TY - JOUR A1 - Jäger, Christian A1 - Groom, N. S. A1 - Bowe, Elizabeth A. A1 - Horner, A. A1 - Davies, M. Elisabeth A1 - Murray, Rachel C. A1 - Duer, M. J. T1 - Investigation of the Nature of the Protein-Mineral Interface in Bone by Solid-State NMR JF - Chemistry of materials N2 - Hydrogen-bearing species in the bone mineral environment were investigated using solid-state NMR spectroscopy of powdered bone, deproteinated bone, and B-type carbonated apatite. Using magic-angle spinning and cross-polarization techniques three types of structurally-bound water were observed in these materials. Two of these water types occupy vacancies within the apatitic mineral crystal in synthetic carbonated apatite and deproteinated bone and serve to stabilize these defect-containing crystals. The third water was observed at the mineral surface in unmodified bone but not in deproteinated bone, suggesting a role for this water in mediating mineral-organic matrix interactions. Direct evidence of monohydrogen phosphate in a 1H NMR spectrum of unmodified bone is presented for the first time. We obtained clear evidence for the presence of hydroxide ion in deproteinated bone by 1H MAS NMR. A 1H-31P heteronuclear correlation experiment provided unambiguous evidence for hydroxide ion in unmodified bone as well. Hydroxide ion in both unmodified and deproteinated bone mineral was found to participate in hydrogen bonding with neighboring water molecules and ions. In unmodified bone mineral hydroxide ion was found, through a 1H-31P heteronuclear correlation experiment, to be confined to a small portion of the mineral crystal, probably the internal portion. KW - NMR KW - Bone KW - Protein-mineral-interface PY - 2005 DO - https://doi.org/10.1529/biophysj.105.070243 SN - 0897-4756 SN - 1520-5002 VL - 17 IS - 12 SP - 3059 EP - 3061 PB - American Chemical Society CY - Washington, DC AN - OPUS4-11010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seto, J. A1 - Ma, Y. A1 - Davis, S.A. A1 - Meldrum, F. A1 - Gourrier, A. A1 - Kim, Y.-Y. A1 - Schilde, U. A1 - Sztucki, M. A1 - Burghammer, M. A1 - Maltsev, Sergey A1 - Jäger, Christian A1 - Cölfen, H. T1 - Structure-property relationships of a biological mesocrystal in the adult sea urchin spine JF - Proceedings of the national academy of sciences of the United States of America : PNAS N2 - Structuring over many length scales is a design strategy widely used in Nature to create materials with unique functional properties. We here present a comprehensive analysis of an adult sea urchin spine, and in revealing a complex, hierarchical structure, show how Nature fabricates a material which diffracts as a single crystal of calcite and yet fractures as a glassy material. Each spine comprises a highly oriented array of Mg-calcite nanocrystals in which amorphous regions and macromolecules are embedded. It is postulated that this mesocrystalline structure forms via the crystallization of a dense array of amorphous calcium carbonate (ACC) precursor particles. A residual surface layer of ACC and/or macromolecules remains around the nanoparticle units which creates the mesocrystal structure and contributes to the conchoidal fracture behavior. Nature’s demonstration of how crystallization of an amorphous precursor phase can create a crystalline material with remarkable properties therefore provides inspiration for a novel approach to the design and synthesis of synthetic composite materials. KW - Calcium carbonate biomineralization KW - Echinoderm skeleton KW - Hierarchical structuring KW - Mesocrystal KW - Skeletal elements PY - 2012 DO - https://doi.org/10.1073/pnas.1109243109 SN - 0027-8424 SN - 1091-6490 VL - 109 IS - 10 SP - 3699 EP - 3704 PB - National Academy of Sciences CY - Washington, DC AN - OPUS4-27726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hieu, D.T. A1 - Kosslick, H. A1 - Riaz, M. A1 - Schulz, A. A1 - Springer, A. A1 - Frank, M. A1 - Jäger, Christian A1 - Minh Thu, N.T. A1 - Son, L.T. T1 - Acidity and Stability of Bronsted Acid Sites in Green Clinoptilolite Catalysts and Catalytic Performance in the Etherification of Glycerol JF - Catalysts N2 - Natural zeolite clinoptilolite CLIN with a framework ratio of Si/Al ≥ 4 containing mainly potassium and calcium ions in its internal channel system was used as a starting material. The acidic HCLIN catalysts were prepared under soft conditions avoiding the use of environmental less benign mineral acids. The starting material was ion exchanged using a 0.2 M aqueous ammonium nitrate solution at a temperature 80 ◦C for 2 h. The obtained NH4CLIN was converted into the acid HCLIN catalyst by calcination at 300–600 ◦C. The obtained samples were characterized by XRD, FTIR, SEM/TEM, AAS, and EDX element mapping. The state of aluminium and silicon was studied by 27Al- and 29SiMAS NMR spectroscopy. The textural properties