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.     

Pteridine studies: III—13C n.m.r. data of pteridine,some of its derivatives and their covalent σ-adducts with ammonia and water

¹³C n.m.r. spectral data of pteridine and nineteen of its derivatives (containing one or more chloro, methylthio, methyl, t-butyl or phenyl substituents) are reported. The ¹³C n.m.r. spectrum of the title compound has been assigned conclusively. ¹³C n.m.r. substituent effects are shown to be very useful in discerning between 6- and 7-substituted pteridines. Additionally, the ¹³C n.m.r. spectra of several covalent amination products, i.e. the 3,4-dihydro-4- amino- and the 5,6,7,8-tetrahydro-6,7-diaminopteridine derivatives, formed by dissolving the appropriate pteridine in liquid ammonia, have been recorded. The ¹³C n.m.r. spectra of the corresponding covalent hydrates are also reported.     

Synthetic and physicochemical studies of divalent metal complexes with cyclic hydrazone and semicarbazone ligands

Summary The syntheses of 3,4,10,11-tetraphenyl-1,2,5,6,8,9,12,13-octaazacyclotetradeca-7, 14-dione-2,4,9,11-tetraene (dbdch) and 6-methoxy-1,6-diphenyl-4-oxo-3,4,5,6-tetrahydro-2,3,5-triazine (bsc) and their complexes with divalent metal ions (copper, nickel, cobalt, zinc, cadmium and mercury) are reported. All compounds were characterized by ¹H n.m.r., ¹³C n.m.r., i.r. and u.v.-vis. spectroscopy and by FAB mass spectrometry; possible structures are presented and discussed.Author to whom all correspondence should be directed.     

1H- und 13C-NMR-untersuchungen an dibromoxabicyclo[n.2.1]alkanen

The ¹H n.m.r. spectra of some dibromooxabicyclo[n.2.1]alkanes are discussed for the determination of the configuration and conformation. The ¹³C n.m.r. spectra confirm the observed stereochemistry. With increasing ring size the ¹³C n.m.r. chemical shifts of the hetero atom substituted C-atoms C-1 and C-2 move steadily to lower fields.     

Complexation of palladium cyanide with imidazolidine-2-thione and its derivatives

Summary Pd(CN)₂ reacts with imidazolidine-2-thione (Imt), 1,3-diazinane-2-thione(Diaz), 1,3-diazipnane-2-thione (Diap) and their derivatives to yield complexes of stoichiometry [PdL₂(CN)₂] or [PdL(CN)₂] (L = Imt, Diaz or Diap and L = Imt having N-Me, Et or Pr substituents), which were characterized by elemental analysis, i.r., ¹H and ¹³C n.m.r. spectroscopy. Both mono- and bis ligand complexes are thought to be square planar with the monoligand binding to metal via sulphur (bridging) and the bis ligand via the monodentate thione group. The ¹³C enriched Pd(¹³CN)₂ complex was prepared and the ¹³C n.m.r. recorded. The C-2 resonance of ¹³C n.m.r. of Imt, Diaz or Diap complexes of the copper(I), silver(I), gold(I) and palladium(II) were compared.     

Nuclear magnetic resonance spectral study of 2-acetylpyridine4 N-alkylthiosemicarbazones and their cobalt(III) complexes

¹H and¹³C n.m.r. spectra are reported for a series of 2-acetylpyridine⁴ N-alkylthiosemicarbazones in order to study the effect of increased size of the alkyl function on the ratio of isomers present in solution. Similarly, n.m.r. data for the bis(thiosemicarbazone)cobalt(III) complexes are included, as well as these complexes' ligand field parameters. TMC 2698     

Borchelate und Bormetallchelate, 4. Mitt.

The i.r., u. v.,¹H n.m.r.,¹³C n.m.r., and¹¹B n.m.r. spectra of several substituted diphenylboron chelates derived from salicylaldehyde azomethines were compared with respect to the influence of the amine substituentR. O–B–N-6-ring constitution of the chelates29–32 [R=OH, NH₂, NHC₆H₅, N(CH₃)₂] can be deduced from the spectra.

Als 3. Mitt. gilt:F. Umland undE. Hohaus mit Beiträgen vonW. Riepe, K. Brodte, C. Schleyerbach undD. Szonn. Untersuchungen über borhaltige Ringsysteme vom Chelattyp. Forschungsbericht des Landes Nordrhein-Westfalen Nr. 2538. Opladen: Westdeutscher Verlag. 1976.     

