TY - JOUR
T1 - Preparation, structural characterization, and reactions of tantalum-alkyne complexes TaCl3(R1C≡CR2)L2 (L2 = DME, Bipy, and TMEDA; L = Py)
AU - Oshiki, Toshiyuki
AU - Tanaka, Kouji
AU - Yamada, Jun
AU - Ishiyama, Takaya
AU - Kataoka, Yasutaka
AU - Mashima, Kazushi
AU - Tani, Kazuhide
AU - Takai, Kazuhiko
PY - 2003/2/3
Y1 - 2003/2/3
N2 - Tantalum-alkyne complexes with the general formula TaCl3(R1C≡CR2)(dme) (1a, R1 = R2 = Et; 1b, R1 = R2 = n-C5H11; 1c, R1 = Ph, R2 = Me; 1d, R1 = R2 = Ph; DME = 1,2-dimethoxyethane) were synthesized by treatment of the corresponding alkynes with a low-valent tantalum derived by reduction of tantalum pentachloride with zinc powder in a mixed solvent of toluene and DME. The DME ligand can be replaced by 2 equiv of pyridine to afford the corresponding dipyridine complexes TaCl3(R1C≡CR2)(py)2 (2a, R1 = R2 = Et; 2b, R1 = R2 = n-C5H11; 2c, R1 = Ph, R2 = Me; 2d, R1 = R2 = Ph). Additionally, the reaction of 1a with the bidentate nitrogen ligands bipyridine and N,N,N′,N′-tetramethyethylenediamine (= TMEDA) gave TaCl3(EtC≡CEt)(bipy) (3) and TaCl3(EtC≡CEt)(tmedia) (4), respectively. The η2- and 4e-coordination mode of an alkyne with a large contribution of a metalacyclopropene canonical structure was revealed by spectroscopic methods (NMR and IR) and crystallographic analyses of 1a, 1c, 2a, and 4. The reactivies of the tantalum-3-hexyne complexes 1a, 2a, 3, and 4 toward 3-phenylpropanal were investigated. Only the pyridine complex 2a reacted with a stoichiometric amount of the aldehyde to afford the corresponding allylic alcohol in 77% yield upon hydrolysis. The reaction proceeded via an oxatantalacyclopentene species.
AB - Tantalum-alkyne complexes with the general formula TaCl3(R1C≡CR2)(dme) (1a, R1 = R2 = Et; 1b, R1 = R2 = n-C5H11; 1c, R1 = Ph, R2 = Me; 1d, R1 = R2 = Ph; DME = 1,2-dimethoxyethane) were synthesized by treatment of the corresponding alkynes with a low-valent tantalum derived by reduction of tantalum pentachloride with zinc powder in a mixed solvent of toluene and DME. The DME ligand can be replaced by 2 equiv of pyridine to afford the corresponding dipyridine complexes TaCl3(R1C≡CR2)(py)2 (2a, R1 = R2 = Et; 2b, R1 = R2 = n-C5H11; 2c, R1 = Ph, R2 = Me; 2d, R1 = R2 = Ph). Additionally, the reaction of 1a with the bidentate nitrogen ligands bipyridine and N,N,N′,N′-tetramethyethylenediamine (= TMEDA) gave TaCl3(EtC≡CEt)(bipy) (3) and TaCl3(EtC≡CEt)(tmedia) (4), respectively. The η2- and 4e-coordination mode of an alkyne with a large contribution of a metalacyclopropene canonical structure was revealed by spectroscopic methods (NMR and IR) and crystallographic analyses of 1a, 1c, 2a, and 4. The reactivies of the tantalum-3-hexyne complexes 1a, 2a, 3, and 4 toward 3-phenylpropanal were investigated. Only the pyridine complex 2a reacted with a stoichiometric amount of the aldehyde to afford the corresponding allylic alcohol in 77% yield upon hydrolysis. The reaction proceeded via an oxatantalacyclopentene species.
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U2 - 10.1021/om020510x
DO - 10.1021/om020510x
M3 - Article
AN - SCOPUS:0037416028
VL - 22
SP - 464
EP - 472
JO - Organometallics
JF - Organometallics
SN - 0276-7333
IS - 3
ER -