Synthesis, structure and unique reactivity of the ethylzinc derivative of a bicyclic guanidine

Abstract

An equimolar reaction between ZnEt(2) and 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (hppH) results in the formation of EtZn(hpp) (1) which crystallizes as a trinuclear agglomerate with the guanidinate ligands spanning 4-coordinate Zn centers. Exposure of a pre-formed THF solution of 1 to undried air leads to a ZnO-incorporating derivative 1(4)·ZnO, while an analogous experiment with CH(2)Cl(2) as solvent leads to a novel tetranuclear mixed aggregate formulated as [EtOZn(hpp)](2)[ClZn(hpp)](2) (2). The composition of 2 indicates that its formation proceeds via a complex multi-step reaction route that involves not only the oxygenation of ZnEt moieties, but also the activation of CH(2)Cl(2), causing the transfer of a chloride anion to the Zn center. Compounds were characterized by (1)H NMR spectroscopy and single-crystal X-ray diffraction analysis.

From Well‐Defined Alkylzinc Phosphinates to Quantum‐Sized ZnO Nanocrystals

“…In the course of our systematic investigations on the self‐supporting wet‐organometallic processing approach to high‐quality quantum‐sized ZnO NCs coated with a shell composed of X‐type ligands, we wondered whether molecular alkylzinc phosphinates (i.e., ethylzinc phosphinates) might be efficient precursors of phosphinate‐coated ZnO NCs. Our recent scrupulous examination also allowed us to disclose that some organozinc reaction systems exhibit a unique ability to form entrapped zinc‐oxo or zincoxane moieties . Thus, we also decided to examine the reactivity of well‐defined phosphinates (i.e., 3 4 , 4 , and 8 2 ⋅THF ) toward O 2 and H 2 O in the context of mimicking the intimate steps of the transformation of molecular organozinc precursors through intermediate oxo‐zinc clusters to phosphinate ligand‐coated ZnO NCs.…”

“…Our recent scrupulous examination also allowed us to disclose that some organozinc reaction systems exhibit au nique ability to form entrapped zinc-oxo or zincoxane moieties. [13,15] Thus, we also decided to examinet he reactivity of well-defined phosphinates (i.e., 3 4 , 4, and 8 2 ·THF)t oward O 2 and H 2 Oi nt he contexto fm imicking the intimates teps of the transformation of molecular organozinc precursors through intermediate oxo-zinc clusters to phosphinate ligand-coated ZnO NCs. We note that, despite the continual interest in ZnO-based nanomaterials, the chemistry of ZnO-based molecular clusters is still ar elatively unexplored area.…”

“…To the best of our knowledge,t here are only af ew examples of structurally characterized alkylzinc complexesi ncorporating phosphonate, [12] phosphate, [13] and phosphinate [14] ligands( Scheme 1). Latterly,w ehave also convincingly shown that alkylzinc complexes, that is, organozincdiorganophosphates [13] and an ethylzinc derivative of ab icyclic guanidine, [15] exhibit au nique ability to form entrapped zincoxaneu nits. Strikingly,t he resulting phosphate zincoxanes may elucidate the structuralc hanges that precursor molecules may undergo during transformation from organozinc phosphates to ZnO NCs.…”

Unprecedented Variety of Outcomes in the Oxygenation of Dinuclear Alkylzinc Derivatives of an N,N‐Coupled Bis(β‐diketimine)

“…and . OR radicals, which are likely responsible for the formation of a variety of products, including zinc oxo,,, hydroxide,, and even carboxylate species. Such diversity of products has usually been observed as a distinguishing feature of divergent reaction systems involving mononuclear, three‐coordinate alkylzinc complexes.…”

Synthesis and characterization of bioactive binuclear transition metal complexes of Schiff base ligand derived from 4-amino-pyrimidine-2-one, diacetyl and glycine

“…11,12 Recently synthesized Cu(II), Ni(II), Co(II) and Zn(II) complexes show the current interest of researchers in the field of coordination chemistry of these metal ions. [13][14][15] Some other transition metal complexes were also synthesized for the study of their biological activities viz. antimicrobial, fluorescence quenching study in proteins, toxicity and DNA interaction.…”