Open AccessSynthesis and Alkali‐Metal‐Ion Complexation of P‐Stereogenic Diphosphacrowns
Author(s) -
Morisaki Yasuhiro,
Kato Ryosuke,
Chujo Yoshiki
Publication year - 2016
Publication title -
chemistryopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 29
ISSN - 2191-1363
DOI - 10.1002/open.201600033
Subject(s) - stereocenter , chemistry , phosphine , steric effects , alkali metal , moiety , enantiopure drug , selectivity , metal , metal ions in aqueous solution , stereochemistry , medicinal chemistry , crystallography , organic chemistry , enantioselective synthesis , catalysis
Phosphine is conformationally stable because of the high inversion energy barrier of the phosphorus atom, which allows the phosphorus atom to become a chiral center. Thus, enantiopure P‐stereogenic 12‐, 15‐, 18‐, and 21‐membered aliphatic phosphines “diphosphacrowns” were synthesized from secondary P‐stereogenic bisphosphine as a chiral building block. Their complexation behaviors with alkali metal ions are investigated in comparison with benzo‐18‐diphosphacrown‐6 and benzo‐18‐crown‐6. 15‐, 18‐, and 21‐Membered diphosphacrowns captured alkali metal ions to form 1:1 metal complexes. Unique guest selectivity was observed, as diphosphacrowns encapsulated smaller alkali metal ions than common crown ethers; for example, 18‐membered diphosphacrowns interacted more strongly with Na + than K + . The difference in guest selectivity between diphosphacrowns and common crown ethers is speculated to result from the cavity size, owing to the large phosphorus atom as well as steric hindrance around the phosphine moiety.