Premium
Noncovalent Synthesis in Aqueous Solution and Spectroscopic Characterization of Multi‐Porphyrin Complexes
Author(s) -
Gulino Fabio G.,
Lauceri Rosaria,
Frish Limor,
EvanSalem Tamar,
Cohen Yoram,
De Zorzi Rita,
Geremia Silvano,
Di Costanzo Luigi,
Randaccio Lucio,
Sciotto Domenico,
Purrello Roberto
Publication year - 2006
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200500825
Subject(s) - porphyrin , stoichiometry , calixarene , chemistry , aqueous solution , molecule , crystallography , photochemistry , combinatorial chemistry , organic chemistry
The interactions of the tetracationic meso ‐tetrakis( N ‐methyl‐4‐pyridyl)porphyrin (H 2 TMPyP) and its metallo derivatives (MTMPyP) (where M=copper( II ), zinc( II ), and gold( III ) with the octa‐anionic form (at neutral pH) of 5,11,17,23‐tetrasulfonato‐25,26,27,28‐tetrakis(hydroxycarbonylmethoxy)calix[4]arene (C 4 TsTc) lead to a series of complex species whose stoichiometry and porphyrin sequence can be easily tuned. Crystallographic, spectroscopic, and diffusion NMR studies converge towards a common picture in which a central 1:4 porphyrin/calixarene unit serves as a template for the formation of more complex species. These species arise by successive, stepwise addition of single porphyrin molecules above and below the plane of the 1:4 central core to ultimately give a 7:4 complex. Noticeably, the stoichiometry of the various complex species corresponds to the actual concentration ratio of porphyrins and calixarenes in solution allowing the stoichiometry of these species to be easily tuned. This behavior and the remarkable stability of these species allow homo‐porphyrin and hetero‐(metallo)porphyrin species to be formed with control of not only the stoichiometry but also the sequence of the porphyrin array. The flexibility and ease of this approach permit, in principle, the design and synthesis of porphyrin arrays for predetermined purposes. For example, we have shown that it is very easy to design and obtain mixed porphyrin species in which a foreseen photoinduced electron‐transfer is indeed observed.