Browsing by Author "Lee, Gene-Hsiang"

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A novel photoinduced ring opening and isomerization of adamantane-2-spiro isoxazolines using MO(CO)(6)
(2006-10-02)
Senthilvelan, Annamalai
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Lee, Gene-Hsiang
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Chung, Wen-Sheng
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應用化學系
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Department of Applied Chemistry
The MO(Co)(6)-mediated photoinduced ring-opening reactions of adamantane isoxazolines involve novel rearrangement that provide enaminoketones as major products and beta-hydroxy ketones as minor ones; in contrast, only beta-hydroxy ketones and alpha,beta-unsaturated ketones were obtained under thermal condition. (c) 2006 Elsevier Ltd. All rights reserved.
Alkyl-Spacer Enhancement in Performance of Light-Emitting Electrochemical Cells
(1970-01-01)
Shiu, Ler-Chun
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Chang, Bo-Ren
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Hsiao, Miles C-S
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Sie, Wu-Sian
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Wu, Ming-Lun
Synthetic, structural, photophysical, and electrochemical study of [Ir(ppy)(2)(py)(2)](BF4) (1(BF4)) and four di-N-N-bridged complexes of [Ir(ppy)(2)(bpa)](2)(BF4)(2)(2A(BF4)(2)), [Ir(ppy)(2)((cis-bpe))](2)(BF4)(2)(2B(BF4)(2)), [Ir(ppy)(2)(tmp)](2)(BF4)(2)(2C(BF4)(2)), and [Ir(ppy)(2)(bpy)](4)(BF4)(4)(3(BF4)(4)) are described with Hppy = 2-phenylpyridine, py = pyridine, N-N= dipyridyl ligands of 1,2-bis(4-pyridyl)ethane (bpa),cis-1,2-bis(4-pyridyl)ethylene (cis-bpe), 1,3-di(4-pyridyl)propane (tmp), and 4,4'-dipyridine (bpy). Five single-crystal structures of1(PF6),2A(NO3)(2),2A(PF6)(2),2B(PF6)(2), and3(NO3)(4)were determined, supporting the dibridged structures and presence of a variety of stereoisomers. Application of four luminescent complexes,1(BF4),2A(BF4)(2),2C(BF4)(2), and3(BF4)(4), in solid-state light-emitting electrochemical cells (LECs) is reported. The work demonstrates an effective approach to realize efficient LECs based on dibridged di- and multinuclear cationic transition-metal complexes with a suitably long alkyl spacer in the bridging ligand.
Capping the upper and lower rims of calix[4]arenes by aryl dinitrile oxide reactions
(2006-11-20)
Shiao, Ya-Jiun
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Chiang, Pei-Chen
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Senthilvelan, Annamalai
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Tsai, Ming-Tsung
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Lee, Gene-Hsiang
1, 3-Dipolar cycloadditions of upper- and lower-rim diallylcalix[4]arenes (1 and 3) with aryl dinitrile oxides provide a unique and efficient way of capping the calix[4]arenes. When dinitrile oxides reacted with 5-allylcalix[4]arene 7, they underwent a 1,3-dipolar cycloaddition on one side and an electrophilic substitution on the other side, which led to a novel type of asymmetric calix[4]arenes (9 and 12). (c) 2006 Elsevier Ltd. All rights reserved.
