Hexamethylenetetramine Complexes Research Articles

Complexes of hexamethylenetetramine with zinc-tetraarylporphyrins, and their assembly modes in crystals as clathrates and hydrogen-bonding network polymers

This study reveals self-assembly patterns of the tetra(4-pyridyl), tetra(4-hydroxyphenyl) and tetra(4-carboxyphenyl) zinc porphyrin moieties when reacted with a hexamethylenetetramine ligand, forming 1 ∶ 1 five-coordinate, 1 ∶ 2 and 1 ∶ 2 six-coordinate complexes, respectively. Detailed structural characterization of the supramolecular organization in the resulting ordered solids is reported. Crystals of the 1 ∶ 1 complex (1) represent a common tetraarylporphyrin clathrate found earlier in the “porphyrin sponges”. Those of the 1 ∶ 2 complexes consist of multiporphyrin polymeric networks that are sustained by extensive hydrogen bonding, involving the four hydroxylic (in 2) or carboxylic (in 3) functional substituents as proton donors and the N-sites of the hexamethylenetetramine ligand as proton acceptors. The polymeric frameworks are characterized by three-dimensional (in 2) or two-dimensional (in 3) open architectures with wide interporphyrin voids; yet, they do not interpenetrate into one another, giving rise to the formation of open channels that perforate the corresponding crystals and are loosely occupied by guest species of the crystallization solvent. The pronounced effect of the hexamethylenetetramine ligand on the supramolecular aggregation is highlighted, by relating the current findings to previously designed networks of the porphyrin building blocks in question.

Solid Phase Synthesis, Characterization of Hexamethylenetetramine Complexes of Antimony and Bismuth Trichloride

New hexamethylenetetramine complexes of antimony and bismuth trichloride were synthesized through a solid phase reaction of hexamethylenetetramine and antimony or bismuth trichloride. The formula of the complex is MCl3(C6H12N4)2⋅H2O (M=Sb, Bi).The crystal structure of the complexes belongs to monoclinic system and the lattice parameters: a=1.249 nm, b=1.4583 nm, c=1.6780 nm andβ=91.78° for SbCl3(C6H12N4)2⋅H2O and a=1.3250 nm, b=1.3889 nm, c=1.7449 nm and β=98.94° for BiCl3(C6H12N4)2⋅H2O. Far-infrared spectra reveal that the antimony or bismuth ion is coordinated by the nitrogen atom of the hexamethylenetetramine. The thermal analysis also demonstrates the complex formation between the antimony or bismuth ion and hexamethylenetetramine. The intermediate and final residues in the thermal decomposition process have been analyzed to check the pyrolysis reaction.

Effect of hydrogen bond in hexamethylenetetramine–MOH (M=Li, Na, K) complexes

14N NQR and IR spectra of the hexamethylenetetramine(HMT)–MOH complexes (M=Li, Na, and K) were investigated at room temperature. NQR lines were assigned to two (for LiOH and NaOH complexes) and three (for KOH complex) inequivalent nitrogen sites. The frequency shift is accounted for redistribution of the charges because of the charge transfer, and the line broadening is deduced from the difference of electronegativity between the charge donor and acceptor in the hydrogen bond. For the IR spectra, there are deformations of CNC bond owing to the hydrogen bond of nitrogen in HMT with OH in MOH and the direct bonding of nitrogen with alkali metal (Li, Na, and K) ion. In view of the deformation of the CNC bond in HMT molecules from the IR results one may propose that the most important part of polarization produced by the crystalline field in the HMT complexes is the electronic polarization.

The catalytic effect of some transition metal hexamethylenetetramine complexes in hydrogen peroxide decomposition

The kinetics of the catalytic decomposition of H 2O 2 with Wofatit KPS resin (4% DVB, 40–80 μm) in the form of 1:1 copper(II)-, manganese (II)-, cobalt(II)- and nickel(II)-hexamine complexes was studied in an aqueous medium. The decomposition reaction was first order with respect to [H 2O 2] and the rate constant, k (per g of dry resin) increased in the following sequence: Mn (II) &>; Co (II) &>; Cu (II) &>; Ni (II). The active species, formed as an intermediate at the beginning of the reaction, had an inhibiting effect on the reaction rate. An anionic surfactant, sodium dodecyl sulphate (SDS), considerably inhibited the reaction rate. A probable mechanism for the decomposition process has been suggested, which is consistent with the results obtained.