13C-NMR-spektroskopische und stereochemische Untersuchungen: XI—Konformationen von Bicyclo[3.3.1]nonanen und ihre Unterscheidbarkeit durch lanthanideninduzierte Verschiebungen

The ¹³C chemical shifts of bicyclo[3.3.1]nonane and of the corresponding 9-hydroxy- and 9-oxo- derivatives are compared with chemical shifts calculated on the basis of stereospecific shift increments. These results as well as the ¹H n.m.r. spectrum of the ketone indicate a predominant chair-chair conformation CC. A low temperature ¹³C n.m.r. study as well as an analysis of the temperature dependence of ¹³C chemical shifts in bicyclo[3.3.1]nonane furnish a limit for the free energy difference between CC and BC conformations of ΔG ≧ 5,85 kJ mol^?1. The distinction between CC, BC and BB provides a test for the applicability of lanthanide-induced ¹H and ¹³C shifts for the assignment of flexible geometries. The typical occurrence of several and/or flat minima in the LIS geometry analysis allows only the exclusion of boat–boat conformations.     

Complexes of 4-hydroxyphenylthiocarboxyhydrazide with iron(II), cobalt(II,III), nickel(II), copper(II) and zinc(II)

Summary The 4-hydroxyphenylthiocarboxyhydrazide (Hoth) ligand has been characterized by i.r.,¹H and¹³C spectral studies. Its metal complexes with Fe^II, Co^II,III, Ni^II, Cu^II and Zn^II have been prepared and characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility. Mössbauer, visible, e.s.r., i.r.,¹H and¹³C n.m.r. spectral studies. The bonding and stereochemistry of the complexes are discussed. Hoth and its Cu^II complexes have been screened towards bacteria, viruses and fungi.     

13C NMR spectroscopy of polycyclic aromatics. VIII—amino derivatives of quinoline,isoquinoline, acenaphthene and fluoranthene

Complete assignments of the ¹³C n.m.r. spectra have been made for 5-aminoquinoline, 5-aminoisoquinoline, 5-aminoacenaphthene and 3-aminofluoranthene. Substituent-induced shifts are compared with those of the structurally related 1-aminonaphthalene. Some deviations within the series can be interpreted in terms of an increase of the exocyclic peri angle. An analysis of the ¹H n.m.r. spectrum of 3-aminofluoranthene is also given.     

Copper(II) and nickel(II) complexes of 2-formylpyridine 3-piperidinyl-, 3-hexamethyleneiminyl- and 3-azabicyclo[3.2.2]nonylthiosemicarbazones

Summary Copper(II) and nickel(II) complexes of 2-formylpyridine 3-piperidinyl-, 3-hexamethyleneiminyl- and 3-azabicyclo-[3.2.2]nonylthiosemicarbazones were prepared and characterized spectroscopically. ¹H and ¹³C n.m.r. spectra of the thiosemicarbazones and a diamagnetic nickel(II) complex are reported, together with i.r., electronic and e.s.r. spectra of the metal complexes. The thiosemicarbazones and their copper(II) and nickel(II) complexes exhibit considerable growth inhibitory activity against Paecilomyces variotii, but show minimal activity against Aspergillus niger.     

Spectral and biological studies of copper(II) complexes of 2-acetyl-pyridine thiosemicarbazones with bulky 4N-substituents

Summary Copper(II) complexes of a large number of 2-acetylpyridine ⁴N-alkyl thiosemicarbazones were prepared and characterized. I.r., electronic and e.s.r. spectra of the complexes, as well as ¹H and ¹³C n.m.r. spectra of the thiosemicarbazones, were obtained. Both the thiosemicarbazones and their complexes show either modest or no growth inhibitory activity against Aspergillus niger, but many have considerable activity against Paecilomyces variotii. There is a relationship between the antifungal activity and size of the ⁴N-substituent for both the thiosemicarbazones and their copper(II) complexes.     

