Synthesis and spectroscopic and electrochemical studies of pyrazine- or pyridine-ring-fused tetraazachlorins, bacteriochlorins, and isobacteriochlorins

Inorg Chem. 2009 Jan 5;48(1):164-73. doi: 10.1021/ic801552u.

Abstract

Mixed condensation of tetramethylsuccinonitrile and either 2,3-dicyano-5,6-diethylpyrazine, 2,3-dicyanopyridine, or 3,4-pyridinedicarboximide in the presence of nickel chloride forms novel pyrazine-, 2,3-pyridine-, or 3,4-pyridine-ring-fused tetraazachlorin (TAC), tetraazabacteriochlorin (TABC), and tetraazaisobacteriochlorin (TAiBC) derivatives. All possible structural isomers were separated using repeated thin-layer chromatography and have been investigated by absorption and magnetic circular dichroism spectroscopy. Similarly to previously reported TAC analogues, the TAC and TABC derivatives show large splitting of the Q band, while a single, intense absorption band is observed for the TAiBC derivatives. Although the absorption spectra are practically identical in shape for the separated structural isomers of TACs and TABCs, the Q-band maxima of the TAiBCs depend significantly on their structures. The observed spectroscopic properties were interpreted on the basis of electrochemical data and the results of (time-dependent) DFT calculations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorption
  • Aza Compounds / chemistry*
  • Circular Dichroism
  • Electrochemistry
  • Isomerism
  • Magnetic Resonance Spectroscopy
  • Magnetics
  • Nitrogen / chemistry
  • Photosensitizing Agents / chemistry
  • Photosensitizing Agents / isolation & purification
  • Porphyrins / chemistry*
  • Porphyrins / isolation & purification
  • Pyrazines / chemistry*
  • Pyridines / chemistry*
  • Quantum Theory
  • Spectrophotometry, Ultraviolet
  • Time Factors

Substances

  • Aza Compounds
  • Photosensitizing Agents
  • Porphyrins
  • Pyrazines
  • Pyridines
  • bacteriochlorin
  • isobacteriochlorin
  • Nitrogen
  • pyridine