Since our previous review article (Curr. Org. Chem. 2002, 6, 35), significant improvements and an array of 15N NMR applications in structural analysis have been published. This report aims to update coverage methodology various types published over the period 2001 - 2005. Substantial progress cryogenic probe technology commercial availability cryoprobes facilitated measurement parameters. The number solid-state has increased significantly during past few years. In contrast review, this...

A series of Pd and Pt chloride complexes with pyridine (py), 2,2'-bipyridine (bpy) 1,10-phenanthroline (phen), general formulae trans-/cis-[M(py)2Cl2], [M(py)4]Cl2, trans-/cis-[M(py)2Cl4], [M(bpy)Cl2], [M(bpy)Cl4], [M(phen)Cl2], [M(phen)Cl4], where M = Pd, Pt, was studied by 1H, 195Pt, 15N NMR. The 90-140 ppm low-frequency coordination shifts are discussed in terms such structural features the as type platinide metal, oxidation state, sphere geometry ligand. results quantum-chemical NMR...

Abstract Room‐temperature hydro‐pressure‐driven densification of amorphous silica (nanoparticles and microbeads) is developed. This technique inspired by biological silicification with reference to dissolution, precipitation, hardening mechanisms. Cold sintering based on uniaxial pressure taken as a benchmark. Starting from green‐body relative density 70%, exceeding 99% achieved adding distilled water or caustic solution an powder under hydrostatic 450–600 MPa for 5–30 min. Translucent...

New hybrid sol–gel coatings based on tetraethoxysilane (TEOS) and phytic acid (PA) were designed applied to cotton; the flame-retardant properties of treated fabrics thoroughly investigated by means flame-spread forced-combustion tests. The first goal was identify TEOS:PA weight ratio that allowed achievement best properties, with lowest final dry add-on fabrics. Therefore, different sols prepared cotton, resulting coated investigated. In particular, solid-state NMR spectroscopy exploited...

Abstract Au(III), Co(III) and Rh(III) chloride complexes with pyridine (py), 2,2′‐bipyridine (bpy) 1,10‐phenanthroline (phen) of the general formulae [M 1 LCl 3 ], trans ‐[M 2 L 4 Cl ] + , mer (LL)Cl cis (LL) where M = Au; Co, Rh; py; LL bpy, phen, were studied by H 13 C HMBC 15 N HMQC/HSQC. The H, coordination shifts (the latter from ca − 78 to 107 ppm) are discussed in relation type metal, electron configuration, sphere geometry ligand. chemical also calculated quantum‐chemical NMR...

Abstract The 15 N NMR chemical shifts of 7 ‐ and 9 ‐substituted purine derivatives were investigated systematically at the natural abundance level isotope. determined assigned using GSQMBC, GHMBC, GHMQC GHSQC experiments in solution. cross‐polarization magic angle spinning data recorded for selected compounds order to study principal values shifts. Geometric parameters obtained by RHF/6–31G** single‐crystal x‐ray structural analysis used calculate chemical‐shielding constants (GIAO IGLO)...

Abstract 1 H, 13 C and 15 N NMR studies of platinide(II) (M = Pd, Pt) chloride complexes with methyl phenyl derivatives 2,2′‐bipyridine 1,10‐phenanthroline [LL 4,4′‐dimethyl‐2,2′‐bipyridine (dmbpy); 4,4′‐diphenyl‐2,2′‐bipyridine (dpbpy); 4,7‐dimethyl‐1,10‐phenanthroline (dmphen); 4,7‐diphenyl‐1,10‐phenanthroline (dpphen)] having a general [M(LL)Cl 2 ] formula were performed the respective chemical shifts (δ 1H , δ 13C 15N ) reported. H high‐frequency coordination (Δ coord complex − ligand...

Adenine, an essential building block of nucleic acids present in all living systems, can occur several tautomeric forms. The phenomenon tautomerism be investigated by experimental methods, including nuclear magnetic resonance. In this study, long-range 1H−13C and 1H−15N coupling constants for N-alkyl derivatives related to four tautomers adenine are DMSO DMF solutions. To investigate the structural dependence understand how polarization propagates system, Fermi contact (FC) terms were...