N-Heterocyclic carbene complexes of palladium(II) and rhodium(I) with pendant ferrocenylmethyl groups: synthesis and electrochemistry

1-Ferrocenylmethyl-3-benzylimidazolidinium iodide and 1-ferrocenylmethyl-3-(2,4,6-trimethylbenzyl)imi-dazolidinium iodide were prepared in good yields by boiling, under reflux, a solution of (ferrocenylmethyl)- trimethylammonium iodide and the appropriate N-alkyl-2-imidazoline in MeCN. From the 1-ferrocenylmethyl-3-ben- zylimidazolidinium iodide salt, N-heterocylic carbene complexes of Pd^II and Rh^I were synthesized by in situ deprotonation and subsequent trapping. The new compounds were characterized by C, H, N analyses, ¹H-n.m.r., ¹³C-n.m.r. and by cyclic voltammetry. The n.m.r. properties of the complexes are compared with those of non-ferrocenylated carbene derivatives. The c.v.'s of these compounds show a number of resolved redox processes, indicating that CH₂Fc substituents are electronically isolated from the remaining molecular framework.     

Determination of ΔH≠ and ΔS≠ by simultaneous 1H and 13C dynamic n.m.r. studies: Importance of the accuracy of temperature measurement

From ΔG_Tc^≠ values obtained by ¹H and ¹³C dynamic nuclear magnetic resonance studies of the same dynamic process, it is possible to estimate ΔH^≠ and ΔS^≠. Nevertheless, the accuracy of the temperature measurement is a factor which limits the applicability of this method. A very simple procedure for calibrating the usual temperature sensors is described, which can be applied to all types of n.m.r. probes. By the use of this procedure it is possible to measure coalescence temperatures in ¹H and ¹³C n.m.r. with such an accuracy that ΔS^≠ can be effectively determined from the difference between ΔG_Tc^≠ values.     

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.     

Applications de la Résonance Dynamique du Proton et du Carbone-13 à l'Etude d'Azines Hétérocycliques. Mécanismes de Formation et d'Isomérisation

A ¹H and ¹³C n.m.r. study of heterocyclic azines is presented and the influence of Z/E isomerism on the ¹³C chemical shifts is examined. The kinetic study of the formation and Z/E isomerization of these compounds has been carried out and mechanisms of these reactions are discussed.     

Platinum(II) and palladium(II) complexes with substituted pyrimidines

Summary Platinum(II) and Palladium(II) complexes with 2-mercaptopyrimidine, 2-thiocytosine (4-aminopyrimidine 2-thione), and isocytosine (2-amino-4-hydroxy pyrimidine) were prepared and characterised by elemental analysis, conductivity data, i.r.,¹H n.m.r. and¹³C n.M.r. spectral studies. 2-Mercaptopyrimidine and 2-thiocytosine are coordinated to the metal ion through N(3) and C₂S, thus forming a four-membered chelate ring. Isocytosine acts as a monodentate ligand and coordinates to the metal ion through N(1). All the complexes are non-electrolytes.     

Etude par Résonance Magnétique Nucléaire de dérivés anthracéniques: II—Anisotropie magnétique du phényle et effets steriques

The peri effect induced by the phenyl group has been studied in the anthracene series by means of ¹H and ¹³C n.m.r. The chemical shifts of overcrowded protons can be explained by a combination of magnetic anisotropy and steric effects. Steric contributions amount to c. 25% of the phenyl induced shift at the peri position. Amongst published ring-current theories, only the model of Johnson and Bovey is capable of describing correctly the shielding region of the phenyl group. The unexpected shieldings and deshieldings, observed by ¹³C n.m.r. in the case of very hindered derivatives, is probably due to distortions of the anthracene skeleton.     

Coordinated lanthanide metal complexes ofN-benzoylglycine hydrazide

Summary N-benzoylglycine hydrazide (BzGH) reacts with trivalent lanthanide metal ions forming complexes of the type [Ln(BzGH)₂Cl(H₂O)₂]Cl₂·nH₂O, where Ln=La^III, Pr^III, Nd^III, Sm^III, Eu^III, Gd^III, Tb^III, Dy^III, or Y^III;n=1 or 2. 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 nephelauxetic ratio, the bonding parameter, Sinha's parameter and the covalency angular overlap parameter have been calculated from the electronic spectra of Pr^III, Nd^III and Sm^III complexes. Seven-coordination is proposed in the Nd^III complex. The i.r. and¹H n.m.r. spectral data suggest bidentate BzGH in all the complexes.     

N.m.r. spectra of prostaglandin metabolites and precursors and of related pyrazoline adducts

The ¹³C n.m.r. spectra of the major human urinary metabolite of prostaglandin PGE₂ and PGE₁ are discussed together with some unsaturated precursors. Δ-2-Pyrazolines, formed by addition of diazomethane to the 11-oxo dienediones in this series, were identified by ¹³C and ¹H n.m.r. and by other physical methods.