Li Yahong, Turnas Angie, Ciszewski James T, Odom Aaron L
Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
Inorg Chem. 2002 Dec 2;41(24):6298-306. doi: 10.1021/ic0259484.
Syntheses and properties of group-4 complexes incorporating the tridentate, dianionic ligand N,N-(dipyrrolyl-alpha-methyl)-N-methylamine, dpma, have been investigated. Addition of 1 equiv of H(2)dpma to Ti(NMe(2))(4) and Zr(NMe(2))(4) results in transamination with 2 dimethylamides providing Ti(NMe(2))(2)(dpma) and Zr(NMe(2))(2)(NHMe(2))(dpma), respectively. Addition of 2 equiv of H(2)dpma to Zr(NMe(2))(4) and Hf(NMe(2))(4) results in production of the homoleptic complexes Zr(dpma)(2) and Hf(dpma)(2). Conversely, treatment of Ti(NMe(2))(4) with 2 equiv of H(2)dpma does not provide Ti(dpma)(2), which was available by addition of 2 Li(2)dpma to TiCl(4). The properties of the isostructural series M(dpma)(2) were investigated by single crystal X-ray diffraction, cyclic voltammetry, (14)N NMR, and other techniques. By (14)N NMR, it was found that the pyrrolyl resonance chemical shift changes approximately linearly with the electronegativity of the metal center, which was attributed to pi-interaction between the pyrrolyl nitrogen lone pair and the metal. Other complexes produced during this study include Ti(CH(2)SiMe(3))(NMe(2))(dpma), TiCl(2)(THF)(dpma), and Ti(OCH(2)CF(3))(2)(THF)(dpma). Two isomers for Ti(CH(2)SiMe(3))(NMe(2))(dpma) were isolated and characterized.
已对包含三齿二价阴离子配体N,N-(二吡咯基-α-甲基)-N-甲胺（dpma）的第4族配合物的合成及性质进行了研究。将1当量的H₂dpma添加到Ti(NMe₂)₄和Zr(NMe₂)₄中，会与2个二甲基酰胺发生转氨反应，分别生成Ti(NMe₂)₂(dpma)和Zr(NMe₂)₂(NHMe₂)(dpma)。将2当量的H₂dpma添加到Zr(NMe₂)₄和Hf(NMe₂)₄中，会生成均配配合物Zr(dpma)₂和Hf(dpma)₂。相反，用2当量的H₂dpma处理Ti(NMe₂)₄并不能得到Ti(dpma)₂，而通过向TiCl₄中添加2 Li₂dpma可得到Ti(dpma)₂。通过单晶X射线衍射、循环伏安法、¹⁴N NMR及其他技术研究了同构系列M(dpma)₂的性质。通过¹⁴N NMR发现，吡咯基共振化学位移随金属中心的电负性近似呈线性变化，这归因于吡咯基氮孤对与金属之间的π相互作用。本研究过程中产生的其他配合物包括Ti(CH₂SiMe₃)(NMe₂)(dpma)、TiCl₂(THF)(dpma)和Ti(OCH₂CF₃)₂(THF)(dpma)。分离并表征了Ti(CH₂SiMe₃)(NMe₂)(dpma)的两种异构体。
