TY - JOUR
T1 - Reversible Catenation of Coordination Rings with Pd(ii) and/or Pt(ii) Metal Centers
T2 - Chirality Induction Through Catenation
AU - Hori, Akiko
AU - Kataoka, Hisashi
AU - Akasaka, Akihiko
AU - Okano, Takashi
AU - Fujita, Makoto
PY - 2003/11/15
Y1 - 2003/11/15
N2 - A Pd(II)-linked coordination ring is reversibly transformed into its catenanted dimer at room temperature through the efficient organic stacking of the component rings. An analogous Pt(II)-linked ring is also catenated only at high temperature (100 °C), but not at room temperature because of the kinetic inertness of Pt(II)-ligand interaction. Interestingly, the combination of the Pd(II)- and the Pt(II)-linked coordination rings selectively gives a Pd(II)/Pt(II) cross-catenane, because the kinetically inert Pt(II) ring can be catenated only via the dissociation of the kinetically labile Pd(II) ring. Planer conformation of the monomer rings is twisted upon catenation, inducing helical chirality in the catenated structure. Thus, induced circular dichroism (ICD) is observed in the catenation when chiral-1,2-cyclohexandiamine is attached as a chiral auxiliary on the metal centers. The ICD decreases with increasing temperature due to less effective chiral aromatic stacking at higher temperature. The Pd(II) ring shows higher ICD than the Pt(II) ring, probably due to the more flexible conformation of the Pd(II) ring that can adopt chiral orientation easily.
AB - A Pd(II)-linked coordination ring is reversibly transformed into its catenanted dimer at room temperature through the efficient organic stacking of the component rings. An analogous Pt(II)-linked ring is also catenated only at high temperature (100 °C), but not at room temperature because of the kinetic inertness of Pt(II)-ligand interaction. Interestingly, the combination of the Pd(II)- and the Pt(II)-linked coordination rings selectively gives a Pd(II)/Pt(II) cross-catenane, because the kinetically inert Pt(II) ring can be catenated only via the dissociation of the kinetically labile Pd(II) ring. Planer conformation of the monomer rings is twisted upon catenation, inducing helical chirality in the catenated structure. Thus, induced circular dichroism (ICD) is observed in the catenation when chiral-1,2-cyclohexandiamine is attached as a chiral auxiliary on the metal centers. The ICD decreases with increasing temperature due to less effective chiral aromatic stacking at higher temperature. The Pd(II) ring shows higher ICD than the Pt(II) ring, probably due to the more flexible conformation of the Pd(II) ring that can adopt chiral orientation easily.
KW - Induced circular dichroism
KW - Palladium
KW - Platinum
KW - Reversible catenation
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U2 - 10.1002/pola.10844
DO - 10.1002/pola.10844
M3 - Article
AN - SCOPUS:0242440875
VL - 41
SP - 3478
EP - 3485
JO - Journal of Polymer Science, Part A: Polymer Chemistry
JF - Journal of Polymer Science, Part A: Polymer Chemistry
SN - 0887-624X
IS - 22
ER -