Michael T. H. Liu
University of Prince Edward Island
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Journal of the American Chemical Society | 2008
Takeshi Akasaka; Takayoshi Kono; Yuji Takematsu; Hidefumi Nikawa; Tsukasa Nakahodo; Takatsugu Wakahara; Midori O. Ishitsuka; Takahiro Tsuchiya; Yutaka Maeda; Michael T. H. Liu; Kenji Yoza; Tatsuhisa Kato; Kazunori Yamamoto; Naomi Mizorogi; Zdenek Slanina; Shigeru Nagase
We report here the results on single crystal X-ray crystallographic analysis of the Gd@C82 carbene adduct (Gd@C82(Ad), Ad = adamantylidene). The Gd atom in Gd@C82(Ad) is located at an off-centered position near a hexagonal ring in the C2v-C82 cage, as found for M@C82 (M = Sc and La) and La@C82(Ad). Theoretical calculation also confirms the position of the Gd atom in the X-ray crystal structure.
Journal of Physical Chemistry A | 2008
Takeshi Akasaka; Takayoshi Kono; Yoichiro Matsunaga; Takatsugu Wakahara; Tsukasa Nakahodo; Midori O. Ishitsuka; Yutaka Maeda; Takahiro Tsuchiya; Tatsuhisa Kato; Michael T. H. Liu; Naomi Mizorogi; Zdenek Slanina; Shigeru Nagase
The photochemical reaction of La@C82(Cs) with 2-adamantane-2,3-[3H]-diazirine (1) affords the adduct 2 of La@C82(Cs) with adamantylidene (Ad:) in a high selectivity. The two isomers of La@C82(Cs)(Ad), 2a and 2b, are isolated by HPLC and characterized by electron spin resonance, mass, and UV-vis-near-infrared spectroscopies. The electronic properties of 2a and 2b are very similar to that of the pristine La@C82(Cs), suggesting that 2a and 2b retain the essential electronic and structural character of La@C82(Cs).
Journal of the American Chemical Society | 2011
Midori O. Ishitsuka; Shogo Sano; Haruka Enoki; Satoru Sato; Hidefumi Nikawa; Takahiro Tsuchiya; Zdenek Slanina; Naomi Mizorogi; Michael T. H. Liu; Takeshi Akasaka; Shigeru Nagase
Bis-functionalization of endohedral metallofullerene La(2)@C(80) by carbene addition is reported herein. Adducts were characterized using spectroscopic and single-crystal X-ray structure analyses. Crystallographic data for bisadduct La(2)@C(80)(CClPh)Ad (3, Ad = adamantylidene) revealed that both carbene additions occur at the 6,6-bond junction on the C(80) cage with ring cleavages and that La atoms are positioned collinearly with spiro carbons. It is noteworthy that the La-La distance in 3 is highly elongated by carbene bis-functionalization compared to the distance in pristine La(2)@C(80) and reported functionalized derivatives. The metal positions were confirmed through density functional calculations.
Tetrahedron Letters | 1988
Michael P. Doyle; Jack Taunton; Su Min Oon; Michael T. H. Liu; N. Soundararajan; Matthew S. Platz; James E. Jackson
Abstract Reactivities for intermolecular C-H/Si-H/Sn-H insertion reactions of chlorophenylcarbene follow the order tri-n-butyltin hydride⪢diphenylsilanetriethylsilane⪢ cumenethylbenzene⪢toluene, and these reactions are competitive with addition to the double bond of α,β-unsaturated esters.
Tetrahedron Letters | 2001
Yuri N. Romashin; Michael T. H. Liu; Roland Bonneau
Abstract Reaction of arylchlorodiazirines with trimethylenesulfide gives a mixture of aryldi(3-chloropropyl)thioacetal and aryl(2-propenyl)(3-chloropropyl)thioacetal in a good yield. The reaction goes through a formation of a sulfur ylide as an intermediate. Rate constants have been determined using laser flash photolytic techniques.
Tetrahedron Letters | 1989
James E. Jackson; N. Soundararajan; Matthew S. Platz; Michael P. Doyle; Michael T. H. Liu
Abstract The activation energies for reaction of phenylchloro carbene with pyridine, tri-n-butyl-tin hydride and triethylsilane are reported. The data argues against reversibly formed complexes in the reaction of this carbene with olefins.
Tetrahedron Letters | 1986
Toshikazu Ibata; Michael T. H. Liu; Jiro Toyoda
Abstract 3-chloro-3-p-nitrophenylcarbene readily reacts with acetone to from carbonyl ylide which undergoes 1,3 cycloaddition with dipolarophiles.
Journal of Photochemistry and Photobiology A-chemistry | 1994
Michael T. H. Liu; R. Bonneau; Stefan Wierlacher; Wolfram Sander
Abstract Laser Flash photolysis of 3-chloro-3-benyzldiazirine and 3-chloro-3(phenyldideuteriomethyl)diazirine in isooctane over the 60 to −80°C temperature range gives rise to curved Arrhenius plots for both 1,2-H and 1,2-D migration in benzylchlorcarbene. The κ H /κ D values increase smoothly from 0.87 to 2.62 when the temperature increases from −60 to +30 °C. The κ H /κ D value is approximately 4 for most of the temperatures studied if a solvent correction is applied. Quantum mechanical tunnelling or the influence of the solvent may be a possible explanation for these observations.
Tetrahedron Letters | 1999
Yuri N. Romashin; Michael T. H. Liu; Wei Ma; Robert A. Moss
Abstract 2,2′-Pyridyl- and 2,2′-thienylpyrroles containing substitutets at the 1- and 3-positions of the pyrrole ring have been prepared from the reaction of heteroarylchlorocarbenes with 1-azabuta-1,3-dienes. Laser flash photolysis of heteroarylchlorocarbene in isooctane in the presence of 1-azabuta-1,3-diene yields an azomethine ylide (λ=550 nm) as an intermediate. The kinetic parameters for the ylide formation and further 1,5-intramolecular cyclization to the pyrrole ring have been determined.
Journal of Photochemistry and Photobiology A-chemistry | 1992
Roland Bonneau; Michael T. H. Liu
Abstract Phenylchlorocarbenes, produced by photolysis of the parent diazirines, have a very limited lifetime in alkane solvents. The rate of disappearance of p-methyl- and p-chlorophenylch-lorocarbenes has been measured in iso-octane, cyclohexane and n-hexane as well as in benzene for comparison. The rate constants of several processes (dimerization, addition to the diazirine, reaction with the solvent, etc. ) contributing to the disappearance of the phenylchlorocarbenes have been determined. The rate of reaction with the solvent, which is much lower in benzene than in alkanes and depends strongly on the nature of the alkane, is assumed to be an insertion of the carbene in the CH bonds of the solvent. Consequences of this reaction on the chemistry of carbenes produced by continuous irradiation (or thermolysis) of diazirines in alkanes are briefly discussed.