular dichroism of porphin, protoporphyrin, and porphyrin a

Cited by 46 publications

References 26 publications

Synthesis, Spectroscopic, and Electrochemical Studies of 1,2‐Naphthalene‐Ring‐Fused Tetraazachlorins, ‐bacteriochlorins, and ‐isobacteriochlorins: The Separation and Characterization of Structural Isomers

Synthesis, Spectroscopic, and Electrochemical Studies of 1,2‐Naphthalene‐Ring‐Fused Tetraazachlorins, ‐bacteriochlorins, and ‐isobacteriochlorins: The Separation and Characterization of Structural Isomers

Azaphenalene Phthalocyanines: Phthalocyanine Analogues with Six‐Membered‐Ring Units Instead of Five‐Membered‐Ring Units

Cyclophanes Containing Bowl‐Shaped Aromatic Chromophores: Three Isomers of anti‐[2.2](1,4)Subphthalocyaninophane

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