NMR-SPECTRA OF THE PORPHYRINS .39. PARAMAGNETIC SHIFTS IN COBALT(II) PORPHYRINS

被引:14
作者
ABRAHAM, RJ
MARSDEN, I
XIUJING, L
机构
[1] Chemistry Department, University of Liverpool, Liverpool, L69 3BX
关键词
H-1; NMR; COBALT(II) PORPHYRINS; PARAMAGNETIC SHIFTS;
D O I
10.1002/mrc.1260281211
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
A model of the paramagnetism in cobalt(II) prophyrin complexes has been developed which successfully calculates paramagnetic shifts for protons not affected by the contact term. The model utilizes a single large dipole positioned on the cobalt(II) atom, and calculates the pseudo-contact shift using the dipole approximation. With this model the angle of twist of the peripheral meso phenyl rings in tetraphenylporphyrin (TPP) derivatives was determined. In TPP and the meta- and para-substituted derivatives studied the phenyl rings are at ca. 65-degrees to the porphyrin plane, whereas in the ortho-substituted derivatives the phenyl rings are essentially orthogonal. Similarly, the geometry for the beta-ethyl groups of octaethylporphyrin and etioporphyrin I was found to be 50-degrees out of the plane of the porphyrin inclined to the meso proton, and that of the comparable propionate groups of coproporphyrin I to be 55-degrees. Finally, the novel compound meso-tetra(p-phenoxyphenyl)porphyrin, an analogue of diphenyl either, was prepared to determine the twist angles between the two phenyl rings. These were found to be 60-degrees by correlating observed paramagnetic shifts with those calculated. This agrees well with MNDO studies, which gave a value of 59-degrees.
引用
收藏
页码:1051 / 1057
页数:7
相关论文
共 35 条
[1]  
ABRAGAM A, 1961, PRINCIPLES NUCL MAGN, P191
[2]   ROTATIONAL ISOMERISM .7. EFFECT OF SUBSTITUENT ON VICINAL COUPLING CONSTANTS IN XCH2.CH2Y FRAGMENTS [J].
ABRAHAM, RJ ;
GATTI, G .
JOURNAL OF THE CHEMICAL SOCIETY B-PHYSICAL ORGANIC, 1969, (08) :961-&
[3]   NMR-SPECTRA OF THE PORPHYRINS - 38 - CONFORMATIONAL-ANALYSIS OF AZACYCLOHEPTANE AND AZACYCLOOCTANE USING A NOVEL COBALT(III) PORPHYRIN SHIFT-REAGENT [J].
ABRAHAM, RJ ;
MEDFORTH, CJ .
MAGNETIC RESONANCE IN CHEMISTRY, 1990, 28 (04) :343-347
[4]  
ABRAHAM RJ, UNPUB
[5]   A SIMPLIFIED SYNTHESIS FOR MESO-TETRAPHENYLPORPHIN [J].
ADLER, AD ;
LONGO, FR ;
FINARELLI, JD ;
GOLDMACH.J ;
ASSOUR, J ;
KORSAKOF.L .
JOURNAL OF ORGANIC CHEMISTRY, 1967, 32 (02) :476-+
[7]   ELECTRON SPIN RESONANCE OF ALPHA- AND BETA-COBALT PHTHALOCYANINE [J].
ASSOUR, JM ;
KAHN, WK .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1965, 87 (02) :207-&
[8]  
BARALDI I, 1986, J CHIM PHYS, V83, P10
[9]   MAGNETIC-RESONANCE STUDY OF METAL-PORPHYRIN-CAFFEINE COMPLEXES [J].
BARRY, CD ;
HILL, HAO ;
SADLER, PJ ;
WILLIAMS, RJP .
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 1973, 334 (1599) :493-504
[10]   MOLECULAR-STRUCTURES OF PORPHYRIN COMPLEXES IN SOLUTION - H-1 NUCLEAR MAGNETIC-RESONANCE SPECTROSCOPIC INVESTIGATION OF INTERACTION BETWEEN 2,4,7-TRINITROFLUORENONE AND NICKEL (II) AND COBALT(II) MESOPORPHYRIN IX DIMETHYL ESTERS [J].
BARRY, CD ;
HILL, HAO ;
MANN, BE ;
SADLER, PJ ;
WILLIAMS, RJP .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1973, 95 (14) :4545-4551