Solid-state Phosphorus-31 Nuclear Magnetic Resonance Research Articles

Modifying cellulose with metaphosphoric acid and its efficiency in removing brilliant green dye

In this study, cellulose was chemically modified through the addition of the phosphorylating agent, metaphosphoric acid in order to obtain a new material (MPCel) with higher adsorptive properties than the starting material. Both materials were characterized by infrared spectroscopy, X-ray diffraction, solid-state phosphorus-31 nuclear magnetic resonance spectroscopy and thermogravimetric analysis. Maximal adsorption capacity, at 45°C for pure cellulose, was 90.5mgg−1, at pH=10 and contact time of 40min, with experimental isotherms better adjusted to the Langmuir model. MPCel at the same temperature conditions showed contact time of 10min, pH=10, and maximal adsorption capacity of 150.0mgg−1, being better adjusted to the Temkin model. The kinetic study of both materials followed the pseudo-second-order model. Modification successfully occurred and both adsorbents were shown able to be capable of removing the brilliant green dye, but MPCel was more efficient for purpose, when compared to the pure cellulose.

Structure–property relationship of new polyimide–organically modified silicate–phosphotungstic acid hybrid material system

A new hybrid material system was successfully developed from the combination of polyimide (PI), organically modified silicate (ORMOSIL), and phosphotungstic acid (HPW) from polycondensation reactions and sol–gel process. The materials were obtained in the form of flexible and free-standing films, with the formation of PI and ORMOSIL network confirmed by Fourier transform infrared. Solid-state phosphorus-31 nuclear magnetic resonance evaluated the HPW structure and confirmed its presence and also structural integrity in the materials after synthesis procedure. Thermogravimetric analysis revealed that the materials were thermally stable up to 773 K, and scanning electron microscopy images and X-ray micro-fluorescence mapping showed very good compatibility between the organic and inorganic phases with ORMOSIL improving the HPW dispersion. Furthermore, both ORMOSIL and HPW enhanced the permittivity of the materials from 2.5 to 4.3, compared to the neat PI, appointing them as potential candidates for electric and electronic applications.

Quantitative Evaluation of MDP-Ca Salt and DCPD after Application of an MDP-based One-step Self-etching Adhesive on Enamel and Dentin.

To investigate the effects of an experimental 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-based one-step self-etching adhesive (EX adhesive) applied to enamel and dentin on the production of calcium salt of MDP (MDP-Ca salt) and dicalcium phosphate dehydrate (DCPD) at various periods. The EX adhesive was prepared. Bovine enamel and dentin reactants were prepared by varying the application period of the EX adhesive: 0.5, 1, 5, 30, 60 and 1440 min. Enamel and dentin reactants were analyzed using x-ray diffraction and solid-state phosphorus-31 nuclear magnetic resonance (31P NMR). Curvefitting analyses of corresponding 31P NMR spectra were performed. Enamel and dentin developed several types of MDP-Ca salts and DCPDs with amorphous and crystalline phases throughout the application period. The predominant molecular species of MDP-Ca salt was determined as the monocalcium salt of the MDP monomer. Dentin showed a faster production rate and greater produced amounts of MDP-Ca salt than did enamel, since enamel showed a knee-point in the production rate of the MDP-Ca salt at the application period of 5 min. In contrast, enamel developed greater amounts of DCPD than did dentin and two types of DCPDs with different crystalline phases at application periods > 30 min. The amounts of MDP-Ca salt developed during the 30-s application of the EX adhesive on enamel and dentin were 7.3 times and 21.2 times greater than DCPD, respectively. The MDP-based one-step adhesive yielded several types of MDP-Ca salts and DCPD with an amorphous phase during the 30-s application period on enamel and dentin.

Quantitative solid-state NMR imaging of synthetic calcium phosphate implants.

