Hemilabile Coordination Complexes as Fluorescent Chemosensors The Groundwork: RuPOMe Anthony Tomcykoski

Overview Introduction Synthetic Approach CharacterizationConclusions Future Work

Introduction Hemilabile Coordination Hemilabile Coordination Polydentate chelates Polydentate chelates Inert and labile binding positions Inert and labile binding positions Phosphine-ether ligands Phosphine-ether ligands Hemilabile coordination complex in the presence of a small polar molecule (1)

Introduction Examples of Hemilabile Ligands Examples of Hemilabile Ligands POMe Diphenyl(2- methoxyphenyl)phosphine Bis(2-methoxyphenyl)phenylphosphine P(OMe) 2 Tris(2,6- methoxyphenyl)phosphine P(OMe) 6

Introduction Photosensitizer Photosensitizer [Ru(bpy) 3 ] +2 [Ru(bpy) 3 ] +2 Long lived 3 MLCT Long lived 3 MLCT Fluorescent Chemosensor Fluorescent Chemosensor Molecular sensing Molecular sensing Monitor photophysical properties Monitor photophysical properties

Synthetic Approach. 2 H 2 O Starting Material Ru(bpy) 2 Cl 2. 2H 2 O Step One: Make a suitable starting material

Synthetic Approach 2 Step Two: Remove inner sphere chloride Introduce non- coordinating anion (BF 4 - ) Solvated bis(bipyridyl) complex

Synthetic Approach Step Three: Coordinate phosphine-ether hemilabile ligand Isolate product RuPOMe

Hemilabile Coordination Complexes RuPOMe Ru(bpy) 2 P(OMe) 6 RuP(OMe) 6 RuP(OMe) 2 Tolylterpyridyl chromophores Tridentate Ligands Bipyridyl Chromophores Bidentate Ligands

Characterization UV/Vis Spectroscopy Infrared Spectroscopy Emission Spectra Excited State Lifetime NMR ( 1 H, 13 C, 31 P)

UV/Vis Spectroscopy Bipyridyl Systems RuCl 3. nH 2 O Ru(bpy) 2 Cl 2. 2H 2 O [Ru(bpy) 3 ](PF 6 ) 2 MLCT energy gap varies in each complex [Ru(bpy) 3 ](PF 6 ) 2 450nm RuCl 3.nH 2 O420nm Ru(bpy) 2 Cl 2 376, 548nm [RuPOMe](PF 6 ) 2 450nm [Ru(bpy) 2 P(OMe) 6 ](PF 6 ) 2 430nm in EtOH/Acet476nm in EtOH/Acet476nm

Jablonski Diagram MLCT [Ru(bpy) 3 ] +2 1 MLCT 3 MLCT S0S0S0S0 S1S1S1S1 T1T1T1T1 Short, sub-picosecond ISC Long, ~5 μ s hνhνhνhν E Radiative Decay Nonradiative Decay  Interested in Monitoring  3 MLCT Lifetime  Radiative Decay or Emission

UV/Vis Spectroscopy Tolylterpyridyl Systems MLCT Bands Ru(ttpy)Cl 3 Ru(ttpy)Cl 3 440nm 440nm [Ru(ttpy) 2 ]Cl 2 [Ru(ttpy) 2 ]Cl 2 486nm 486nm [RuP(OMe) 6 ](BF 4 ) 2 [RuP(OMe) 6 ](BF 4 ) 2 460nm 460nm

Emission Spectra Room Temperature [RuPOMe](PF 6 ) 2 emission emission 601nm 601nm excitation excitation 463nm 463nm RuP(OMe) 6 ](BF 4 ) 2 emission emission 413nm 413nm excitation excitation 343nm 343nm [Ru(bpy) 2 P(OMe) 6 ](PF 6 ) 2 emission emission 505nm 505nm excitation excitation 430nm 430nm

Excited State Lifetime [Ru(bpy) 3 ] +2  = 5µs (77K, literature)  = 5µs (77K, literature)  = 132.4ns (Room Temperature, CH 3 CN, experimental)  = 132.4ns (Room Temperature, CH 3 CN, experimental) emission emission 610nm 610nm RuPOMe  = 319ns  = 319ns emission emission 601nm 601nm  Conclusion:  Room temperature lifetimes are inconsistent  The lifetime of tolylterpyridine ruthenium complexes are on the order of picoseconds

