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A low-cost template-free solution chemical route to highly porous nanocrystalline sponges of ZnO-EuO1.5 with 0-5 mol % Eu is presented. The process uses Zn- and Eu-acetate-nitrate and triethanolamine as precursors in methanol. After evaporation of the solvent and heating at 200 °C for 3 min, crystalline ZnO:Eu sponges with minor amounts of organic residues were obtained. Heating to 400 °C replaced the organics with carbonate, which in its turn was decomposed at temperatures below 600 °C, forming ZnO:Eu sponges. Samples heated to 200-1000 °C for 3 min were studied with XRD, SEM, TEM, TG, XPS, and IR spectroscopy. The ZnO:Eu crystallite sizes could be tuned from below 10 nm for sponges prepared at 200-500 °C, to over 100 nm range at 900 °C, without sintering of the overall microstructure. XRD showed the presence of hexagonal ZnO:Eu (or at 700-1000 °C, ZnO:Eu and cubic Eu2O3) as the only phases present. The ZnO:Eu had slightly larger unit cell dimensions than the literature value of ZnO for samples obtained at 200-600 °C, while the unit cells of samples obtained at higher temperatures were quite close to the value of undoped ZnO. XPS showed that Eu was mainly in its 3+ state and well-distributed within the sponges but segregated at the ZnO sponge surface upon heating at 700-1000 °C, in accordance with XRD studies showing Eu2O3 formation.

An efficient, template-free solution-chemical route to nanostructured ZnO sponges is presented: A mixture of Zn(NO3)2·6H2O, Zn(OAc)2·2H2O, and triethanolamine in methanol was evaporated to a highly viscous liquid and rapidly heated to >200 °C for 1–3 min to achieve highly porous, nanocrystalline sponges of ZnO. The viscous precursor concentrate obtained on evaporation in air was characterized by TG, DSC, and IR spectroscopy, and the product ZnO sponges by XRD, SEM, TEM, and IR spectroscopy. The fast reaction forming ZnO started at 140 °C and finished within a few seconds. Scherrer analysis of the XRD peak broadening showed average crystallite sizes of 8 to 11 nm for ZnO prepared by annealing at 200–450 °C (3 min), while grain growth to 134 nm was observed from 500 to 900 °C (3 min). The ZnO powders obtained at 200–900 °C had cell dimensions of a = 3.25 A and b = 5.21 A, matching the ZnO literature data well. SEM and TEM analyses showed highly porous, bread-like 3D nanostructures built by ca. 30–70 nm thic...

The novel mixed-valence alkoxide [Eu3+(4)Eu2+O(OPri)12(HOPri)]HOPri (1) has been prepared and structurally and spectroscopically characterized. The three synthesis routes (i) metathesis of 4EuCl3, EuI2, and 14KOPri combined with hydrolysis with 1H2O, (ii) oxidation of 5[Eu4(OPri)10(HOPri)3]2HOPri with 1.5O2, and (iii) reduction of Eu5O(OPri)13 with 0.8[Eu4(OPri)10(HOPri)3]2HOPri all yielded pure 1, whereas (iv) reduction of Eu5O(OPri)13 with 0.36-0.5 mol of europium metal produced impure 1. The compound, having the average Eu oxidation number +2.8, is very sensitive toward further oxidation to Eu5O(OPri)13 and is part of a redox series of europium 2-propoxides with average oxidation states +2.5, +2.8, and +3. The square pyramidal molecular structure, containing an oxo-oxygen atom in the basal plane, is similar to that of the well-known Ln5O(OPri)13; the main difference is the substitution of an Eu3+(-)OPri pair for an Eu2+(-)HOPri pair in the basal plane. Fourier transform infrared (FT-IR) and UV-visible spectroscopy showed that the solid-state structure was retained on dissolution in hexane and toluene-HOPri. The compound was further characterized by differential scanning calorimetry and solubility studies.

The reaction of Eu metal with HOPr(i)/toluene solutions yielded the mixed Eu(2+)/Eu(3+) alkoxide [Eu(4)(OPr(i))(10)(HOPr(i))(3)] x 2HOPr(i) (1), in contrast to the other lanthanide metals, which exclusively yield trivalent lanthanide ions in the alkoxides formed. Metathesis between EuCl(3) and 3KOPr(i) and stoichiometric hydrolysis yielded the square-pyramidal Eu(5)O(OPr(i))(13) (2), and metathesis with EuCl(3) and 3KAl(OPr(i))(4) gave EuAl(3)(OPr(i))(12) (3). The structures of these compounds were determined by single-crystal X-ray diffraction. IR spectroscopic studies showed that the solid-state molecular structure of the three alkoxides remained close to intact in solution. Further characterizations were made with UV-vis spectroscopy, differential scanning calorimetry, and solubility studies. It was also found that 1 can be converted to 2 by oxidation with dioxygen, but 2 was not reduced by Eu metal to 1. The reactions of 2 and 1 with Al(4)(OPr(i))(12) in toluene/HOPr(i) solvent were studied by IR and UV-vis spectroscopy; 2 reacted completely to form 3 in 2 h at 75 degrees C, while 1 reacted to yield 3 and other unidentified Eu(2+) containing product(s) in the same time.

A Ni-Sb alkoxide of the formula Ni 6 Sb 4 O 4 (OEt) 16 (HOEt) 4 has been prepared by reacting anhydrous NiBr 2 with 2KOEt and Sb(OEt) 3 in a toluene/ethanol solution under a dry, oxygen-free atmosphere. Ni 6 b 4 O 4 (OEt) 16 (HOEt) 4 crystallizes with the centrosymmetric tetragonal space group symmetry P4 2 /n, with a=13.003(1) A, c=19.332(3) A, V=3269(1) A 3 , Z=2, D x =1.833(1) g/cm 3 , and M=1808.6

A new Ni-Sb alkoxide of the formula Ni 5 Sb 3 O 2 (OEt) 15 (HOEt) 4 has been prepared by reacting anhydrous NiCl 2 with NaSb(OEt) 4 and NaOEt in a toluene/ethanol solution in dry, oxygen-free atmosphere. Ni 5 Sb 3 O 2 (OEt) 15 (HOEt) 4 crystallizes in the noncentrosymmetric space group Pca2 l , with a=17.909 (2) A,b=20.608 (3) A,c=17.221 (2) A,V=6356 (1) A 3 , Z=4,D x =1.621 (4) g/cm 3 , and fw=1550.89

The hetero metallic alkoxide ErAl3(OPri)12 has been prepared and its molecular structure has been established by single-crystal X-ray diffraction technique. The Er atom is encapsulated by three Al(...