Browsing by Author "Peng, SM"

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Calix[4]arenes with a lid in their upper rims: 1,3-dipolar cycloaddition reactions of benzonitrile oxides with 5-allyl-, 5,11-dially- and 5,17-diallylcalix[4]arenes
(2000-02-01)
Shu, CM
;
Lin, WL
;
Lee, GH
;
Peng, SM
;
Chung, WS
The upper rim substituted mono- and diisoxazolinomethylcalix[4]arenes 9-23 are synthesized in good yields from 1,3-dipolar cycloaddition reactions of para-substituted phenyl nitrileoxides with 5-allyl-, 5,11-diallyl- and 5,17-diallycalix[4]arenes 5-7; the structures of 9-23 are consistent with a 'cone' conformation and the 'vase-with-a-lid' structure of 11 was confirmed by a single-crystal x-ray analysis. Preliminary results show that the monoisoxazolinomethylcalix[4]arene can form an inclusion complex with ammonium cation.
Formation of mononuclear nitrido complexes of chromium(VI) and molybdenum(VI); Syntheses and X-ray crystal structures of N Cr(OBu(t))(3) and N Mo(OSiMe(3))(3)(py)
(1996-01-21)
Chiu, HT
;
Chen, YP
;
Chuang, SH
;
Jen, JS
;
Lee, GH
Mononuclear nitrido complexes of Cr and Mo, N=Cr(OBu(t))(3) and N=Mo(OSiMe(3))(3)(py), are synthesized; the chromium complex has an idealized C-3v symmetry while the molybdenum complex has a distorted square-pyramidal geometry with the nitrido ligand at apical position; the N-Cr distance is 1.538(5) Angstrom while the average N-Mo distance is 1.627 Angstrom.
Highly efficient red phosphorescent osmium(II) complexes for OLED applications
(2004-07-19)
Tung, YL
;
Wu, PC
;
Liu, CS
;
Chi, Y
;
Yu, JK
The nonionic, red-emitting complexes [Os(fppz)(2)L-2] (L = PPh2Me (1), PPhMe2 (2)) and [Os(bptz)(2)L-2] (L = PPh2Me (3)) were synthesized, showing highly intense red phosphorescent emission in CH2Cl2 solution at lambda(max) 617, 632, and 649 nm, respectively. The electroluminescent properties of these compounds on OLEDs showed promising device efficiencies required for future OLED applications.
Interplay between intra- and interligand charge transfer with variation of the axial N-heterocyclic ligand in osmium(II) pyridylpyrazolate complexes: Extensive color tuning by phosphorescent solvatochromism
(2005-10-21)
Li, SW
;
Cheng, YM
;
Yeh, YS
;
Hsu, CC
;
Chou, PT
The rational design and syntheses of a new series of Os-II complexes with formula [Os(fppz)(2)(CO)(L)] (1: L=4-dimethylaminopyridine; 2: L=pyridine; 3: L = 4,4'bipyridine; 4: L=pyridazine; 5: L = 4-cyanopyridine), bearing two (2-pyridyl)pyrazolate ligands (fppz) together with one carbonyl and one N-heterocyclic ligand at the axial positions are reported. Single-crystal X-ray diffraction studies of, for example, 2 reveal a distorted octahedral geometry in which both fppz ligands reside in the equatorial plane with a trans configuration and adopt a bent arrangement at the metal center with a dihedral angle of similar to 23 degrees, while the carbonyl and pyridine ligands are located at the axial positions. Variation of the axial N-heterocyclic ligand leads to remarkable changes in the photophysical properties as the energy gap and hence the phosphorescence peak wavelength can be tuned. For complexes 1 and 2 the solvent-polarity-independent phosphorescence originates from a combination of intraligand (3)pi-pi* ((ILCT)-I-3) and metal-to-ligand charge transfer transitions ((MLCT)-M-3). In sharp contrast, as supported by cyclic voltammetry measurements and theoretical calculations, complexes 3-5 exhibit mainly ligand-to-lilgand charge transfer (LLCT) transitions, resulting in a large dipolar change. The phosphorescence of complexes 3-5 thus exhibits a strong dependence on the polarity of the solvent, being shifted for example, from 560 (in C6H12) to 665 nm (in CH3CN) and from 603 (in C6H12) to 710 nm (in CH3CN) for complexes 3 and 5, respectively. The results clearly demonstrate that a simple, straightforward derivatization of the axial N-heterocyclic ligand drastically alters the excitation properties per se from intraligand charge transfer (ILCT) to LLCT transitions. The latter exhibit remarkable LLCT phosphorescence solvatochromism so that a broad range of color tunability can be achieved.
