Synthesis and Characterization of Stable Cationic [Hydrotris(1-pyrazolyl)borato]Mo(CO)(NO)(3-allyl) Complexes-Solid-State a
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- 作者：Lawrence A. Villanueva ; Yancey D. Ward ; Rene Lachicotte ; and Lanny S. Liebeskind
- 刊名：Organometallics
- 出版年：1996
- 出版时间：October 1, 1996
- 年：1996
- 卷：15
- 期：20
- 页码：4190 - 4200
- 全文大小：459K
- 年卷期：v.15,no.20(October 1, 1996)
- ISSN：1520-6041
文摘
From the correspondingTpMo(CO)2(
-allyl) complexes, foursymmetrically substitutedTpMo(CO)(NO)(-allyl)+ complexes(-allyl = propenyl, 2-methylpropenyl, cyclohexenyl,andcyclooctenyl) were prepared and characterized by IR, by 1Hand 13C NMR spectroscopy, andin one case by X-ray crystallography. TheBF4- salts of the cationic nitrosyl complexeswereunstable in solution; however, using the noncoordinating counterion[(3,5-(CF3)2C6H3)4B]-(BAr'4-) robust complexes were produced,permitting a thorough spectroscopic investigation.The crystal structure of[TpMo(CO)(NO)(
3-C3H5)][(3,5-(CF3)2C6H3)4B]revealed a significant3 
2 distortion of the allyl moiety.HETCOR and COSY NMR experiments were conductedin order to assign the chemical shifts of each of the allyl hydrogenand carbon atoms,unambiguously. These data also revealed the 3 2 distortion of the allyl complexes.1HNOE experiments were carried out in order to determine the conformationof the allylfragment for each nitrosyl complex.[TpMo(CO)(NO)(3-C3H5)][BAr'4]was formed as amixture of exo/endo rotamers (5.2:1), while[TpMo(CO)(NO)(3-C4H7)][BAr'4]existed exclusively as the endo rotamer in solution. Only theexo rotamer was observed for the cycliccomplexes[TpMo(CO)(NO)(3-C6H9)][BAr'4]and[TpMo(CO)(NO)(3-C8H13)][BAr'4].A plausible mechanism for the formation of the cationic nitrosyl complexesinvolves the electrophilicaddition of NO+ to the neutralTpMo(CO)2(3-allyl) complex withconcurrent slippage of theallyl form 3 to 1 to generate aseven-coordinate cationic 1-allyl complex. Adeuteriumlabeling study usingTpMo(CO)2(3-C3H4D)provided evidence for the 3 1mechanismresponsible for the formation of exo/endoisomers.
-allyl) complexes, foursymmetrically substitutedTpMo(CO)(NO)(-allyl)+ complexes(-allyl = propenyl, 2-methylpropenyl, cyclohexenyl,andcyclooctenyl) were prepared and characterized by IR, by 1Hand 13C NMR spectroscopy, andin one case by X-ray crystallography. TheBF4- salts of the cationic nitrosyl complexeswereunstable in solution; however, using the noncoordinating counterion[(3,5-(CF3)2C6H3)4B]-(BAr'4-) robust complexes were produced,permitting a thorough spectroscopic investigation.The crystal structure of[TpMo(CO)(NO)(3-C3H5)][(3,5-(CF3)2C6H3)4B]revealed a significant3 2 distortion of the allyl moiety.HETCOR and COSY NMR experiments were conductedin order to assign the chemical shifts of each of the allyl hydrogenand carbon atoms,unambiguously. These data also revealed the 3 2 distortion of the allyl complexes.1HNOE experiments were carried out in order to determine the conformationof the allylfragment for each nitrosyl complex.[TpMo(CO)(NO)(3-C3H5)][BAr'4]was formed as amixture of exo/endo rotamers (5.2:1), while[TpMo(CO)(NO)(3-C4H7)][BAr'4]existed exclusively as the endo rotamer in solution. Only theexo rotamer was observed for the cycliccomplexes[TpMo(CO)(NO)(3-C6H9)][BAr'4]and[TpMo(CO)(NO)(3-C8H13)][BAr'4].A plausible mechanism for the formation of the cationic nitrosyl complexesinvolves the electrophilicaddition of NO+ to the neutralTpMo(CO)2(3-allyl) complex withconcurrent slippage of theallyl form 3 to 1 to generate aseven-coordinate cationic 1-allyl complex. Adeuteriumlabeling study usingTpMo(CO)2(3-C3H4D)provided evidence for the 3 1mechanismresponsible for the formation of exo/endoisomers.