title: Synthesis, spectroscopic, and electrochemical studies of 1,2-naphthalene-ring-fused tetraazachlorins, -bacteriochlorins, and -isobacteriochlorins: the separation and characterization of structural isomers.
abstract: 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.
authors.affiliation: Organic Intermediates and Dyes Institute, 1/4 B. Sadovaya Str., 103787 Moscow, Russia.
authors.forename: Elena A
authors.initials: EA
authors.lastname: Makarova
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Fukuda
authors.forename: Evgeny A
authors.initials: EA
authors.lastname: Luk Yanets
authors.forename: Nagao
authors.initials: N
authors.lastname: Kobayashi
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002855:Chromatography, Thin Layer / Q000379:methods; D002942:Circular Dichroism / Q000379:methods; D004563:Electrochemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D013058:Mass Spectrometry / Q000379:methods; D008958:Models, Molecular; D015394:Molecular Structure; D009281:Naphthalenes / Q000138:chemical synthesis* / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D011789:Quantum Theory; D012015:Reference Standards; D013055:Spectrophotometry, Infrared / Q000379:methods; D013237:Stereoisomerism
chemical_list: D001372:Aza Compounds; D009281:Naphthalenes; D011166:Porphyrins; C452433:bacteriochlorin; C452434:isobacteriochlorin; C077206:1,2-naphthalenedicarboxylic acid