Metal-templated receptors

Goodman, M.S., Jubian, V. and Hamilton, A.D, (1995) Metal templated receptors for the effective complexation of dicai boxylates. Tetrahedron Lett., 36, 2551-2554. 

Figure 14 Schematic approach to metal-templated receptors...

In a completely different approach to metal-templated receptors, Schwa-bacher et al. have prepared a series of bis(amino add) derivatives like (57) which, on addition of transition metals such as mckel(II) or cobalt(II), dimerize to form cyclophane-like macrocycles (58) that are capable of substrate recognition in water [68]. These designs have the advantage that the metal can provide electrostatic binding to polar substituents on the substrate in addition to the primarily hydrophobic interactions [69]. 

Prepare a solution of each metal-templated receptor of equal concentration (roughly 0.25 mM was used for these procedures). For these protocols 5% acetonitrile/chlo-roform was most effective, although other solvents are possible (see Note 11). 

Remove residual liquid under reduced pressure. Visually evaluate the color of each resin compared to a control containing no receptor. The degree of color change is consistent with the degree of binding by the metal-templated receptors. 

Hamilton, A. D., Linton, B., Formation of artificial receptors by metal-templated self-assembly. Chem. S t Y 1997. 97,1669-1680. 

B. Linton, A.D. Hamilton, Formation of Artificial Receptors by Metal-Templated Self-Assembly , Chem. Rev., 97, 1669 (1997)... 

K. Uezu, M. Goto, S. Furusaki, Required properties for functional monomers to produce a metal template effect by a surface molecular imprinting technique, Macromolecules, 1999, 32, 1236 S.A. Piletsky, I.A. Panasyuk, E.V Pletskaya, I.A. Nicholls, M. Ulbricht, Receptor and transport properties of imprinted polymer membranes - review, J. Membr. Sci., 1999, 157, 263. 

Fig. 1. Formation of dimeric receptor by metal-templated self-assembly. R...

This metal-templated self-assembly approach to combinatorial receptors is presented below, starting from functionalized terpyridine derivatives. Methods include the creation of monomers, dimerization with several metals to form dimeric receptors, and several procedures used to gauge association strength and catalytic activity of library components. 

Calix[n]arenes have attracted great attention as ionophoric receptors [1-4] and potential enzyme mimics [5] in host-guest chemistry. Shinkai et al. have reported the preparation and ionophoric properties of four conformers of tetra-terf-butyl-tetrakis[(ethoxycarbonyl)methoxy]calix[4]arene [6-8]. Cone and partial-cone conformers are obtained by the metal template effect using sodium and cesium ions, respectively, but the 1,2-altemate and 1,3-altemate conformers were synthesized by the protection-deprotection method [8-10]. They also found that the cone conformer shows a selectivity for sodium [6] and the other conformers show a selectivity for potassium [8]. 

Formation of artificial receptors by interaction of metal with macroheterocycles as templates 97CRV1669. 

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