Nucleophilic substitution reactions of acetylides on substituted tricarbonyl(#eta#~6-fluoroarene)chromium and reactions of tricarbonyl[#eta#~6-(2-trimethylsiylsilylethynyl)toluene]chromium and tricarbonyl[#eta#~6-(p-ethynylphenylethynyl)benzene]chrom

摘要

Nucleophilic substitution reactions of various acetylides on substituted tricarbonyl(#eta#~6-fluoroarene)chromiums were pursued. The reaction presumably underwent a more complicated mechanism rather than the direct substitution on the fluorine-bearing carbon. The organometallic compounds (#eta#~6-C_6H_3R~1R~2R~3)Cr(CO)_3 (R~1 : C ident to C-C_6H_4CH_3, R~2 : o-Me, R~3 : H (5a), R~1 : C ident to C-C_6H_4CH_3, R~2 : o-OMe, R~3 : H (6a), R~1 : C ident to C-C_6H_4CH_3, R~2 : m-OMe, R~3 : H (6b), R~1 : C ident to CPh, R~2 : o-Me, R~3 : o-OMe (8b), R~1 : C ident to CPh, R~2 : m-Me, R~3 : m-OMe (8c), R~1 : C ident to CSiMe_3, R~2: o-Me, R~3: h (9a). R~1 : C ident to C-C_6H_4C ident to CH, R~2: H, R~3: H (12), R~1 : C ident to C-C_6H_4C ident to CH, R~2 : o-Me, R~3: H (13)) as well as the organometallic dimmer [{(#eta#~6-o-Me-C_6H_4)Cr(CO)_3(di-ethynyl)] (di-ethynyl : C ident to C-C_6H_4 C ident to C (14)) have been synthesized from nucleophilic substitution reactions of tricarbonyl(#eta#~6-fluoroarene)(chromium) compounds with suitable acetylides. The products have been characterized by spectroscopic means. In addition, (8b) and (8c) were characterized by X-ray diffraction studies. Further reactions of (9a) and (12) with appropriate amount of Co_2(CO)_8 yielded #mu#-alkyne bridged bimetallic complexes, Co_2(CO)_6{#mu#-Me_3Si C ident to C-(o-tolueneCr(CO)_3)} (10) and (Co_2(CO)_6)_2{#mu#-HC ident to C-C_6H_4-C ident to C-(benzene)Cr(CO)_3)}(15), respectively. Both (10) and (15) were characterized by spectroscopic means as well as single crystal X-ray crystallography. The core of these molecules is quasi-tetrahedron containing a Co_2C_2 unit. A two-dicobalt-fragments coordinated di-enyls complex, (Co_2(CO)_6)_2{#mu#-HC ident to C-C_6H_4-C ident to C-H} (17), was synthesized from the reaction of 1,3-diethynylbenzene with Co_2(CO)_8. Crystallographic studies of (17) show that it exhibits a distorted Co_2C_2 quasitetrahedral geometry.