Synthesis and Characterization of Thiolate‐Oxo Ligated Zinc Alkyl Derivatives for Production of Zn‐Based Nanoparticles

Abstract

A series of mercapto-oxo containing reagents [3-mercaptopropionic acid (H2-3MPA), 4-mercaptophenol (H2-4MP), 2-mercaptopyridine-N-oxide (H-2MPO)] was reacted with diethyl zinc (ZnEt2) in hexanes/pyridine (py) to yield {(μ4-3MPA)[Zn(Et)(py)]4}∞ (1), [(py)2(Et)Zn(μ3-4MP)Zn(Et)(py)]2 (2), and (2MPO)Zn(Et)py (3). For polymeric 1, each of the functional sites of the 3MPA was bound to four tetrahedral (Td) coordinated Zn(Et)(py) subunits. The sulfur of the 3MPA bridges two of the ‘Zn(Et)(py)’ subunits, which are also bridged by the two carboxylate oxygens of another 3MPA to propagate the chain. In contrast, 2 forms a discrete tetranuclear species consisting of two Zn(Et)(py) moieties bridged by the oxygens of two 4MP ligands with the thiolate sites of each terminated by Zn(Et)(py)2 moieties. Compound 3 adopts a monomeric species using a chelating 2MPO, a terminal Et, and a bound py to fill the Td coordination of the Zn metal center. Compounds 1 - 3 were then used to generate nanoparticles via solution precipitation and solvothermal routes to determine the effect these precursors have on the morphology and composition of the final materials produced. Compounds 1 - 3 were found to form zincite, zinc metal, or mixed zincite/wurtzite phases from solution precipitation or solvothermal routes; however, no routes yielded the mixed anion (i.e., ZnOxSy) materials.

Synthesis and Dynamic Behavior of Chiral NNO‐Scorpionate Zinc Initiators for the Ring‐Opening Polymerization of Cyclic Esters

“…The coordination environment of each Zn atom can be described as a distorted tetrahedron with a heteroscorpionate ligand acting in a tridentate fashion (two coordinated pyrazole rings bridge the two zinc atoms and the oxygen atom from the alkoxide fragment, which also bridges the two zinc atoms), and the other two coordination positions of the two zinc atoms are completed with an oxygen atom from the aryl oxide ligand bridging the two zinc atoms, and finally an alkyl ligand on each zinc atom. The dimeric aggregate is based on Zn 2 O 2 four‐membered rings, which have previously been observed in other zinc compounds that contain, for example, thiolate‐oxo, alkoxide‐imino, aryl oxide, or amino alcoholate ligands and, more recently, by our research group with dinuclear complexes of the type [Zn(R)(κ‐NNµ‐O)] 2 Additionally, the Zn–O bond lengths from the scorpionate ligand in these complexes are similar to those in complex 3 , in which the oxygen atoms also bridge the two zinc atoms. However, the Zn–N bond lengths from the two pyrazole rings in complexes 5 and 6 , in which these rings bridge the two zinc atoms, are generally longer (nearly 2.13 Å) than in complex 3 , in which both pyrazole rings are coordinated in a chelating fashion to one zinc atom (nearly 2.10 Å).…”

Copolymerization of Cyclic Esters Controlled by Chiral NNO-Scorpionate Zinc Initiators

“…The other two coordination positions of the two zinc atoms are completed with an oxygen atom from the aryloxide ligand bridging the two zinc atoms and finally by an alkyl ligand on each zinc atom. The dimeric aggregate is based on Zn 2 O 2 four-membered rings, which have previously been observed in other zinc compounds that contain, for example, thiolate-oxo, 25 alkoxide-imino, 26 aryloxide, 27 or alkoxideamino 28 ligands and, more recently, by our research group with dinuclear complexes of the type [Zn(R)(κ-NNμ-O)] 2 . 29 Additionally, the Zn−O bond distance from the scorpionate ligand in this complex is similar to those in complex 1, where the oxygen atoms also bridge the two zinc atoms.…”

Structural Diversity of Ethylzinc Carboxylates

“…In the case of benzilic acid, a more robust hexanuclear complex was isolated . An alkylzinc derivative with a bifunctional carboxylate acid with thiol termini forms a linear polymeric chain [(EtZn­(py)) 2 L] n (L = mercaptopropionic acid, py = pyridine) …”