Phase and chemical effects on the reaction of13N formed in pile-irradiated carboxylic acid-dx

A remarkable temperature effect was observed on the formation of¹³NH₃ and H¹³NO_x in pile-irradiated acetic acid-d₄ and trifluoroacetic acid-d, although little effect was recognized on [¹³N] amide and [¹³N] amino acid. The scavenger effect of acetic anhydride-d₄ was examined for the¹³N-compounds formed in acetic acid-d₄. On¹³NH₃ and H¹³NO_x formed in acetic acid-d₄, propionic acid-d₆ and trifluoroacetic acid-d, a linear correlation was obtained between the yields of the¹³N-compounds and the number of hydrogen atoms in a target molecule. A reaction mechanism containing radical reactions is discussed.     

Chemical effect of13N formed in butyric-d7 acid irradiated in a pile

A distinct phase effect was observed on the formation of¹³NH₃, H¹³NO_x and [¹³N]-amide in pile-irradiated butyric-d₇ acid, although the magnitude of the effect was rather smaller than that in deuterated trifluoroacetic, acetic and propionic acids previously reported. In frozen butyric-d₇ acid, most of¹³N was found in the forms such as¹³NH₃ (54.8±0.7%), H¹³NO_x (26.8±0.6%). and [¹³N]amide (15.9±1.8%). The yields of HC¹³N and [¹³N]aminobutyric acid were only 0.6±0.3 and 1.2±0.3% even in the liquid, respectively. The scavenger effect of acetic anhydride-d₆ on the formation of¹³NH₃, H¹³NO_x and [¹³N]amide was examined. In liquid and frozen carboxylic acids, the yields of¹³NH₃ and H¹³NO_x were proportional and inversely proportional to the number of hydrogen atoms in a target molecule in the region of the number of hydrogen from unity to eight.     

Reaction of13N atoms formed in propionic acid-d6 irradiated in a nuclear reactor

The chemical behaviour of¹³N formed by the¹²C/d,n/¹³N reaction by recoil deuterons was studied in propionic acid-d₆ irradiated at 195 to 295 K for 10 min in a reactor. The yields of¹³NH₃ and H¹³NO_x showed remarkable change with the phase change of the media from solid to liquid, i.e., the yield of¹³NH₃ increased from 49.1±2.6 to 57.3±1.5% and that of H¹³NO_x decreased from 28.9±1.8 to 20.4±1.9%. Based on the results, reaction mechanisms involved were argued as: /A/ formation of primary radicals, NH and HNO or NO, and /B/ subsequent reactions converting primary products to the final forms.     

Phase and dose effects of13N in pile-irradiated propionic-d2 acid

A sharp phase effect on the yields of¹³NH₄ ⁺ and¹³NO₂ ^– has been observed in propionic-d₂ acid irradiated in a reactor similarly to the other carboxylic acids previously reported. In the formation of¹³NH₄ ⁺,¹³NO₂ ^– and [¹³N]amide, there is no (H/D)-isotope effect between CH₃CD₂COOH and C₂D₅COOD systems unlike for protiated and deuterated benzene and cyclohexane. With a rise in irradiation dose from 100 to 400 MGy, the yield of¹³NH₄ ⁺ increased, but that of¹³NO₂ ^– decreased in proportion to the dose. The dose effect was clear more in liquid phase than in frozen one. The results are in harmony with the reaction mechanism proposed in our previous works.     

Kinetic Study of the Isotope Exchange Reactions of Malonic Acid and Malonate Ion Using 1H NMR Spectroscopy. Inhibition of Acid and Base

The isotope exchange reactions of malonic acid and a malonate ion were investigated in acidic and basic D₂O solutions, respectively, using ¹H NMR spectroscopy. The isotope exchange reaction of malonic acid is inhibited by the presence of DNO₃ (0–3 M) and DSO₄^? ion (0–0.1 M), whereas it is catalyzed by the presence of DSO₄^? ion (> 0.2 M), D₃PO₄, D₂PO₄^? ion or DPO₄^2– ion. The order of relative reactivity for catalyzing the isotope reaction of malonic acid in D₂O is DPO₄^2– > D₂PO₄^? > D₃PO₄ > DSO₄^? > DNO₃. The rate of the isotope exchange reaction of malonate ion in D₂O decreases to a minimum and then increases with increased [NaOD]₀. The mechanism of the isotope exchange reaction of malonic acid in acidic D₂O is different from the general acid-catalyzed mechanism generally observed for organic acids like acetic and dichloroacetic acids. The bimalonate ion plays an important role in the isotope exchange reactions of this system.     

