1 dark-field oxidative addition-based chemosensing: new bis-cyclometalated pt(ii) complexes and...
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Dark-Field Oxidative Addition-Based Chemosensing: New Bis-cyclometalated Pt(II) Complexes and Ph
osphorescent Detection of Cyanogen Halides
Samuel W. Thomas III, Koushik Venkatesan, Peter Muller, and Timothy M. Swager
J. Am. Chem. Soc. 2006, 128, 16641 -16648
演講者:李光凡
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Blue-Shifting Transduction Event
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Phosphorescence
ATKINS’ Physical Chemistry 8th EDITION p 494
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Ir(ppy)3 Ir(thpy)3Pt(ppy) Pt(o,p-tpy)
Thompson, M. E. Inorg. Chem. 2002, 41, 3055-3066
Ueno, K. J. Am. Chem. Soc. 2003, 125, 12971-12979
Highly Phosphorescent Bis-Cyclometalated Complexes
Metal : Pt & Ir
Ligand : bidentate ligand. ex : 2 - phenylpyridine
5von Zelewsky, A. Inorg. Chem. 1987, 26, 2814-2818Stoeckli-Evans, H. Inorg. Chem. 1996, 35, 4883-4888
Homoleptic Complexes and Heteroleptic Complexes
Homoleptic Complexes
Heteroleptic Complexes
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Oxidative Addition Reactions
von Zelewsky, A. Inorg. Chem. 1987, 26, 2814-2818
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Some Phosphorescent Complexes Designed for The Sensing of other Vapors
Pilato, R. S. J. Am. Chem. Soc. 1998, 120, 12359-12360Swager, T. M. J. Am. Chem. Soc. 2003, 125, 3420-3421
Past : Now : Cyanogen halides
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1b : R=CH3 – 97%
1c : R=OCH3 – 93%
2a : R=H – 62%
2b : R=CH3 – 51%
Synthesis of thpy Ligands
1d : 4-methyl – 68%
1e : 5-methyl – 29%
1f : 6-methyl – 96%
Stille coupling
Suzuki coupling
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Synthesis of Bis-Cyclometalated Pt(II) Complexes 3
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Synthesis of Bis-Cyclometalated Pt(II) Complexes 4
Steric congestion
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Synthesis of Bis-Cyclometalated Pt(II) Complexes 5
1a : thienylpyridine
N
S
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Photophysical Parameters of Pt(II) Complexes 3-5
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Normalized UV/vis Spectra of Complexes 3a-d in THF
MLCT
Ligand-centered absorption
3a in THF : 423 nm
3a in acetone : 419 nm (blue-shift)
3a in toluene : 430 nm (red-shift)
3b and 3c electron density↑ (red-shift)
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Normalized UV/vis Spectra of Complexes 3e, 3f, 4a, and 5 in THF
3f & 4a : broadened MLCT absorbance band.
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Room-Temperature Emission Spectra of Phosphorescent Bis-Cyclometalated Pt(II) Complexes in THF
Quantum yields of emission between 0.05 and 0.30
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X-ray Crystal Structures of 3b (left) and 3f (right)
Pt1 – N1 = 2.169 Å
Pt1 – N2 = 2.165 Å
Pt1 – C7 = 1.985 Å
Pt1 – C17 = 1.982 Å
Pt1 – N1 = 2.139 Å
Pt1 – N2 = 2.179 Å
Pt1 – C3 = 1.98 Å
Pt1 – C13 = 1.974 Å
Slightly distort
16.4°
Severely distort
46.4°
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UV/vis Spectra of 3b During Its Reaction with 1.0 M MeI in Benzene
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Pseudo-First-Order Rate Plot for 3b in 1.0M MeI/Benzene
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UV/vis, for 3a, with Either MeI or BrCN (in Benzene)
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UV/vis Spectra of 3b React with 0.00013 M BrCN in Benzene
MLCT disappearance
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First-Order Kinetic Plot for The Reaction of 3b with BrCN
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Percentage Conversion of 3a In Either Toluene or Benzene
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Conversion Percentages of Several Pt(II) Complexes
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Bimolecular Rate Constants of Platinum Complexes with MeI in Benzene
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What Is PMMA?
1.聚甲基丙烯酸甲酯,又稱做壓克力或有機玻璃。
2.可見光: PMMA 是目前最優良的高分子透明材料,透光率達到 92 %,比玻璃的透光度高。
3.紫外光:石英能完全透過紫外線,但價格高昂,普通玻璃只能透過 0.6 %的紫外線,但 PMMA 卻能透過 73 %。
http://zh.wikipedia.org/w/index.php?title=%E9%A6%96%E9%A1%B5&variant=zh-tw
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Normalized Emission Spectra of 3a In degassed THF Solution and Doped into PMMA Films
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PMMA/Pt(II) Spun-Cast Films of 4a (Top) and 3a (Bottom) under UV Light
+ BrCN
S
N
S
NPt
S
N
S
NPt
N
S
N
S
Pt
N
S
N
S
Pt + BrCN
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PMMA Film Emission Spectra of 3a (a) and 4a (b) before (Dotted) and after (Solid) Exposure to BrC
N Vapor for 15 s
S
N
S
NPtN
S
N
S
Pt
3a 4a
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Conclusions
• A new dark-field turn-on optical chemosensing scheme has been developed using bis-cyclometalated platinum complexes. A series of these complexes was synthesized, most of which have not been previously reported in the literature.
• Thin polymer films containing these complexes, which were phosphorescent at room temperature, also reacted with cyanogen halide vapors to give the blue-shifted Pt(IV) products.
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HOMEWORK1.BrCN接到此錯合物的構型是 cis或是 trans ?Ans: 由此文章中得知,當結構扭曲越嚴重時 BrCN 接上的速度越快,代表不可
能是 trans 的構型因此是屬於 cis 的結構,因此由構造可以再次證明 BrCN是屬於 SN2 的反應。且由本文中的圖 1 可推出構造可能是 cis 。
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HOMEWORK2.Homoleptic和 Heteroleptic有哪些不同之處 ?Ans: 由 table 1 知道 Homoleptic complex 3a 的量子產率比 Heteroleptic complex 5
的量子產率明顯高很多,代表 Homoleptic complex 的放光強度比 Heteroleptic complex 高出許多。而 Heteroleptic complex 5 和 BrCN 反應的速率比 Homoleptic complex 3a 和 BrCN 反應的速率快,作者在此篇文章說原因不明,個人猜測是因為 3a 上的 S 會拉電子導致 BrCN 接上的速度比較慢。