Cooperative Recognition of a Copper Cation and Anion by a Calix[4]arene Substituted at the Lower Rim by a beta-Amino-alpha,beta-Unsaturated Ketone
(2009)
Senthilvelan, Annamalai
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ho, I. -Ting
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Chang, Kai-Chi
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Lee, Gene-Hsiang
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Liu, Yi-Hung
We report herein a new ditopic calix[4]arene receptor 25,27-bis{[4-amino-4-(1-naphthyl)-2-oxo-3-butenyl]oxy}-26,28-dihydroxycalix[4]arene (2) for the simultaneous complexation of anionic and cationic species. The host molecule 25,27-bis{[3-(1-naphthyl)-5-isoxazolyl]methoxy}-26,28-dihydroxycalix[4]arene (1) was synthesised first and was followed by a [Mo(CO)(6)]mediated ring-opening reaction to give the target receptor 2. The binding properties of ligands 1 and 2 towards metal ions in CH(3)CN were investigated by UV/Vis and fluorescence spectroscopies. The results showed that both ligands I and 2 were highly selective for Cu(II) ions. Upon titration with Cu(II), the fluorescence of I was severely quenched, whereas 2 showed strong fluorescence enhancement because the metal ions help to lock the conformation of the fluorophores. During the complexation of 2 with Cu(II), the Cu(II) was reduced to Cu(I) by the free phenolic OH of 2, whereas the phenol was oxidised by Cu(II), after which it assisted in the trapping of Cu(I). Ditopic behaviour was observed for the complex 2 center dot Cu(I), which showed further enhancement of its fluorescence intensity upon complexation with anions such as acetate or fluoride.
Design and synthesis of triazolyl coumarins as Hg2+ selective fluorescent chemosensors
(2012)
Ho, I-Ting
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Lai, Ting-Ling
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Wu, Ren-Tsung
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Tsai, Ming-Tsung
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Wu, Chun-Ming
A series of triazolyl coumarin derivatives L1-L4, with and without spacer groups between the coumarin and the triazole groups, were synthesized as fluorescent sensors to study their binding ability and selectivity toward metal ions. Ligand L3, which contains an acetyl linker between the triazole and the coumarin, exhibited a high selectivity toward Hg2+ in polar protic solvents MeOH-CHCl3 (9 : 1, v/v) with fluorescent enhancement, furthermore, it was found to bind two Hg2+ at a high concentration (>12.5 mM) of Hg(ClO4)(2). In contrast, L4, in which position 4 of the triazole unit was replaced by a benzyl group instead of the 4-tert-butylphenoxymethyl group used in L1-L3, showed a binding stoichiometry toward only one Hg2+. On the basis of the fluorescent sensing, IR, and H-1 NMR titration results of ligands L1-L4, we proposed that not only the acetyl C=O but also the ether group of the 4-tert-butylphenoxymethyl of L3 assisted the triazole nitrogen atoms in the complexation of Hg2+ to form a 1 : 2 complex (L3 center dot(Hg2+)(2)).
Journey from Mo-Mo Quadruple Bonds to Quintuple Bonds
(2009-09-09)
Tsai, Yi-Chou
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Chen, Hong-Zhang
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Chang, Chie-Chieh
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Yu, Jen-Shiang K.
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Lee, Gene-Hsiang
Heating K(4)Mo(2)Cl(8) and 2 equiv of Li[RC(NDipp)(2)] (R = H, Ph; Dipp = 2,6-i-Pr(2)C(6)H(3)) in tetrahydrofuran (THF) at 60 degrees C gives two paddlewheel type quadruply bonded dimolybdenum complexes, Mo(2)(mu-Cl)[Cl(2)Li(OEt(2))][mu-eta(2)-RC(N-2,6-i-Pr(2)C(6)H(3))(2)](2) (R = H (1), Ph (2)). The Mo-Mo bond lengths of 1 and 2 are 2.0875(4) and 2.0756(8) angstrom, respectively, indicating typical Mo-Mo quadruple bonds. Reduction of 1 and 2 by two electrons results in the isolation of their corresponding Mo-Mo quintuple bonded complexes, Mo(2)[mu-eta(2)-RC(N-2,6-i-Pr(2)C(6)H(3))(2)](2) (R = H (3), Ph (4)), and the Mo-Mo bond lengths dramatically decrease to 2.0187(9) angstrom (3) and 2.0157(4) angstrom (4), a consequence of the formation of the second delta bond and representing the shortest metal-metal bonds beyond the first row elements. The Mo-Mo quintuple bonding characters are corroborated by DFT calculations at the level of BP86/def2-TZVP and BP86/def2-TZVPP.