Kinetics of polymerization of N,N-methylenebisacrylamide initiated by KMnO4-H2C2O4 redox system

A kinetic study of the gel free polymerization of the divinyl monomer N,N′-methylenebisacrylamide has been made using permanganate-oxalic acid system as redox initiator; R_p is proportional to [monomer]², [KMnO₄] and [H₂C₂O₄]⁰. A cyclopolymerization mechanism is proposed. A complex between monomer and Mn³⁺ participates, in addition to the complex [Mn(HC₂O₄)₂]⁺.     

Greener approach: Ionic liquid [Et3NH][HSO4]-catalyzed multicomponent synthesis of 4-arylidene-2-phenyl-5(4H)oxazolones under solvent-free condition

We have developed simple, greener, safer multicomponent synthesis series of 4-arylidene-2-phenyl-5(4H) oxazolones 4(a-r) catalyzed by Bronsted acid ionic liquid as triethylammonium hydrogen sulfate [Et₃NH][HSO₄] and catalytic amount of acetic anhydride and sodium acetate with excellent yields (90–99%). The protocol offers economical, environmentally benign, solvent-free conditions, and recycle–reuse of the catalyst and easily available starting as benzoyl chloride 1, amino acid 2 and a variety of aldehydes 3. The cyclization followed by condensation of benzoyl chloride, amino acid, and a variety of aldehydes catalyzed by ILs [Et₃NH][HSO₄] and catalytic amount of acetic anhydride and sodium acetate. The final products were confirmed by their characterization data such as FTIR, ¹H-NMR, ¹³C-NMR, Mass, high-resolution mass spectra and were compared with its reported method.     

Monitoring and Understanding the Paraelectric–Ferroelectric Phase Transition in the Metal–Organic Framework [NH4][M(HCOO)3] by Solid‐State NMR Spectroscopy

The paraelectric–ferroelectric phase transition in two isostructural metal–organic frameworks (MOFs) [NH₄][M(HCOO)₃] (M=Mg, Zn) was investigated by in situ variable‐temperature ²⁵Mg, ⁶⁷Zn, ¹⁴N, and ¹³C solid‐state NMR (SSNMR) spectroscopy. With decreasing temperature, a disorder–order transition of NH₄⁺ cations causes a change in dielectric properties. It is thought that [NH₄][Mg(HCOO)₃] exhibits a higher transition temperature than [NH₄][Zn(HCOO)₃] due to stronger hydrogen‐bonding interactions between NH₄⁺ ions and framework oxygen atoms. ²⁵Mg and ⁶⁷Zn NMR parameters are very sensitive to temperature‐induced changes in structure, dynamics, and dielectric behavior; stark spectral differences across the paraelectric–ferroelectric phase transition are intimately related to subtle changes in the local environment of the metal center. Although ²⁵Mg and ⁶⁷Zn are challenging nuclei for SSNMR experiments, the highly spherically symmetric metal‐atom environments in [NH₄][M(HCOO)₃] give rise to relatively narrow spectra that can be acquired in 30–60 min at a low magnetic field of 9.4 T. Complementary ¹⁴N and ¹³C SSNMR experiments were performed to probe the role of NH₄⁺–framework hydrogen bonding in the paraelectric–ferroelectric phase transition. This multinuclear SSNMR approach yields new physical insights into the [NH₄][M(HCOO)₃] system and shows great potential for molecular‐level studies on electric phenomena in a wide variety of MOFs.     

Lanthanide Complexes of Polyacid Ligands derived from 2, 6-bis(pyrazol-1-yl)pyridine,pyrazine, and 6, 6′-bis(pyrazol-1-yl)-2, 2′-bipyridine: Synthesis and luminescence properties

