Synthesis and characterization of several zinc(II) complexes containing the bulky heteroscorpionate ligand bis(5-tert-butyl-3-methylpyrazol-2-yl)acetate: relevance to the resting states of the zinc(II) enzymes thermolysin and carboxypeptidase A

Autor: Zahida Shirin, Brian S. Hammes, Matthew T. Kieber-Emmons, Lev N. Zakharov, Arnold L. Rheingold, Joseph A Letizia, Carl J. Carrano
Rok vydání: 2003
Předmět:
Zdroj: Inorganica Chimica Acta. 346:227-238
ISSN: 0020-1693
DOI: 10.1016/s0020-1693(02)01338-5
Popis: The syntheses and characterization of a series of zinc complexes containing the tripodal ligand bis(5-tert-butyl-3-methylpyrazol-2-yl)acetic acid (H2) which is designed to model the 2-His-1-carboxylate facial triad observed in the active sites of various metalloenzymes such as carboxypeptidase A (CPA) and thermolysin (TLN) are reported. Pseudotetrahedral complexes isolated include [Zn2(CH3)], [Zn2(Cl)], [Zn2(SPh)], [Zn2(OAc)], [Zn2(NCS)] and [Zn2(AH)]. In addition, a four (solution) or five-coordinate (solid state) cationic zinc aqua complex, [Zn2(OH2)]+ and a 5-coordinate zinc acetohydroxamate complex, [Zn2(AH)] were synthesized and structurally characterized. The former represents a structural mimic of the resting state while the latter depicts the inhibited state of zinc enzymes CPA and TLN. Crystal data: [Zn2(CH3)] crystallizes in the triclinic space group , with cell dimensions a=6.638(6) A, b=12.249(10) A, c=13.327(12) A, α=82.862(15)°, β=76.811(15)°, γ=88.988(17)° and Z=2; [Zn2(Cl)] crystallizes in the triclinic space group , with cell dimensions a=8.9933(7) A, b=9.7985(8) A, c=12.1536(9) A, α=94.0420(10)°, β=105.3950(10)°, γ=95.6490(10)° and Z=2; [Zn2(SPh)]·0.5CH2Cl2 crystallizes in the triclinic space group , with cell dimensions a=12.1273(15) A, b=12.9073(16) A, c=17.824(2) A, α=87.194(2)°, β=78.769(3)°, γ=76.027(2)° and Z=4; [Zn2(OH2)]ClO4 crystallizes in the monoclinic space group P21/n, with cell dimensions a=12.620(2) A, b=11.1416(18) A, c=19.315(3) A, β=101.883(2)°, and Z=4; [Zn2(AH)]·3.25CH2Cl2 crystallizes in the orthorhombic space group Pccn, with cell dimensions a=23.7791(6) A, b=14.1675(3) A, c=22.1213(5) A, α=β=γ=90° and Z=8. The 1H NMR spectra of these diamagnetic zinc complexes suggests that all complexes retain their overall symmetry in solution.
Databáze: OpenAIRE
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