title: Hydrogenated tetraazaporphyrins--old but new core-modified phthalocyanine analogues.
abstract: The synthesis, and spectroscopic and electrochemical properties of hydrogenated tetraazaporphyrins (TAPs), namely tetraazachlorins (TACs), tetraazabacteriochlorins (TABCs) and tetraazaisobacteriochlorins (TAiBCs), have been reviewed. While the first synthesis of this type of hydrogenated aromatic macrocycle was achieved as early as 1958 by Linstead et al. (G. E. Ficken, R. P. Linstead, E. Stephen and M. Whalley, J. Chem. Soc., 1958, 3879), the development of modern synthetic strategies enables us to isolate stable forms of the hydrogenated TAP derivatives. Benzo-, 2,3-naphtho- and 1,2-naphtho-fused derivatives were synthesized extensively, and all structural isomers have been elucidated. The chemical structures have been characterized using a variety of techniques, including mass spectrometry, (1)H and (13)C NMR, X-ray crystallography and IR spectroscopy. The spectroscopic properties (e.g., electronic absorption, magnetic circular dichroism (MCD), and fluorescence) of these compounds differ significantly from those of the original TAPs, or phthalocyanines (Pcs), due to the symmetry-lowering effects of the core aromatic macrocycles. The experimentally observed properties have been rationalized on the basis of electrochemical studies and quantum chemical calculations. As an application of the TAC skeleton, the synthesis and electronic structures of tribenzo TAC (TBTAC)-C(60) conjugates, in which both components are covalently connected directly and thus show remarkable molecular orbital (MO) mixing between the constituting moieties, have also been reviewed.
authors: Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan.
authors: Takamitsu
authors: T
authors: Fukuda
authors: Nagao
authors: N
authors: Kobayashi
mesh_terms: D004563:Electrochemistry; D004583:Electrons; D006859:Hydrogen / Q000737:chemistry*; D006865:Hydrogenation; D007211:Indoles / Q000737:chemistry*; D054833:Isoindoles; D011166:Porphyrins / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D007211:Indoles; D054833:Isoindoles; D011166:Porphyrins; D006859:Hydrogen; C013647:phthalocyanine