TY - JOUR
T1 - Supramolecular Surface Photochemistry
T2 - Cascade Energy Transfer between Encapsulated Dyes Aligned on a Clay Nanosheet Surface
AU - Tsukamoto, Takamasa
AU - Ramasamy, Elamparuthi
AU - Shimada, Tetsuya
AU - Takagi, Shinsuke
AU - Ramamurthy, V.
N1 - Funding Information:
This work was partly supported by a Grant-in-Aid for Scientific Research on Innovative Areas "All Nippon Artificial Photosynthesis Project for Living Earth (AnApple)" (25107521), a Grant-in-Aid for Scientific Research (B) (24350100) from the JSPS, and a Grant-in-Aid for SPS Fellows (2603441). V. Ramamurthy is grateful to the National Science Foundation (CHE-1411458) for financial support.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/3/29
Y1 - 2016/3/29
N2 - Three coumarin derivatives (7-propoxy coumarin, coumarin-480, and coumarin-540a, 2, 3, and 4, respectively) having different absorption and emission spectra were encapsulated within a water-soluble organic capsule formed by the two positively charged ammonium-functionalized cavitand octaamine (OAm, 1). Guests 2, 3, and 4 absorb in ultraviolet, violet, and blue regions and emit in violet, blue, and green regions, respectively. Energy transfer between the above three coumarin@(OAm)2 complexes assembled on the surface of a saponite clay nanosheet was investigated by steady-state and time-resolved emission techniques. Judging from their emission and excitation spectra, we concluded that the singlet-singlet energy transfer proceeded from 2 to 3, from 2 to 4, and from 3 to 4 when OAm-encapsulated 2, 3, and 4 were aligned on a clay surface as two-component systems. Under such conditions, the energy transfer efficiencies for the paths 2∗ to 3, 2∗ to 4, and 3∗ to 4 were calculated to be 33, 36, and 50% in two-component systems. When all three coumarins were assembled on the surface and 2 was excited, the energy transfer efficiencies for the paths 2∗ to 3, 2∗ to 4, and 3∗ to 4 were estimated to be 32, 34, and 33%. A comparison of energy transfer efficiencies of the two-component and three-component systems revealed that excitation of 2 leads to emission from 4. Successful merging of supramolecular chemistry and surface chemistry by demonstrating novel multi-step energy transfer in a three-component dye encapsulated system on a clay surface opens up newer opportunities for exploring such systems in an artificial light-harvesting phenomenon.
AB - Three coumarin derivatives (7-propoxy coumarin, coumarin-480, and coumarin-540a, 2, 3, and 4, respectively) having different absorption and emission spectra were encapsulated within a water-soluble organic capsule formed by the two positively charged ammonium-functionalized cavitand octaamine (OAm, 1). Guests 2, 3, and 4 absorb in ultraviolet, violet, and blue regions and emit in violet, blue, and green regions, respectively. Energy transfer between the above three coumarin@(OAm)2 complexes assembled on the surface of a saponite clay nanosheet was investigated by steady-state and time-resolved emission techniques. Judging from their emission and excitation spectra, we concluded that the singlet-singlet energy transfer proceeded from 2 to 3, from 2 to 4, and from 3 to 4 when OAm-encapsulated 2, 3, and 4 were aligned on a clay surface as two-component systems. Under such conditions, the energy transfer efficiencies for the paths 2∗ to 3, 2∗ to 4, and 3∗ to 4 were calculated to be 33, 36, and 50% in two-component systems. When all three coumarins were assembled on the surface and 2 was excited, the energy transfer efficiencies for the paths 2∗ to 3, 2∗ to 4, and 3∗ to 4 were estimated to be 32, 34, and 33%. A comparison of energy transfer efficiencies of the two-component and three-component systems revealed that excitation of 2 leads to emission from 4. Successful merging of supramolecular chemistry and surface chemistry by demonstrating novel multi-step energy transfer in a three-component dye encapsulated system on a clay surface opens up newer opportunities for exploring such systems in an artificial light-harvesting phenomenon.
UR - http://www.scopus.com/inward/record.url?scp=84962433699&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84962433699&partnerID=8YFLogxK
U2 - 10.1021/acs.langmuir.5b03962
DO - 10.1021/acs.langmuir.5b03962
M3 - Article
C2 - 26963843
AN - SCOPUS:84962433699
VL - 32
SP - 2920
EP - 2927
JO - Langmuir
JF - Langmuir
SN - 0743-7463
IS - 12
ER -