The synthesis of three novel pyrazole-containing complexing acids, N,N,N′,N′-{2, 6-bis[3-(aminomethyl)pyrazol-1-yl]-4-methoxypyridine}tetrakis(acetic acid)( 1 ), N,N,N′,N′-{2, 6-bis[3-(aminomethyl)pyrazol-1-yl]pyrazine}-tetrakis(acetic acid) ( 2 ), and N,N,N′,N′-{6, 6′-bis[3-(aminomethyl)pyrazol-1-yl]-2, 2′-bipyridine}tetrakis(acetic acid) ( 3 ) is described. Ligands 1–3 formed stable complexes with Eu^III, Tb^III, Sm^III, and Dy^III in H₂O whose relative luminescence yields, triplet-state energies, and emission decay lifetimes were measured. The number of H₂O molecules in the first coordination sphere of the lanthanide ion were also determined. Comparison of data from the Eu^III and Tb^III complexes of 1–3 and those of the parent trisheterocycle N,N,N′,N′-{2, 6-bis[3-(aminomethyl)pyrazol-l-yl]pyridine}tetrakis(acetic acid) showed that the modification of the pyridine ring for pyrazine or 2, 2′-bipyridine strongly modify the luminescence properties of the complexes. MeO Substitution at C(4) of 1 maintain the excellent properties described for the parent compound and give an additional functional group that will serve for attaching the label to biomolecules in bioaffinity applications.     

Heck coupling reaction using monomeric ortho‐palladated complex of 4‐methoxy‐ benzoylmethylenetriphenylphosphorane under microwave irradiation

The activity of [Pd(C₆H₄CH₂ NH₂‐κ²‐C‐N)PPh₃MOBPPY]OTf complex, A (MOBPPY = 4‐methoxybenzoylmethylenetriphenyl‐ phosphoraneylide), was investigated in the Heck–Mizoroki C? C cross‐coupling reaction under conventional heating and microwave irradiation conditions. The complex is an active and efficient catalyst for the Heck reaction of aryl halides. The yields were excellent using a catalytic amount of [Pd(C₆H₄CH₂ NH₂‐κ²‐C‐N)PPh₃MOBPPY]OTf complex in N‐methyl‐2‐pyrrolidinone (NMP) at 130 °C and 600 W. In comparison to conventional heating conditions, the reactions under microwave irradiation gave higher yields in shorter reaction times. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.     

A liquid membrane ammonium-selective electrode based on the tris(2-nitroso-4-chlorophenol)iron(II) anion

Liquid membrane electrodes based on ion-association extraction systems responding to the ammonium ion are described. The tris(2-nitroso-4-chlorophenol)iron(II) anion in a nitrobenzene solution gives an electrode exhibiting Nernstian response in the range 1–10^-4 M ammonium ion (slope, 60 mV) in solutions of pH 4–9. The order of the selectivity coefficients (K_ij) is N(CH₃)⁺₄ > NH(CH₃)⁺₃ > NH₂(CH₃)⁺₂ > NH₃CH⁺₃ > K⁺ > NH⁺₄ > Na⁺ > Li⁺.     

Synthesis and Dehydrogenation of Organic Salts of a Five-Membered B/N Anionic Chain,a Novel Ionic Liquid

We have synthesized the tetrabutylammonium ([Bu₄N]⁺), tetraethylammonium ([Et₄N]⁺), guanidinium ([C(NH₂)₃]⁺), and methylguanidinium ([C(N₃H₅CH₃)]⁺) salts of the [BH₃(NH₂BH₂)₂H]⁻ anion, a five-membered B/N anionic chain, in high yields by the metathesis reactions of Na[BH₃(NH₂BH₂)₂H] with the corresponding halides and characterized them by NMR (¹¹B, ¹¹B{¹H}, ¹H, ¹H{¹¹B}, ¹³C), IR, elemental analysis, TGA-DSC, and TGA-MS. These complexes behave like ionic liquids (ILs), in which the melting point of the [Bu₄N][BH₃(NH₂BH₂)₂H] is the lowest (−51 °C). The dehydrogenation of these ILs have been studied through the thermal decomposition and catalytic hydrolysis in aqueous solution using the noble or non-noble metals or their salts as catalysts, and the results indicate that these ILs of five-membered B/N anionic chain are promising hydrogen storage materials.     

Stereoselektive Synthesen vons-Decahydropyrenen

Incomplete catalytic hydrogenation of [2.2]metacyclophane (1) or 5,13-dimethyl[2.2]metacyclophane (2) yields (1,2,3,3arH, 4,5,9,10,10acH, 10btH)-decahydropyrene (9) and the dimethylanalogue10, resp.via atransanular cyclisation between positions 8 and 16. Under the same reaction conditions catalytic deuteration (D₂, acetic acid-d₁) affords a selectively deuterated10 (10-d₅).9 is identical with as-decahydropyrene, obtained by high pressure hydrogenation of pyrene. The configurations of9 and10 were established by means of¹³C and¹H-NMR spectroscopy and by comparison with10-d₅.A compound formerly believed to be as-decahydropyrene isomer is shown to be (±)-(1,2,3,3a,4,5,9,10)-octahydropyrene (4).

