The structural mobility of zinc complexes with tetradentate tripodal ligands derived from the amino acids glycine and phenylalanineElectronic supplementary information (ESI) available: Fig. S1: 1H NMR spectra (CDCl3 solutions) of the bpaAc–Phe–OMe complexes 1b/2b, 3bo, 5b and 8b at room temperature. See http://www.rsc.org/suppdata/dt/b2/b212049f/

Synthetic Analogues Relevant to the Structure and Function of Zinc Enzymes

“…A variety of tridentate ligands with [N 2 O] donor arrays has been introduced to model zinc enzymes such as carboxypeptidase and thermolysin, 8b,e,− as have [N 3 O] donors. 108g,− Many of these ligands, however, do not enforce tetrahedral coordination geometries akin to those in the enzymes. For example, bis[(3,5-diisopropylpyrazolyl)ethyl]ether, O(CH 2 CH 2 pz Pr i 2 ) 2 , binds to zinc with a meridional (i.e., a “T-shaped”) configuration, rather than the desired facial configuration which would mimic that in the enzymes .…”

“…A tripod ligand employing benzimidazole and acetate donors has allowed the complex {[N(CH 2 BIM) 2 (CH 2 CO 2 )]Zn(OH 2 )} + to be prepared (Figure ), as have related derivatives. , However, in contrast to the [(HCO 2 )Bp Bu t ,Pr i ] and [HC(pz Me 2 ) 2 (C 6 H 2 MeBu t O)] ligands, the central nitrogen of the [N(CH 2 BIM) 2 (CH 2 CO 2 )] tripod also interacts with the zinc center (ca. 2.36 Å), and so {[N(CH 2 BIM) 2 (CH 2 CO 2 )]Zn(OH 2 )} + is best described as five-coordinate.…”