Synthetic Models for the Urease Active Site

From Uncommon Ethylzinc Complexes Supported by Ureate Ligands to Water-Soluble ZnO Nanocrystals: A Mechanochemical Approach

“…Urea-derived ligands are characterized by the versatility of coordination modes to metal centers 51−56 as well the presence of multiple hydrogenbond donor sites capable of interacting with various external guests. 57,58 These inherent features make urea derivatives extremely prominent as neutral or monoanionic ligands in coordination chemistry, [52][53][54][55]58 pivotal components of supramolecular gels 59 and metal−organic cages, 58 models for enzyme activity, 60 and building units of other bioinspired materials. 59,61,62 Nevertheless, metal complexes incorporating ureate ligands have essentially not been applied as precursors of hybrid organic−inorganic nanomaterials.…”

“…Now, we turn our attention to organozinc complexes incorporating urea derivatives as new potential self-supporting precursors of ligand-coated ZnO NCs. Urea-derived ligands are characterized by the versatility of coordination modes to metal centers − as well the presence of multiple hydrogen-bond donor sites capable of interacting with various external guests. , These inherent features make urea derivatives extremely prominent as neutral or monoanionic ligands in coordination chemistry, − , pivotal components of supramolecular gels and metal–organic cages, models for enzyme activity, and building units of other bioinspired materials. ,, Nevertheless, metal complexes incorporating ureate ligands have essentially not been applied as precursors of hybrid organic–inorganic nanomaterials. Only very recently, two works on the preparation of ZnO NCs via the classical sol–gel process using zinc acetate as a precursor and urea as a modification agent were reported, , but the surface coordination chemistry of the NCs or the role of urea moieties has not been investigated in detail.…”

Synthesis, Magnetic Properties, and Catalytic Properties of a Nickel(II)-Dependent Biomimetic of Metallohydrolases

“…In contrast to other bioinorganic systems Ni(II) complexes have received less attention. A limited number of studies have focussed on di-Ni(II) model complexes for urease (Meyer, 2009 ) and FeNi complexes for hydrogenases (Vaissier and Van, 2017 ), and Neves and colleagues have developed several Ni(II) models for phosphatases, in particular purple acid phosphatases (PAPs) (Greatti et al, 2008 ; Piovezan et al, 2012 ; Xavier and Neves, 2016 ). PAPs present an ideal system to study biomimetics, in parts because of the wealth of sequence (Flanagan et al, 2006 ), structural and functional data available (Schenk et al, 2013 ), but also because these enzymes occur in homo- and hetero-bimetallic form in nature, using a range of metal ions (Fe, Zn, Mn; Mitić et al, 2009 , 2010 ).…”

Dinuclear Allylpalladium Complexes ofC2-Symmetric Pyrazolate-Bridged Bis(oxazoline) Ligands (pyrbox's): Structures, Dynamic Behavior, and Application in Asymmetric Allylic Alkylation

“…Further enhancement of preorganization of the two metal ions can be achieved by the attachment of chelating side arms to the 3,5-positions of the pyrazole heterocycle, and a variety of symmetrical and unsymmetrical 3,5-disubstituted ligands with mono-, bi-, and tridentate side arms have been developed over the past decade . By varying the lengths of these side arms and the nature or the quantity of the donor atoms, a fine tuning of the metal−metal distance can be achieved. , Such highly preorganized pyrazolate-based bimetallic complexes have been successfully used in metallobiosite modeling, and their favorable properties in two-center organometallic chemistry are increasingly recognized. − While a pyrazolate-bridged bimetallic array has inherent 2-fold symmetry, however, little is known as yet about C 2 -symmetric systems with chiral chelate arms such as the ligand HL bearing two ( R )-2-(methoxymethyl)pyrrolidine substituents at the central pyrazole core …”