Dey Subhayan, Sun Wei, Müller Jens
Department of Chemistry and ‡Saskatchewan Structural Sciences Centre, University of Saskatchewan , 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada.
Inorg Chem. 2016 Apr 4;55(7):3630-9. doi: 10.1021/acs.inorgchem.6b00170. Epub 2016 Mar 17.
The in situ prepared dilithio derivative of the known species 1-bromo-1'-(trimethylsilylamino)ferrocene (1) reacted with tBuPCl2 to form the first example of a [2]ferrocenophane ([2]FCP) bridged by nitrogen and phosphorus (2). Sulfurization of 2 followed by column chromatography on silica gel gave the expected [2]FCP with a tBu(S)PN(SiMe3) bridging moiety (3a) and its desilylated counterpart with a tBu(S)PNH bridging moiety (3b). The molecular structure of 3b was determined by single-crystal X-ray analysis (α = 18.40(11)°). Using a common synthetic methodology, two new 1-amino-1'-bromoferrocene derivatives were prepared, one species with a PhCH2 (6a) and another with a tBuCH2 group (6b) on nitrogen. Dilithiation of 6a followed by addition of tBuPCl2 gave a mixture of three constitutional isomers: the targeted [2]FCP (7a), the 1,1'-disubstituted ferrocene derivative (tBuPH)(PhCH═N)fc (8a), and the [3]FCP bridged by a (NH)(CHPh)PtBu moiety (9a). NMR spectroscopy revealed that 8a is the precursor for 9a. The salt-metathesis reaction of the dilithio derivative of 6b with tBuPCl2 exclusively gave the 1,1'-disubstituted ferrocene derivative (tBuPH)(tBuCH═N)fc (8b), which does not isomerize to the respective [3]FCP. DFT calculations at the M06/6-311+G(d,p) level were used to better rationalize these unexpected results.
已知物种1-溴-1'-(三甲基硅氨基)二茂铁(1)的原位制备的二锂衍生物与叔丁基磷酰二氯反应，形成了第一个由氮和磷桥联的[2]二茂铁环([2]FCP)(2)。2经硫化后，在硅胶上进行柱色谱分离，得到了预期的具有叔丁基(S)PN(SiMe3)桥联部分的[2]FCP(3a)及其具有叔丁基(S)PNH桥联部分的脱硅对应物(3b)。通过单晶X射线分析确定了3b的分子结构(α = 18.40(11)°)。采用常见的合成方法，制备了两种新的1-氨基-1'-溴二茂铁衍生物，一种在氮上带有苄基(6a)，另一种在氮上带有叔丁基甲基(6b)。6a经二锂化后，加入叔丁基磷酰二氯，得到三种构造异构体的混合物：目标[2]FCP(7a)、1,1'-二取代二茂铁衍生物(tBuPH)(PhCH═N)fc(8a)和由(NH)(CHPh)PtBu部分桥联的[3]FCP(9a)。核磁共振光谱表明，8a是9a的前体。6b的二锂衍生物与叔丁基磷酰二氯的盐复分解反应仅得到1,1'-二取代二茂铁衍生物(tBuPH)(tBuCH═N)fc(8b)，其不会异构化为相应的[3]FCP。采用M06/6-311+G(d,p)水平的密度泛函理论计算，以更好地解释这些意外结果。
