188638-75-7Relevant academic research and scientific papers
Intramolecular benzoate exchange in benzoato meso-tetra (4-methoxyphenylporphyrinato) thallium(III), Tl(tmpp)(C6H5CO2)
Sheu, Yeong-Horng,Hong, Tay-Ning,Chen, Jyh-Horung,Liao, Feng-Ling,Wang, Sue-Lein,Wang, Shin-Shin,Yang, Thomas C.
, p. 1621 - 1628 (1997)
The new compound benzoato meso-tetra(4-methoxyphenylporphyrinato)thallium(III), Tl (tmpp) (C6H5CO2), has been synthesized and its molecular structure determined by X-ray analysis. The coordination sphere of the Tl3+ ion is an approximate square-based pyramid in which the apical site is occupied by an asymmetric-bidentate C6H5CO-2 group. The average Tl - N bond distance is 2.24(1) A and the Tl atom is displaced 0.811 A from the porphyrin plane. The Tl(1) - O(5) and Tl(1) - O(6) distances are 2.57(2) and 2.27(2) A, respectively. Variable temperature 13C NMR measurements show that the benzoato group of Tl (tmpp) (C6H5CO2) in CD2Cl2 solvent undergoes intramolecular exchange. In the slow exchange region, the carbonyl and C1'' carbons of the benzoato group are separately located at 167.8 ppm [with 2J(Tl-13C) coupling constant 212 Hz] and 128.3 ppm [with 3J (Tl-13C) coupling constant 282 Hz] for Tl(tmpp)(C6H5CO2) in CD2Cl2 at - 90°C. In the fast exchange region, the C*OO and C1'' carbons of the C6H5CO-2 ligand in CD2Cl2 at 21°C are singlets at 168,4 and 130.3 ppm, respectively. The comparison of the ring current effect (Δδ) for the benzoate ligand of Tl(tmpp)(C6H5CO2) and benzoato meso-tetra(4-methoxyphenylporphyrinto)tin(IV), Sn(tmpp)(C6H5CO2)2, is also reported.
