Synthesis of silicophosphates containing SiO6-octahedra under ambient conditions – reactions of anhydrous H3PO4 with alkoxysilanes

Jähnigen, Sandra; Brendler, Erica; Böhme, Uwe; Kroke, Edwin

doi:10.1039/c2cc31600e

Cited by 30 publications

(21 citation statements)

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“…The peaks at about -97 ppm and -107 ppm represent Q units of self-condensation products from TEOS [42,43] or Q groups with neighboring phosphorus. [34,43,45] Its chemical shift is in line with reported data for [SiO 6 ] units in Si(HPO 4 ) 2 [37] and corresponds also to o-SiOP. [44] The main signal at -210 ppm represents [SiO 6 ] units in silicophosphates.…”

Section: Synthesis Of Si(hpo 4 ) 2 With Silicon Nanopowdersupporting

confidence: 89%

“…[33,34] Previous investigations of the reaction of diphosphoric acid and tetraalkoxysilanes [41] suggest, that an excess of phosphate promotes the generation of [SiO 6 ] environments. [33,34] Previous investigations of the reaction of diphosphoric acid and tetraalkoxysilanes [41] suggest, that an excess of phosphate promotes the generation of [SiO 6 ] environments.…”

Section: Synthesis Of Si(hpo 4 ) 2 With Silicon Nanopowdermentioning

confidence: 99%

“…[30][31][32] Beside the Si:P ratio the formation of [SiO 6 ] moieties is controlled by temperature, precursor concentration, and pH value. In contrast to hydrolytic and non-hydrolytic sol-gel reactions we used in this and in preceding works [33][34][35] a "water-free" sol-gel route. That means no water or alcohols were used as solvents, but the starting materials could include hydroxy groups.…”

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Structural Insight into Layered Silicon Hydrogen Phosphates Containing [SiO₆] Octahedra Prepared by Different Reaction Routes

et al. 2019

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The layered silicophosphate Si(HPO 4 ) 2 was prepared via a novel synthesis approach using silicon nanopowder and ortho-phosphoric acid at 150°C providing a polycrystalline product. Silicophosphate compounds with sixfold coordinated silicon atoms obtained from pyrophosphoric acid H 4 P 2 O 7 and tetraalkoxysilanes via a sol-gel route exhibit the same shortrange order. The solid products were analyzed with XRD, ele- IntroductionSilicophosphates, i.e. in narrower sense compounds in the element system Si/P/O/(H), can show in contrast to most naturally occurring silicates and related silicon-oxygen compounds a sixfold coordination of the silicon with oxygen. [1] Typically, this phenomenon is only known from several high pressure materials and minerals, e.g. stishovite. [2] Not only in phosphorus containing glasses [3][4][5][6] but also in a number of crystalline silicophosphates, e.g. SiP 2 O 7 , [7][8][9] Si 5 P 6 O 25 , [10] and Si(HPO 4 ) 2 ·xH 2 O (x = 0,1), [11,12] the silicon is present in [SiO 6 ] units at ambient pressure. Additionally, molecular compounds with [SiO 6 ] moieties are also known in literature. [13][14][15][16] Furthermore, a tris(imidodiphosphinato) silicon complex synthesized from bis(diphenyldiphosphinyl)imine and silicon(IV) chloride, offers [SiO 6 ] structures surrounded by phosphorus atoms. [17] The role of phosphorus for building up [SiO 6 ] octahedra in silicophosphates has been discussed in several theoretical investigations. [18,19] Furthermore, the optical [20] and material properties [21] of silicophosphates, which are partly different from silicate materials due to the phosphorus content, are of basic interest relating to applications in laser technique, [22,23] implants research, [24] or [a]

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Section: Synthesis Of Si(hpo 4 ) 2 With Silicon Nanopowdersupporting

confidence: 89%

Section: Synthesis Of Si(hpo 4 ) 2 With Silicon Nanopowdermentioning

confidence: 99%

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Structural Insight into Layered Silicon Hydrogen Phosphates Containing [SiO₆] Octahedra Prepared by Different Reaction Routes

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“…The reported chemical shifts for octahedral complexes with organic ligands bearing the [SiO 6 ] skeleton cover the range of −130 to −150 ppm,9 whereas the high‐pressure modification of SiO 2 , the rutile‐type mineral stishovite, shows the 29 Si NMR signal at −191.3 ppm 21. For a recently reported organic silicophosphate, the 29 Si NMR signal is even found at approximately −212 pm 22…”

Section: Resultsmentioning

confidence: 99%

Reactions with Oleum under Harsh Conditions: Characterization of the Unique [M(S₂O₇)₃]²⁻ Ions (M=Si, Ge, Sn) in A₂[M(S₂O₇)₃] (A=NH₄, Ag)

