Unusual Reactivity of Silicon Grease Towards Metal Alkoxides: Serendipity for Structural Chemistry

Controlled synthesis of moisture sensitive metal alkoxides demands the use of silicon grease for the inert synthetic manipulation of starting materials using glass apparatus to avoid adventitious hydrolysis. Spontaneous reaction of the siloxane units (-OSi(Me-3)(2))(n)) with the synthesized alkoxides often leads to molecular metal alkoxides based siloxane frameworks. These spontaneous incorporation of siloxane units into homo- and heterometallic alkoxide building blocks lead to the new multinuclear homo- and heterometallic alkoxide-siloxide compounds [Ce-2(OtBu)(4){Me2Si(OtBu)O}(2)(NO3)(2)] (1), [Zr{(OiPr)(2){Me2SiO2}Sr{Zr-2(OiPr)(8)}}(2)] (2) and [Sn2In2O2{Me2Si(OiPr)O}(OiPr)(5)](2) (3). Multifunctional coordination properties of these siloxane units enable the molecular approach to synthetically demanding polymetallic complexes for potential MOx-SiOx nanocomposites fabrication

Unusual Reactivity of Silicon Grease Towards Metal Alkoxides: Serendipity for Structural Chemistry

Controlled synthesis of moisture sensitive metal alkoxides demands the use of silicon grease for the inert synthetic manipulation of starting materials using glass apparatus to avoid adventitious hydrolysis. Spontaneous reaction of the siloxane units (-OSi(Me-3)(2))(n)) with the synthesized alkoxides often leads to molecular metal alkoxides based siloxane frameworks. These spontaneous incorporation of siloxane units into homo- and heterometallic alkoxide building blocks lead to the new multinuclear homo- and heterometallic alkoxide-siloxide compounds [Ce-2(OtBu)(4){Me2Si(OtBu)O}(2)(NO3)(2)] (1), [Zr{(OiPr)(2){Me2SiO2}Sr{Zr-2(OiPr)(8)}}(2)] (2) and [Sn2In2O2{Me2Si(OiPr)O}(OiPr)(5)](2) (3). Multifunctional coordination properties of these siloxane units enable the molecular approach to synthetically demanding polymetallic complexes for potential MOx-SiOx nanocomposites fabrication

Molecular level synthesis of InFeO3 and InFeO3 Fe2O3 nanocomposites

New heterometallic In–Fe alkoxides [InFe(OtBu)4(PyTFP)2] (1), [InFe2(OneoPen)9(Py)] (2), and [InFe3(OneoPen)12] (3) were synthesized and structurally characterized. The arrangement of metal centers in mixed-metal framework was governed by the In:Fe ratio and the coordination preferences of Fe(III) and In(III) centers to be in tetrahedral and octahedral environments, respectively. 3 displayed a star-shaped so-called “Mitsubishi” motif with the central In atom coordinated with three tetrahedral {Fe(OneoPen)4}− anionic units. The deterministic structural influence of the larger In atom was evident in 1 and 2 which displayed the coordination of neutral coligands to achieve the desired coordination number. Thermal decomposition studies of compounds 1–3 under inert conditions with subsequent powder diffraction studies revealed the formation of Fe2O3 and In2O3 in the case of 3 and 2, whereas 1 intriguingly produced elemental In and Fe. In contrary, the thermal decomposition of 1–3 under ambient conditions produced a ternary oxide, InFeO3, with additional Fe2O3 present as a secondary phase in a different stoichiometric ratio predetermined through the In:Fe ratio in 2 and 3. The intimate mixing of different phases in InFeO3/Fe2O3 nanocomposites was confirmed by transmission electron microscopy of solid residues obtained after the decomposition of 1 and 2. The pure InFeO3 particles demonstrated ferromagnetic anomalies around 170 K as determined by temperature-dependent field-cooled and zero-field-cooled magnetization experiments. A first-order magnetic transition with an increase in the ZFC measurements was explained by temperature-induced reduction of the Fe–Fe distance and the corresponding increase in superexchange

Piezo-enhanced activation of dinitrogen for room temperature production of ammonia

The catalytic conversion of nitrogen to ammonia remains an energy-intensive process, demanding advanced concepts for nitrogen fixation. The major obstacle of nitrogen fixation lies in the intrinsically high bond energy (941 kJ mol(-1)) of the N equivalent to N molecule and the absence of a permanent dipole in N-2. This kinetic barrier is addressed in this study by an efficient piezo-enhanced gold catalysis as demonstrated by the room temperature reduction of dinitrogen into ammonia. Au nanostructures were immobilized on thin film piezoelectric support of potassium sodium niobate (K0.5Na0.5NbO3, KNN) by chemical vapor deposition of a new Au(III) precursor [Me2Au(PyTFP)(H2O)] 1 (PyTFP = (Z)-3,3,3-trifluoro-1-(pyridin-2-yl)-prop-1-en-2-olate) that exhibited high volatility (60 degrees C, 10(-3) mbar) and clean decomposition mechanism to produce well adherent elemental gold films on KNN and Ti substrates. The gold-functionalized KNN films served as an efficient catalytic system for ammonia production with a Faradaic efficiency of 18.9% achieved upon ultrasonic actuation. Our results show that the spontaneous polarization of piezoelectric materials under external electrical fields augments the sluggish electron transfer kinetics by creating instant dipoles in adsorbed N-2 molecules to deliver a piezo-enhanced catalytic system promising for sustained activation of dinitrogen molecules