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Mit 4 Abbildungen

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Herrn Prof. Dr.F. Hecht zum 70. Geburtstag gewidmet.

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Auszugsweise vorgetragen bei der Tagung des Vereins Österreichischer Chemiker in Linz am 27. September 1973.     

Synthesis and characterization of Hg(II) and Zn(II) complexes based on 3-[(4-chlorophenylamido)]propenoic acid

3-[(4-Chlorophenylamido)]propenoic acid has been synthesized by reaction of maleic anhydride and 4-chloroaniline in 1:1 molar ratio in glacial acetic acid and its metal complexes have been synthesized by the reaction of 3-[(4-chlorophenylamido)]propenoic acid with HgCl₂ and [Zn(CH₃COO)₂] · 2H₂O in 2: 1 molar ratio, respectively. All the synthesized compounds have been characterized by the elemental analysis, IR, UV/Vis and NMR (¹H, ¹³C) spectroscopy. Conductance for the reported compounds has been recorded in ethanol and suggests the non-electro lytic nature of complexes. IR data of metal complexes shows that the ligand is bound to the metal via both carboxylate oxygen atoms and complexes exhibits 4-coordinated geometry in solid state. NMR (¹H, ¹³C) study confirms the structure of the 3-[(4-chlorophenylamido)]propenoic acid and the reported complexes.     

A comparative homocoupling reaction of aryl halides using monomeric orthopalladated complex of 4‐methoxybenzoylmethylenetri‐ phenylphosphorane under conventional and microwave irradiation conditions

The activity of [Pd(C₆H₄CH₂NH₂‐κ²‐C‐N)PPh₃MOBPPY]OTf complex, A (MOBPPY = 4‐methoxybenzoylmethylenetriphenylphosphoraneylide) was investigated in the homocoupling reaction of a vast range of aryl halides under both conventional and microwave irradiation conditions and their results were compared. The complex was active and showed high efficiency in the formation of new C‐C bonds. The yields were excellent using a catalytic amount of [Pd(C₆H₄CH₂NH₂‐κ²‐C‐N)PPh₃MOBPPY]OTf complex in N, N‐dimethylformamide at 120 °C. In comparison to conventional heating conditions, the reactions under microwave irradiation gave higher yields in shorter reaction times. Copyright © 2011 John Wiley & Sons, Ltd.     

Rubidium-decaamidodichromat(III), Rb4Cr2(NH2)10 – Synthese und Kristallstruktur

Rubidium Decaamidodichromate(III), Rb₄Cr₂(NH₂)₁₀ – Synthesis and Crystal Structure The reaction of chromium(III) with rubidium amide in a molar ratio of Cr(NH₂)₃/RbNH₂ = 1 : 1.75 at 140 °C and p(NH₃) = 3 kbar in a high-pressure autoclave results after 90 days in dark violet crystals of Rb₄Cr₂(NH₂)₁₀. Structure determination was done by single crystal X-ray methods:Pna2₁ (No. 33), Z = 4, a = 12.244(3) Å, b = 6.727(1) Å, c = 19.775(5) Å, N(F²_o > 3σ(F²_o)) = 1046, N(Var.) = 94, R/R_w = 0,051/0,059&#TAB;The structure of Rb₄Cr₂(NH₂)₁₀ contains isolated, face-sharing N-octahedra around two Cr³⁺-ions giving [Cr(NH₂)₃(NH₂)_3/2]₂^3–. These are arranged to oneanother following the motif of a hexagonal closest packing. They are connected via Rb⁺- and one further amide ion not bound to Cr³⁺. The compound is characterized by thermoanalytical and IR-/Raman-spectroscopic measurements.     

Transannular Addition of Phenols to 1,1′‐Dialkynylferrocenes: Unanticipated Formation of Phenoxy[4]ferrocenophanedienes

The reaction of some 1,1′‐dialkynylferrocenes with a variety of phenols in the presence as well as in the absence of [Mo(CO)₆] yields good to high yields of phenoxy[4]ferrocenophanedienes. Similar reactivity was observed with a thiophenol and with acetic acid. Reaction under basic reaction conditions led to the formation of the [4]ferrocenophanone 17 . The phenoxy[4]ferrocenophanedienes obtained show dynamic behavior as a result of a torsional twist of the carbon bridge as indicated by the ¹H and ¹³C NMR spectra. The reaction mechanism is discussed in view of recent related results of Sato et al. as well as of Pudelski et al. A vinyl cation intermediate is postulated in this context, whose relative stability is evident from the mass spectra of the compounds prepared.     

