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

Abstract

Urea and its derivatives, due to their unusual versatility of coordination modes to metal centers and the presence of multiple hydrogen-bond donor sites, are widely utilized as neutral or monoanionic ligands in coordination and bioinorganic chemistry and as building units of bioinspired materials. However, metal complexes with ureate ligands have essentially not been applied as precursors of hybrid organic–inorganic nanomaterials. We report on the synthesis and structure characterization of two novel organozinc ureate complexes incorporating N-phenylureate or N,N′-dicyclohexylureate ligands, the latter being the first reported complex with the μ3-μ2(O):κ1(N) ureate coordination mode. These findings not only expand the horizon of urea–zinc chemistry but also pave the way for efficient bottom-up mechanochemical synthesis of sub-10 nm diameter zinc oxide nanocrystals (ZnO NCs) coated by the ureate ligands. We explored the NC formation triggered by mechanical force from both a well-defined monocrystalline precursor and an insoluble hard-to-process amorphous organozinc precursor. Moreover, the organic shell of the N-phenylureate-coated ZnO NCs was modified via a facile, fast, and solventless host–guest complexation with β-cyclodextrin using a mechanochemical approach, which afforded water-soluble ZnO NCs. The reported procedure is the first example of rapid and sustainable mechanochemical synthesis of hybrid nanomaterials from organometallic precursors.

Synthesis, Characterization, and Assessment of Anti-Cancer Potential of ZnO Nanoparticles in an In Vitro Model of Breast Cancer

“…It was considered that the repeated use of chemical methods contributes to the appearance on the surface of nanoparticles of certain toxic chemicals that could have a harmful impact in medical applications [ 28 ]. Sol-gel processing [ 29 ], homogeneous precipitation [ 30 ], mechanical milling [ 31 ], organometallic synthesis [ 32 ], the microwave approach [ 33 ], spray pyrolysis [ 34 ], thermal evaporation [ 35 ], and mechanochemical synthesis [ 36 ] are all strategies for producing ZnO NPs. Chemical methodologies and hazardous reducing chemicals, the majority of which are very reactive and harmful to the environment, are often used in these procedures [ 37 ].…”

Cyclodextrin-Templated Co(II) Grids: Symmetry Control over Supramolecular Topology and Magnetic Properties

“…As part of our continuing research on the design and synthesis of functional materials based on CD building units 5 , 6 and homo- and heterometallic clusters incorporating magnetically active metal ions 7 herein, we demonstrate how the type of CD ligand influences the formation, self-organization, and magnetic properties of Co/Li sandwich-type complexes. To this effect, we have isolated and structurally characterized a new sandwich-type complex, [(α-CD) 2 Co 3 Li 6 (H 2 O) 9 ], which represents a smaller macrocycle analogue of the [(γ-CD) 2 Co 4 Li 8 (H 2 O) 12 ] cluster.…”

ZnO Nanoplatelets with Controlled Thickness: Atomic Insight into Facet‐Specific Bimodal Ligand Binding Using DNP NMR

“…[50,51] Furthermore, the ligand shell's appropriate functionalization affects solubility and self-organization processes since it directly impacts post-synthetic functionalization. [48,49,[54][55][56] In the course of our investigations on the development of efficient organometallic strategies for the preparation of high-quality ZnO nanocrystalline materials, a vast array of organozinc precursors incorporating monoanionic O,O′-and N,O′-anchoring ligands like carboxylates, [48,49,52,55,56] phosphinates, [50] phosphates, [42] amides, [57] ureates, [58] and chiral aminoalkoxides [51] were tested. Subsequently, we turn our attention to benzamidinate (bza) ligands that possess an N,N′-mode, in contrast to the carboxylate and amidate ligands used so far.…”