Multiple Isomers of a Small, Strained Phosphaphane: Multiple Isomers of a Small, Strained Phosphaphane
Multiple Isomers of a Small, Strained Phosphaphane: Multiple Isomers of a Small, Strained Phosphaphane
复制标题
小的、应变的磷酸烷的多种异构体： 小的、应变的磷酸烷的多种异构体
DOI：
10.1002/ejoc.201801106
复制
发表时间：
2018
影响因子：
2.8
通讯作者：
Pascal, Jr., Robert A.
中科院分区：
文献类型：
--
作者：
Xiao, Yonglong;Mague, Joel T.;Pascal, Jr., Robert A.
从碱促进的三(2-巯基苯基)膦(4)和三(3-溴丙基)甲烷(5)的大环化反应中分离得到三个环番化合物，式为(C28H31PS3)n，其中en=1或2。光谱分析和X-射线分析表明它们是Thein，In-异构体1，Thein，Out-异构体2，以及二聚体，Out，In，Out-异构体3。化合物1和化合物3在晶体中分别表现出近似的C3对称和Ci对称结构，但化合物2在固态中采用两种不同的低对称构象。在每种情况下，观察到的结构对应于在B3PW91/6-31G(D)理论水平上计算的各自异构体的最低能量构象。In，In-异构体1显示了膦-孤对和亚甲基团之间的紧密接触，其贯穿空间的自旋-自旋耦合常数分别为JPh=9 Hz和JPc=24 Hz，后者似乎是已报道的最大的磷-碳贯穿空间耦合常数。
Three cyclophanes with the formula (C28H31PS3)n, wheren= 1 or 2, were isolated from the base‐promoted macrocyclization of tris(2‐mercaptophenyl)phosphine (4) and tris(3‐bromopropyl)methane (5). Spectroscopic and X‐ray analysis showed them to be thein,in‐isomer1, thein,out‐isomer2, and a dimericin,out,in,out‐isomer3. Compounds1and3display approximatelyC3‐symmetric andCi‐symmetric structures, respectively, in the crystal, but compound2adopts two distinct low‐symmetry conformations in the solid state. In each case, the observed structures correspond to the lowest energy conformations of their respective isomers as calculated at the B3PW91/6‐31G(d) level of theory. Thein,in‐isomer1displays a close contact between the phosphinein‐lone pair and thein‐methine group, with through‐space spin–spin coupling constants ofJPH= 9 Hz andJPC= 24 Hz, the latter of which appears to be the largest reported phosphorus‐carbon through‐space coupling constant.