NMR Studies 1 H NMR 1 H NMR Methoxy proton shifts Methoxy proton shifts Observe bound and unbound ligand signal Observe bound and unbound ligand signal 13 C NMR 13 C NMR Signal:Noise low, numerous peaks Signal:Noise low, numerous peaks 31 P NMR 31 P NMR High number of scans (6400 scans) High number of scans (6400 scans) Unique 31 P resonances with analyte complexation Unique 31 P resonances with analyte complexation Long T 1 Relaxation (PPh 3 =13.369s, POMe=18.396s) Long T 1 Relaxation (PPh 3 =13.369s, POMe=18.396s)

1 H NMR POMe free ligand -OCH ppm -OCH ppm 2,2’-bipyridine free ligand Aromatics > 7ppm [RuPOMe](PF 6 ) 2 -OCH ppm -OCH ppm

31 P NMR [RuPOMe](PF 6 ) 2 [2.85 x M] in Acetone-d 6 [2.85 x M] in Acetone-d 6 56ppm Ether Bound 56ppm Ether Bound -143ppm(septet) PF ppm(septet) PF 6 - POMe free ligand ppm ppm [RuP(OMe) 6 ](BF 4 ) 2 [3.0 x M] in Acetone-d 6 [3.0 x M] in Acetone-d ppm Ether bound 15.5ppm Ether bound -63.5ppm(d) undesired product -63.5ppm(d) undesired product -68.5ppm(d) undesired product -68.5ppm(d) undesired product P(OMe) 6 free ligand -70.8ppm -70.8ppm

Conclusions [RuPOMe](PF 6 ) 2 successfully synthesized and characterized [RuPOMe](PF 6 ) 2 successfully synthesized and characterized [RuP(OMe) 2 ] and [RuP(OMe) 6 ] require different synthetic approach [RuP(OMe) 2 ] and [RuP(OMe) 6 ] require different synthetic approach Tolylterpyridine is not ideal as a chromophoric ligand Tolylterpyridine is not ideal as a chromophoric ligand MLCT electronic state observed for bipyridyl and tolylterpyridyl chromophores MLCT electronic state observed for bipyridyl and tolylterpyridyl chromophores Complexes are luminescent, but minimal at room temperature Complexes are luminescent, but minimal at room temperature

Future Work Concentration Dependence Concentration Dependence Analyte selectivity titrations Analyte selectivity titrations Low Temperature (77K) Photophysics Low Temperature (77K) Photophysics 31 P NMR in Determining Equilibrium 31 P NMR in Determining Equilibrium Quantum Yield Measurements Quantum Yield Measurements Use Fluorescent Polymer Units as Hemilabile Ligands Use Fluorescent Polymer Units as Hemilabile Ligands

Acknowledgements Jones’ Group Jones’ Group Dr. Jones, Dr. Martin, Dr. Flynn Dr. Jones, Dr. Martin, Dr. Flynn Jasper, Wenrong, Catherine, Sherryllene, Dickson, Peter Jasper, Wenrong, Catherine, Sherryllene, Dickson, Peter Undergraduates Undergraduates Dr. Jürgen Schulte Dr. Jürgen Schulte Chemistry Department Chemistry Department Binghamton University Binghamton University

References 1) Rogers, C.W.; Zhang, Y.; Patrick, B.O.; Jones, W.E.; Wolf, M.O. Inorg. Chem. 2002, 41, ) Kalyanasundaram, K. Photochemistry of Polypyridine and Porphyrin Complexes; Academic Press: London, ) Angell, S.E.; Zhang, Y.; Rogers, C.W.; Wolf, M.O.; Jones, W.E.; Inorg. Chem. 2005, 44, ) Alary, F.; Heully, J.L.; Bijeire, L.; Vicendo, P. Inorg. Chem. 2007, 46, ) Wang, J.; Fang, Y.Q.; Hanan, G.S.; Loiseau, F.; Campagna, S. Inorg Chem. 2005, 44, ) Rogers, C.W.; Wolf, M.O. Chem. Comm. 1999, ) Angell, S.E., Rogers, C.W.; Zhang, Y.; Wolf, M.O.; Jones, W.E.; Coordination Chemistry Reviews. 2006, 250, ) Demas, J.N.; Adamson, A.W. J. Am. Chem. Soc. 1971, 93,