Exceptional electronic modulation of porphyrins through meso-arylethynyl groups. Electronic spectroscopy, electronic structure, and electrochemistry of [5,15-bis[(aryl)ethynyl]-10,20-diphenylporphinato]zinc(II) complexes. X-ray crystal structures of [5,15-bis[(4`-fluorophenyl)ethynyl]-10,20-diphenylp orphinato]zinc(II) and 5,15-bis [(4`-methoxyphenyl)ethynyl]-10,20-diphenylporphyrin

Journal Article · Wed Nov 27 04:00:00 EST 1996 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja962403y· OSTI ID:437399

LeCourse, S M; DiMagno, S G; Therien, M J ^[1]

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1. Univ. of Pennsylvania, Philadelphia, PA (United States)

A new class of porphyrins in which intervening ethynyl moieties connect aryl groups to the porphyrin 5- and 15-positions is described. The synthesis and optical spectroscopy of five new compounds are reported. The X-ray structure of one of these complexes, [5,15-bis[(4`-fluorophenyl)ethynyl]-10,20-diphenyl porphinato]zinc (II), is usual in that it shows the arylethynyl-phenyl rings to be coplanar with the porphyrin macrocycle. This arrangement of aryl rings with respect to the porphyrin macrocycle underscores the fact that the steric barrier to rotation between the porphyrin and arylethynyl-phenyl aromatic systems has been removed and highlights the enhanced {pi}-conjugative interactions responsible for the unusual electronic characteristics of these molecules. Electronic spectroscopy and electrochemistry of these systems evince the ability of this new porphyrin structural motif to modulate extensively chromophore electronic structure. ZINDO-determined (INDO-1 semiempirical parameters; Cl level = 20) frontier orbital energies for the [5,15-bis[(aryl)ethynyl]-10, 20-diphenylporphinato]zinc(II) complexes demonstrate that these properties derive from energetic differences between the porphyrin HOMO and HOMO-1 and a substantial splitting of the formerly degenerate porphyrin LUMO. 24 refs., 8 figs., 7 tabs.

• DOE Contract Number: FG02-94ER14494
• OSTI ID: 437399
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 47 Vol. 118; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
BOND ANGLE
BOND LENGTHS
ELECTRON SPECTRA
ELECTRONIC STRUCTURE
EXCITED STATES
EXPERIMENTAL DATA
MODIFICATIONS
MOLECULAR ORBITAL METHOD
PORPHYRINS
STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
VOLTAMETRY
X-RAY DIFFRACTION
ZINC COMPLEXES