Iridium(III) complexes with orthometalated quinoxaline ligands: Subtle tuning of emission to the saturated red color
(2005-03-07)
Hwang, FM
;
Chen, HY
;
Chen, PS
;
Liu, CS
;
Chi, Y
Rational design and syntheses of four iridium complexes (1-4) bearing two substituted quinoxalines and an additional 5-(2-pyridyl) pyrazolate or triazolate as the third coordinating ligand are reported. Single-crystal X-ray diffraction studies of 1 reveal a distorted octahedral geometry, in which two dpqx ligands adopt an eclipse configuration, for which the quinoxaline N atoms and the C atoms of orthometalated phenyl groups are located at the mutual trans-and cis-positions, respectively. The lowest absorption band for all complexes consists of a mixture of heavy-atom Ir(III)-enhanced (MLCT)-M-3 and (3)pipi(*) transitions, and the phosphorescent peak wavelength can be fine-tuned to cover the spectral range of 622-649 nm with high quantum efficiencies. The cyclic voltarnmetry was measured, showing a reversible, metal-centered oxidation with potentials at 0.76-1.03 V, as well as two reversible reduction waves with potentials ranging from -1.61 to -2.06 V, attributed to the sequential addition of two electrons to the more electron-accepting heterocyclic portion of two distinctive cyclometalated CAN ligands. Complex 1 was used as the representative example to fabricate the red-emitting PLEDs by blending it into a PVK-PBD polymer mixture. The devices exhibited the characteristic emission profile of 1 with peak maxima located at 640 nm. The maximum external quantum efficiency was 3.15% ph/el with a brightness of 1751 cd/M-2 at a current density of 67.4 mA/cm(2) and the maximum brightness of 7750 cd/m(2) was achieved at the applied voltage of 21 V and with CIE coordinates of (0.64, 0.31).
Low-temperature solution route to molybdenum nitride
(1998-12-01)
Chiu, HT
;
Chuang, SH
;
Lee, GH
;
Peng, SM
;
應用化學系
Low-temperature solution route to molybdenum nitride
(1998-12-01)
Chiu, HT
;
Chuang, SH
;
Lee, GH
;
Peng, SM
;
應用化學系
Metallo-organic chemical vapor deposition of tantalum carbide and tantalum nitride thin films from (BuCH)-Bu-t=Ta(CH2 Bu-t)(3) and (BuN)-Bu-t=Ta(CH2 Bu-t)(3).
(2002-04-07)
Chiu, HT
;
Chang, YH
;
Chang, PJ
;
Wu, JB
;
Peng, SM
Nonlinear optical chromophores with configuration-locked polyenes possessing enhanced thermal stability and chemical stability
(1998-11-01)
Shu, CF
;
Shu, YC
;
Gong, ZH
;
Peng, SM
;
Lee, GH
A synthetic strategy has been developed for preparation of NLO chromophores with all the pi-conjugated methine groups incorporated into plane-rigidified, fused, six-membered rings. The comparison of the rigidified chromophores to the analogous nonrigid chromophores shows that the configuration-locking methods provide a dramatic enhancement of molecular thermal stability. The data from W-vis spectroscopy and X-ray crystallography reveal that the rigidity of the annulated rings does not diminish the planarity and the electron delocalization efficiency of the polyenic chain.
Nonlinear optical chromophores with configuration-locked polyenes possessing enhanced thermal stability and chemical stability
(1998-11-01)
Shu, CF
;
Shu, YC
;
Gong, ZH
;
Peng, SM
;
Lee, GH
A synthetic strategy has been developed for preparation of NLO chromophores with all the pi-conjugated methine groups incorporated into plane-rigidified, fused, six-membered rings. The comparison of the rigidified chromophores to the analogous nonrigid chromophores shows that the configuration-locking methods provide a dramatic enhancement of molecular thermal stability. The data from W-vis spectroscopy and X-ray crystallography reveal that the rigidity of the annulated rings does not diminish the planarity and the electron delocalization efficiency of the polyenic chain.
