NMR-Untersuchungen an Dicyclopentadienderivaten. IV—1-Syn/anti-Epimere von endo-Dicyclopentadienderivaten

The syn/anti-arrangement of some substituents R in position 1 of endo-dicyclopentadiene derivatives is investigated by ¹H-and ¹³C n.m.r. spectroscopy. The HH-coupling constants of the epimeric alcohols 2 and 3 are determined by paramagnetic shift experiments [Eu(fod)₃] and the observed relative paramagnetic shifts ΔEu used for the determination of the configuration. The increasing steric compression in the syn-epimers is well reflected by the ¹H- and ¹³C n.m.r. chemical shifts.     

NMR–Untersuchungen an Dicyclopentadienderivaten: I—1H-NMR: Anwendung von paramagnetischen Verschiebungsreagenzien (Eu(fod)3) zur Vereinfachung der Spektren exo/endo-isomerer Diole

The determination of the stereochemistry of a series of exo/endo-isomeric dihydro- and tetrahydro-dicyclopentadiene-9.10-diols (exo/exo or endo/endo), using Eu(fod)₃ for separation of the signals in their ¹H n.m.r. spectra, is discussed in detail. The paramagnetic shift values ΔEu determined for half-molar ratios Eu(fod)₃/diol allow an unambiguous stereochemical assignment of the diols with regard to exo/endo isomerism. The ΔEu quantities are correlated with the distance H_i…O-atom (R_i).     

NMR-Untersuchungen an Dicyclopentadienderivaten: II.—13C-NMR: γ-gauche-Effekt in Abhängigkeit von der exo/endo-Isomerie an Dicyclopentadien diolen

The ¹³C FT n.m.r. spectra of some exo- and endo-dihydro- and tetrahydrodicyclopentadiene-9,10-diols(exo/exo or endo/endo) are studied and the chemical shifts of the C-atoms are assigned by application of Eu(fod)₃ paramagnetic shift investigations and additional chemical shift parameters. Thus relatively strong γ-effects up to 12,8 ppm were observed for the C-atoms 4, 5, 7, 9, 10 and 1, 3, dependent on the exo/endo configuration of the OH-groups and the attached 5-ring, giving an interesting insight into the gemetry of these norbornane systems.     

1H n.m.r. spectra of some bicyclic compounds: I—relative configurations of the diastereomeric endo-α-methyl-5-norbornene-2-methanols,the corresponding saturated analogues,and their cyclization ether products

The configurational and conformational relationship at C-2 and C-α in the two racemic diastereomeric endo-α-methyl-5-norbornene-2-methanols and the corresponding saturated endo-α-methyl-2-norbornanemethanols were determined by first-order analysis of the ¹H n.m.r. spectra of these compounds and of their cyclization ether products, i.e. 3-methyl-2-oxatricyclo[4.2.1.0^4,8]nonanes and 5-methyl-4-oxatricyclo[4.3.0.0^3,8]nonanes. In addition, the conformational preference of the hydroxyl group in the unsaturated and saturated alcohols was confirmed by the lanthanide induced shift technique, using Eu(fod)₃ as shift reagent, combined with a computer program involving various conformations of the –CHOHMe group.     

Etudes d'Alkylidènehydrazono-2 Méthyl-3 Dihydro-2,3 Benzothiazoles par RMN 1H en Présence d'Eu(fod)3

The study of the ¹H n.m.r. spectra of a series of 2-alkylidenehydrazono-3-methyl-2,3-dihydrobenzothiazoles in the presence of Eu(fod)₃ shows that the site of coordination of the lanthanide complex at the two nitrogen atoms of these azines varies as a function of either steric or polar factors. The use of Eu(fod)₃ also makes it possible to determine the Z or E configuration of these compounds, as well as their isomer ratio in different solvents.     

Long range 13C shift effects (δ and ϵ) in methylcyclohexanes

¹³C n.m.r. spectra of a number of methyl substituted cyclohexanes, some of them conformationally homogeneous, have been recorded in CDCl₃ and used to determine shift effects engendered by the introduction of methyl groups on carbon atoms remote from the site of substitution. Sizeable changes in shifts are found, including a substantial effect of an equatorial methyl group on an axial methyl group δ to it (+0.6₇ ppm, ‘δ_ea’). The effects reported are of consequence in investigations of conformational problems by ¹³C n.m.r. techniques.     

1H-Festkörper-NMR-Untersuchungen am synthetischen Pektolith Ca2NaHSi3O9

Solid-state ¹H N.M.R. Studies of Synthetic Pectolite Ca₂NaHSi₃O₉ A synthetic pectolite Ca₂NaHSi₃O₉ is studied by means of conventional ¹H pulse-fourier-transform wide line n.m.r. and methods of solid-state high-resolution ¹H n.m.r. (MREV8 multiple pulse technique, combined multiple pulse magic angle spinning experiments). The n.m.r. spectra consist of a dominant signal due to SiOH groups and a small signal which can be assigned to water molecules. The parameters of the ¹H n.m.r. spectra for the SiOH groups are discussed in comparison with the known structure of pectolite. It can be shown that the structural details for the proton of the SiOH groups are reflected by the ¹H n.m.r. spectra.     

