Stepwise helicity inversions by multisequential metal exchange.
Development of artificial helical molecules that can undergo responsive helicity inversion has been a challenging research target in functional molecular chemistry. However, most reported helicity inversions are based on a single-mode transition, i.e., the conversion between right- and left-handed states. We report here the first molecular system that allows stepwise multisequential helicity inversion utilizing metal exchange of helical complexes derived from a hexaoxime ligand, H6L(1). The ligand H6L(1) underwent a four-step conversion (H6L(1) → L(1)Zn3 → L(1)Zn5 → L(1)Zn3Ba → L(1)Zn3La) upon sequential metal addition (Zn(2+), Ba(2+), then La(3+)). Associated with the conversion, three-step helicity inversion took place (L(1)Zn3, right-handed → L(1)Zn5, left-handed → L(1)Zn3Ba, right-handed → L(1)Zn3La, left-handed). This is the first example of stepwise multimode helicity inversion of a discrete molecule, which could be useful as a platform for construction of dynamic regulation systems with multiple asymmetric functions.
Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan. akine@chem.tsukuba.ac.jp
Shigehisa
S
Akine
Shiho
S
Sairenji
Takanori
T
Taniguchi
Tatsuya
T
Nabeshima
D001464:Barium / Q000737:chemistry*; D007811:Lanthanum / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010091:Oximes / Q000737:chemistry; D015032:Zinc / Q000737:chemistry*
D008024:Ligands; D009942:Organometallic Compounds; D010091:Oximes; D001464:Barium; D007811:Lanthanum; D015032:Zinc