187Os subspectra in 1H and 31P{1H} spectra of triosmium carbonyl clusters

A survey of the use of ¹⁸⁷Os satellite subspectra in ¹H and ³¹P{¹H} spectra of triosmium carbonyl clusters is reported. By varying evolution delays in HMQC spectra of [Os₃(µ‐H)₂(CO)₁₀] we have selectively extracted the values for ¹J(Os,H) and ²J(Os,H), respectively. An analysis of the principal modes of phosphine coordination in triosmium clusters demonstrates that ³¹P{¹H}¹⁸⁷Os satellite subspectra are diagnostic for equatorial coordination [¹J(Os,P) = 211–223 Hz] or for axial coordination (perpendicular to the plane of the cluster) [¹J(Os,P) ≈ 147 Hz]. Chelating and bridging diphosphines yield ¹⁸⁷Os satellite subspectra which are the sum of A₂X and AA′X spin systems. If significant P–P coupling is present, the AA′X component requires simulation. All observed ²J(Os,P) trans‐equatorial couplings fall in the range 38–65 Hz. Copyright © 2001 John Wiley & Sons, Ltd.     

磷酸三甲(丁)酯质子化的^3^1P和1HNMR研究

测量了与水无限混溶的磷酸三甲酯(TMP)质子化过程的^3^1P化学位移的变化,解析后得到H2O.TMP(H.M)和H2O.2TMP(H.2M)两配合物的平衡常数,用^1H NMR研究混合物中水的化学位移,找出了自由水^1H化学位移值与浓度的关系,并在TBP体系中进行验证.     

Dependence of geminal1H−1H and31P−1H spin-spin coupling constants on the specific intramolecular C−H...X interaction

Participation of the proton in a specific intramolecular C−H...X (X=N, 0) interaction leads to an increase in its geminal¹H−¹H and¹H−³¹P spin-spin coupling constants (SSCC). According toab initio calculations carried out in the 6–31G^** basis set, the observed effect is mainly due to the change in the diamagnetic spin-orbital contribution to SSCC. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 306–309, February, 1997.     

Application of chemometrics to 1H NMR spectroscopic data to investigate a relationship between human serum metabolic profiles and hypertension

The application of chemometric methods to 1H NMR spectroscopic data has been documented for pathophysiological processes. In this study we show the application of 1H NMR-based metabonomics to investigate a relationship between serum metabolic profiles and hypertension. Although hypertension can be defined using blood pressure measurements, the underlying aetiology and metabolic effects are not so readily identified. Serum profiles for patients with low/normal systolic blood pressure (SBP < or = 130 mm Hg; n = 28), borderline SBP (131-149 mm Hg; n = 19) and high SBP (> or = 150 mm Hg; n = 17) were acquired using 1H NMR spectroscopy. Orthogonal signal correction followed by principal components analysis were applied to these NMR data in order to facilitate interpretation, and the resulting chemometric models were validated using Soft Independent Modelling of Class Analogy. Using 1H NMR-based metabonomics, it was possible to distinguish low/ normal SBP serum samples from borderline and high SBP samples. Borderline and high SBP samples, however, were indiscriminate from each other. Our preliminary results showed that there was a relationship between serum metabolic profiles and blood pressure which, in part, was due to lipoprotein particle composition differences between the samples. Furthermore, our results indicated that serum pathology associated with blood pressure is apparent at SBP values > 130 mm Hg, which the WHO and ISH currently define as the limit between normal and high-normal.     

Determination of 31P,31P coupling constants in cyclotriphosphazenes and their influence on 1H and 13C NMR spectra of phosphorus substituents

¹H and ¹³C NMR spectra of symmetrically substituted cyclotriphosphazenes exhibit second‐order effects. The influence of the ³¹P,³¹P coupling constants between ring phosphorus atoms on these effects was studied. Some values of this coupling constant between phosphorus bearing identical substituents were measured using ¹³C satellites of the ³¹P signals or by introduction of a chiral substituent on the third phosphorus atom. Copyright © 2003 John Wiley & Sons, Ltd.     

