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Structures, Photoluminescence, and Reversible Vapoluminescence Properties of Neutral Platinum(II) Complexes Containing Extended π -Conjugated Cyclometalated Ligands. Steven C. F. Kui, Stephen Sin-Yin Chui, Chi-Ming Che,* and Nianyong Zhu presenter : 戴 如妮
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Structures, Photoluminescence, and Reversible Vapoluminescence Properties of Neutral Platinum(II)Complexes Containing Extended π-Conjugated Cyclometalated Ligands Steven C. F. Kui, Stephen Sin-Yin Chui, Chi-Ming Che,* and Nianyong Zhu presenter : 戴如妮 J. Am. Chem. Soc. 2006,128, 8297-8039
Supramolecular Coordination Chemistry Hydrogen bonding p-p interaction Metal to ligand binding van der Waals forces Holliday, B. J. et. al.Angew. Chem. Int. Ed.2001, 40, 2022-2043.
C-H … p p…p Supramolecular Assembly of Polyhedra Stang, P. J.; Olenyuk, B. Acc. Chem. Res.; 1997, 30, 502-518
(C^N^N)Pt(II) Complex Containing a Monoaza-15-Crown-5 Mg HC^N^N = 4-(4-tolyl)-6-phenyl-2,2'-bipyridine CH3CN (1.2x10-5M) Photoinduced Electron Transfer (PET) Yang, Q. -Z. et. al. Inorg. Chem. 2004, 43, 5195.
Organoplatinum Crystals forGas-Triggered Switches Koten, G. V. et. al. Nature. 2000, 406, 970-974.
a) Vapoluminescence Volatile Organic Compounds ( VOCs ) b) (i) the facile reversible change of the molecular structure of the luminophore (ii) alterations in the molecular packing when the analyte molecule enters and exits the crystal structure of the luminescent sensory material. a) Eisenberg, R. et. al. J. Am. Chem. Soc. 2004, 126, 16841-16849. b) William, B. C. et. al. J. Am. Chem. Soc. 2004, 126, 1594-1595.
CHCl3 Crystal Structure of [(C^N^C)2Pt2(μ-dppm)] anti- B [(C^N^C)2Pt2(μ-dppm)] [(C^N^C)2Pt2(μ-dppm)] [(C^N^C)2Pt2(μ-dppm)]∙CHCl3 P(1)-Pt(1)-N(1) = 171.2(2) P(2)-Pt(2)-N(2) = 174.6(3) P(1)-Pt(1)-N(1) = 170.6(2) P(2)-Pt(2)-N(2) = 172.4(2) Che, C.-M. et. al. Organometallics. 2001, 20, 2477-2486.
Rourke’s Method [(R-C^N^C)Pt(DMSO)] [(R-C^N^C)Pt(L)] [(Ph-C^N^C)Pt(PPh3)] [(R-C^N^C)2Pt2(μ-dppm)] Rourke, J. P. et. al. Organometallics. 2000, 19, 1355-1364.
Simulated 31P{1H}NMR Spectra of 4b inSyn- and Anti- syn- anti- Simulated based on AA′XX′ system, 31P NMR (162 MHz,CD2Cl2)
syn- 31P{1H} NMR Spectrum of 4b in CD2Cl2 Experiment
ligand p* ligand-ligand transition s* metal d metal-ligand charge transfer n metal d n ligandp s ligand-metal charge transfer metal-metal (d-d) transition 2b ~ excimeric (A-A*)3ππ* excited states4b ~ excimeric 3ππ*excited states 3 ~ intraligant 3ππ*excited states UV-Vis Absorption and Solid-State Emission Spectra of 2b, 3, and 4b at R. T. charge transfer d-d transition
Vibronic coupling – interaction between electronic and vibrational modes, increase intensity Emission Spectra of 2b & 4b a) b) 2b in the solid state at 77 K in 2-MeTHF at 77 K 4b in the solid state at 77 K in 2-MeTHF at 77 K
Emission Spectra of 3 Emission spectra of 3 in the solid state at room temperature, 77 K, and as a glassy solutionin 2-MeTHF at 77 K
The Emission Spectra of 4b at Various Temperature 523 nm 566 nm non - emission Emission spectra of 4b in 2-MeTHF solution at 103-263 K • the molecular motion of the flexible Pt-P-CH2-P-Pt unit • (ii) the presence of a low-lying non-emissive d-d excited state
Solid 4a under Ambient Light and under UV Light Irradiation a) b) anbient light UV light Solid 4a under ambient light and under UV light irradiation (350 nm). (a) Orange crystals of 4a upon exposure to air. (b) A reversible vapoluminescence for the desolvated form of 4a within 1 min of being exposed to CHCl3 vapor.
Vapoluminescent Behavior of 4a Ivoc is the emission intensity of desolvated 4a upon exposure to VOC under saturation conditions Idesolvateis the emission intensity of desovated 4a
The Crystal Structure for 2a Perspective view of 2a with omission of hydrogen atoms (left) and the head-to-tail pairs molecular orientation (right).
The Crystal Structures for 2b & 2c 2b.CHCl3 2c.CH2Cl2 Perspective view of 2b·CHCl3 & 2c·CH2Cl2with the omission of hydrogen atoms.
C-H…πC-H(solvent)…πC-H…X Perspective View of Syn - and Anti - 4a.6CHCl3.C5H12
Porous Molecular Structure of 4a·6CHCl3·C5H12 syn- anti- solvent channels 6.5 Å X4.3 Å
solvent channels 7.4 Å X2.8 Å solvent channels 4.6 Å X2.0Å The Structures of 4c & 4d syn -4c·3CH2Cl2 anti -4d·2CHCl3
loss of solvent 2q = 5.297o Volume = 7374 Å3 2q = 5.877o Volume = 6188 Å3 (hkl) 2q q Compared with PXRD of Structures of Solvated and Desolvated 4a Ewald Sphere http://ruppweb.dyndns.org/xray/tutorial/ewald.htm
layer of syn-molecules layer of anti-molecules layer of syn-molecules layer of anti-molecules layer of syn-molecules Packing Diagram of Desolvated 4a Molecular packing within desolvated 4a viewed from the c-axis
loss of solvent ΔG = ΔH –T .ΔS The Vapoluminescent Propertiesfor Solvated & Desolvated 4a
Conclusions • Mononuclear and dinuclear cyclometalated [(R-C^N^C)Pt-L] complexes were prepared and structurally characterized. • Accessible solvent channels and the presence of weak and reversible non-covalent C-H … π, π… π,C-H…X, and X…X interactions account for the vapoluminescent behavior of 4a. • The sensitivity of theemission properties of squar planar Pt(II)complexes is the basic operating principle behind their application as molecular VOC sensory materials.
Excimers ~~ excited-state dimers excimeric (A-A*)3ππ* http://en.wikipedia.org/wiki/Excimer
Vibronic Coupling • When there is an atom common to the two vibrations. • Bending vibrations requires a common bond between the vibrating groups. • The stretching bond forms one side of the angle that varies in the bending vibration. • The coupled groups have individual energies that are approximately equal.
Is a short-lived dimeric molecule formed from two species, at least one of which is in an electronic excited state. Excimers are often diatomic and are formed between two atoms or molecules that would not bond if both were in the ground state. The lifetime of an excimer is very short, on the order of nanoseconds.The excimeric emission is red-shifted relative to the emission from the compound monomers
2q Rietveld Method for the Desolvated Structutre of 4a A graphical plot of the final cycle of Rietveld refinement for the desolvated structutre of 4a (red cross — experimental data point, green line — calculated data, and magenta line — the difference plot between experimental and calculated data points).