Int. Symp. Mol. Spectrosc. (June 21-25, 2010) Laser Spectroscopic Study on Encapsulation Structure of Functional Molecules in Supersonic Jets Laser Spectroscopic Study on Encapsulation Structure of Functional Molecules in Supersonic Jets Universite de Paris-Sud Prof. Christophe Jouvet Prof. Claude Dedonder-Lardeux Pacific Northwest National Laboratory Prof. Sotiris Xantheas Prof. Yoshiya Inokuchi Mr. R. Kusaka(D2) (Crown Ether) Mr. N. Hontama Mr. S. Kokubu (M2) (Crown Ether) Mr. Shouhei Kaneko (M1) (C4A) Takayuki Ebata Dept. of Chemistry, Graduate School of Science, Hiroshima University Takayuki Ebata Dept. of Chemistry, Graduate School of Science, Hiroshima University H 2 H 2

Ar, CH 4, C 2 H 2 H 2 O, NH 3, Structure of C4A-X (X=rare gas,CH 4, H 2 O, NH 3, H 2 O, H 2 O, ) complexes 1.Which isomer (endo- or exo-isomer) do the complexes form? 2.What is the main interaction (dispersion, H-bonding etc.) to form the complex. 3.Relationship between the electronic transition and the structure. 4.Design of the molecule having better encapsulation performance. Endo-complex Exo-complex Calix[4]arene (C4A) ◎ Laser spectroscopic study for jet-cooled complexes ◎ Quantum chemical calculation (MP2, CCSD,DFT(B3LYP, M05-2X) ) guest

Calix[4]arene(C4A)-M complexes C4A C4A-Ar C4A-N 2 C4A-CH ４ C4A-H 2 O 0, C4A can easily form complexes with hydrophobic as well as hydrophilic molecules

Red-shifts and the structures of the complexes Endo-structure C4A-Ar

Binding energy (De) of C4A-Ar (inside, outside) speciesDe / cm -1 MP2/aug-cc-pVQZ De / cm -1 CCSD(T)/aug-cc-pVQZ EXP. / cm -1 Endo-C4A-Ar2328 (1561) Exo-C4A-Ar762 (511) Benzene-Ar ±7 Phenol-Ar ±13 BSSE corrected Endo(inside)-isomerExo(outside)-isomer De of endo-isomer is 3 times larger than the exo-isomer PCCP, 12, 4569 (2010)

S 1 -S REMPI spectra Structure of C4A-H 2 O, NH 3 Low freq. vibrations

IR-UV Double Resonance spectra of C4A and C4A-H 2 O 3 CH stretch H-bonded OH 3 (H 2 O) 1 (H 2 O)

(a) endo-isomer (b) exo-isomer Determination of C4A-H 2 O structure from the IR spectrum 55 cm -1 red-shifted from free 3 0 cm cm -1 MP2/aug-cc-pVQZ

Binding Energy of C4A-H 2 O endo-isomer 3127 cm -1 (MP2/aug-cc-pVQZ level and BSSE-corrected) exo-isomer 1985 cm JPCA, 114, 1967 (2010)

S 1 -S REMPI spectra The spectrum of C4A-NH 3 resembles C4A-H 2 O Structure of C4A-NH 3

IR-UV spectrum of C4A-NH 3 in the OH stretch region C4A-NH 3 C4A-NH 3 has the endo-complex structure (M05-2X/6-31+G*) M05-2X/6-31+G*

Binding Energy (BE) of C4A-NH 3 C4A fragment monitor 2810 Both C4A - H 2 O and C4A – NH 3 are bound by Dipole-Dipole interaction  (NH 3 )= 1.4 Debye <  (H 2 O)= 1.8 Debye  (C4A)= 2.37 Debye BE(C4A-NH 3 ) < 2810 cm -1 BE(C4A-H 2 O) = 3140 cm -1 <

Structure of C4A-C 2 H 2 endo-isomer exo-isomer MP2/aug-cc-pVDZ Endo-isomer is 11.7 kcal/mol (4100 cm -1 ) is more stable than the exo-isomer Side-view

3.70 A 3.83 A In the endo-isomer, the O--O bond distance is shortened by the CH--  H-bonding. Endo IR spectrum and the structure of C4A-C 2 H 2 Top view 3.77 A Exo

Summary Structure, electronic spectra and IR spectra of Calix[4]arene(C4A) complexes have been investigated by various laser spectroscopic methods and quantum chemical calculations(MP2, CCSD, DFT). C4A encapsulates hydrophobic as well as hydrophilic molecules in its cavity. ◎ C4A-Ar n : BE(endo-C4A-Ar) = 1560 cm-1 ( 3-4 times larger than that of Bz—Ar) n>2 : C4A encapsulates large size Ar n clusters ◎ C4A-H 2 O,-NH 3 : The complexes are bound by dipole-dipole interaction. “World’s smallest cup of water” ◎ C4A-C 2 H 2, N 2 : The guest species lies perpendicular to the C 4 axis.