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Synthesis, Structure and Photophysical Properties of Ferrocenyl or Mixed Sandwich Cobaltocenyl Ester Linked meso ‐Tetratolylporphyrin Dyads
Author(s) -
Gokulnath Sabapathi,
Achary Balahoju Shivaprasad,
Kumar Chakka Kiran,
Trivedi Rajiv,
Sridhar Balasubramanian,
Giribabu Lingamallu
Publication year - 2014
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12372
Subject(s) - ferrocene , porphyrin , metallocene , photochemistry , intramolecular force , chemistry , quenching (fluorescence) , electron transfer , photoinduced electron transfer , excited state , crystallography , electrochemistry , fluorescence , polymerization , stereochemistry , organic chemistry , polymer , physics , electrode , quantum mechanics , nuclear physics
We report here the design and synthesis of porphyrin–metallocene dyads consisting of a metallocene [either ferrocene or mixed sandwich η 5 ‐[C 5 H 4 (COOH)]Co( η 4 ‐C 4 Ph 4 ) connected via an ester linkage at meso phenyl position of either free‐base or zinc porphyrin. All these dyad systems were characterized by various spectroscopic and electrochemical methods. A dimeric form of this molecule was observed in the X‐ray crystal structure of Zn‐TTPCo. The absorption spectra of all four dyads indicated the absence of electronic interactions between porphyrin macrocycle and metallocene in the ground state. However, interestingly, in all four dyads, fluorescence emission of the porphyrin was quenched (19–55%) as compared to their monomeric units. The quenching was more pronounced in ferrocene derivatives rather than cobaltocenyl derivatives. The emission quenching can be attributed to the excited‐state intramolecular photoinduced electron transfer from metallocene to singlet excited state of porphyrin and the electron‐transfer rates ( k ET ) were established in the range 1.51 × 10 8 to 1.11 × 10 9 s −1 . They were found to be solvent dependent.