1H and 31P NMR spectra of the phenyl ester of dichlorophosphoric acid in a nematic phase

The ¹H and ³¹P NMR spectra of the phenyl ester of dichlorophosphoric acid dissolved in Merck nematic phase IV have been recorded and analysed. The values of the dipole dipole couplings have been discussed in terms of several different geometric models. Non-planarity of C-1, O, P and the phenyl ring must be assumed in order to account for the results; a twist angle of 49° was found.     

Kinetics of 1H --> 31P NMR cross-polarization in bone apatite and its mineral standards

Kinetics of NMR cross-polarization (CP) from protons to phosphorus-31 nuclei was studied in the following samples: mineral of whole human bone, apatite prepared from bone, natural brushite, synthetic hydroxyapatite (hydrated and calcined), and synthetic carbonatoapatite of type B with 9 wt% of CO(3) (2-). In order to avoid an effect of magic angle spinning on CP and relaxation, the experiments were carried out on static samples. Parameters of the CP kinetics were discussed for trabecular and cortical bone tissue from adult subjects in comparison to the synthetic mineral standards. It was found that carbonatoapatite shows similar CP behavior to the bone mineral. Both materials undergo two-component CP kinetics. The fast-relaxing classical component is from the surface of apatite crystals and the slow-relaxing nonclassical component comes from the crystal interior. The components have been unambiguously assigned using inverse CP from phosphorus-31 to protons. The study provides information on a structured water layer, which covers crystal surface of carbonato- and bone apatite. The layer encompasses ca 40% of apatite phosphorus and its thickness is more than ca 2 nm.     

13C, 1H and 31P dynamic NMR studies of tetraalkyldiphosphanes: Barrier to internal rotation about the P?P Bond in tetraisopropyldiphosphane

The ¹H, ³¹P and ¹³C NMR spectra of tetramethyldiphosphane (1), tetraethyldiphosphane (2) and tetraisopropyldiphosphane (3) have been studied in the temperature range 30 to ?150°C and at magnetic induction up to 5.87 T. In the range ?100 to ?135 °C, the ¹H and ¹³C spectra of 3 show important changes which can be attributed to freezing the interconversion between two equivalent non-trans conformations. The line shape analysis of the ¹³C signals leads to ΔG^≠ = 29.4 kJ mol^?1 at ?113 °C for the dynamic process involved. The spin coupling parameters ¹J(PP) and N(PC) = ¹J(PC) + ²J(PC) observed for 1 in the temperature range 30 to ?120 °C show variations which could be due to a preference for the trans conformation in this diphosphane.     

Use of the diffusive gradients in thin films technique to evaluate (bio)available trace metal concentrations in river water

Concentrations of Cd, Cu, Cr, Pb, Ni and Zn were monitored in the Svitava River (the Czech Republic) during April and September 2005. Total concentrations and total dissolved concentrations were obtained through regular water sampling, and the diffusive gradients in thin films technique (DGT) were used to gain information on the kinetically labile metal concentrations. Each measured concentration was compared with the corresponding average (bio)available concentration calculated from the mass of metal accumulated by the moss species Fontinalis antipyretica. The concentrations of Cd, Pb, Cr and Zn measured using DGT corresponded well with those obtained after the deployment of Fontinalis antipyretica moss bags in the Svitava River, but the concentrations of Cu and Ni did not. The calculated (bio)available Cu concentration correlated well with the total dissolved concentration of Cu, whereas no correlation was found to exist between the concentrations of Ni. Scheme of the Svitava River monitoring station, including the DGT sampling units and Fontinalis antipyretica moss bags Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Exchange effects on the 1H and 31P nmr spectra of cyclodiphosph(III)azane selenides and tellurides

Oxidation of the isomeric cyclodiphosph(III)azanes, (Me₂ NPNBu-t)₂, by selenium and by tellurium gives both isomeric monoselenides but only one monotelluride. Variable temperature ¹H and ³¹P NMR studies provide evidence for restricted rotation about the exocyclic PN bonds, and in the telluride, of exchange of tellurium between the phosphorus atoms.     