of the catalysts were investigated by nitrogen adsorption and desorption measurements. The Brønsted acidity of the HCLIN catalysts was studied by temperature-programmed decomposition of the exchanged ammonium ions releasing ammonia as well as 1H MAS NMR, {1H–27Al} Trapdor, and {1H–27Al} Redor experiments. The strongly agglomerated samples were crystalline and thermally stable up to >500 ◦C. Although a part of the clinoptilolite framework is maintained up to 600 ◦C, a loss of crystallinity is already observed starting from 450 ◦C. The specific surface areas of the starting CLIN and ammonium exchanged NH4CLIN are low with ca. 26 m2/g. The pores are nearly blocked by the exchangeable cations located in the zeolite pores. The thermal decomposition of the ammonium ions by calcination at 400 ◦C causes an opening of the pore entrances and a markable increase in the specific micropore area and micropore volume to ca. 163 m2/g and 0.07 cm3/g, respectively. It decreases with further rising calcination temperature indicating some structural loss. The catalysts show a broad distribution of Brønsted acid sites (BS) ranging from weak to strong sites as indicated the thermal decomposition of exchanged ammonium ions (TPDA). The ammonium ion decomposition leaving BS, i.e., H+ located at Al–O–Si framework bridges, starts at ≥250 ◦C. A part of the Brønsted sites is lost after calcination specifically at 500 ◦C. It is related to the formation of penta-coordinated aluminium at the expense of tetrahedral framework aluminium. The Brønsted sites are partially recreated after repeated ammonium ion exchange. The catalytic performance of the acidic HCLIN catalysts was tested in the etherification of glycerol as a green renewable resource with different C1 -C4 alcohols. The catalysts are highly active in the etherification of glycerol, especially with alcohols containing the branched, tertiary alkyl groups. Highest activity is observed with the soft activated catalyst HCLIN300 (300 ◦C, temperature holding time: 1 min). A total of 78% conversion of glycerol to mono and di ether were achieved with tert-butanol at 140 ◦C after 4 h of reaction. The mono- and di-ether selectivity were 75% and 25%, respectively. The catalyst can be reused. KW - Etherification KW - Glycerol KW - Zeolite KW - Clinoptilolite KW - Bronsted acidity KW - Dehydroxylation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546982 DO - https://doi.org/10.3390/catal12030253 VL - 12 IS - 3 SP - 1 EP - 24 PB - MDPI AN - OPUS4-54698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koudelka, L. A1 - Mosner, P. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Structural study of PbO-B2O3-P2O5 glasses by NMR, Raman and infrared spectroscopy T2 - Proceedings of the XIX International Congress on Glass (Physics and chemistry of glasses 43C.2002) T2 - 19th International Congress on Glass CY - Edinburgh, Scotland, UK DA - 2001-07-01 PY - 2002 SN - 0-900682-39-6 N1 - Serientitel: Physics and chemistry of glasses – Series title: Physics and chemistry of glasses VL - 43C IS - 43C.2002 SP - 1 EP - 6 PB - Soc. of Glass Techn. CY - Sheffield AN - OPUS4-11012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeyer, M. A1 - Montagne, L. A1 - Kostoj, V. A1 - Palavit, G. A1 - Prochnow, D. A1 - Jäger, Christian T1 - 17O nuclear magnetic resonance study of Na2O-P2O5 glasses JF - Journal of non-crystalline solids N2 - The preparation and structural investigation of 17O-enriched xNa2O–(100-x)P2O5 glasses (46.5<=x<=62.8) by nuclear magnetic resonance (NMR) is described. Enriched phosphoric acid was prepared by hydrolysis of PCl5 with 17O-enriched water and neutralized with sodium carbonate. The sodium metaphosphate was then melted at 800 °C for 15 h and quenched. Polyphosphate and ultraphosphate glass compositions were prepared by remelting the metaphosphate with sodium carbonate and phosphorus pentoxide, respectively. 31P magic angle sample spinning (MAS) NMR was used to determine the Na2O/P2O5 content in the glasses. 17O NMR spectra (quadrupole echo for non-rotating samples and multiple-quantum excitation for rotating samples (MQMAS)) show two oxygen sites in the samples with large quadrupolar coupling constants (4.7 and 7.7 MHz), in accordance with the high phosphorus electronegativity. According to the correlation of 17O quadrupolar constants with bond ionicity, these two components are attributed to bridging P–O–P and non-bridging P–O...Na oxygens. The average P–O–P bond angle is estimated with the quadrupolar asymmetry derived from the fit of the static echo spectra. The MQMAS spectrum shows a distribution of non-bridging oxygen chemical shifts, attributed to a variation of bond length and angle. PY - 2002 SN - 0022-3093 VL - 311 IS - 3 SP - 223 EP - 232 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-11013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Structure