NMR study on the coordination of dibenzylideneacetone to chiral palladium(0) units. Fluxional behaviour including an intramolecular double bond exchange
NMR study on the coordination of dibenzylideneacetone to chiral palladium(0) units. Fluxional behaviour including an intramolecular double bond exchange
复制标题
二亚苄基丙酮与手性钯(0)单元配位的NMR研究。
DOI：
10.1039/b101912k
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
M. Maestro
中科院分区：
文献类型：
--
作者：
F. A. Jalón;B. Manzano;Felipe Gómez;Ana M. Lopez;Ana M. Rodríguez;W. Weissensteiner;T. Sturm;J. Mahía;M. Maestro
具有通式Pd（L-L）（η2-dba）的新衍生物（dba =二亚苄基丙酮），L-L = 1-二苯基膦基-2，1 ′-（1-dimethylaminopropanediyl）ferrocene，PAPF，1; 2-[1-（二甲氨基）乙基]-1-（二苯基膦基）二茂铁，PPFA，2; N，N-二甲基-1-[1′，2-双（二苯基膦基）二茂铁基]乙胺，BPPFA，3;以Pd 2（dba）3·CHCl 3和合适的二茂铁配体为原料，合成了1-二苯基膦基-2，1 ′-（1-二环己基膦基丙二基）二茂铁，PPCyPF，4.当使用过量的PPFA时，与P-配位的PPFA配体形成配合物Pd（PPFA）3。dba单元优先采用s-顺式，反式构象，其中s-反式烯烃与Pd（L-L）片段配位。确定了几个分子内的动态过程：在室温下，一个快速旋转的dba的烯烃-Pd键，Pd-N键断裂过程的配合物2，在高温下，分子内的非对映异构体的相互转化，涉及烯烃的面交换伴随着由配位和非配位的dba双键之间的互换。配合物2的晶体结构经X射线衍射测定。
New derivatives with the general formula Pd(L–L)(η2-dba) (dba = dibenzylideneacetone), L–L = 1-diphenylphosphino-2,1′-(1-dimethylaminopropanediyl)ferrocene, PAPF, 1; 2-[1-(dimethylamino)ethyl]-1-(diphenylphosphino)ferrocene, PPFA, 2; N,N-dimethyl-1-[1′,2-bis(diphenylphosphino)ferrocenyl]ethylamine, BPPFA, 3; 1-diphenylphosphino-2,1′-(1-dicyclohexylphosphinopropanediyl)ferrocene, PPCyPF, 4 were synthesized from Pd2(dba)3·CHCl3 and the appropriate ferrocenyl ligand. When an excess of PPFA was used, the complex Pd(PPFA)3 with P-coordinated PPFA ligands was formed. The dba unit preferentially adopts an s-cis,trans conformation with the s-trans alkene coordinated to the Pd(L–L) fragment. Several intramolecular dynamic processes were identified: at room temperature a fast rotation of dba about the alkene–Pd bond, a Pd–N bond rupture process for complex 2 and, at elevated temperatures, an intramolecular diastereomer interconversion involving an alkene face exchange accompanied by an interchange between the coordinated and non-coordinated dba double bonds. The crystal structure of complex 2 was determined by X-ray diffraction.