Probing the relationship between interfacial concentrations and lipase activity in cationic W/O microemulsions: a quantitative study by chemical trapping

Interfacial concentrations and/or space: which one is the predominant factor in regulating lipase activity at the water-oil interface? This work is an endeavor toward probing the relationship between lipase activity and interfacial concentrations in cationic water-in-oil (W/O) microemulsions through quantitative study by a chemical trapping method. The interfacial concentrations of water ([H2Oi]), bromide ([Bri-]), and n-hexanol ([HexOHi]) were estimated in the W/O microemulsions of six surfactants with varying headgroup architecture and hydrophilicity across a wide W0 ([H2O]/[surfactant]) range. The surfactants were prepared by the replacement of methyl groups of cetyltrimethylammonium bromide (1) by n-propyl (2-4), one hydroxyethyl (5), and one methoxyethyl (6) group. The estimated [H2Oi] was found not to change much (30.0-36.7 M) with the variation in headgroup hydrophilicity or size from 1-5. However, [Bri-] was found to increase with a decrease in the degree of dissociation (alpha), being higher for 1 and 5 (2.4-3.3 M) and relatively lower (0.9-1.9 M) for others depending on W0. Interestingly, [H2Oi] was found to be little higher (41.5-42.2 M) in the case of 6. The present study elucidates the importance of interfacial water and counterion concentrations in modulating the lipase activity in reverse micelles. In our previous report, the lipase activity was found to increase from 1-4 and in 6, whereas that observed in 5 was comparable with 1, being largely regulated by the surfactant head group size (Das, D.; Roy, S.; Mitra, R. N.; Dasgupta, A.; Das, P. K. Chem.-Eur. J. 2005, 11, 4881). The only other parameter that increased distinctly with lipase activity is the headgroup size, not [H2Oi]. Thus, the role of [H2Oi] in comparison to the surfactant's headgroup size is not found to be that significant. Moreover, the lower [Bri-] in 2-4 and 6 perhaps enhances the probability of enzyme and substrate localization at the interface, leading to higher lipase activity.     

Indirect coupling to quadrupolar nuclei: observation of 1J(105Pd,31P) in one- and two-dimensional 31P CP/MAS spectra

High-resolution solid-state 31P cross-polarization magic angle spinning (CP/MAS) spectra of a series of Pd(II) complexes were obtained. All of these spectra exhibit low-intensity satellite peaks flanking the main resonances which are assigned to originate from a combination of direct (D) and indirect (J) spin-spin coupling between the 31P and the 105Pd spins. The parameter 1J(105Pd,31P) is found to be sensitive to the nature of the ligand in a trans position and thus of great value in assigning the configuration, i.e. cis or trans, in square-planar complexes of Pd(II). A linear relationship between 1J(105Pd,31P) and 1J(195Pt,31P) in analogous Pd(II) and Pt(II) complexes is suggested, the latter parameter being a factor of ca 14 larger. Two-dimensional exchange spectroscopy proved valuable in resolving overlapping resonances and relating pairs of inequivalent 31P spins within the same complex and spreading their satellite manifolds into two dimensions. These two spectral features are unrelated, being due to dipolar coupling among the phosphorus spins in the former and finite lifetimes of the spin states of the 105Pd isotope in the latter case.     

TADDOL organophosphorus derivatising agents for the determination of the enantiomeric excess of chiral alcohols and carboxylic acids by 31P and 1H NMR spectroscopy

The use of an organophosphorus derivatisation agent prepared from TADDOL for the NMR determination of enantiomeric composition of chiral alcohols and carboxylic acids is described.