MARIYAM FATIMA 1,2,3, CRISTÓBAL PÉREZ1,2,3 , MELANIE SCHNELL 1,2,3 BROADBAND MICROWAVE SPECTROSCOPY AS A TOOL TO STUDY INTERMOLECULAR INTERACTIONS IN THE DIPHENYLETHER - WATER SYSTEM MARIYAM FATIMA 1,2,3, CRISTÓBAL PÉREZ1,2,3 , MELANIE SCHNELL 1,2,3 1 Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany, 2Deutsches Elektronen-Synchrotron, Hamburg, Germany 3Christian-Albrechts-Universität zu Kiel, Kiel, Germany

INTRODUCTION DIPHENYLETHER (DPE) φ1 φ2 twist φ1 ≈ φ2 ≈ 41° ∆E=0 kJ/mol O---H φ1 ≈ φ2 ≈ 41° ∆E=0 kJ/mol π skew φ1 = 90°, φ2 = 0° ∆E=1 kJ/mol Floppy molecule Two stable conformers (twist, skew) Most stable: twist conformer Offers two different docking sites for intermolecular interaction n = 1, 2, 3 WATER

CHIRPED PULSE MICROWAVE SPECTROSCOPY Sample introduction 2-8 GHz 20 kHz linewidth Microwave Horn Antenna (Receiver) Supersonic Expansions Microwave Horn Antenna (Emitter) Backing pressure of neon: 3 bar Temperature for diphenylether: 90° C

DIPHENYLETHER-WATER (I): AB INITIO RESULTS OH---O OH---π ∆E=1.4 kJ/mol ∆E=0 kJ/mol Calculated at B3LYP-D3/aug-cc-pVTZ

DIPHENYLETHER-WATER (I): EXPERIMENTAL RESULTS 5 million acquisitions, 19 hours measurement Other lines from DPE monomer, 13C’s of DPE- water (I), DPE-water (II), DPE-water (III)

DIPHENYLETHER-WATER (I): RESULTS OH---π   State 0- State 0+ B3LYP-D3/aug-cc-pVTZ MP2/6-311G++(d,p) A(MHz) 1359.68029(42) 1362.4557(11) 1414.67 1377.04 B(MHz) 409.24121(14) 409.12297(45) 404.91 413.82 C (MHz) 365.31297(13) 365.43020(43) 366.04 370.50 ∆J (kHz) 0.02233(85) 0.0235(24) ∆JK (kHz) 0.2683(48) 0.263(21) µa/µb/µc (D) 0.6/1.1/0.8 1.5/0.13/0.15 σ (kHz) 5.6 6.6 Nlines a 95 (71/0/24) 78 (57/0/21) a The number of fitted lines.

DIPHENYLETHER-WATER (I): RESULTS b a c OH---O   Experiment (b type) B3LYP-D3/aug-cc-pVTZ A(MHz) 1062.0824 1096.08 B(MHz) 434.2999 429.67 C (MHz) 343.60408 341.38 µa/µb/µc (D) 1.3/2.5/0.6 Nlines a 29 a The number of fitted lines.

DIPHENYLETHER-WATER (II): EXPERIMENTAL RESULTS S/N ratio for DPE-water (II) is 450:1

DIPHENYLETHER-WATER (II): AB INITIO RESULTS Calculated at B3LYP-D3/aug-cc-pVTZ

DIPHENYLETHER-WATER (II): RESULTS   Experiment B3LYP-D3/aug-cc-pVTZ A(MHz) 823.80379(24) 850.51 B(MHz) 390.51117(13) 391.08 C (MHz) 334.18534(13) 335.29 ∆J (kHz) 0.02964(86) ∆JK (kHz) 0.1766(34) ∆K (kHz) 0.6324(47) δJ 0.00787(31) δK 0.142(12) µa/µb/µc (D) 1.4/1.6/1.4 σ (kHz) 9.9 Nlines a 294 (81/119/94) a The number of fitted lines.

DIPHENYLETHER-WATER: EXPERIMENTAL STRUCTURES H218O measurement to find the experimental positions of water Experimental structural positions obtained from Kraitchman method vs results from B3LYP-D3/aug-cc-pVTZ

DIPHENYLETHER-WATER (III): EXPERIMENTAL RESULTS

DIPHENYLETHER-WATER (III): AB INITIO RESULTS

DIPHENYLETHER-WATER (III): RESULTS   Experiment B3LYP-D3/aug-cc-pVTZ A(MHz) 621.58779(33) 651.20 B(MHz) 358.17136(13) 354.10 C (MHz) 279.70640(12) 282.18 ∆J (kHz) 0.02406(56) ∆K (kHz) 0.331(11) δJ (kHz) 0.00814(37) µa/µb/µc (D) 1.3/1.8/1.8 σ (kHz) 6.9 Nlines a 190 (68/69/53) a The number of fitted lines.

CONCLUSION: DIPHENYLETHER-WATER skew twist φ1 φ2 φ1 = 90° φ2 = 0° φ1 ≈ φ2 ≈ 41° ∆E=0 kJ/mol ∆E=1 kJ/mol OH-π OH-O φ1 = 47° φ2 = 35° φ1 = 50° φ2 = 31° DPE-water (II) DPE-water (III) φ1 = 70° φ2 = 19° φ1 = 87° φ2 = 7°

CONCLUSIONS AND OUTLOOK Identified diphenylether-water complexes up to three molecules of water. Addition of water molecule changes the structure of diphenylether from most stable twist structure to skew structure (∆E = 1kJ/mol). Increase in the intermolecular interaction is stabilizing skew structure of diphenylether. b a c

ACKNOWLEGEMENTS Benjamin Arenas MF07 Sérgio Domingos TC03 Cristóbal Pérez TE09, WG08 Melanie Schnell RG11 Anna Krin RG02 Amanda Steber TH02 Sébastien Gruet WD07

THANK YOU