3470 zyxwvutsrqpon J. Org. Chem. zyxwvut 1991,56,3470-3472 ated cyclooctatriene acts zyxwvuts as a slow donor of tritium re- sulting in the formation of C8H7T.-, Scheme I. This mechanism is supported by the fact that addition of in- dependently svnthesized dideuteriocyclooctatriene to a C8H8'- solution results in formation of C8H7D*-. Acknowledgment. We wish to thank the National Science Foundation (Grant CHE-9011801) for support of zyxwvutsrqp - - this work. We also thank Dr. Richard biter for shdating the EPR spectra. (10) Roth, W. R. Annalen 1964, 671,25. Synthesis and Characterization of the First Water-Soluble Closely Interspaced Cofacial Porphyrin Dimer Rdik Karaman and Thomas C. Bruice* Department of Chemistry, University of California at Santa Barbara, Santa Barbara, California 93106 Received February 6, 1991 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Summary: The first closely spaced quadruply bridged water-soluble cofacial dimer (5) was successfully syn- thesized by the reaction of porphyrin 2 with sulfonamide 3 followed by N-methylation with methyl iodide. The conformations of 5 and its precursor 4 are largely de- pendent on the solvent, and the solvent effect is inhibited by protonation or metalation of the porphyrin cores. Metal-centered cofacial dimeric prophyrins have been recognized as intriguing compounds since they were first prepared and reported.' They have been offered as pu- tative models for the study of cytochrome c3,2 cyto- chrome-c-oxidase? and other'# metallo enzymes. Binding affinities of dioxygen and carbon monoxides by metal- centered cofacial dimeric prophyrins have been studied, and it has been shown that they may serve as effective catalysts for the four-electron reduction of dioxygen to water? These agents have been employed in the study of (1) Dolphin, D.; Hiom, J.; Paine, J. B., 111 Heterocycles 1981,16,417. (2) Yagi, T.; Aruyama, K. Biochim. Bwphys. Acta 1971, 243, 214. (3) (a) Chang, C. K. J. Chem. SOC., Chem. Commun. 1977,800. (b) Hatada, M. H.; Tulinsky, A,; Chang, C. K. J. Am. Chem. SOC. 1980,102, 7116. (c) Chnng, C. K.; Wang, C.-B. In Electron Transport and Oxygen Utilization; Ho, C., Ed.; Elsevier: A", 1982; pp 237-243. (d) Liu, H. Y.; Weaver, M. J.; Wang, C.-B.; Chang, C. K. J. Electroanal. Chem. 1983,145,439. (e) Chnng, C. K.; Liu, H. Y.; Abdalmuhdi, I. J. Am. Chem. zyxwvut Soc. 1984, lM, 2725. (0 Liu, H. Y.; Abdalmuhdi, I.; Chang, C. K.; Anson, F. C. J. Phys. Chem. 1986,89,665. (g) Filler, J. P.; Ravichnndran, K. G.; Abdalmuhdi, I.; Tulineky, A.; Chnng, C. K. J. Am. Chem. SOC. 1986, 108, 417. (h) Proniewicz, L. M.; Odo, J.; Goral, J.; Chang, C. K.; Nakamoto, K. Zbid. 1989,111, 2105. (i) Collman, J. P.; Marrocco, M.; Denisevich, P.; Koval, C.; Anson, F. C. J. Electroanal. Chem. 1979,101,117. G) Collman, J. P.; Marrocco, M.; Elliott, C. M.; L'Her, M. Zbid. 1981,124, 113. (k) Collman, J. P.; Aneon, F. C.; Barnes, C. E.; Bencoeme, C. S.; Geiger, T.; Evitt, E. R.; Kreh, R. P.; Meier, K.; Pettman, R. B. J. Am. Chem. SOC. 1983, 106, 2694. (1) Durand, R. R., Jr.; Benmme, C. 5.; tollman, J. P.; h n , F. C. Zbid. 1988,106, '2710. (m) Le Meat, Y.; L'Her, M.; Courtot-Coupez, J.; Collman, J. P.; Evitt, E. R.; Bencoeme, C. S. J. Chem. Soc., Chem. Commun. 1983,1286. (n) Le Meat, Y.; L'Her, M.; Collman, J. P.; Hendricke, N. H.; McElwee-White,L. J. Am. Chem. SOC. 1986,108,533. (0) Collman, J. P.; Kim, K. Zbid. 1986, lOB, 7847. (p) Ngameni, E.; Le Meet, Y.; L'Her, zyxwvutsr M., Collman, J. P.; Hendricke, N. H.; Kim, K. J. Electroanal. Chem. 1987,220,247. (9) Collman, J. P.; Hen- dricks, N. H.; Kim, K.; Bencoeme, C. 5. J. Chem. Soc., Chem. Commun. 1987,1537. (r) Kim, K.; Collman, J. P.; Ibem, J. A. J. Am. Chem. SOC. 1988,110,4242. (4) (a) Winter, H. C.; Burria, R. H. Annu. Rev. Biochem. 1976,45,409. (b) Shah, V. K.; Brill, W. J. hoc. Natl. Acad. Sci. U.S.A. 1979,74,3249. (5) Cohen, I. A. Struct. Bonding 1980,40, 1. (6) (a) Ward, B.; Wang, C.-B.; Chang, C. K. J. Am. Chem. SOC. 1981, 103,5236. (b) Traylor, T. G.; Taeuno, Y.; Powell, D. W.; Cannon, J. P. J. Chem. SOC., Chem. Commun. 1977,732. (c) Nishide, H.; Maeda, H.; Wang, S.-G.; Teuchida, E. J. Chem. Soc., Chem. Commun. 1986,573. See also ref 3c. 0022-3263 zyxwvutsr f 91 f 1956-3470$02.50 f 0 antiferromagnetic coupling as seen with superoxide dis- mutase and cytochrome-c-oxidase? To this date, studies have been restricted to organic solvents. Cofacial dimeric tetraphenylporphyrins may be singly, doubly, triply, or quadruply bridged. The number of bridges determine the rigidity of the structure, and the length of the bridges determine the closeness of interspacing of the porphyrin planes. With the exception of the single compound prepared by Kagan in 1977: quadruply bridged closely interspaced dimeric tetraphenylporphyrins were unknown. We report now the synthesis of and preliminary observations on the first closely spaced water-soluble cofacial dimeric tetra- phenylporphyrin 5 and ita biszinc(I1) complex (Znp5). The synthesis of 5 is based on recently devised tech- nology for the synthesis of quadruply two- and threeatom, aza-bridged cofacial tetraphenylporphyrins? Porphyrin (7) (a) Landrum, J. T.; Reed, C. A,; Hatano, K.; Scheidt, W. R. J. Am. Chem. SOC. 1978,100,3232. (b) Landrum, J. T.; Grimmett, D.; Haller, K. J.; Scheidet, W. R.; Reed, C. A. Zbid. 1981,109, 2640. (8) Kagan, N. E.; Mauzerall, D.; Merrifield, R. B. J. Am. Chem. SOC. 1977,99,5484. 0 1991 American Chemical Society