Hydrazinic Nitrogen Atoms Research Articles

Crystal and molecular structures of two polymorphs of 2,2-di(p-nitrophenyl)-1-picrylhydrazine dichloromethane, C18H11N7O10•CH2Cl2

Two polymorphic crystal forms (yellow and orange) of 2,2-di(p-nitrophenyl)-1-picrylhydrazine were crystallized from the same dichloromethane solution, and their crystal structures determined. The yellow form is triclinic, P1, a = 9.055(3), b = 10.396(4), c = 13.3187(3) Å, α = 89.83(2), β = 79.89(3), γ = 70.83(3)° at 228 K; R = 0.060, and Rw = 0.057 for 3511 reflections with I > 2σI. The orange form is monoclinic, P21/c, a = 8.999(3), b = 25.041(11), c = 12.207(5) Å, β = 121.66(2)° at 223 K; R = 0.053, and Rw = 0.058 for 3651 reflections with I > 2σI. The molecular structures in the two crystal forms are very similar. Both forms contain one solvent molecule per molecule of 2,2-di(p-nitrophenyl)-1-picrylhydrazine. In each, the two hydrazine nitrogen atoms have strong resonance interactions with the vicinal aromatic groups and both are sp2 hybridized. The molecular structure around the N—N linkage shows a staggered conformation. Thus the resonance interaction between the picryl group and the other two p-nitrophenyl groups is negligible. The difference in color between the two crystal forms is attributed to a difference in molecular packing. Key words: crystal structure, polymorphism, picrylhydrazine, conformation.

Mononuclear and binuclear lanthanum(III) complexes of macrocyclic ligands derived from 2,6-diacetylpyridine

Two novel series of complexes of types [La(DAPCH)X2]X and [La(DAPTC)X2]X (DAPCH = a potentially pentadentate ligand derived from 2,6-diacetylpyridine and carbohydrazide; DAPTC = a potentially tridentate ligand derived from 2,6-diacetylpyridine and thiocarbohydrazide; X = Cl, Br or NO3) have been synthesized and characterized by elemental analyses, conductance measurements and IR spectral data. All these complexes contain terminal hydrazinic nitrogen atoms with an unshared electron pair and may take part in nucleophilic condensations. Therefore, the reactions of these complexes with 2,6-diacetylpyridine have also been studied which cause ring closure and formation of macrocyclic ligand complexes. Two types of cyclic products, viz. mononuclear [La(mac)X2]X, [La(mac′)X2]X and binuclear [La2(mac)X4]X2, [La2(mac′)X4]X2 (mac- = macrocyclic ligand derived from DAPCH and 2,6-diacetylpyridine; mac′ = macrocyclic ligand derived from DAPTC and 2,6-diacetylpyridine; X = Cl, Br or NO3) have been isolated by carrying out the reactions by different methods. The IR spectra of these cyclic products are reported.

N-pyridoxylidenehydrazine-N',N'-diacetic acid. III. Formation of metal chelates in solution.

Metal chelate formation of N-pyridoxylidenehydrazine-N ', N '-diacetic acid (1) and related hydrazines in solution was studied by means of absorption spectroscopy. Compound 1 and N-pyridoxylidene-N'-methylhydrazine (2) in methanol formed Cu (II) chelates of the same spectral character, which indicated the chelation of the phenolate oxygen and the hydrazine nitrogen atoms to Cu (II). The compositions of the chelates were 1 : 1 for 1 and 1 : 2 for 2, indicating that 1 acts as a tri- or tetradentate ligand. N- (3-Hydroxy-4-pyridylmethylene) hydrazine-N', N'-diacetic acid formed a Cu (II) chelate similar to that of 1 but N-pyridoxylidene-N', N'-dimethylhydrazine and N-pyridoxylidene-N', N'-diphenylhydrazine did not form chelates under similar conditions. Addition of an equimolar or excess amount of Co (II), Ni (II), Zn (II), Cd (II) or La (III) salt to 1 in methanol gave rise to absorption assignable to the chelate of 1, whereas 2 did not form metal chelates under the same conditions. It was concluded that the iminodiacetic acid moiety of 1 coordinated to the metal ions and enhanced the stability constant of the metal chelates.

Mechanisms of heterocycle ring formation. Part 5. A carbon-13 nuclear magnetic resonance study of pyrazolinone synthesis by the reaction of β-ketoesters with substituted hydrazines

The 16 reactions between each of four hydrazines and four β-ketoesters have been followed by 13C n.m.r. spectroscopy. Peaks were assigned to starting materials, intermediates, and products, and reaction mechanisms determined and rationalized. Most reactions proceed by attack of the least hindered hydrazine nitrogen atom on the keto carbon group of the ketoester. Relative rates of nucleophilic attack determine the build-up of intermediate and in some cases the nature of the products formed.