X-ray diffraction studies on hexamethylenetetramine complexes with cobalt(II) and nickel(II) thiocyanates

X-ray diffraction studies on hexamethylenetetramine complexes with cobalt(II) and nickel(II) thiocyanates

Metal complexes of polycyclic tertiary amines. Part VII. Preparation and crystal structure determination of polymeric hexamethylenetetramine—mercury(II) thiocyanate ( [formula omitted]), (CH 2) 6N 4·2Hg(SCN) 2

A 1:2 complex of hexamethylenetetramine with mercury(II) thiocyanate, (CH 2) 6N 4·2Hg(SCN) 2, was prepared and shown by X-ray crystallography to be polymeric. The mixed-ligand complex crystallizes in the space group P2 1/ m, with a = 6.059(2), b = 19.710(5), c = 7.895(2) Å, β = 105.63(2)°, and Z = 2. The structure was refined to R F = 0.060 for 1634 observed MoKα diffractometer data. Mercury(II) atoms in a row are linked pairwise by two thiocyanato groups in an end-to-end bridging mode, to give an infinite chain running in the a direction. Two neighboring chains are further laterally connected, successively by bidentate organic ligands which lie on a crystallographic mirror plane. The coordination geometry about Hg(II) is distorted tetragonal pyramidal, the metal atom binding strongly to two S atoms and a tertiary amino N atom (apex), and weakly to two thiocyanato N atoms.

Nuclear quadrupole resonance study of some hydrogen-bonded complexes of hexamethylenetetramine

Abstract The 14N NQR spectrum of complexes of hexamethylenetetramine (HMT) with p-chlorophenol (1:2) (also the 3501 NQR spectrum in this compound), hydroquinone (1:1), and thiourea (1:2) was observed at 77 K. The analysis of the NQR data obtained for the H-bonded and non-H-bonded N atoms in the HMT complexes showed that effects like polarization, exchange, and dispersion are as important as charge transfer in the charge rearrangement produced by weak and moderately strong H bonds. It was also found that the effect of the H bond on the electronic distribution is extended over the entire molecule and that the crystalline electric field also produced additional molecular charge rearrangement.

14N NQR study of hydrogen bonded complexes of 1,4 diazabicyclo [2,2,2] octane (ted) with phenols and thiourea

The 14N NQR spectra of H bonded complexes of 1,4 diazabicyclo [2,2,2] octane, also known as triethylenediamine (TED), with phenol (1:2), p-chlorophenol (1:2), p-nitrophenol (1:2), hydroquinone (1:1), resorcinol (1:1) and thiourea (1:2) were observed at 77 K. The 14N frequency shifts produced by the H bonds in the TED complexes were approximately two times larger than those found for similar complexes of Hexamethylenetetramine (HMT). Such change was explained by the effect on the remaining N atoms of the increase in the number of -CH 2- groups and the decrease in N atoms in passing from HMT to TED. From the above results it seems that the inductive effect plays an important role in the formation of H bonds in tertiary amines like HMT and TED.

Spectrophotometric assay of hexamethylenetetramine

The intense charge-transfer band in the ultraviolet spectra of the molecular complex of hexamethylenetetramine with iodine has been utilised in the sensitive spectrophotometric assay of this compound. From the various polar and halogenated solvents that were investigated, 1,2-dichloroethane and chloroform were selected. The hexamethylenetetramine-iodine complex has two peaks. Maximum intensity was attained at the shorter wavelength band, 273 nm, Iµ= 2.0 × 104 l mol–1 cm–1 in 1,2-dichloroethane and 270 nm, Iµ= 1.6 × 103 l mol–1 cm–1 in chloroform. The effect of time on the stability of the complex was investigated. A Job's plot of absorbance versus the molar ratio of hexamethylenetetramine to iodine indicated a 1 : 1 hexamethylenetetramine to iodine ratio. Accurate analysis of hexamethylenetetramine, free and in tablet form, in conjunction with cholic acid or potassium hydrogen phosphate, was possible by this method in the concentration range 1–12 µg ml–1 of hexamethylenetetramine with a relative standard deviation of 0.005.

Hexamethylenetetramine complexes with some uranyl salts

Hexamethylenetetramine complexes with some uranyl salts

Crystal data for some molecular complexes of hexamethylenetetramine with phenols

Crystal data are reported for molecular compounds of hexamethylenetetramine with phenol (1:1), resorcinol (1:1), hydroquinone (1:1), o-cresol (1 : 1), m-cresol (1:2), p-chlorophenol (1:2), and p-bromophenol (1:2).

