Tin Nanoparticles in Carbon/Silica Hybrid Materials by the Use of Twin Polymerization

Spirocyclic tin salicyl alcoholates - a combined experimental and theoretical study on their structures, 119Sn NMR chemical shifts and reactivity in thermally induced twin polymerization

The spirocyclic tin salicyl alcoholate, 4H,4'H-2,2'-spirobi[benzo[d][1,3,2]dioxastannine] (1), and its 6,6'-dimethoxy (2) and 8,8'-di-tert-butyl-6,6'-dimethyl derivative (3) were synthesized and thermally induced twin polymerization of precursor 2 was performed to give a SnO2-containing hybrid material. Studies on the molecular structures of 1-3 were carried out using 119Sn{1H} CP MAS NMR spectroscopy and DFT calculations. Crystallization of compound 3 from dimethyl sulfoxide solution provided the Lewis acid-base adduct 3(dmso)2 exhibiting a hexacoordinated tin atom in the solid state, in agreement with the results of the spectroscopic and DFT calculation data. 119Sn NMR spectroscopy of the compounds 1-3 and 3(dmso)2 revealed equilibria among the diverse oligomers in solution phase pointing at hexacoordinated tin atoms.

Chiral molecular fluoridosilicates and their twin polymerization for the preparation of fluorine-doped mesoporous silica and microporous carbon

The synthesis of organic–inorganic hybrid materials, microporous carbon and fluorine-doped mesoporous silica by the twin polymerization of pentacoordinated fluoridosilicates is reported.

From molecular germanates to microporous Ge@C via twin polymerization

Four molecular germanates based on salicyl alcoholates, bis(dimethylammonium) tris[2-(oxidomethyl)phenolate(2-)]germanate (1), bis(dimethylammonium) tris[4-methyl-2-(oxidomethyl)phenolate(2-)]germanate (2), bis(dimethylammonium) tris[4-bromo-2-(oxidomethyl)phenolate(2-)]germanate (3) and dimethylammonium bis[2-tert-butyl-4-methyl-6-(oxidomethyl)phenolate(2-)][2-tert-butyl-4-methyl-6-(hydroxymethyl)phenolate(1-)]germanate (4), were synthesized and characterized including single crystal X-ray diffraction analysis. In the solid state, compounds 1 and 2 exhibit one-dimensional hydrogen bonded networks, whereas compound 4 forms separate ion pairs, which are connected by hydrogen bonds between the dimethylammonium and the germanate moieties. The potential of these compounds for thermally induced twin polymerization (TP) was studied. Germanate 1 was converted by TP to give a hybrid material (HM-1) composed of phenolic resin and germanium dioxide. Subsequent reduction with hydrogen provided a microporous composite containing crystalline germanium and carbon (Ge@C -C-1, germanium content ∼20%). Studies on C-1 as an anode material for Li-ion batteries revealed reversible capacities of ∼370 mA h gGe@C(-1) at a current density up to 1384 mA g(-1) without apparent fading for 500 cycles.

Mesoporous SnO2–SiO2 and Sn–silica–carbon nanocomposites by novel non-hydrolytic templated sol–gel synthesis

A novel non-hydrolytic sol–gel (NHSG) synthesis of mesoporous tin silicate xerogels is presented.

Nanocomposites by the use of simultaneous twin polymerization: tin alloys in a carbon/silica matrix

Twin polymerization is used as a novel nonaqueous route to synthesize composites composed of nanoparticular tin alloys in a porous carbon/silica matrix.

Twin Polymerization--a New Principle for Hybrid Material Synthesis

Twin polymerization is a novel modular approach for the synthesis of hybrid materials. Using this strategy two distinct polymers of either inorganic or organic nature are produced from a single source monomer in a mechanistically coupled process. Twin polymerization is an elegant way for producing nanostructured organic-inorganic hybrid materials of composition and morphology on demand. The main objective of this Review is the explanation of the principle of various twin polymerization processes and their appropriate terminologies. Different types of twin polymerization are classified with respect to the underlying processes as described in individual examples, demonstrating its potential in material synthesis. Prospects of the synthetic methodology of twin polymerization are demonstrated for different molecular structures of twin monomers and the resulting hybrid materials. A comparison with other scenarios for the synthesis of two different polymers within one procedure is included.

Zirconium and Hafnium Twin Monomers for Mixed Oxides

The synthesis of Zr and Hf twin monomers of type [M(2-OCH₂ ^c C₄ H₃ O)₄ (x HOCH₂ ^c C₄ H₃ O)] (3, M=Zr, x=0; 4, M=Hf, x=1) and M[(2-OCH₂ -C₆ H₄ O)₂ (2-HOCH₂ -C₆ H₄ OH)] (5, M=Zr; 6, M=Hf) by reacting M(OR)₄ (M=Zr, R=ⁿ C₃ H₇ , 1; M=Hf, R=ⁿ C₄ H₉ , 2) with 2-furylmethanol or 2-hydroxybenzyl alcohol is discussed. Complexes 3-6 were homopolymerized under acidic conditions. Additionally, 5 and 6 were copolymerized with 2,2'-spirobi[4 H-1,3,2-benzodioxasiline] (SBS). Under acidic conditions SBS forms a phenolic resin/SiO₂ nanostructured material. The resulting hybrid materials from the homopolymerization of 3-6 and the copolymerized materials from 5 and 6 were characterized by standard solid-state analytics. The inorganic lattice of the MO₂ materials from the homopolymerized complexes 3-6 and SiO₂ /MO₂ from the copolymerization of 5 and 6 with SBS was obtained by air oxidation. The oxide materials were characterized by X-ray powder diffraction (XRPD) and energy-dispersive X-ray analysis, which proved their identity. The inner surface area was determined by N₂ adsorption/desorption studies, which revealed surface areas of 100 m²  g^-1 for MO₂ . The mixed oxides SiO₂ /MO₂ were additionally investigated by differential scanning calorimetry and variable-temperature XRPD to study the thermal behavior. It was found that crystallization of tetragonal MO₂ nanoparticles is characteristic within the SiO₂ matrix, but higher sintering temperatures caused crystallization of the SiO₂ lattice.