Syntheses and characterization of organoimido complexes of niobium(V); Potential CVD precursors
(1998-06-01)
Chiu, HT
;
Lin, JC
;
Chuang, SH
;
Lee, GH
;
Peng, SM
New niobium imido complexes (RN)Nb(NEt2)(3) (R = Pr-n, Pr-i and Bu-t), potential precursors to grow niobium containing thin films by chemical vapor deposition (CVD), were prepared by reacting the corresponding (RN)NbCl(3)py(2) complexes (R = Pr-n, Pr-i and Bu-t; py = pyridine) with LiNEt2 in hydrocarbon solvents. The structures of (RN)NbCl(3)py(2) (R = Pr-i and Bu-t), determined by X-ray crystallography, are mononuclear with distorted octahedral geometries. For each complex, three chloride ligands are cia to the imido ligand and occupy meridional positions. One of two py ligands is cia to and the other is trans to the imido ligand. For ((PrN)-N-i)NbCl(3)py(2), the Nb = NPri bond distance (Angstrom) is 1.733(3) and the angle Nb=N-Pr-i angle (degrees) is 178.0(3). Crystal data: monoclinic, space group P2(1)/n, a = 8.805(2), b = 14.930(4), c = 13.407(3) Angstrom, beta = 93.37(2)degrees, V = 1759.5(7) Angstrom(3), Z = 4, D-c 1.565 g cm(-3). For ((BuN)-N-t)NbCl(3)py(2), the Nb=NBut bond distance (Angstrom) is 1.734(4) and the angle Nb=N-Bu-t angle (degrees) is 174.8(4). Crystal data: monoclinic, space group P2(1)/c, a = 9.609(1), b = 13.591(6), c = 14.615(2) Angstrom, beta = 90.05(1)degrees, V = 1908.5(9) Angstrom(3), Z = 4, D-c = 1.492 g cm(-3).
Syntheses and characterization of organoimido complexes of tantalum; potential single-source precursors to tantalum nitride
(1998)
Chiu, HT
;
Chuang, SH
;
Tsai, CE
;
Lee, GH
;
Peng, SM
New single-source precursor to tantalum nitride thin films, ((BuN)-N-t)Ta(NEt2)(3), and related complexes, (RN)Ta(NEt2)(3) (R = Pr-i and Pr-n), were prepared by reacting corresponding (RN)TaCl(3)py(2) complexes (R = Bu-t, Pr-i and Pr-n) with LiNEt2 in hydrocarbon solvents. The structure of ((BuN)-N-t)TaCl(3)py(2) was determined by X-ray crystallography. (C) 1998 Elsevier-Science Ltd. All rights reserved.
Syntheses of molybdenum nitrido complexes from (NH4)(2)Mo2O7.
(2002-04-07)
Yeng, MY
;
Chiu, HT
;
Chuang, SH
;
Lo, CP
;
Peng, SM
Upper rim allyl- and arylazo-coupled calix[4]arenes as highly sensitive chromogenic sensors for Hg2+ ion
(2005-04-15)
Kao, TL
;
Wang, CC
;
Pan, YT
;
Shiao, YJ
;
Yen, JY
The syntheses and chromogenic properties of calix[4]arenes, carrying 5,17-bisallyl-11,23-bis(p-X-phenyl)azo 3a-c, 5,11,17-triallyl-23-(p-X-phenyl)azo 4a-c, and 5,17-bis(hydroxypropyhl)-11,23-bis(p-X-phenyl)azo groups on the upper rims 5a,b, are described. Unexpectedly, UV/vis spectra of the very popular 4-(4-nitrophenyl)azophenol-coupled calix[4]arenes 3c and 4c did not show any shift in lambda(max) when 10 different metal perchlorates were added separately to the host in a methanol-chloroform (v/v = 1/399) cosolvent. In contrast, the absorption spectra of calix[4]arenes with either 4-methoxyphenylazo (3b-5b) or 4-phenylazo (3a-5a) on the upper rim showed substantial batho-chromic shifts (Delta lambda = 128-162 nm) upon the addition of soft metal ions (such as Hg2+, Cr3+, and Cu2+). The 4-(4-methoxyphenyl)azophenol-coupled calix[4]arenes (the 3b-5b series) are found to be highly sensitive for mercury ion (Hg2+) among the 10 different metal ions screened. Strong interactions between Hg2+ ion and the 4-(4-methoxyphenyl)azophenol(s) as well 18 the p-allyl groups, are corroborated by the H-1 NMR studies of 3a,b center dot Hg2+ complexes. Furthermore, Job's plots revealed 1:1 binding stoichiometry for all these p-allyl- and arylazo-coupled calix[4]arenes with transition metal ions, and Benesi-Hilderbrand plots were used for the determination or their association constants.