Synthesis and Reactivity of a New Oxidation‐Labile Heterobimetallic Mn₆Zn₂ Carbamate Cluster and Precursor to Nanosized Magnetic Oxide Particles

Abstract

The synthesis and characterization of the new octanuclear mixed carbamate complex [Zn2Mn6(μ4‐O)2(O2CN(iPr)2)12] is reported. This complex is readily oxidized by O2 to give [Zn2Mn6(μ4‐O)2(μ3‐O)(O2CN(iPr)2)12] featuring a central O atom statistically distributed over two sites within the void of the inner Mn6 cage of the carbamate complex. In relation to the situation before oxidation, the metal cage is expanded by a change of the carbamate bonding mode. The two carbamate complexes were used as precursors to magnetic oxide nanoparticles under mild conditions (210–270 °C depending on the heating rate). A mixture of crystalline ZnMn2O4 and MnO nanoparticles resulted. The experimental data are complemented by some quantum chemical (DF) calculations.

The role of intermolecular interactions involving halogens in the supramolecular architecture of a series of Mn(ii) coordination compounds

“…3. The Mn/Mn distance within the metal chain is 3.867(2) Å and the intrachain Mn/ Mn/Mn angle is 125.90(4) , which is comparable to those previously reported for [MnCl 2 (mapy)] (Mn/Mn ¼ 3.6533 (8) Å and :Mn/Mn/Mn ¼ 123.08(1) ) by Himmel and his coworkers. 8 As depicted in Fig.…”

Recent Advances in the Chemistry of Metal Carbamates

“…Typically, this method exploits silver or alkali metal carbamates as transfer reagents, taking advantage of the precipitation of the metal halide side-product (e.g., NaCl, LiCl, AgCl, AgBr) as the driving force of the reaction (Scheme 28a) [109,133,159,166,212,280]. Attempts to realize trans-metalation based on other combinations of metals may result in carbamato ligand transfer [42] or in the formation of a hetero-bimetallic product [281,282]. Another type of ligand transfer reaction can be performed by mixing equimolar amounts of a metal halide and its corresponding homoleptic carbamate, selectively affording a mixed halido-carbamato complex (Scheme 28b) [109,172].…”

“…Typically, this method exploits silver or alkali metal carbamates as transfer reagents, taking advantage of the precipitation of the metal halide side-product (e.g., NaCl, LiCl, AgCl, AgBr) as the driving force of the reaction ( Scheme 28 a) [ 109 , 133 , 159 , 166 , 212 , 280 ]. Attempts to realize trans-metalation based on other combinations of metals may result in carbamato ligand transfer [ 42 ] or in the formation of a hetero-bimetallic product [ 281 , 282 ].…”

“…The same principles can be applied to the preparation of metal oxide nanoparticles by thermal decomposition of metal carbamates at 200–300 °C and ordinary pressure. Thus, pyrolysis of [ZnEt(O 2 CNR 2 )] 4 and [M(O 2 CNR 2 ) 4 ] (M = Zr, Hf, Nb; R = Me, Et, i Pr) gives ZnO, ZrO 2 , HfO 2 and Nb 2 O 5 nanoparticles [ 203 , 334 ], whereas Zn/Co and Zn/Mn heterobimetallic carbamates have been employed to obtain Zn x (Co, Mn) (1−x) O mixed oxide nanoparticles [ 281 , 282 ]. In these cases, the excessive volatilization of the metal carbamate is a possible disadvantage [ 334 ].…”

Three Unique Barium Manganese Vanadates from High-Temperature Hydrothermal Brines

“…Furthermore, the apical anion site (O5, Cl3) serves as a common cap for three square pyramids to form an unusual [Mn 3 O 12 (OH,Cl)] trimer as a discrete structural unit (Figure c). More often, the Mn 3 O 13 unit built of three [MnO 5 ] groups is merely a substructure of a larger Mn–O–Mn network. − Attempting to refine the Mn 3 -μ 3 anion site as a fully occupied oxygen atom resulted in nonpositive definite anisotropic displacement parameters (ADPs), while a fully occupied chlorine atom produced larger ADPs with a shorter than ideal bond length for Mn to Cl. Modeling the site as a substitutional disorder primarily with oxygen character (75% O5, 25% Cl3) improved the refinement statistics and results in good ADPs.…”