It is shown that solid-state phosphorus-31 nuclear magnetic resonance imaging can be used to measure quantitatively the mass of hydroxyapatite (HA), a synthetic calcium phosphate used as an orthopedic implant material, in the presence of bone. A three-dimensional projection reconstruction technique was used to produce solid-state images from 998 free induction decays sampled in the presence of a fixed amplitude field gradient whose direction was varied uniformly over the unit sphere. Chemical selection is achieved using T1 contrast, as the synthetic calcium phosphate has a shorter T1 (1.8 sec at 4.7 T) compared with the bone (approximately 15 sec at 4.7 T in vivo, 42 sec ex vivo). Experimental results demonstrating the linear relationship between image intensity and HA density in phantoms containing HA and silicon (IV) oxide, and HA and bone are shown. Chemically pure images of bone mineral and synthetic HA have been computed from images of New Zealand White rabbits acquired in vivo at two different recycle times. The technique can be used to follow noninvasively the resorption and remodeling of calcium phosphate implants in vivo.

Proton induced vesicle fusion and the isothermal L α→H II phase transition of lipid bilayers: a 31P-NMR and titration calorimetry study

The proton-induced isothermal fusion of unilamellar lipid vesicles (Duzgunes et al., Biochemistry 24 (1985) 3091–3098) is compared with the lamellar (L α)→hexagonal (H II) phase transition of multilamellar lipid dispersions. Both lipid systems are composed of 1-palmitoyl-2-oleoyl- sn-glycero-3-phosphoethanolamine (POPE) and oleic acid (OA) at a 7:3 molar ratio. Using solid-state phosphorus-31 nuclear magnetic resonance ( 31P-NMR) it is demonstrated that the multilamellar lipid dispersions are in the bilayer state at physiological pH and undergo a L α→H II phase transition between pH 6.3 and 5.7. This phase transition can also be induced at constant pH by increasing the temperature. The midpoint of the temperature-induced L α→H II transition is T h=56°C (at pH 7.4) and the corresponding transition enthalpy is Δ H=0.7±0.1 kcal/mol as determined with differential scanning calorimetry. Both the proton-induced and the temperature-induced phase transition can be completely inhibited by addition of 30 mol% of 1-palmitoyl-2-hydroxy- sn-glycero-3-phosphocholine (LPC). In a second set of experiments unilamellar vesicles are prepared either by sonication or by extrusion through polycarbonate filters at pH 7.4 and are titrated into buffer at pH 5.7. The proton-induced fusion of the lipid vesicles is monitored with isothermal titration calorimetry, light scattering and fluorescence spectroscopy. The fusion reaction is characterized by an endothermic enthalpy of Δ H=0.5±0.2 kcal/mol (at 28°C). The fusion enthalpy is independent of the vesicle diameter and is only slightly reduced by an increase in temperature to 50°C. Vesicle fusion is accompanied by an increase in light scattering, indicating the formation of larger lipid structures. The transition from unilamellar vesicles to fused lipid structures occurs in the same narrow pH range of 6.3–5.7 as observed for the L α→H II transition of multilamellar dispersions. Vesicle fusion can be inhibited with 30% LPC. The virtually identical set of parameters found for the L α→H II phase transition and the vesicle fusion reaction suggests that vesicle fusion also entails a L α→H II phase transition.

Characterization of Phosphate Sites in Native Ovine, Caprine, and Bovine Casein Micelles and Their Caseinomacropeptides: A Solid-State Phosphorus-31 Nuclear Magnetic Resonance and Sequence and Mass Spectrometric Study

The phosphate sites in native ovine, caprine, and bovine casein micelles have been analyzed using sequence analysis, mass spectrometric analysis, and solid-state 31P nuclear magnetic resonance spectroscopy. Using a combination of S-ethylcysteine derivatization, sequence analysis, and mass spectrometric analysis, the phosphorylation sites of ovine (SerP151 and SerP168) caprine (SerP151 and SerP168), and bovine (SerP149) caseinomacropeptides have been localized. Various solid-state 31P methods using magic angle spinning have been applied to ascertain the local structure and dynamics of the phosphorylated serine residues and the inorganic calcium phosphates within the micelles. Contributions from the phosphorylated serine residues of κ-CN, located in the C-terminal portion of the molecule, to the mobile constituents of the micelles were assigned by comparison with 31P nuclear magnetic resonance spectra of purified caseinomacropeptides from the various species in the dissolved state. Comparison of the 31P magic angle spinning nuclear magnetic resonance spectra of ovine, caprine, and bovine casein micelles indicates that the micelles from these species are very similar but not identical.