A 13C n.m.r. study of the charge-transfer complexes between o-chloranil and some aromatic electron donors

The ¹³C n.m.r. spectra of complexes between o-chloranil and aromatic electron donors were studied. Complexation leads to a general diamagnetic shift of the ¹³C n.m.r. signals for the acceptor (o-chloranil), but for signals from the ¹³C nuclei in the donors both diamagnetic and paramagnetic shifts are found. These phenomena are thought to be the result of competing anisotropy and charge-migration effects. Charge migration in o-chloranil complexes appears to be more important than in corresponding 1,3,5-trinitrobenzene complexes.     

Microwave spectroscopy and nuclear magnetic resonance study of the molecular geometry of 2-fluorophenylisocyanate

Analysis of the microwave spectra of the vibrational ground state of 2-fluorophenyl-isocyanate in the gaseous state shows the existence of a single planar cis conformer. Rotational spectra of the excited torsional states out of the plane and spectra of in-plane vibrations have also been studied. MINDO III type theoretical calculations corroborate the experimental results. Similarly, the configuration of 2-fluorophenylisocyanate in the liquid phase has been studied by NMR using the chemical shift reagent, Eu(fod)₃. Induced paramagnetic shifts have been measured on the ¹³C spectra, for different quantities of the reagent. The results clearly show a higher paramagnetic shift for the carbon bonded to the fluorine atom than for the other nuclei of the aromatic cycle (with the exception of the quaternary carbon), indicating the probable presence of the cis isomer.     

Synthesis and spectral studies ofo-hydroxyacetophenone (N-benzoyl)glycyl hydrazone and some of its lanthanide(III) complexes

Summary o-Hydroxyacetophenone (N-benzoyl)glycyl hydrazone (o-HABzGH) has been characterized by i.r.,¹H n.m.r.,¹³C n.m.r. and mass spectral studies, and its complexes of the types [Ln(o-HABzGH)Cl₂(H₂O)₂]Cl and [Ln(o-HABzGH–2H)OH(H₂O)₃], where Ln=La, Pr, Nd, Sm and Eu, have been synthesized. The structures of the complexes have been studied by conductance, magnetic, electronic, i.r.,¹H n.m.r. and¹³C n.m.r. spectral techniques. The hypersensitive bands of the electronic spectra suggest coordination numbers six and seven around Nd^III in its adduct and neutral complexes respectively. I.r. and n.m.r. spectral data suggest a neutral bidentate behaviour for the ligand in the adducts and a dinegative tridentate nature in the neutral complexes.     

The origin of aromatic solvent-induced shifts in 19F n.m.r.

Aromatic solvent-induced shifts (ASIS) in ¹⁹F n.m.r. spectra of several organic fluoro compounds have been determined in several solvents. ¹⁹F n.m.r. signals of unsaturated fluoro compounds in C₆F₆ and C₆H₆ show excess high field shifts corresponding to the term σ_c (solvent shift caused by chemical interactions). The mechanism of this shift is discussed in connection with the presence of an F-π interaction. A thermal study also supports this idea.     

The stereochemistry of nevskin

Summary The relative configurations of the substituents in nevskin have been determined from the H¹ NMR spectra in CDCl₃ with additions of Eu(FOD)₃ as paramagnetic shift reagent.Institute of Botany, Academy of Sciences of the Azerbaidzhan SSR, Baku. All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 450–452, July–August, 1976.     

Constituents of Satureia calamintha. Application of Eu(fod)3 to the assignments of the methyl resonances of triterpenes related to 12-ursene

The n.m.r. spectra of triterpenoids related to 12-ursene have been examined using the shift reagent Eu(fod)₃. The assignment of all the methyl resonances has been achieved for ursolic acid derivatives and the corresponding compounds of the 3-epi series, which have not been investigated previously. The additive shielding effects of various substituents on the methyl resonance frequencies have been deduced from the results.     

N-Methyl-N-diäthoxyphosphorylamido-Derivate des Hexachlorocyclotriphosphazatriens. IV. NMR-spektroskopische Untersuchungen zur Konstitution der Ammonolyseprodukte von N-Methyl-N-diäthoxyphosphorylamido-chloro-cyclotriphosphazatrienen

N-Methyl-N-Diethoxyphosphorylamido Derivatives of Hexachlorocyclotriphosphazatriens. IV N.M.R. Spectroscopic Investigations of the Products of the Ammonolysis of N-methyl-N-diethoxyphosphorylamindo-chloro-cyclotriphosphazatrienes Broad band ¹H decoupled ³¹P n.m.r. spectra of products obtained by ammonolysis of N-methyl-N-diethoxyphosphorylamido-chloro-cyclotriphosphazatrienes provide essential hints at the constitution of these compounds. In this connection it may be easily demonstrated, both amino groups of N₃P₃Cl₃[NCH₃P(O)(OC₂H₅)₂][NH₂]₂ as well as of N₃P₃Cl₂[NCH₃P(O)(OC₂H₅)₂]₂ [NH₂]₂ are arranged geminally. The spectral parameters were found and verified by simulation of spectra. The simulated ³¹P spectra agree closely with the observed ones. The conclusions from the ³¹P n.m.r. spectra are complemented by these from the ¹H n.m.r. spectra.     