The crystal structure of potassium 1-(N,N-diphenylhydrazono)-2,4,6-trinitrobenzenide

Crystals of potassium 1-(N,N-diphenylhydrazono)-2,4,6-trinitrobenzenide, C18H12N5O6K, are monoclinic, P21/c, a = 9.871(2), b = 12.940(3), c = 16.754(4) Å, β = 118.31(1)°, Z = 4, T = 22 °C. Diffraction data were collected on a modified Picker FASC-1 diffractometer. The structure was solved by direct methods and refined by full-matrix least-squares to R = Rw = 0.056 using the 2627 independent reflections with [Formula: see text]. The benzenide ring shows a significant puckering toward the boat conformation. Some important canonical structures contributing to the average geometry of the molecule are discussed. The bonding sphere of the K+ cation contains all of the oxygen atoms and the hydrazine nitrogen atom bonded to the trinitrobenzenide group. Two phenyl carbon atoms also have short contact distances to the cation.

Novel Mononuclear and Binuclear Zinc(II), Cadmium(II) and Mercury(II) Complexes of Macrocyclic Ligands

Abstract A novel series of complexes of the type [M(DAPTH)X2] (M = Zn(II), Ca(II) or Hg(II); DAPTH = pentadentate ligand derived from 2,6-diacetylpyridine and thiocarbohydrazide, X = Cl, Br, CH3COO), have been synthesized and characterized by elemental analyses, electrical conductance measurements and infrared spectral data. The ligand DAPTH is found to behave as a pentadentate ligand having coordination sites at the pyridine nitrogen, two azomethine nitrogens and two thioamide sulphur atoms. Tentative structures have been proposed for these complexes. All of these complexes contain terminal hydrazinic nitrogen atoms with an unshared electron pair and may take part in nucleophilic condensations. Therefore, the reactions of these complexes with 2,6-diacetylpyridine have also been studied which cause ring closure and formation of macrocyclic ligand complexes. Two types of cyclic products, viz. mononuclear [M(L«)X2] and binuclear [M2(L«)X4] (M = Zn(II), Cd(II) or Hg(II); L« = macrocyclic ligand derived from ...

ZINC(II), CADMIUM(II) AND MERCURY(II) COMPLEXES OF MACROCYCLIC LIGANDS DERIVED FROM 2,6-DIACETYLPYRIDINE

Abstract A novel series of complexes, of the type [M(DAPCH)X2(M=Zn(II), Cd(II) or Hg(II); DAPCH =planar pentadentate ligand derived from 2,6-diacetylpyridine and carbohydrazide, X=Cl, Br, I, NO3, CH3COO) have been synthesized and characterized by elemental analyses, conductance measurements and infrared spectral data. The ligand DAPCH appears to behave as a pentadentate ligand, having coordination sites at one pyridine nitrogen, two azomethine nitrogen and two amide oxygen atoms. Possible structures are proposed for these complexes. All the complexes contain terminal hydrazinic nitrogen atoms with an unshared electron pair and may take part in nucleophilic condensations. Therefore, the reactions of these complexes (X=Cl, Br, NO3) with 2,6-diacetylpyridine have also been studied viz., ring closure and formation of macrocyclic ligand complexes. Two types of cyclic products viz., mononuclear [M(L′)X2] and binuclear [M2(L′)X4] (M=Zn(II), Cd(II) or Hg(II); L=macrocyclic ligand derived from DAPCH and 2,6-diacet...

Beiträge zur Chemie des Bors, CVII [1] Über Darstellung und Struktur eines tetraborylierten Hydrazins / Contributions to the Chemistry of Boron, CVII [1] On the Preparation and Structure of a Tetraborylated Hydrazine

N,N,N′-Tris- and N,N,N′,N′-tetrakis(1,3-dimethyl-1,3,2-diazaborolidinyl)hydrazine (4)were prepared via N,N′-lithiated N,N′-bis(1,3-dimethyl-1,3,2-diazaborolidinyl)hydrazine. 4 crystallizes monoclinic.The N-N axes of the 4 molecules coincide with the crystallo-graphic twofold axes. Its N-N bond is rather long(146.4qm and the ring BN bonds are shorter than the BN bond to the hydrazine nitrogen atoms. This indicates preferential electronic saturation of the boron atoms via ring BN II bonding.

Electron impact mass spectral studies of hydrazine monoamine oxidase inhibitor drugs

Identification of hydrazine monoamine oxidase inhibitor drugs such as isoniazid, iproniazid, nialamide, isocarboxazid and iproclozide is made by electron impact mass spectrometry using the direct insertion technique. The molecular ion itself, although of low relative abundance, is found in the mass spectra of all compounds studied. Relative intensities of the major fragments and data on metastable ions useful in the identification of these compounds are reported. With the aid of synthesized structurally related products, deuterium labelling of exchangeable hydrazidic and hydrazinic protons and by the use of hexadeuterated isopropylic analogues, detailed information about fragmentation patterns is obtained. Splitting processes are chiefly governed by the nature of the aromatic substituent at the hydrazidic end and the alkyl sidechain located at the second hydrazinic nitrogen. The major fragmentations occurring are loss of small neutral molecules, double rearrangement, cleavage of the NN bond, amide bond rupture, β-cleavage to the hydrazinic nitrogen atom and McLafferty rearrangements.