Vibrational and solid-state phosphorus-31 nuclear magnetic resonance spectroscopic studies of 1 : 1 complexes of PPh3 with gold(I) halides; crystal structure of [AuBr(PMe3)

The crystal structure of [AuBr(PMe3)], like that of the corresponding chloride, was found to consist of three crystallographically independent molecules linked through weak Au ⋯ Au contacts to form helical chains. The Au ⋯ Au distances [3.648(1), 3.980(2), 3.548(2)Å] are, however, significantly longer than in the chloro- and iodo-complexes, implying that the Au ⋯ Au interaction is weakest in the bromide. The far-IR and Raman spectra of [AuX(PMe3)](X = Cl, Br or I) have been measured, and assignments made for the bands observed. The spectra were analysed to see whether they show any effects of the weak Au ⋯ Au bonding evident in the crystal structures. In particular, the low-wavenumber limit of previously reported Raman spectra for these species has been extended in order to search for ν(Au2) bands. The X = Cl or I compounds show a strong Raman band which can be assigned to the δ(PAuX) deformation, but no ν(Au2) bands were found in the region predicted on the basis of recent assignments for such modes in other complexes which display Au ⋯ Au contacts of similar length. Possible reasons, including an interaction between ν(Au2) and δ(PAuX) modes, are discussed. The solid-state cross polarization magic angle spinning 31P NMR spectra of the chloride and iodide complexes consist of doublets due to the presence of 1J(197Au–31P) coupling. This is a rare observation of spin–spin coupling between the spin I=½31P nucleus and the strongly quadrupole coupled 197Au nucleus, and permits estimation of the 1J(197Au–31P) coupling constants for these complexes.

Solid-State Phosphorus-31 Nuclear Magnetic Resonance Differentiation of Bone Mineral and Synthetic Apatite Used to Fill Bone Defects

Bioabsorption of synthetic apatite compounds used to promote bone healing and remodeling has been difficult to evaluate. In this study, solid-state phosphorus-31 nuclear magnetic resonance (NMR) has been used to characterize and quantitate bone mineral and a synthetic apatite in order to establish a model for bioabsorption studies. Pulverized solid samples of cortical rabbit bone and a synthetic fluoridated apatite were examined in vitro at variable degrees of hydration. A 9.4 T superconducting spectrometer was used to obtain 31P magic angle spinning NMR spectra and T1 relaxation times. Quantitation was attempted in mixed samples using T1 recovery data. Bone mineral and synthetic apatite could be distinguished by chemical shift and T1 relaxation time in variable hydration states, and were readily differentiated in mixtures by their T1 relaxation time. NMR estimates of relative proportions of components in mixed samples were accurate within 2% of evaluations based on weight. Solid-state 31P NMR therefore provides a suitable method for monitoring the bioabsorption of synthetic apatites.

ChemInform Abstract: LEWIS BASE ADDUCTS OF GROUP IB METAL COMPOUNDS. 8. HIGH‐RESOLUTION SOLID‐STATE PHOSPHORUS‐31 NUCLEAR MAGNETIC RESONANCE SPECTRA OF TETRAMERIC ((TRIPHENYLPHOSPHINE)COPPER(I) HALIDE) COMPLEXES AND CRYSTAL STRUCTURE DETERMINATION OF “CUBANE” (PPH3CUBR)4