Logemann

Gunzelmann

Klüner

et al. 2012

Chemistry A European J

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The reactions of group 14 tetrachlorides MCl(4) (M=Si, Ge, Sn) with oleum (65% SO(3)) at elevated temperatures lead to the unique complex ions [M(S(2)O(7))(3)](2-), which show the central M atoms in coordination with three chelating S(2)O(7)(2-) groups. The mean distances M-O within the anions increase from 175.6(2)-177.5(2) pm (M=Si) to 186.4(4)-187.7(4) pm (M=Ge) to 201.9(2)-203.5(2) pm (M=Sn). These distances are reproduced well by DFT calculations. The same calculations show an increasing positive charge for the central M atom in the row Si, Ge, Sn, which can be interpreted as the decreasing covalency of the M-O bonds. For the silicon compound (NH(4))(2)[Si(S(2)O(7))(3)], (29)Si solid-state NMR measurements have been performed, with the results showing a signal at -215.5 ppm for (NH(4))(2)[Si(S(2)O(7))(3)], which is in very good agreement with theoretical estimations. In addition, the vibrational modes within the [MO(6)] skeleton have been monitored by Raman spectroscopy for selected examples, and are well reproduced by theory. The charge balance for the [M(S(2)O(7))(3)](2-) ions is achieved by monovalent A(+) counter ions (A=NH(4), Ag), which are implemented in the syntheses in the form of their sulfates. The sizes of the A(+) ions, that is, their coordination requirements, cause the crystallographic differences in the crystal structures, although the complex [M(S(2)O(7))(3)](2-) ions remain essentially unaffected with the different A(+) ions. Furthermore, the nature of the A(+) ions influences the thermal behavior of the compounds, which has been monitored for selected examples by thermogravimetric differential thermal analysis (DTA/TG) and XRD measurements.

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“…Several other examples should also be mentioned in this context. Silicophosphates were prepared from anhydrous phosphoric acid and tetraalkoxysilanes by Jähningen et al [197,198] and Tokuda et al [199]. Hybrid silicophosphates with various organic groups were prepared by solventless condensations of anhydrous phosphoric acid with alkyl-and arylchlorosilanes by the Takahashi group [200][201][202][203].…”

Section: New Compositionsmentioning

confidence: 99%

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

et al. 2017

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This review is devoted to non-hydrolytic sol-gel chemistry. During the last 25 years, non-hydrolytic sol-gel (NHSG) techniques were found to be attractive and versatile methods for the preparation of oxide materials. Compared to conventional hydrolytic approaches, the NHSG route allows reaction control at the atomic scale resulting in homogeneous and well defined products. Due to these features and the ability to design specific materials, the products of NHSG reactions have been used in many fields of application. The aim of this review is to present an overview of NHSG research in recent years with an emphasis on the syntheses of mixed oxides, silicates and phosphates. The first part of the review highlights well known condensation reactions with some deeper insights into their mechanism and also presents novel condensation reactions established in NHSG chemistry in recent years. In the second section we discuss porosity control and novel compositions of selected materials. In the last part, the applications of NHSG derived materials as heterogeneous catalysts and supports, luminescent materials and electrode materials in Li-ion batteries are described.

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Synthesis of silicophosphates containing SiO6-octahedra under ambient conditions – reactions of anhydrous H3PO4 with alkoxysilanes

Cited by 30 publications

References 29 publications

Structural Insight into Layered Silicon Hydrogen Phosphates Containing [SiO₆] Octahedra Prepared by Different Reaction Routes

Structural Insight into Layered Silicon Hydrogen Phosphates Containing [SiO₆] Octahedra Prepared by Different Reaction Routes

Reactions with Oleum under Harsh Conditions: Characterization of the Unique [M(S₂O₇)₃]²⁻ Ions (M=Si, Ge, Sn) in A₂[M(S₂O₇)₃] (A=NH₄, Ag)

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

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Synthesis of silicophosphates containing SiO6-octahedra under ambient conditions – reactions of anhydrous H3PO4 with alkoxysilanes

Cited by 30 publications

References 29 publications

Structural Insight into Layered Silicon Hydrogen Phosphates Containing [SiO6] Octahedra Prepared by Different Reaction Routes

Structural Insight into Layered Silicon Hydrogen Phosphates Containing [SiO6] Octahedra Prepared by Different Reaction Routes

Reactions with Oleum under Harsh Conditions: Characterization of the Unique [M(S2O7)3]2− Ions (M=Si, Ge, Sn) in A2[M(S2O7)3] (A=NH4, Ag)

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

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Structural Insight into Layered Silicon Hydrogen Phosphates Containing [SiO₆] Octahedra Prepared by Different Reaction Routes

Structural Insight into Layered Silicon Hydrogen Phosphates Containing [SiO₆] Octahedra Prepared by Different Reaction Routes

Reactions with Oleum under Harsh Conditions: Characterization of the Unique [M(S₂O₇)₃]²⁻ Ions (M=Si, Ge, Sn) in A₂[M(S₂O₇)₃] (A=NH₄, Ag)