Abstract 1 H, 13 C and 15 N NMR studies of gold(III), palladium(II) platinum(II) chloride complexes with picolines, [Au(PIC)Cl 3 ], trans ‐[Pd(PIC) 2 Cl / cis ‐[Pt(PIC) ] [Pt(PIC) 4 ]Cl , were performed. After complexation, the H signals shifted to higher frequency, whereas ones lower (by ca 80–110 ppm), respect free ligands. The shielding phenomenon was enhanced in series < ]; it increased following Pd(II) → Pt(II) replacement, but decreased upon ‐transition. Experimental chemical shifts...

Abstract 1 H, 13 C, and 15 N NMR studies of platinide(II) (M = Pd, Pt) chloride complexes with quinolines (L quinoline–quin, or isoquinoline–isoquin; LL 2,2′‐biquinoline–bquin), having the general formulae trans‐/cis‐ [ML 2 Cl ] [M(LL)Cl ], were performed respective chemical shifts (δ 1H , δ 13C 15N ) reported. H coordination various signs magnitudes (Δ coord complex − ligand are discussed in relation to changes diamagnetic contribution relevant shielding constants. The comparison literature...

Abstract 1 H, 13 C and 15 N nuclear magnetic resonance studies of gold(III), palladium(II) platinum(II) chloride complexes with phenylpyridines (PPY: 4‐phenylpyridine, 4ppy; 3‐phenylpyridine, 3ppy; 2‐phenylpyridine, 2ppy) having the general formulae [Au(PPY)Cl 3 ], trans ‐/ cis ‐[Pd(PPY) 2 Cl ] ‐[Pt(PPY) were performed respective chemical shifts (δ , δ ) reported. coordination (i.e. differences between same atom in complex ligand molecules: $\Delta_{\rm {coord}}^{1_{\rm {H}}} = \delta_{\rm...

1H, 13C and in some cases also 15N chemical shifts of quaternary benzo[c]phenanthridine alkaloids (fagaronine, chelerythrine, chelilutine, chelirubine, nitidine, sanguilutine, sanguinarine, sanguirubine) were systematically studied by NMR spectroscopy ab initio calculations. The assignment signals the 1H spectra was obtained from 2D NOE gradient-enhanced single-quantum multiple bond correlation (GSQMBC) experiments. geometry optimization using Gaussian 94 at RHF/6–31 G** level, followed...

The interpretation of nuclear magnetic resonance (NMR) parameters is essential to understanding experimental observations at the molecular and supramolecular levels designing new more efficient probes. In many aromatic natural compounds, unusual (13)C NMR chemical shifts have been reported for out-of-plane methoxy groups bonded ring (~62 ppm as compared typical value ~56 an group). Here, we analyzed this phenomenon a series compounds using Density Functional Theory (DFT) calculations. First,...

A new technique for the production of glass foams, based on alkali activation and gel casting, previously applied to soda-lime glass, was successfully extended boro-alumino-silicate recovered from recycling pharmaceutical vials. weak (2.5 M NaOH or NaOH/KOH aqueous solutions) fine powders (below 70 µm) allowed obtainment well-dispersed concentrated suspensions, undergoing gelation by treatment at low temperature (75 °C). Unlike progressive hardening could not be attributed formation...

Abstract Fused five‐membered nitrogen heterocycles comprise a very important group of compounds frequently utilized in pharmaceutical applications. In this study, we report the first systematic synthesis substituted pyrazolo[4,3‐ c ]pyrazoles and three regioisomers their N ‐methyl derivatives. All were fully characterized by NMR spectroscopy solution selected also studied X‐ray diffraction solid state. 1 H, 13 C, 15 spectroscopic data for all isomers interpreted DFT calculations nuclear...

Indoloquinoline alkaloids represent an important class of antimalarial, antibacterial and antiviral compounds. They have been shown to bind DNA via intercalation preferentially at GC-rich sequences containing nonalternating CC sites. The stability complexes formed with biological macromolecules depends on noncovalent binding. In the present study, ability indoloquinolines form intermolecular interactions solvents was investigated by using NMR spectroscopy density functional theory (DFT)...

Abstract Substituted pyrazolopyridines are potent inhibitors of phosphodiesterases and cyclin‐dependent kinases. In this study, NMR was used to investigate the potential N1‐H N2‐H tautomerism 5‐substituted pyrazolo[3,4‐ c ]pyridine derivatives. Six compounds were fully characterized by using 1 H, 13 C, 15 N chemical shifts indirect H C coupling constants. The H spectra measured over a broad range temperatures. All shown exist predominantly in tautomeric form. Complementary quantum‐chemical...