Dynamic control of topological asymmetry:
Physical studies

Once the ligands were made, complexes with Zn(II) and Cu(II) were obtained. Crystals of these complexes were grown and X-ray data collected as shown in Table 2 below:

Table 2: X-ray structures of metal-ligand complexes
[Zn(TPA)Cl]ClO4 (a) [1]
[Zn((R,S)-a-MeTPA)Cl]ClO4 (b) [2]
[Zn((R,S)-a-PhTPA)Cl]ClO4 (b) [2]
[Zn((R,S)-a-MeBQPA)Cl]ClO4 (b) [3]
[Cu(R-a-MeBQPA)(CH3CN)](ClO4 )2 (c) [2]
(a) Structure shown is the d conformer. (b) Structures obtained using racemic ligand. (c) Structure determined using enantiomerically pure ligand.
A list of the full chemical names for the ligands is available.

NOTE: Netscape 2.x users with the Chemscape Chime plug-in will see spacefilling representations of the X-ray structures in the table above which can be manipulated.

To observe the conformation of the complexes in solution, Circular Dichroism (CD) spectra for a selected number of these compounds obtained from the enantiomerically pure ligands, were acquired as shown below (Figure 6).

Figure 6: CD and UV-vis spectra (in methanol)

[Zn(R-a-MeTPA)Cl]ClO4
[CD and UV-vis spectra: [Zn(MeTPA)Cl]ClO4 in methanol]

[Zn(S-a-MeBQPA)Cl]ClO4
[CD and UV-vis spectra: [Zn(MeBQPA)Cl]ClO4 in methanol]
References:
  1. Allen, C.S.; Chuang, C-L.; Cornebise, M.; Canary, J.W. Inorg. Chim. Acta 1995, 239, 29.
  2. Canary, J.W.; Allen, C.S.; Castagnetto, J.M.; Wang, Y.; Xu, X., manuscript in preparation.
  3. Canary, J.W.; Allen, C.S.; Castagnetto, J.M.; Wang, Y. J. Am. Chem. Soc. 1995, 117, 8484.
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Page maintained by Jesus M. Castagnetto, [Send e-mail to author] [jesus@canarylab.chem.nyu.edu]. Last Updated: June 2 ,1996