Chemischer InformationsdienstVolume 16, Issue 9 Physical Organic Chemistry ChemInform Abstract: LEWIS BASE ADDUCTS OF GROUP IB METAL COMPOUNDS. 8. HIGH-RESOLUTION SOLID-STATE PHOSPHORUS-31 NUCLEAR MAGNETIC RESONANCE SPECTRA OF TETRAMERIC ((TRIPHENYLPHOSPHINE)COPPER(I) HALIDE) COMPLEXES AND CRYSTAL STRUCTURE DETERMINATION OF “CUBANE” (PPH3CUBR)4 P. F. BARRON, P. F. BARRONSearch for more papers by this authorJ. C. DYASON, J. C. DYASONSearch for more papers by this authorL. M. ENGELHARDT, L. M. ENGELHARDTSearch for more papers by this authorP. C. HEALY, P. C. HEALYSearch for more papers by this authorA. H. WHITE, A. H. WHITESearch for more papers by this author P. F. BARRON, P. F. BARRONSearch for more papers by this authorJ. C. DYASON, J. C. DYASONSearch for more papers by this authorL. M. ENGELHARDT, L. M. ENGELHARDTSearch for more papers by this authorP. C. HEALY, P. C. HEALYSearch for more papers by this authorA. H. WHITE, A. H. WHITESearch for more papers by this author First published: March 5, 1985 https://doi.org/10.1002/chin.198509059AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume16, Issue9March 5, 1985 RelatedInformation

Lewis-base adducts of Group 1B metal(I) compounds. Part 16. Synthesis, structure, and solid-state phosphorus-31 nuclear magnetic resonance spectra of some novel [Cu4X4L4](X = halogen, L = N, P base)‘cubane’ clusters

Recrystallization of [Cu4l4(PPh3)4] from toluene has yielded a new polymorph of that compound, (1), which has been shown by single-crystal X-ray diffraction analysis to have a tetrametallic ‘cubane’ structure rather than the expected ‘step’ structure. Crystals are monoclinic, space group P21/n, with a= 19.47(1), b= 26.94(1), c= 13.528(5)A, β= 98.98(4)°, Z= 4 tetramers; R was 0.06 for No= 3 681. Cu–I distances range from 2.653(3) to 2.732(3)A, with Cu ⋯ Cu 2.874(5)–3.164(4) and I ⋯ I 4.234(2)–4.496(3)A. All adducts of stoicheiometry [M4X4(PPh3)4](M = Cu or Ag; X = Cl, Br, or I) have now been synthesized and structurally characterized in a cubane configuration. Recrystallization of copper(I) chloride and bromide from triethylamine also yields tetrameric cubane 1 : 1 adducts [X = Cl (2) or Br (3)], as does the reaction of copper(I) chloride with the very bulky ligand 2-[bis(trimethylsilyl)methyl]pyridine, to give [Cu4Cl4(tmspy)4](4). These three complexes have also been crystallographically characterized, (2) and (4) being the first reported cubane type tetramers for the copper(I) chloride–nitrogen base system. Complexes (2) and (3) are isostructural with their triethylarsine and -phosphine counterparts, being cubic, space group I3m, with a= 12.162(5)A in (2) and 12.368(3)A in (3); Z= 2 tetramers. Cu–Cl,Br distances are 2.441(4) and 2.537(3)A respectively. For (4), the crystals are tetragonal, space group I41/a, with a= 18.620(4), c= 20.079(5)A, Z= 4 tetramers. Although the Cu4Cl4 cubane core of the molecule has crystallographically imposed symmetry, the geometry is very unsymmetrical as a consequence of the ligand bulk, with Cu–Cl 2.225(2)–2.636(2), Cu ⋯ Cu 2.960(2)–3.194(2), and Cl ⋯ Cl 3.838(3)–3.866(3)A. Residuals R for (2), (3), (4) were 0.040, 0.038, and 0.040 respectively for No= 136, 136, and 1 008 ‘observed’ reflections. The solid-state 31P n.m.r. spectra of the triphenylphosphine cubane clusters show significant differences to those with a ‘step’ geometry; these differences are related to the crystallographic environment of the phosphorus nuclei.

Solid-state phosphorus-31 nuclear magnetic resonance studies of synthetic solid phases of calcium phosphate: potential models of bone mineral.

Phosphorus-31 NMR spectra have been obtained from a variety of synthetic, solid calcium phosphate mineral phases by magic angle sample spinning. The samples include crystalline hydroxyapatite, two type B carbonatoapatites containing 3.2 and 14.5% CO3(2-), respectively, a hydroxyapatite in which approximately 12% of the phosphate groups are present as HPO4(2-), an amorphous calcium phosphate, monetite, brushite, and octacalcium phosphate. Spectra were observed by the standard Bloch decay and cross-polarization techniques, as well as by a dipolar suppression sequence, in order to distinguish between protonated and unprotonated phosphate moieties. The spectra of the synthetic calcium phosphates provide basic information that is essential for interpreting similar spectra obtained from bone and other calcified tissues.