New Series of Ruthenium(II) and Osmium(II) Complexes Showing Solid-State Phosphorescence in Far-Visible and Near-Infrared
(2010-02-01)
Chen, Jing-Lin
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Chi, Yun
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Chen, Kellen
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Cheng, Yi-Ming
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Chung, Min-Wen
A new Ru(II) complex, [Ru(fpbpymH)(2)]Cl(2) (1), in which fpbpymH = [5-(trifluoromethyl)pyrazol-3-yl](2,2'-bipyrid-6-yl)methane, was prepared by the treatment of [Ru(DMSO)(4)Cl(2)] with 2 equiv of the terdentate chelate fpbpymH in refluxing ethanol. A single-crystal X-ray diffraction study of 1 revealed a distorted octahedral Ru(II) framework, showing strong N-H center dot center dot center dot Cl hydrogen bonding between the fpbpymH ligand and Cl anions. In the presence of Na(2)CO(3), the methylene linkers of chelates in 1 underwent stepwise oxygenation, forming the charge-neutral complexes [Ru(fpbpym)(fpbpyk)] (2) and [Ru(fpbpyk)(2)] (3) [fpbpykH = [5-(trifluoromethyl)pyrazol-3-yl](2,2'-bipydd-6-yl) ketone] in sequence. The respective charge-neutral Os(II) complex [Os(fpbpyk)(2)] (4) was also isolated by the treatment of OsCl(3)center dot 3H(2)O with 2 equiv of the terdentate chelate fpbpymH, Electrochemical analysis indicated that the introduction of the electron-withdrawing ketone group in 2-4 increased the metal-based oxidation potential in sequence. For the photophysical properties, complexes 1-4 are essentially nonluminescent in solution (e.g., CH(2)Cl(2) or MeOH) at room temperature, but all exhibit 600-1100 nm phosphorescence with moderate intensity for the powdery, solid sample at room temperature. The trend in terms of the emission peak wave ength of 1 (666 nm) < 3 (795 nm) < 2 (810 nm) < 4 (994 nm) among titled complexes is in agreement with the corresponding onset of absorption spectra as well as the time-dependent density functional theory calculation of 1 < 3 < 2 < 4.
Orange and red organic light-emitting devices employing neutral Ru(II) emitters: Rational design and prospects for color tuning
(2006-08-04)
Tung, Yung-Liang
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Chen, Li-Shiuan
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Chi, Yun
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Chou, Pi-Tai
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Cheng, Yi-Ming
A new series of charge-neutral Ru(II) pyridyl and isoquinoline pyrazolate complexes, [Ru(bppz)(2)(PPh2Me)(2)] (bbpz: 3-tert-butyl-5-pyridyl pyrazolate) (1), [Ru(fppz)(2)(PPh2Me)(2)] (fppz: 3-trifluoromethyl-5-pyridyl pyrazolate) (2), [Ru(ibpz)(2)(PPhMe2)(2)] (ibpz: 3-tert-butyl-5-(1-isoquinolyl) pyrazolate) (3), [Ru(ibpz)(2)(PPh2Me)(2)] (4), [Ru(ifpz)(2)(PPh2Me)(2)] (ifpz: 3-trifluoromethyl-5-(1-isoquinolyl) pyrazolate) (5), [Ru(ibpz)(2)(dpp=)] (dpp= represents cis-1,2-bis-(diphenylphosphino)ethene) (6), and [Ru(ifpz)(2)(dpp=)] (7), have been synthesized, and their structural, electrochemical, and photophysical properties have been characterized. A comprehensive time-dependant density functional theory (TDDFT) approach has been used to assign the observed electronic transitions to specific frontier orbital configurations. A multilayer organic light-emitting device (OLED) using 24 wt % of 5 as the dopant emitter in a 4,4'-N,N'-dicarbazolyl-1,1'-biphenyl (CBP) host with 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB) as the hole-transport layer exhibits saturated red emission with an external quantum efficiency (EQE) of 5.10%, luminous efficiency of 5.74 cd A(-1), and power efficiency of 2.62 lm W-1. The incorporation of a thin layer of poly(styrene sulfonate)-doped poly(3,4-ethylenedioxythiophene) (PEDOT) between indium tin oxide (ITO) and NPB gave anoptimized device with an EQE of 7.03%, luminous efficiency of 8.02 cd A(-1), and power efficiency of 2.74 lm W-1 at 20 mA cm(-2). These values represent a breakthrough in the field of OLEDs using less expensive Ru(II) metal complexes. The nonionic nature of the complexes as well as their high emission quantum efficiencies and short radiative lifetimes are believed to be the key factors enabling this unprecedented achievement. The prospects for color tuning based on Ru(II) complexes are also discussed in light of some theoretical calculations.
Pt(II) Complexes with 6-(5-Trifluoromethyl-Pyrazol-3-yl)-2,2 '-Bipyridine Terdentate Chelating Ligands: Synthesis, Characterization, and Luminescent Properties
(2008-01-01)
Chen, Jing-Lin
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Chang, Sheng-Yuan
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Chi, Yun
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Chen, Kellen
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Cheng, Yi-Ming
A series of Pt(II) complexes Pt(fpbpy)Cl (1), Pt(fpbpy)(OAc) (2), Pt(fpbpy)(NHCOMe) (3), Pt(fpbpy)(NHCOEt) (4), and [Pt(fpbpy)(NCMe)](BF(4)) (5) with deprotonated 6-(5-trifluoromethyl-pyrazol-3-yl)-2,2'-bipyridine terdentate ligand are prepared, among which 1 is converted to complexes 2-5 by a simple ligand substitution. Alternatively, acetamide complex 3 is prepared by hydrolysis of acetonitrile complex 5, while the back conversion from 3 to 1 is regulated by the addition of HCl solution, showing the reaction sequence 1 -> 5 -> 3 -> 1. Mullilayer OLED devices are successfully fabricated by using triphenyl-(4-(9-phenyl-9H-fluoren-9-yl)phenyl) silane (TPSi-F) as host material and with doping concentrations of 1 varying from 7 to 100%. The electroluminescence showed a substantial red-shifting versus the normal photoluminescence detected in solution. Moreover, at a doping concentration of 28%, the device showed a saturated red luminescence with a maximum external quantum yield of 8.5% at 20 mA cm(-2) and a peak luminescence of 47543 cd m(-2) at 18.5 V.
Pt-II Complexes with 6-(5-Trifluoromethyl-Pyrazol-3-yl)-2,2 '-Bipyridine Terdentate Chelating Ligands: Synthesis, Characterization, and Luminescent Properties
(2008-01-01)
Chen, Jing-Lin
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Chang, Sheng-Yuan
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Chi, Yun
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Chen, Kellen
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Cheng, Yi-Ming
A series of Pt-II complexes Pt(fpbpy)Cl (1), Pt(fpbpy)(OAc) (2), Pt(fpbpy)(NHCOMe) (3), Pt(fpbpy)(NHCOEt) (4), and [Pt(fpbpy)(NCMe)](BF4) (5) with deprotonated 6-(5-trifluoromethyl-pyrazol-3-yl)-2,2'-bipyridine terdentate ligand are prepared, among which 1 is converted to complexes 2-5 by a simple ligand substitution. Alternatively, acetamide complex 3 is prepared by hydrolysis of acetonitrile complex 5, while the back conversion from 3 to 1 is regulated by the addition of HCl solution, showing the reaction sequence 1 -> 5 -> 3 -> 1. Mullilayer OLED devices are successfully fabricated by using triphenyl-(4-(9-phenyl-9H-fluoren-9-yl)phenyl) silane (TPSi-F) as host material and with doping concentrations of 1 varying from 7 to 100%. The electroluminescence showed a substantial red-shifting versus the normal photoluminescence detected in solution. Moreover, at a doping concentration of 28%, the device showed a saturated red luminescence with a maximum external quantum yield of 8.5% at 20 mA cm(-2) and a peak luminescence of 47543 cd m(-2) at 18.5 V.
Quintuply-Bonded Dichromium(I) Complexes Featuring Metal-Metal Bond Lengths of 1.74 angstrom
(2008)
Hsu, Chia-Wei
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Yu, Jen-Shiang K.
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Yen, Chun-Hsu
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Lee, Gene-Hsiang
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Wang, Yu
Regioselectivity in the 1,3-dipolar cycloaddition of adamantylidenefulvene and its modification by inclusion in cyclodextrins' solutions
(2006-07-31)
Chu, Jean-Ho
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Li, Wan-Sheung
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Chao, Ito
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Lee, Gene-Hsiang
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Chung, Wen-Sheng
The 1,3-dipolar cycloaddition of adamantylidenefulvene (1) with 2 equiv of nitrile oxides 2a-d gave 1/1 cycloadducts, 3a-d and 4a-d, as the major products, and four other 1/2 minor cycloadducts 5-8a,b. The ratios of 1/1 cycloadducts 3a-d to 4a-d in THF solution were about 1/1 in the four different nitrile oxides 2a-d studied and microwave was found to accelerate the reactions and enhance their yields. It is noteworthy that the regioselectivity of 3a/4a was enhanced to 71/29 in beta-cyclodextrin (beta-CD) aqueous solution compared to that of 40/60 in the absence of P-CD. The regioselectivity of 3b/4b was further enhanced to 99/1 when 4-tert-butylphenyl hydroximinoyl chloride (9b) was complexed with beta-CD and then proceeded to react with 1; this is in sharp contrast with that of 33/67 in the absence of beta-CD. The binding constant of 1 center dot beta-CD in acetone-d(6)/D2O (1/1) was determined to be 188 +/- 9 M-1 by H-1 NMR titration experiments. The binding mode of 1 center dot beta-CD was further determined by ROESY experiment. Furthermore, molecular dynamic simulations were carried out to provide information of the complexation modes of 1 center dot beta-CD, 3a center dot beta-CD, 4a center dot beta-CD, 9a center dot beta-CD, and 9b center dot beta-CD. It was found that both steric and electrostatic effects play important roles in determining the regio- and stereochemistry of 1,3-dipolar cycloaddition of 1. Finally, beta-CD is shown to serve as a chiral shift reagent to differentiate the enantiomers of 4a in H-1 NMR. (c) 2006 Elsevier Ltd. All rights reserved.
Remarkably short metal-metal bonds: A lantern-type quintuply bonded Dichromium(I) complex
(2008)
Tsai, Yi-Chou
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Hsu, Chia-Wei
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Yu, Jen-Shiang K.
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Lee, Gene-Hsiang
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Wang, Yu
Solution-Processable Quinoidal Dithioalkylterthiophene-Based Small Molecules Pseudo-Pentathienoacenes via an Intramolecular S center dot center dot center dot S Lock for High-Performance n-Type Organic Field-Effect Transistors
(2020-06-03)
Vegiraju, Sureshraju
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Torimtubun, Alfonsina Abat Amelenan
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Lin, Po-Shen
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Tsai, Hsin-Chia
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Lien, Wei-Chieh
A new organic small-molecule family comprising tetracyanoquinodimethane-substituted quinoidal dithioalky(SR)terthiophenes (DSTQs) (DSTQ-6 (1); SR = SC6H13, DSTQ : 10 (2); SR = SC10H21, DSTQ14 (3); SR = SC10H21) was synthesized and contrasted with a nonthioalkylated analogue (DRTQ14 (4); R = C14H29). The physical, electrochemical, and electrical properties of these new compounds are thoroughly investigated. Optimized geometries obtained from density functional theory calculations and single-crystal X-ray diffraction reveal the planarity of the SR-containing DSTQ core. DSTQs pack in a slipped pi-pi stacked two-dimensional arrangement, with a short intermolecular stacking distance of 3.55 A and short intermolecular S center dot center dot center dot N contacts of 3.56 angstrom. Thin-film morphological analysis by grazing incident X-ray diffraction reveals that all DSTQ molecules are packed in an edge-on fashion on the substrate. The favorable molecular packing, the high core planarity, and very low lowest unoccupied molecular orbital (LUMO) energy level (-4.2 eV) suggest that DSTQs could be electron-transporting semiconductors. Organic field-effect transistors based on solution-sheared DSTQ : 14 exhibit the highest electron mobility of 0.77 cm(2) V-1 s(-1) with good ambient stability, which is the highest value reported to date for such a solution process terthiophene-based small molecular semiconductor. These results demonstrate that the device performance of solution-sheared DSTQs can be improved by side chain engineering.