Synthesis of Ammonium‐ and 4‐Dimethylaminopyridinium Amidofluorophosphates and Crystal Structure of [DMAPH][PO2F(NH2)]

NH₄[PO₂F(NH₂)] has been prepared by the reaction of a betaine py·PO₂F with excess ammonia in acetonitrile solution, while the ammonolysis of DMAP·PO₂F with a stoichiometric amount of NH₃ yields [DMAPH][PO₂F(NH₂)]. The crystal structure of the latter was determined by single‐crystal X‐ray diffraction, which revealed that the anions [PO₂F(NH₂)]^— are linked to infinite chains by double N—H···O bridges. Additional strong N—H···O bridging bonds connect each anion with its [DMAPH]⁺ counterion. The formation of a new betaine NH₃·PO₂F in the solution of py·PO₂F in liquid ammonia was proved by ³¹P NMR spectroscopy and by identification of its hydrolysis products.     

Synthesis and physico-chemical studies of metal(II) complexes with diacetyl benzaldehyde acyldihydrazones and their bio-activity

Complexes of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with diacetyl benzaldehyde oxalic acid dihydrazone (dbodh), CH₃COC(CH₃)=NNHCOCONHN=CHC₆H₅ and diacetyl benzaldehyde malonic acid dihydrazone (dbmdh), CH₃COC(CH₃)=NNHCOCH₂CONHN=CHC₆H₅ of general composition [M(dbodh)Cl]Cl and [M(dbmdh)Cl]Cl were synthesized and characterized by microanalyses, molar conductance, magnetic susceptibility, UV–Vis, ESR and IR spectra and X-ray diffraction studies. The complexes are 1 : 1 electrolytes in DMF and are insoluble in water and common organic solvents. The dbodh and dbmdh are neutral tridentate ligands in most complexes and coordinate via one >C=O and two >C=N–groups. In Cu(II) complexes the ligands are pentadentate coordinating through three >C=O and two >C=N–groups. The magnetic moment values and UV–Vis spectra suggest square-planar geometry for Co(II) and Ni(II) complexes and distorted octahedron for both Cu(II) complexes. The ESR spectra of Cu(II) complexes show well-defined copper hyperfine lines in DMSO solution at 120 K and exhibit d _{x ² ?y ²} as the ground state. The X-ray diffraction parameters for [Ni(dbodh)Cl]Cl and [Co(dbmdh)Cl]Cl correspond to a tetragonal crystal lattice. The complexes show significant antifungal activity against Alternaria sp., Curvularia sp. and Colletotrichum sp. and fair antibacterial activity against Bacillus subtilis and Pseudomonas fluorescence.     

Transition Metal Complexes with the Thiosemicarbazide-based ligands. XII. Complexes of nickel(II) with benzoylacetone S-methylisothiosemicarbazone and N(1)-2-butylidene-4-oxo-4-phenyl-N(4)-salicylidene-S-methylisothiosemicarbazide

A template synthesis procedure yielded [Ni(HL¹)NH₃]I, where HL¹ is the monoanion of the terdentate ONN benzoylacetone S-methylisothiosemicarbazone ligand. The reaction of this complex with an excess of NH₄NCS, pyridine, or hydrazine resulted in the complexes [Ni(HL¹)(NH₃)NCS] and [Ni(L¹)A] (A = Py, N₂H₄). The monoanionic form of the ligand is obtained by deprotonation of the enolic form of the benzoylacetone moiety, whereas the dianion is formed by additional deprotonation of the terminal NH₂ group. Finally, the reaction of [Ni(HL¹)NH₃]I with salicyladehyde produced the NiL² complex in which L² stands for the dianion of the ONNO ligand N(1)-2-butylidene-4-oxo-4-phenyl-N(4)-salicylidene-S-methylisothiosemicarbazide. All complexes are diamagnetic and have a square-planar configuration, except for [Ni(HL¹)(NH₃)NCS], for which te data of i.r. spectra suggest a square-pyramidal structure. The electronic absorption spectra of the ethanolic solutions of all complexes are characteristic of typical square-planar coordination of nickel(II).