Photoinduced molecular motions

The electronic structure of Ni(CO)4 is not as well defined as those of either Cr(CO)6 or Fe(CO)5. This makes the assignment of processes in the early development of the excited-state dynamics somewhat speculative. However there are a number of unique features to the photophysics of CO-loss from Ni(CO)4. Firstly, the CO loss is very slow compared to the other two systems outlined herein taking approximately 600 fs. In addition the Ni(CO)3 fragment is produced in its St state and this state persists because there is no facile deactivation process available based on molecular motions. Deactivation can be achieved only by further CO loss or by radiative processes of either fluorescence or phosphorescence. The overall scheme of potential energy curves and pathways for photoinduced loss of CO from Ni(CO)4 is represented in Fig. 29. 

Natansohn, A., Rochon, P., Meng, X., Barrett, C., Buffeteau, X, Bonenfant, S., and Pezolet, M. Molecular addressing Selective photoinduced cooperative motion of polar ester groups in copolymers containing azobenzene groups. Macromolecules 31, 1155 (1998). 

Nagamani SA, Norikane Y, Tamaoki N. 2005. Photoinduced hinge like molecular motion studies on xanthene based cyclic azobenzene dimers. J Org Chem 70(23) 9304 9313. 

Sandanayaka, A. S. D. et al. Photoinduced electron transfer processes in rotaxanes containing [60]fuller-ene and ferrocene Effect of axle charge on light-induced molecular motion. Aust. J. Chem. 59, 186-192, 2006. 

Photochemical and thermal isomerization of azobenzene derivatives were studied in silica-gel matrices (Ueda, 1993, 1994). Triethoxysily groups linked with the azobenzene moiety had no effect on isomerization reaction. The first-order kinetics of the thermal isomerization of the photoinduced cis isomer reveals that the steric restrictions to suppress the molecular motion decreased in the following order sol-gel films > poly(methyl... 

Chiorboli C, Indelli MT, Scandola F (2005) Photoinduced Electron/Energy Transfer Across Molecular Bridges in Binuclear Metal Complexes. 257 63-102 Collin J-P, Heitz V, Sauvage J-P (2005) Transition-Metal-Complexed Catenanes and Rotax-anes in Motion Towards Molecular Machines. 262 29-62 Collyer SD, see Davis F (2005) 255 97-124 Commeyras A, see Pascal R (2005) 259 69-122 Correia JDG, see Santos I (2005) 252 45-84 Costanzo G, see Saladino R (2005) 259 29-68 Credi A, see Balzani V (2005) 262 1-27 Crestini C, see Saladino R (2005) 259 29-68... 

Photoinduced electron transfer, using the presently described molecular systems, remains an interesting and promising topic—particularly in relation to charge separation and ultimately artificial photosynthesis. Nevertheless, a new area has recently emerged, which is that of multicomponent molecular sets undergoing controlled motions, under the action of an external signal. There is no doubt that this... 

---