Femtochemistry of Rhodopsins

The review considers the spectral kinetic data obtained by us by femtosecond absorption laser spectroscopy for the photochromic reaction of retinal isomerization in animal rhodopsin (type II), namely, bovine visual rhodopsin and microbial rhodopsins (type I), such as Exiguobacterium sibiricum rhodopsin and Halobacterium salinarum bacteriorhodopsin. It is shown that the elementary act of the photoreaction of retinal isomerization in type I and type II rhodopsins can be interpreted as a transition through a conical intersection with retention of the coherence of the vibrational wave packets generated during excitation. The coherent nature of the reaction is most pronounced in visual rhodopsin as a result of the barrier-free movement along the excited surface of potential energy, which also leads to an extremely high rate of retinal isomerization compared to microbial rhodopsins. Differences in the dynamics of photochemical reactions of type I and type II rhodopsins can be related to both differences in the initial isomeric forms of their chromophores (all-trans and 11-cis retinal, respectively), as well as with the effect of the protein environment on the chromophore. Despite the practically identical values of the quantum yields of the direct photoreaction of visual rhodopsin and bacteriorhodopsin, the reverse photoreaction of visual rhodopsin is much less effective (φ = 0.15) than in the case of bacteriorhodopsin (φ = 0.81). It can be assumed that the photobiological mechanism for converting light into an information process in the evolutionarily younger visual rhodopsins (type II rhodopsins) should be more reliable than the mechanism for converting light into a photoenergetic process in the evolutionarily more ancient microbial rhodopsins (type I rhodopsins). The low value of the quantum yield of the reverse reaction of visual rhodopsin can be considered as an increase in the reliability of the forward reaction, which triggers the process of phototransduction.

Functionalization of Cellulose Paper by Coating Nano Metal-Organic Frameworks for Use as Photochromic Material

The cellulose paper-based functional materials modified by Zn-NDI and Cu-NDI were prepared by the coating method. The chemical structures were characterized by FTIR, XRD, UV-vis and SEM, and the photochromic properties of the composite functional materials were studied. The results showed that Zn-NDI and Cu-NDI were successfully prepared and retained on the surface of copy paper, the wavelength of photochromic reaction is between 300-400 nm of MOFs materials. Optical analysis confirmed that the NDI/paper, Zn-NDI/paper and Cu-NDI/paper changed from tan to wheat, light green to olive, and dark tan to brown after 60 seconds of exposure to hernia light irradiations, the MOFs coated paper returned to its original color when it was placed in the dark for 4 hours. The above results indicated that the prepared Zn-NDI and Cu-NDI coated paper composites exhibited excellent photochromic ability and had potential applications in the field of anti-counterfeiting packaging materials.

Functionalization of Cellulose Paper by Coating Nano Metal-Organic Frameworks for Use as Photochromic Material

The cellulose paper-based functional materials modified by Zn-NDI and Cu-NDI were prepared by the coating method. The chemical structures were characterized by FTIR, XRD, UV-vis and SEM, and the photochromic properties of the composite functional materials were studied. The results showed that Zn-NDI and Cu-NDI were successfully prepared and retained on the surface of copy paper, the wavelength of photochromic reaction is between 300-400 nm of MOFs materials. Optical analysis confirmed that the NDI/paper, Zn-NDI/paper and Cu-NDI/paper changed from tan to wheat, light green to olive, and dark tan to brown after 60 seconds of exposure to hernia light irradiations, the MOFs coated paper returned to its original color when it was placed in the dark for 4 hours. The above results indicated that the prepared Zn-NDI and Cu-NDI coated paper composites exhibited excellent photochromic ability and had potential applications in the field of anti-counterfeiting packaging materials.

Functionalization of Cellulose Paper by Coating Nano Metal-Organic Frameworks for Use as Photochromic Material

The cellulose paper-based functional materials modified by Zn-NDI and Cu-NDI were prepared by the coating method. The chemical structures were characterized by FTIR, XRD, UV-vis and SEM, and the photochromic properties of the composite functional materials were studied. The results showed that Zn-NDI and Cu-NDI were successfully prepared and retained on the surface of copy paper, the wavelength of photochromic reaction is between 300-400 nm of MOFs materials. Optical analysis confirmed that the NDI/paper, Zn-NDI/paper and Cu-NDI/paper changed from tan to wheat, light green to olive, and dark tan to brown after 60 seconds of exposure to hernia light irradiations, the MOFs coated paper returned to its original color when it was placed in the dark for 4 hours. The above results indicated that the prepared Zn-NDI and Cu-NDI coated paper composites exhibited excellent photochromic ability and had potential applications in the field of anti-counterfeiting packaging materials.

Reversible multiplexing optical information storage and photoluminescence switching in Eu2+ doped fluorophosphate-based tunable photochromic materials

Luminescent switching materials upon photochromic reaction have received arising research focus due to their potential applications in erasable optical storage. Nevertheless, it's still remains a challenging to build photochromic materials...