Über die Reaktion von Thiophosphoryltrichlorid mit Hexamethyldisilazan

On the Reaction of Thiophosphoryl Chloride with Hexamethyl Disilazane On the basis of a ³¹P n.m.r. spectroscopic study of the reaction of PSCl₃ with hexamethyl disilazane a method for the preparation of Me₃SiNHP(S)Cl₂( 1 ) and the diazadiphosphetidine 2 , [Me₃SiNHP(S)?NSiMe₃]₂ has been developed. These new crystalline compounds have been characterized by i.r., Raman, ³¹P n.m.r. and mass spectroscopy, and their thermal behaviour has been studied. The formation and constitution of 2 are discussed, and its ¹H and ²⁹Si n.m.r. spectra are reported.     

Use of silver trifluoroacetate together with lanthanide shift reagents for simplification of 1H NMR spectra of aromatic hydrocarbons

The equimolar mixtures of typical lanthanide shift reagents such as Eu(fod)₃, Pr(fod)₃ or Yb(fod)₃ with silver trifluoroacetate, previously used to induce paramagnetic shifts in the ¹H NMR spectra of alkenes, have been successfully applied to simple aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylenes. In benzene and p-xylene the signals of all the aromatic protons are shifted identically. In other substituted benzenes the magnitude of the induced shift depends on the distance between the proton and the substituents. In addition, the different behaviour of the signals of the methyl groups in meta-and para-xylene on the addition of the complex shift reagent allows the quantitative analysis of the two xylenes in their mixtures.     

Hétérocycles contenant du phosphore: XXVII—Etude par Résonance Magnétique Nucléaire de quelques dérivés des dioxa-et dithiaphospholanes-1,3,2 monosubstitués en 4

The ¹H n.m.r. spectra of some derivatives of 4-methyl (or 4-phenyl) 1,3,2-dioxa- and 1,3,2-dithiaphospholanes are analysed. The configurational study of the compounds has been investigated. The torsional angle of the C₄? C₅ fragment is calculated and the ring conformation in solution is discussed.     

Silver Cyanide Complexes of Heterocyclic Thiones

Silver(I) cyanide complexes of various thiones (imidazolidine-2-thione, diazinane-2-thione and their derivatives) have been prepared and characterized by elemental analysis, i.r. and n.m.r. (¹H, ¹³C, ¹⁵N and ¹⁰⁷Ag) spectroscopy. It appears from the i.r. data that six out of the ten complexes are nonionic [>C=S—Ag—CN] while the remaining four exist as ionic species [Ag(>C=S)₂]⁺[Ag(CN)₂]^– in the solid state. An upfield shift in the ¹³C-n.m.r. and downfield shifts in the ¹H-, ¹⁵N- and ¹⁰⁷Ag-n.m.r. spectra are consistent with the sulfur coordination to silver(I). The n.m.r. data shows that the [>C=S—AgCN] complexes are stable in solution and do not undergo redistribution.     

Konformationsanalyse und Diastereomerenzuordnung an 1,3-Aza- und 1,3-Oxaphospholanen mittels paramagnetischer Verschiebung

The geometric factor G [G = (3 cos² θ ?1) r^?3] of selected protons relative to a centre of co-ordination [Eu(dpm)₃] is determined using Dreiding models of different conformers of 1,3-aza- and 1,3-oxaphospholanes. The centre of co-ordination is supposed to be joined to the oxygen of the carbonyl group or to the nitrogen and oxygen in the hetero-ring, respectively. The graphs of the geometric factors against the paramagnetic shifts of the relevant protons are straight lines only for the preferred conformers on the basis of a correct centre of co-ordination. As a measure for the paramagnetic shift of a proton the slope of the graph of chemical shift against the concentration of Eu(dpm)₃ (in mol %) is chosen. By variation of the relative configuration at C-5 in the models and calculation of the geometric factor, it is possible to determine the different diastereomers, which are distinguished by the relative position of the substituent at phosphorus and C-5.     

Platinum(II) and platinum(IV) complexes of 2-amino-4, 6-dimethylpyrimidine

Summary Platinum(II) and platinum(IV) complexes of 2-amino-4, 6-dimethylpyrimidine, ADMPY, have been prepared. Solids of formula Pt(ADMPYH⁺)Cl₃, Pt(ADMPY)₂Cl₄ and Pt(ADMPY)₂Cl₄·2HCl have been isolated and characterized by elemental analyses in conjuction with i.r. and n.m.r. spectra. A paramagnetic tan to reddishbrown complex has been reproducibly prepared from the direct reaction of K₂PtCl₄ and ADMPY at pH 6.