Stepwise Construction of the Cr-Cr Quintuple Bond and Its Destruction upon Axial Coordination
(2012)
Huang, Yu-Lun
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Lu, Duan-Yen
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Yu, Hsien-Cheng
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Yu, Jen-Shiang K.
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Hsu, Chia-Wei
Strategic design and synthesis of osmium(II) complexes bearing a single pyridyl azolate pi-chromophore: Achieving high-efficiency blue phosphorescence by localized excitation
(2007-11-26)
Cheng, Yi-Ming
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Li, Elise Y.
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Lee, Gene-Hsiang
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Chou, Pi-Tai
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應用化學系
We present the strategic design and synthesis of Os(II) complexes bearing a single pyridyl azolate T-chromophore with an aim to attain high efficiency blue phosphorescence by way of localized transition. It turns out that our proposal of localized excitation seems to work well upon anchoring a single)T-chromophore on the Os(II) complexes such that the control of MLCT versus pi pi* (or even LLCT) transitions is more straightforward. Among the titled complexes, [OS(CO)(3)(tfa)(fppz)] (1) and [Os(CO)(3)(tfa)(fbtz)] (5) (tfa = trifluoroacetate, (fppz)H = 3-(trifluoromethyl)5-(2-pyridyl)pyrazole, and (fbtz)H = 3-(trifluoromethyl)-5-(4-tert-butyl-2-pyridyl)-1,2,4-triazole) give the anticipated blue phosphorescence with efficiencies of 0.26 (lambda(max) = 460 nm) and 0.27 (lambda(max) = 450 nm), respectively. For their halide analogues [Os(CO)(3)(X)(fppz)] (2, X = Cl; 3, X Br; 4, X = 1) and phosphine-substituted isomeric derivatives [Os(tfa)(fppz)(PPh(2)Me)(2)(CO)] (6-8), the localization of the excitation energy seems to populate at certain vibrational modes with weak bonding strength and hence an associated shallow potential energy surface to induce a facile radiationless transition. Furthermore, their ancillary ligands play an important role in fine-tuning not only the energy gap but also the emission intensity, i.e., in manifesting the radiationless transition pathways. Our results clearly show that there is always a tradeoff upon varying the parameters in an aim to optimize the hue and efficiency of phosphorescence toward blue.
