1. Tridentate Binding Structure of Cu-(2,2:6,2  -Terpyridine) XU WANG and DONG-SHENG YANG Department of Chemistry, University of Kentucky, Lexington, KY, 40506 XU WANG and DONG-SHENG YANG Department of Chemistry, University of Kentucky, Lexington, KY, 40506

2. MotivationsMotivations  Terpyridine:  One of the most used ligands for construction of supramolecular systems;  Important ligand in testing catalytic activity, coordination chemistry, organometallic and photochemistry;  High binding affinity towards transition metal.  Metal complexes:  Polymers, surface;  Electronic and optical properties: solar cell, nano- devices…

3. Cu-PyridineCu-Pyridine AIE: 43703 cm -1

4. Cu-(2,2 ’ -Bipyridine) AIE: 37641 cm -1

5. 2,2:6,2  -Terpyridine

6. MethodologyMethodology  Laser ablation  Time-of-flight mass spectrometry (TOF-MS)  Photoionization efficiency (PIE) spectroscopy  Zero electron kinetic energy (ZEKE) photoelectron Spectroscopy  Calculations: B3LYP/6-311+G(d,p)  Simulations: Franck-Condon and harmonic approximations

7. Schematic Diagram of PFI-ZEKE Apparatus

8. ZEKE Spectrum of Cu-(2,2:6,2  -Terpyridine) AIE: 35190 cm -1 26 cm -1 ! 0-0

9. I I II III IV II I: trans-trans II: trans-gauche III: gauche-gauche (C 2 ) IV: gauche-guache (C s )   PES of 2,2:6,2  -Terpyridine A B C

10. trans-transtrans-gauchegauche-gauchegauche-gauche PG C 2v C1C1C1C1 C2C2C2C2 CsCsCsCs E e (kJ mol -1 ) 022.151.553.3 Dipole (debye) 2.121.933.422.58  ’ (  ) 180.0177.342.641.6  ” (  ) 180.037.142.641.6 Conformers of 2,2:6,2  -Terpyridine

11. 0 5570 7885 8637 9633 ΔE e /cm -1 2 B 1 C 2v T B MIMI M II M III

12. 1 A ’, C s 2 B 1, C 2v 9º9º9º9º

13. B MIMI M II M III ZEKE Experimental and Simulated Spectra of Five Isomers

14. T ZEKE B MIMI M II M III

15. Experimental and Simulated Spectra of Cu-(2,2:6,2  -Terpyridine) AIE: 35190 cm -1 26 cm -1 ?? ? ? ?

16. Observed Vibrations Mid-ring o.p. rock, a, 26 cm -1

17. Cu + -N(side) stretch, a, 114 cm -1 rings distortion, a, 1089 cm -1 Observed Vibrations H atoms swing I, a, 1438 cm -1 H atoms swing II, a, 1493 cm -1

18. Cu-pyridine Cu-(2,2-bipyridine) Cu-(2,2:6,2  -terpyridine) Binding modeMonodentateBidentate Tridentate AIE, cm -1 4370337641 35190 D 0 / D 0 +, kJ mol -1 37.0/276.491.4/405.9 177.6/517.2 Cu-N, Å2.0821.961 2.029, 2.006, 2.029 Cu + -N, Å1.9222.010 2.057, 2.054, 2.057 1A1←2A11A1←2A1 1A1←2B11A1←2B1 1 A’← 2 B 1 SummarySummary

19. To be continued…