Sep, 2011
Porphyrin molecular tweezers for fullerenes
JOURNAL OF PORPHYRINS AND PHTHALOCYANINES
- Volume
- 15
- Number
- 9-10
- First page
- 951
- Last page
- 963
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1142/S1088424611003872
- Publisher
- WORLD SCI PUBL CO INC
Facing zinc bisporphyrins connected with diethanoanthracene and diethanonaphthacene (syn-1 and syn-2) are prepared by double [3+1] porphyrin synthesis of tripyrranedicarbaldehyde with syn-5,11-dimethoxy-4,6,10,12-tetrahydro-4,12;6,10-diethanoanthracene[2,3-c;7,8-c']dipyrrole and syn-4,7,11,14-tetrahydro-4,14;7,11-diethanonaphthacene[2,3-c;8,9-c']dipyrrole. These bisporphyrins contain large clefts with different sizes capable for complexation with fullerenes such as C-60 and C-70. These designed syn-oriented bisporphyrins serve as effective and selective molecular tweezers for C-70. Binding affinity of the zinc bisporphyrins, namely, syn-1 and syn-2, towards C-60 and C-70 in solution is determined by employing UV-vis spectrophotometric technique. Values of binding constants (K) in toluene for the non-covalent complexes of syn-1 with C-60 and C-70 are estimated to be 3.1(4) x 10(4) and 5.0(2) x 10(5) M-1, respectively, and those of syn-2 with C-60 and C-70 are enumerated to be 2.1(4) x 10(4) and 1.70(13) x 10(5) M-1, respectively. Binding of C-60 and C-70 in the clefts of syn-1 and syn-2 is clearly demonstrated by the crystal structures of C-60/syn-1, C-70/syn-1, C-60/syn-2, and C-70/syn-2 complexes. In the crystal structures with C-70, the directions of the long axis of C-70 are found to be quite different: in the case of C-70/syn-1 complex the axis lies perpendicularly to the line connecting two zinc atoms; however, for the C-70/syn-2 complex, the axis occupies in-plane to the same line. Both the clefts of syn-1 and syn-2 are induced to fit the included fullerenes by domed out-of-plane distortion of porphyrin rings. Moreover, the bicyclo[2.2.2]octadiene moieties of syn-1 are widened by complexation with the fullerenes, while the same moieties of syn-2 are narrowed by the complexation. Therefore, syn-1 catches the fullerenes at the shallow part of the cleft. On the other hand, syn-2 catches the fullerenes at the bottom part of the cleft. NMR experiments of the complexes in THF-d(8) also support these orientations even in solution.
- Link information
-
- DOI
- https://doi.org/10.1142/S1088424611003872
- Web of Science
- https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000297067100017&DestApp=WOS_CPL
- URL
- https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=81255210587&origin=inward
- Scopus Citedby
- https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=81255210587&origin=inward
- ID information
-
- DOI : 10.1142/S1088424611003872
- ISSN : 1088-4246
- eISSN : 1099-1409
- SCOPUS ID : 81255210587
- Web of Science ID : WOS:000297067100017