Nanostructured Bimetallic Oxide Ion-Conducting Ceramics from Single-Source Molecular Precursors

Abstract

A new approach for the formation of bimetallic coordination complexes of bismuth containing a 1:1 ratio of the two metal species has been developed. The strategy exploits the Lewis acidic nature of bismuth and has been used to synthesize the new complexes BiV(O)(Hsal)(sal)(salen*)‚CH 2 Cl 2 (1), BiCu(Hsal) 3 (salen) (2), and BiNi(Hsal) 3 (salen)‚CH 2 -Cl 2 (3) (salen ) ethylenebis(salicylimine), salen* ) ethylenebis(3-methoxysalicylimine), salThe compounds have been characterized spectroscopically and, in the case of 2 and 3, by single-crystal X-ray diffraction. The decomposition of the bimetallic complexes by both thermal and hydrolytic routes has been investigated. The ability of the compounds to act as single-source precursors for the formation of bimetallic oxides has been explored. Oxide ion-conducting phases have been produced by direct pyrolysis of 1, which results in the formation of monoclinic BiVO 4 , and by pyrolysis of mixtures of 1 and 2 or 3, which results in isolation of the γ′-related Bi 2 V x M 1-x O 5.5-δ (M ) Cu, Ni). Thermal decomposition of the molecular compounds results in the formation of spherical oxide nanoparticles with diameters ranging from approximately 110 nm to 1 µm. Hydrolytic decomposition of the complexes results in the formation of nanoparticles with an average diameter of 40 nm. The materials produced in this manner have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and powder X-ray diffraction. Conservation of metal stoichiometry in converting the molecular precursor to the corresponding oxide has been confirmed by analysis of the materials by energydispersive X-ray spectroscopy.

The First Metal‐Oxo Cluster Containing Lithium and Bismuth

“…Mixed-metal carboxylates/ alkoxides are also known for some transition metals. [18] [a] Universität Dortmund, Anorganische Chemie II, 4 ], respectively, whereas no reaction was observed with LiOtBu. [12] This prompted us to look at the reaction of [Bi(OtBu …”

Molecular Encoding at the Nanoscale: From Complex Cubes to Bimetallic Oxides

“…[4,9] Some examples for such single-source precursors exist already. [10][11][12][13][14][15][16] In most cases these heterometallic precursors are alkoxides and are thus very moisture sensitive. [17][18][19] Our goal is to identify a new precursor system that enables access to a large variety of nanoscaled bimetallic oxides, and at the same time is readily available and stable.…”

Heterobimetallic Main‐Group–Transition‐Metal Paddle‐Wheel Carboxylates

“…[1] Bismuthcontaining oxide materials cover a broad range of hightechnology applications, including high T c superconductivity, [2] oxide-ion conductivity, [3] nonlinear optics, [4] catalysis, [5] and ferroelectrics. [6] Of all heavy metals, bismuth has the greatest potential for applications within the context of green chemistry.…”

“…Recently we described a rational synthesis of the first bismuth(ii) carboxylate, [Bi 2 (O 2 CCF 3 ) 4 ], which forms a dimeric tetrabridged structure (Figure 1 a). [10] Owing to the high reactivity of this unusual complex and its potential Lewis base character, we decided to study its reactions with Lewis acidic transition-metal carboxylates to obtain mixed-metal complexes of the general formula [BiM(O 2 CR) 4 ].…”

“…, orthorhombic, space group Pbca, a = 9.7378(4), b = 16.8545 (8), c = 20.9850 (10) , V = 3444.2(3) 3 , Z = 8, T = 173(2) K, 1 calcd = 2.947 g cm À3 , 2q max = 56.628. (5) 3 , Z = 8, T = 173(2) K, 1 calcd = 2.461 g cm À3 , 2q max = 56.568.…”