Lewis base adducts of Group IB metal compounds. 8. High-resolution solid-state phosphorus-31 nuclear magnetic resonance spectra of tetrameric ((triphenylphosphine)copper(I) halide) complexes and crystal structure determination of "cubane" [PPh3CuBr

Crystal structure analysis of the tetrameric 1:l adduct of PPh3 with CuBr, [CuBrPPhpl4, recrystallized from refluxing toluene, shows that it has crystallized in a 'cubane rather than the previously recorded step form. A residual of 0.044 was obtained for 3708 independent observed diffractometer reflections recorded at 295 K after full-matrix least-squares refinement; crystals are isomorphous with the chloride, with an orthorhombic Pbcn cell, a = 17.662 ( 5 ) A, b = 20.748 (7) A, c = 18.351 (6) A, and Z(tetramer) = 4. The existence of the cubane form of the bromide was discovered during high-resolution solid-state 31P NMR spectral studies on a series of cuprous halide-triphenylphosphine complexes.

ChemInform Abstract: HIGH‐RESOLUTION SOLID‐STATE PHOSPHORUS‐31 NUCLEAR MAGNETIC RESONANCE OF SOME TRIPHENYLPHOSPHINE TRANSITION‐METAL COMPLEXES

Chemischer InformationsdienstVolume 12, Issue 13 Physical Organic Chemistry ChemInform Abstract: HIGH-RESOLUTION SOLID-STATE PHOSPHORUS-31 NUCLEAR MAGNETIC RESONANCE OF SOME TRIPHENYLPHOSPHINE TRANSITION-METAL COMPLEXES J. W. DIESVELD, J. W. DIESVELDSearch for more papers by this authorE. M. MENGER, E. M. MENGERSearch for more papers by this authorH. T. EDZES, H. T. EDZESSearch for more papers by this authorW. S. VEEMAN, W. S. VEEMANSearch for more papers by this author J. W. DIESVELD, J. W. DIESVELDSearch for more papers by this authorE. M. MENGER, E. M. MENGERSearch for more papers by this authorH. T. EDZES, H. T. EDZESSearch for more papers by this authorW. S. VEEMAN, W. S. VEEMANSearch for more papers by this author First published: March 31, 1981 https://doi.org/10.1002/chin.198113052AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume12, Issue13March 31, 1981 RelatedInformation

High-resolution solid-state phosphorus-31 nuclear magnetic resonance of some triphenylphosphine transition-metal complexes

High resoln. solid state 31P NMR spectra are reported of 4 representative examples of metal phosphine complexes. The spectra from a Rh complex (Wilkinson's catalyst) and Cu complexes show splittings due to 31P-metal coupling. In spite of the Cu quadrupole interaction, the 31P NMR lines of the Cu complexes are narrow (.apprx.2 ppm). For 1 Cu complex the splittings between the lines of the 31P quartet are unequal. Also the spectrum of a Au cluster is reported.

Solid-state phosphorus-31 nuclear magnetic resonance and chlorine-35 nuclear quadrupole resonance studies of some alkyl- and aryl-chlorophosphoranes and their addition compounds with Lewis acids

The 31P n.m.r. and 35Cl n.q.r. spectra (where observable) of a number of solid methyl-, ethyl- and phenyl-chloro-phosphoranes and of their ionic 1 : 1 adducts with Lewis acids X, such as PCl5, SbCl5, BCl3, AlCl3, or ICl, have been recorded. The results show that the compounds PMenCl5–n, (1 ⩽n⩽3), PEt2Cl3, PEt3Cl2, and PPh3Cl2 have ionic structures of the type [PRnCl4–n]Cl in the solid state, whereas PPh2Cl3 and PPhCl4 are molecular. The adducts all have structures of the type [PRnCl4–n][XCl]. The symmetries of the species present are discussed.