@article{184073f71a5a45a39ba1cb32eec4e47c,
title = "Modification of photochemical reactivity by zeolites: Cation controlled photodimerisation of acenaphthylene within faujasites",
abstract = "Photolyses of acenaphthylene included in M+ Y zeolites gave the corresponding cis and trans dimers. The ratio of the dimers formed depends on the type of cation present in the supercage. Dimerization is believed to originate from the excited singlet state in the case of lower atomic weight cations and from the triplet state in the case of higher atomic weight cation exchanged zeolites. Dimerization provides insight into the distribution and migration of molecules within the zeolite internal structures.",
author = "V. Ramamurthy and Corbin, {D. R.} and Kumar, {C. V.} and Turro, {N. J.}",
note = "Funding Information: lifetimes to favor reaction in doubly occupied cages and the formation of cis isomer (Li. Na and Tl Y). The decrease in trans dimer in going from Rb to Cs Y is simply a reflection of the decreasei n triplet lifetime. Higher yields of the cis dimer in triplet reaction within the internal structures of zeolites compared to solution might then be due to the fact that acenaphthylenesa re not subjected to a uniform environment as in homogeneous solution and dimerization results from doubly and singly occupied cages. Present results clearly attest to the vast and untapped potential of zeolites as microenvironments to modify the photochemical and photophysical behavior of organic molecules. The use of cations to effect triplet reactions within the internal structure of zeolite is under active investigation in our laboratory.1B References 1. Turro, N. J. Tetrahedron 1987, 43. 1589. Ramamurthy.V . in “Inclusion Phenomena and Molecular Recognition”, (Ed) Atwood, J. L.; Plenum Press, in press. 2. For a review see: Cowan, D. 0.; Drisko. R. L.; “Elements of Organic Photochemistry”; Plenum Press New York, 1976; pp 435443. For a review in organized media see: Ramamurthy,V . Tetrahedron 1986. 42, 5753. 3. “Zeolite Molecular Sieves Structure, Chemistry and Use”, Breck, D. W.; John Wiley, 1974.; “Zeolite Molecular Sieves”, Dyer, A.; John Wiley, 1988. 4. General method of preparation of complex, irradiation procedure and extraction of products have already been reported:C orbin, D. R.; Eaton, D. F.; RamamurtbyV. . J. Am. Chem. Sot. 1988, I1 0. 4848. Complexes were prepared in trimethylpentanea nd a small amount of residual solvent may be left in the cages. Product dimers are too large to exit the zeolite cages. Therefore, products were extracted with HCl (which dissolves the zeolite) and ether. Control experiments demonstated the stabilty of reactants and produts under acid extraction conditions. No dimerization occured within X-type zeolites. 5. Turro. N. J.; Gould, I. R.; Zimmt. M. B.; Cheng. C. C. Chem. Phys. Lett. 1985.1 19, 484. 6. Samanta,A .; Fessenden,R . W. J. Phys. Chem.. 1989,9 3. 5823. 7. For the effect of heavy cations on the photophysical behavior of included aromatics and olefms see: Ramsmurthy,V .; t&par, J. V.; Corbin, D. R.; Eaton, D. F., J. Photochem. Photobiol., in press. Caspar, J. V.; RamamutthyV, .; Corbin. D. R. Coord. Chem. Rev., in press. 8. Pre-aggregation of pyrene in zeolite cages even under very low occupancy levels (es>= 0.05) has been reportedr ecently: Liu, X.; Iu, K. K.; Thomas. J. K. J. Phys. Chem. 1989, 93. 4120. 9. “Zeolite Molecular Sieves Structure, Chemistry and Use”, Breck, D. W.; John Wiley, 1974. pp. 681.682. Karger. J.; Ruthven, D. M. Zeolites 1989.9 , 267. lO.VR and DC thank A. Pittman. and P. Hollins for valuable technical assistance. NJT thanks Air Force Office of Scientific Research. the National Science Foundation. the Of&e of Naval Research and IBM Corporation for financial support. CVK thanks Merck Sharp & Dome for a Faculty Development Award. Copyright: Copyright 2014 Elsevier B.V., All rights reserved.",
year = "1990",
doi = "10.1016/S0040-4039(00)94330-2",
language = "English (US)",
volume = "31",
pages = "47--50",
journal = "Tetrahedron Letters",
issn = "0040-4039",
publisher = "Elsevier Limited",
number = "1",
}