Syntheses, Photophysics, and Application of Iridium(III) Phosphorescent Emitters for Highly Efficient, Long-Life Organic Light-Emitting Diodes
(2009)
Lee, Tsang-Chi
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Chang, Chiung-Fang
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Chiu, Yuan-Chieh
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Chi, Yun
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Chan, Tzu-Ying
Rational design and synthesis of Ir(III) complexes (1-3) bearing two cyclometalated ligands (C boolean AND N) and one 2-(diphenylphosphino)phenolate chelate (P boolean AND O) as well as the corresponding Ir(III) derivatives (4-6) with only one (C boolean AND N) ligand and two P boolean AND O chelates are reported, where (C boolean AND NH) = phenylpyridine (ppyH), 1-phenylisoquinoline (piqH), and 4-phenylquinazoline (nazoH). Single crystal X-ray diffraction studies of 3 reveal a distorted octahedral coordination geometry. in which two nazo ligands adopt an eclipsed Configuration, with the third P boolean AND O ligand located trans to the phenyl group of both nazo ligands, confirming the general skeletal pattern for 1-3. In sharp contrast, complex 4 reveals a trans-disposition for the PPh(2) groups, along with the phenolate groups residing opposite the unique cyclometalated ppy ligand, which is the representative structure for 4-6. These Ir(III) complexes exhibit green-to-red photoluminescence with moderate to high quantum efficiencies in the degassed fluid state and bright emission in the solid state. For 1-6, the resolved emission spectroscopy and relaxation dynamics are well rationalized by the Computational approach. OLEDs fabricated using 12 wt.% of 3 doped in CBP and with BCP as hole blocking material, give bright electroluminescence with lambda(max) = 628 nm and CIE(xy) coordinates (0.65, 0.34). The turn-on voltage is 3.2 V, while the current efficiency and the power efficiency reach 11.2cd A(-1) and 4.5 lm W(-1) at 20 mA cm(-2). The maximum efficiency reaches 14.7 cd A(-1) and 6.8 lm W(-1) upon switching to TPBI as hole blocking material. For evaluating device lifespan, the tested device incorporating CuPc as a passivation layer, 3 doped in CTP as an emitting layer, and BAlq as hole blocking material, shows a remarkably long lifetime up to 36 000 h at an initial luminance of 500 cd m(-2).
Synthesis of upper-rim allyl- and p-methoxyphenylazocalix[4]arenes and their efficiencies in chromogenic sensing of Hg2+ ion
(2007-03-30)
Ho, I-Ting
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Lee, Gene-Hsiang
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Chung, Wen-Sheng
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應用化學系
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Department of Applied Chemistry
A series of upper-rim p-allyl and p-methoxyphenylazocalix[4]arenes (6, 8, 9a, b, and 10a,b) were synthesized and shown to exhibit substantial color changes upon complexation with Hg2+ ion. Both the upper-rim p-allyl- and p-methoxyphenylazo groups on calix[4]arenes are proven to be key components in the recognition of Hg2+ ion. Job's plots revealed 1:1 binding stoichiometry for all these p-allyl- and p-arylazo-coupled calix[4]arenes with Hg2+ ions and Benesi-Hilderbrand plots were used for determination of their association constants. Our results also demonstrated that two p-methoxyphenylazo groups prefer to bind Hg2+ in a distal orientation rather than a proximal one, and if there are three p-methoxyphenylazo groups, the third flanking p-methoxyphenylazo group plays a role in disturbing the binding of the two distal diazo groups. Furthermore, it should be noted that triazocalix[4]arenes (6, 9a, and 9a) responded to all 14 metal ions without showing much preference among the eight transition-metal ions screened in this work (Cr3+, Ni2+, Cu2+, Ag+, Cd2+, Hg+, Hg2+, and Pb2+).
Theory-Guided Experiments on the Mechanistic Elucidation of the Reduction of Dinuclear Zinc, Manganese, and Cadmium Complexes
(2011)
Lu, Duan-Yen
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Yu, Jen-Shiang K.
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Kuo, Ting-Shen
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Lee, Gene-Hsiang
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Wang, Yu
Triazole- and azo-coupled calix[4]arene as a highly sensitive chromogenic sensor for Ca2+ and Pb2+ ions
(2007-10-08)
Chang, Kai-Chi
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Su, In-Hao
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Lee, Gene-Hsiang
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Chung, Wen-Sheng
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應用化學系
A novel chromogenic calix[4]arene 3, which has within a molecule both the triazoles and the hydroxyl azophenols as the metal-binding sites and the azophenol moiety as a coloration sites was designed and synthesized. Calix[4]arene 3 is highly sensitive to Ca2+ and Pb+ ions, which can be detected by the naked eye. Furthermore, the association constants for the 1:1 complexes of 3 center dot Ca2+ and 3 center dot Pb2+ were determined to be 7.06 x 104 M-1 and 8.57 x 103 M-1, respectively. (c) 2007 Elsevier Ltd. All rights reserved.