pH-controlled multiple chiral inversion that induces molecular dimerization in a gold(I)-cobalt(III) coordination system with L-cysteinate.
Herein, a unique coordination system that exhibits multiple chiral inversions and molecular dimerization in response to a subtle pH change is reported. Treatment of (Δ)2-H3[Au3Co2(L-cys)6] (H3[1 a]) with [Co3(aet)6](NO3)3 (aet=2-aminoethanethiolate) in water at pH 7 gave a 1:1 complex salt of [Co3(aet)6](3+) and [1 a](3-), retaining the Au(I)3Co(III)2 structure and chiral configurations of [1 a](3-). Similar treatment at pH 9 led to not only the inversion of all of the chiral Co(III) and S centers but also the dimerization of [1 a](3-), giving a 2:1 complex salt of [Co3(aet)6](3+) and (Λ)4(R)12-[Au6Co4(L-cys)12](6-) ([2](6-)). When dissociated from [Co3(aet)6](3+) in solution, [2](6-) was converted to (Λ)2(R)6-[Au3Co2(L-cys)6](3-) ([1 b](3-)) with retention of the chiral configurations.
Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan).
Pei-Shan
PS
Lee
Asako
A
Igashira-Kamiyama
Naoto
N
Kuwamura
Nobuto
N
Yoshinari
Takumi
T
Konno
D002942:Circular Dichroism; D003035:Cobalt / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry*; D019281:Dimerization; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008968:Molecular Conformation; D013237:Stereoisomerism
D056831:Coordination Complexes; D003035:Cobalt; D006046:Gold; D003545:Cysteine
S ligands; amino acids; chirality; gold; heterometallic complexes