member-academic-staff
Menahem Kaftory

Menahem Kaftory

Professor Emeritus
+972-4-8293761
+972-4-8295705
453
Solid State Chemistry
  • Chemical Crystallography· Chemical Reactions in the Solid-State
  • Photochemistry in the Solid-State
  • Molecular Magnets

Photochemical reactions in the solid-state

Solid-state photochemical reactions are highly dependent on the geometry of the reacting compound and its product. An important advantage in the understanding of the reaction mechanism, the course of the reaction and the reaction control factors lies in the ability to follow the geometrical changes during the reaction. Unfortunately, most solid-state reactions result in the destruction of the single-crystallinity nature of the sample under study (heterogeneous reaction). In heterogeneous solid-state reactions, the structure of the pre-reacting compound can be established and that of the product be determined after re-crystallization. Therefore, the missing events that take place during the reaction are a matter of speculation. Homogeneous solid-state reactions, in which the single crystallinity nature of the sample remains unchanged during the photoreaction and the crystal does not undergo disintegration to enable determining its crystal structure by X-ray diffraction methods, are quite rare. A recently used general method involves inducing a homogeneous photochemical reaction by irradiating the crystal with wavelengths corresponding to the chromophore’s absorption tail. This method enables monitoring structural changes during photoreactions. Another method we have used quite successfully is inducing the photochemical reaction on reactive guest molecules embedded within the lattice of host molecules. Irradiation of 6-methyl-2(1H)pyridone in its inclusion compound with tetraphenyl-hexa-2,4-diyne-1,6-diol show the following: (a) 6-methyl-2(1H)pyridone molecules related by an inversion center photodimerize (b) the orientation of the two monomers prior to the irradiation is different from that of the dimer at the end of the reaction (c) at the end of the reaction, water molecules penetrated into the crystal forming hydrogen bonds between the photodimers. The single crystal retains its nature throughout the reaction and didn’t undergo disintegration. Similar observation was found for the inclusion compound of 2(1H)pyridone. Other examples of molecular flip in the crystalline state during photodimerization was recently discovered and investigated.

Post doc: ETH, Zurich, Zwitzerland, 1973-75

Ph.D: Technion 1973

Awards

MINERVA Fellowship

Technion and ETH Exchange International Scientific Exchange

JSPS, Japanese Society for Promotion of Science

1. Kaftory M., Shteiman V., Lavy T., Scheffer J. R., Yang J., Enkelmann V., Eur. J. Org. Chem., 847-853 (2005).
2. Lavy T., Sheynin Y., Kaftory M., Eur. J. Org. Chem., 4802-4808 (2004).
3. Zakrassov A., Shteiman V., Sheynin Y., Botoshansky M., Kapon M., Kaftory M.,DelSesto R. E., Joel S. Miller, Helvetica Chimica Acta, 86, 1234-1245 (2003).
4. Lavy T., Kaftory M., CrystEngComm., 9, 123-127 (2007).
5. Deng-Ke Cao, Thekku Veedu Sreevidya, Mark Botoshansky, Gilad Golden, Jason Brown Benedict, Menahem Kaftory., J. Phys. Chem. A. 114, 7377-7381 (2010).
6. Deng-Ke Cao, Thekku Veedu Sreevidya, Mark Botoshansky, Gilad Golden, Jason Brown Benedict, Menahem Kaftory.,CrystEngComm, 13, 3181-88 (2011).