Molecules spectroscopy Supramolecular

Kondo, T., Ueda, M., Yoshida, K., Titani, K., Isobe, M., and Goto, T. 1994. Direct observation of a small-molecule associated supramolecular pigment, commelinin, by electrospray-ionization mass-spectroscopy. J. Am. Chem. Soc. 116 7457-7458. 

Key questions ahead of us concern new concepts for addressing individual molecular switches and the construction of more complex systems which incorporate several switchable functions. Advances in scanning - probe techniques and single molecule spectroscopy as well as supramolecular chemistry will play an important role in this endeavor. 

Fluorescence microscopy techniques are now available which are capable of studying supramolecular interfacial assemblies with excellent spatial and temporal resolution as well as exceptional sensitivity. These methods were initially developed for use in cellular biology, but are finding increasing application in interfacial supramolecular chemistry. This trend is set to continue as methods in single-molecule spectroscopy and time-resolved microscopy evolve. 

Over the last years the utilisation of supramolecular arrays of surfactant molecules as structure-directing templates [1] has been applied to the synthesis of numerous mesostructured aluminophosphates [2-11]. In most cases the preparations were carried out in aqueous systems under hydrothermal conditions, but tetraethylene glycol and/or unbranched primary alcohols were also used [2,4]. Several discussions have been made on the reaction mechanisms that are involved in the syntheses of mesostructured materials [1,12-15] and recently a number of in-situ investigations on the formation processes of mesostructured silica phases in aqueous media have been reported these studies employed small angle X-ray diffraction [16-19] as well as 2H, 13C, 29Si, and 8lBr NMR spectroscopy and polarised light optical microscopy [17]. 

In a supramolecular approach to fullerene-porphyrin hybrids, the assembly of a rigidly connected dyad, in which a zinc tetraphenylporphyrin, Zn(TPP), is noncovalently linked to a C60 derivative via axial pyridine coordination to the metal, was reported [219-222]. Photo excitation of the dyad Zn-complex led to electron transfer with very long lifetimes of the charge-separated pairs, as revealed by optical spectroscopy and confirmed by time-resolved electron paramagnetic resonance spectroscopy. Accordingly, two different solvent-dependent pathways can be considered for the electron-transfer processes. Either the excitation of the porphyrin chromophore is followed by fast intramolecular electron transfer inside the complex, or alternatively the free porphyrin is excited undergoing intermolecular electron transfer when the acceptor molecules ap-... 

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