TY - JOUR
T1 - Substituent effects of pyrazine on construction of crystal structures of Zn(II)-benzoate complexes and their catalytic activities (dinuclear, trinuclear, and pentanuclear to 1-D and 2-D)
AU - Kwak, Han
AU - Lee, Sun Hwa
AU - Kim, Soo Hyun
AU - Lee, Young Min
AU - Park, Byeong Kwon
AU - Lee, Eun Yong
AU - Lee, Yu Jin
AU - Kim, Cheal
AU - Kim, Sung Jin
AU - Kim, Youngmee
N1 - Funding Information:
Financial support from Environmental Technology Educational Innovation Program (2006) of the Ministry of Environment, the Korea Research Foundation (2006-312-C00569 and 2007-314-C00159), The SEOUL R & BD Program, and the SRC program of the Korea Science and Engineering Foundation (KOSEF) through the Center for Intelligent Nano-Bio Materials at Ewha Womans University (Grant R11-2005-008-00000-0) is gratefully acknowledged.
PY - 2008/11/25
Y1 - 2008/11/25
N2 - Several substituted pyrazine ligands (2,3-dimethylpyrazine, 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, quinoxaline) as well as simple pyrazine have been employed to investigate how the bridging pyrazine ligand influences on construction of Zn-benzoate complexes. Simple pyrazine and 2,5-dimethlpyrazine are used as bridging ligands to form two-dimensional and one-dimensional polymeric compounds, respectively. The other quinoxaline and two dimethyl-substituted pyrazine ligands are used only as terminal ligands to form dinuclear, trinuclear, and pentanuclear complexes. This result indicates that the substituents of pyrazine are very important roles for construction of Zn-benzoate complexes. Interestingly, the compounds 1-5 catalyzed efficiently the transesterification of a variety of esters, and among them, the pentanuclear complex 3 showed the most efficient reactivity. The substrates with the electron-withdrawing substituents have undergone faster transesterification, while those with the electron-donating ones have shown slow reaction. In addition, p-nitrophenyl acetate and p-nitrophenyl benzoate, known to be problematic substrates for the transesterification reaction, were also converted quantitatively to the corresponding products. Selectivity test of primary over secondary alcohol protection in the presence of 3 has provided, exclusively, the primary acetate, propyl acetate, suggesting that this catalytic system can be potentially useful in selecting for primary alcohols.
AB - Several substituted pyrazine ligands (2,3-dimethylpyrazine, 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, quinoxaline) as well as simple pyrazine have been employed to investigate how the bridging pyrazine ligand influences on construction of Zn-benzoate complexes. Simple pyrazine and 2,5-dimethlpyrazine are used as bridging ligands to form two-dimensional and one-dimensional polymeric compounds, respectively. The other quinoxaline and two dimethyl-substituted pyrazine ligands are used only as terminal ligands to form dinuclear, trinuclear, and pentanuclear complexes. This result indicates that the substituents of pyrazine are very important roles for construction of Zn-benzoate complexes. Interestingly, the compounds 1-5 catalyzed efficiently the transesterification of a variety of esters, and among them, the pentanuclear complex 3 showed the most efficient reactivity. The substrates with the electron-withdrawing substituents have undergone faster transesterification, while those with the electron-donating ones have shown slow reaction. In addition, p-nitrophenyl acetate and p-nitrophenyl benzoate, known to be problematic substrates for the transesterification reaction, were also converted quantitatively to the corresponding products. Selectivity test of primary over secondary alcohol protection in the presence of 3 has provided, exclusively, the primary acetate, propyl acetate, suggesting that this catalytic system can be potentially useful in selecting for primary alcohols.
KW - Catalytic activity
KW - Pyrazine
KW - Transesterification
KW - Zinc benzoate
UR - http://www.scopus.com/inward/record.url?scp=55549103318&partnerID=8YFLogxK
U2 - 10.1016/j.poly.2008.08.010
DO - 10.1016/j.poly.2008.08.010
M3 - Article
AN - SCOPUS:55549103318
SN - 0277-5387
VL - 27
SP - 3484
EP - 3492
JO - Polyhedron
JF - Polyhedron
IS - 17
ER -