and properties of mixed sodium-lead borophosphate glasses JF - Journal of non-crystalline solids N2 - Mixed sodium–lead borophosphate glasses were prepared in two compositional series xNa2O–(50 - x)PbO–10B2O3–40P2O5 and xNa2O–(50 - x)PbO–20B2O3–30P2O5 with x = 0, 10, 20, 30, 40 and 50 mol% Na2O. Their density decreases and molar volume increases slightly with increasing Na2O content. Chemical durability decreases steeply for glasses containing 40–50 mol% Na2O, whereas glass transition temperatures reveals a minimum at the glasses with 30–40 mol% Na2O. The 31P MAS NMR and Raman spectra of the first series show that with increasing Na2O content the ratio of structural units Q2/Q1 slowly increases and the Q2 phosphate units and BO4 units prevail in the structure of these glasses. In the second series of glasses Q1 diphosphate units together with BO4 and small number of BO3 units form structural network of glasses. The replacement of PbO by Na2O results in higher ionicity of bonding interactions between compensating cations and the anionic network. The lower cation field strength of Na+ ions results in the observed downfield shift of ? (31P) values in Na-rich glasses and narrower vibrational bands in their Raman spectra. PY - 2005 DO - https://doi.org/10.1016/j.jnoncrysol.2005.01.015 SN - 0022-3093 VL - 351 IS - 12-13 SP - 1039 EP - 1045 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-11016 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeyer, M. A1 - Montagne, L. A1 - Jäger, Christian T1 - Measuring oxygen-phosphorus distances and the orientation of electric field gradient tensors using 17O-{31P} REDOR in phosphate glasses JF - Solid state nuclear magnetic resonance N2 - Rotational echo double resonance (REDOR) of spin- nuclei is an extremely useful tool for the determination of distances in solids as well as of relative orientations of chemical shift and dipole tensors. We present the corresponding version for measuring the relative orientation of electric quadrupole and dipole tensors and demonstrate its applicability for non-bridging oxygens in phosphate glasses using 17O–{31P} REDOR NMR. The orientational information is found in the changes of the second-order quadrupole patterns as a function of the echo delay. Results and numeric simulations are presented for 17O–{31P} REDOR NMR of 17O-enriched sodium phosphate glasses. For non-bridging oxygens, the symmetric quadrupole tensor is found to be aligned along the phosphorus–oxygen bond. The distance between P and the non-bridging oxygen is calculated for two glasses of different compositions. KW - REDOR KW - Quadrupolar nuclei KW - O-17-{P-31} double resonance KW - Phosphate glasses PY - 2003 DO - https://doi.org/10.1016/S0926-2040(03)00012-2 SN - 0926-2040 SN - 1527-3326 VL - 23 IS - 3 SP - 136 EP - 144 PB - Academ. Press CY - Orlando, Fla. AN - OPUS4-11018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Lead borophosphate glasses doped with titanium dioxide JF - Journal of non-crystalline solids N2 - Glasses of the compositional series of 50PbO–yB2O3–(50-y)P2O5–xTiO2 (with x=0–16) have been prepared and characterized by the determination of density, molar volume, glass transition temperature, dilatation softening temperature, thermal and chemical durability. Structural changes were evaluated from the studies by 31P and 11B MAS NMR, Raman and infrared spectroscopy. Molar volume of the glasses decreases and the glass transition temperature increases with increasing additions of TiO2. 31P MAS NMR spectra revealed that titanate units enter phosphate chains decreasing the number of Q2 units and increasing the number of Q1 units. This result is confirmed by the observed changes in the Raman and infrared spectra of the TiO2-doped glasses. PY - 2003 DO - https://doi.org/10.1016/S0022-3093(03)00380-6 SN - 0022-3093 VL - 326-327 SP - 72 EP - 76 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-11020 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Petrík, J. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Study of the structure of mixed lead borophosphate glasses by NMR, RAMAN and IR Spectroscopy JF - Phosphorus research bulletin PY - 2002 SN - 0918-4783 VL - 13 SP - 165 EP - 170 CY - Tokyo AN - OPUS4-11021 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nassif, N. A1 - Pinna, N. A1 - Gehrke, N. A1 - Antonietti, M. A1 - Jäger, Christian A1 - Cölfen, H. T1 - Amorphous layer around aragonite platelets in nacre JF - Proceedings of the national academy of sciences of the United States of America KW - Nacre KW - NMR KW - Aragonite KW - Amorphous Surface KW - Protein binding PY - 2005 SN - 0027-8424 SN - 1091-6490 VL - 102 IS - 36 SP - 12653 EP - 12655 PB - National Academy of Sciences CY - Washington, DC AN - OPUS4-11009 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -