1H, 13C, 19F and 11B NMR spectral reference data of some potassium organotrifluoroborates

Complete ¹H, ¹³C, ¹⁹F and ¹¹B NMR spectral data for 28 potassium organotrifluoroborates are described. The resonance for the carbon bearing the boron atom is described for most of the studied compounds. A modified ¹¹B NMR pulse sequence was used and better resolution was observed allowing the observation of ¹¹B–¹⁹F coupling constants for some of the studied compounds. Copyright © 2009 John Wiley & Sons, Ltd.     

Magnetic relaxation characteristics of Gd(III) in N,N-dimethylformamide according to 1H and 14N NMR data

The solvation of Gd³⁺ is studied in N,N-dimethylformamide by ¹H and ¹⁴N NMR in the temperature range of 298–373 K.     

Reversal of stability on metalation of pentagonal-bipyramidal (1-MB6H7(2-) 1-M-2-CB5H7(1-) and 1-M-2,4-C2B4H7) and Icosahedral (1-MB11H12(2-) 1-M-2-CB10H12(1-) and 1-M-2,4-C2B9H12) boranes (M = Al, Ga, In, and Tl): energetics of condensation and relationship to binuclear metallocenes

The usual assumption of the extra stability of icosahedral boranes (2) over pentagonal-bipyramidal boranes (1) is reversed by substitution of a vertex by a group 13 metal. This preference is a result of the geometrical requirements for optimum overlap between the five-membered face of the ligand and the metal fragment. Isodesmic equations calculated at the B3LYP/LANL2DZ level indicate that the extra stability of 1-M-2,4-C(2)B(4)H(7) varies from 14.44 kcal/mol (M = Al) to 15.30 kcal/mol (M = Tl). Similarly, M(2,4-C(2)B(4)H(6))(2)(1-) is more stable than M(2,4-C(2)B(9)H(11))(2)(1-) by 9.26 kcal/mol (M = Al) and by 6.75 kcal/mol (M = Tl). The preference for (MC(2)B(4)H(6))(2) over (MC(2)B(9)H(11))(2) at the same level is 30.54 kcal/mol (M = Al), 33.16 kcal/ mol (M = Ga) and 37.77 kcal/mol (M = In). The metal-metal bonding here is comparable to those in CpZn-ZnCp and H(2)M-MH(2) (M= Al, Ga, and In).     

1-Methyl-2(3,4)-(1-vinylpyrrol-2-yl)pyridinium iodides: some structural features revealed by 1H and 13C NMR spectroscopy

The reactions of 2-, 3-, and 4-(1-vinylpyrrol-2-yl)pyridines with methyl iodide afford the corresponding quaternary salts. Analysis of their ¹H and ¹³C NMR spectra showed that the quaternization of the nitrogen atom considerably enhances the -acceptor effect of the pyridine ring on the pyrrole ring and on the vinyl group. 1-Methyl-2-(1-vinylpyrrol-2-yl)pyridinium iodide contains no weak intramolecular C--H...N hydrogen bond present in the starting compound.     

Spatial and Electronic Structure of 2-(2-Furyl)- and 2-(2-Thienyl)pyrroles According to 1H and 13C NMR Data

In 2-(2-furyl)- and 2-(2-thienyl)pyrroles the heterocycles are in efficient ,-conjugation. The presumably possible for this compounds intramolecular hydrogen bond N-H···O or N-H···S is lacking. The COCF₃ group in position 2 of the pyrrole ring is syn-oriented with respect to pyrrole fragment, and the orientation is fixed by an intramolecular hydrogen bond N-H···O. However no bifurcating hydrogen bonds arise in the molecules containing COCF₃ group.     

Methanol and acetonitrile associates in aqueous and chloroform solutions according to 1H NMR spectroscopic data

Association of methanol and acetonitrile in a nonpolar (CDCl₃) and polar (H₂O and D₂O) solvents was studied by ¹H NMR spectroscopy and quantum chemistry. The results were compared with the data obtained by decomposition of the spectral curves in the range 800–1100 nm by the independent component analysis (ICA) technique. The content of homoassociates consisting of four and two or three molecules in the case of methanol and acetonitrile, respectively, gradually increased with the amount of the organic solvent in solution. The aqueous solutions under study consisted of few associates of compositions 1: 1, 1: 2, and 1: 4.5 for acetonitrile and 1: 1 and 1: 3 for methanol (water: organic solvent). The quantum-chemical calculation of the NMR spectra of the particles existing in solution confirmed our conclusions about the structure of the solutions.     

1H and 13C NMR studies of 2-functionalized 5-(methylsulfonyl)-1-phenyl-1H-indoles

The 1H and 13C NMR resonances of thirty 2-functionalized 5-(methylsulfonyl)-1-phenyl-1H-indoles were assigned completely and unequivocally using the concerted application of one- and two-dimensional experiments (DEPT, gs-HMQC and gs-HMBC). Finally, the influence of the 2-substituent of 5-(methylsufonyl)-1-phenyl-1H-indoles on the carbon atoms of the indole moiety was estimated.     

Studies on aromatic amine boranes by 11B and 1H NMR

¹H and ¹¹B NMR spectroscopy was applied to mono- and bisborane adducts derived from aryl-, benzyl-, phenethyl- and phenylenediamines, but no simple relationship was established between the spectroscopic data and the nature of the NB bond. Comparative studies of the affinity of aromatic amines to BH₃ by equilibria reactions may be of great value in establishing a scale of relative basicity.     

Sterically-induced low temperatur polyhedral rearrangements of carbaplatinaboranes: Synthesis and crystal structures of 1-Ph-3,3-(PMe2Ph)2-3,1,2-PtC2B9H10, 1-Ph-3,3-(PMe2Ph)2-3,1,11-PtC2B9H10, 11-Ph-3,3-(PMe2Ph)2-3,1,11-PtC2B9H10 and 1,11-Ph2-3,3-(PMe2Ph)2-3,1,11-PtC2B9H9

Reaction of cis-Pt(PMe₂Ph)₂Cl₂ with Tl₂[7-Ph-7,8-nido-C₂B₉H₁₀] affords 1-Ph-3,3-(PMe₂Ph)₂-3,1,2-PtC₂B₉H₁₀, mild thermolysis (55°C) of which yields 1-Ph-3,3-(PMe₂Ph)₂-3,1,11-PtC₂B₉H₁₀ and 11-Ph-3,3-(PMe₂Ph)₂-3,1,11-PtC₂B₉H₁₀. Both of the latter compounds are produced by the microwave irradiation of a mixture of cis-Pt(PMe₂Ph)₂Cl₂ and [HNMe₃][7-Ph-7,8-nido-C₂B₉H₁₁]. When cis-Pt(PMe₂Ph)₂Cl₂ is allowed to react with Tl₂[7,8-Ph₂-7,8-nido-C₂B₉H₉] at room temperature the only isolable species is 1,11-Ph₂-3,3-(PMe₂Ph)₂-3,1,11-PtC₂B₉H₉. The generation of rearranged products with 3,1,11-PtC₂B₉ architectures is inconsistent with a diamond-square-diamond mechanism for the isomerisation of icosahedral heteroboranes.     

1H and 13C NMR Study of Steric and Electronic Structure of 2-(2-Acylethenyl)-1-vinylpyrroles

According to the ¹H and ¹³C NMR data, the molecule of 2-(2-benzoylethenyl)-1-vinylpyrrole has a nearly planar structure with trans arrangement of the vinyl and oxovinyl groups. The unsaturated fragments give rise to effective conjugation. The vinyl group in 5-substituted 2-(2-acylethenyl)-1-vinylpyrroles strongly deviates from the heteroring plane because of steric effect of the substituent; however, this effect does not change the arrangement of the other unsaturated fragments.     

Syntheses and Structural Characterization of 1-（4-Phenyl-2-thiazolyl）-3-（4-methylphenyl）-5-（2-furyl）-4,5-dihydro-（1H）-pyrazole and 1-（4-（4-Fluoro）phenyl-2-thiazolyl）-3-（4-methyl-phenyl）-5-（2-furyl）-4,5-dihydro-（1H）-pyrazole

The title compounds were synthesized and characterized by IR,1H-NMR,Mass and elementary analysis and single-crystal X-ray diffraction.In 1a,intermolecular C-H…π interactions produce a three-dimensional network.In 1b,intermolecular C-H…O hydrogen bonds generate an R22(22) ring.The hydrogen bonding is supported by C-H…π interactions.     

An unusual spatial structure of di-ortho-substituted hetaryl vinyl ethers according to1H and13C NMR data

According to¹H and¹³C NMR data, 2,6-dimethyl-3,5-dichloro-4-vinyloxy-pyridine and 2-methyl-4-methoxymethyl-5-hydroxymethyl-3-vinyloxypyridine exist predominantly as the sterically hindered s-cis conformation, with the angle between the hetaryl ring and the vinyloxypyridine plane about 60°.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2040–2044, September, 1991.     

1H and 13C NMR study of the conformations of the atropisomers of some 1-(11-naphthyl)-2,4-dioxo-(or 2-thio-4-oxo)-hexahydro-pyriminides

The ¹H and ¹³C NMR spectra of the atropisomers of 6-(or 5-)-methyl-1-(1¹-naphthyl)-2, 4-dioxo-(or 2-thio-4-oxo)-hexahydro-pyrimidines, 1 to 4, are assigned on the basis of NOE and double resonance experiments. The syn-anti configurations of the isomers of 6-methyl-2,4-dioxo-pyrimidine follow from the close similarity of the NMR parameters to those observed with the isomers of the 6-methyl-2-thio derivative of known configuration. That of the 5-methyl derivatives was assigned from NOE and magnetic anisotropy effects of the naphthalene ring and of the (thio) amide group. Allylic strain between the naphthyl and 5-methyl groups makes the axial confomation prefered int he anti isomers. In the syn isomers, however, the equational and axial conformations are approximately equally populated, apparently due to interference between the remote benzene ring and the axial methyl group. The equatorial conformation is prepared with the 5-methyl derivatives.