Tissue fixation and osmium black formation with nonvolatile octavalent osmium compounds

Several compounds of osmiumVIII, including potassium osmiamate and coordination complexes of OsO4 with ammonia and various heterocyclic nitrogen compounds, have been synthesized and characterized. They have also been evaluated as substitutes for OsO4 in postfixation of biological specimens and in light and electron microscopic cytochemical methods resulting in osmium black formation. The most useful of these osmic compounds, a molecular addition complex of hexamethylenetetramine (methenamine) with OsO4, has a negligible vapor pressure of OsO4. It has the molecular formula C6H12N4.2OsO4 and has been designated osmeth. Although it has only limited solubility, aqueous solutions of the compound (or of OsO4) can be rapidly prepared by dissolution in a minimal amount of dimethylformamide and subsequent dilution with distilled water or buffer. Although stable in the solid state, the complex in solution undergoes partial dissociation releasing OsO4, and the odor of OsO4 becomes apparent. Such solutions of osmeth are (approximately 0.25%) considerably less concentrated with respect to OsO4 than solutions (1-2%) ordinarily employed for ultrastructural preservation or in cytochemical studies. Osmeth has limited value for postosmication after glutaraldehyde fixation because the generation (release) of OsO4 appears to be slow. Adequate osmication of tissue blocks exists only at the surface, but effective osmication can be achieved throughout tissue sections. In cytochemical reactions resulting in the formation of osmium blacks, the osmeth solutions are as effective as OsO4 solutions of equivalent concentrations. Our findings indicate that OsO4 solutions of less than 1% may be satisfactorily utilized in many cytochemical studies. Osmeth is safer and more convenient to handle than OsO4 because small amounts may be solubilized as needed. It should be considered as a substitute for OsO4 in ultrastructural cytochemistry. These results suggest that the effectiveness of OsO4 as a fixative may, in part, be related to its nonpolarity. The infrared spectra indicate that the OsO4 molecule is tetrahedral, perfectly symmetrical and, therefore, as a whole nonpolar. As a consequence, it could be expected to readily penetrate charged surfaces of tissues, cells, and organelles. The spectral studies show that osmeth is much less symmetrical and, to that extent, polar; thus, it penetrates biomembranes less readily.

The vibrational spectra and structure of the 1 : 1 hexamethylenetetraminebromine complex

The i.r. and Raman spectra of the crystalline 1 : 1 complex of hexamethylenetetramine (hx) with bromine have been obtained, and these suggest that the solid consists entirely of (hx)2Br+ and Br3- ions. A structure similar to that found for other bis(amine)halogen(r) ions is proposed for the previously unreported (hx)2Br+ ion, and a method is given for the preparation of its perchlorate. The i.r. spectrum of this compound, and that of the I : 2 hx-bromine complex, have also been obtained, and these support the proposed ionic structure for the 1 : 1 complex.

129I Mössbauer Effect in Several Charge-Transfer Complexes of Iodine

The Mössbauer effect of the 27.8-keV transition in 129I has been studied in the iodine complexes I2·phenazine, I2·acridine, and I2·hexamethylenetetramine. The Mössbauer spectrum of the I2·phenazine complex has shown only one chemical species of iodine, whereas those of the other complexes have shown the existence of two species of bridging and terminal iodine. From the Mössbauer parameters such as the isomer shift, quadrupole coupling constant, and asymmetry parameter, the electron distribution on the iodine atoms in the complexes was calculated. In the I2·phenazine complex, 0.09e− is transferred to the iodine atom from the phenazine molecule. In the I2·acridine and I2·hexamethylenetetramine complexes, the charges on the bridging iodine atoms are decreased and those on the terminal atoms are increased. In the later complex, a net charge of 0.08e− is transferred to the iodine molecule through the nitrogen atom from the hexamethylenetetramine molecule.

The vibrational spectra and structure of the Bis(hexamethylenetetramine)iodine(I) cation

The crystalline compound reported in the literature as the 1 : 1 addition complex of hexamethylenetetramine (hx) with iodine is shown by means of i.r. and Raman spectroscopy to be an ionic compound consisting of bis(hexamethyl-enetetramine)iodine(I) ions, (hx)2I+, and I3- ions. A crystalline compound consisting of molecules of the true 1 : 1 addition complex (hx)I2 does exist, however, and its preparation is described. On standing, this compound undergoes an unusual solid state transformation, resulting in the formation of the ionic complex. The (hx)2I+ ion is the first documented example of a bis(amine)halogen(I) ion involving an amine other than pyridine or its derivatives. A structure for this ion is proposed in which the hexamethylenetetramine molecules are bound to the iodine atom through one of their nitrogen atoms, the resulting N...I...N arrangement being linear, centrosymmetric, and lying along the threefold axis passing through the coordinated nitrogen atom of each hexamethylenetetramine molecule. The evidence for this structure obtainable from the vibrational spectra of the ion is discussed. A preliminary investigation of the valence force field indicates unusually strong nitrogen-iodine bonding in this ion. The literature method for preparing bis-(pyridine)halogen(I) perchlorates has been modified and used to prepare the perchlorate of bis(hexamethylenetetramine)iodine(I).

Transition metal halide complexes of hexamethylenetetramine

Complexes of hexamethylenetetramine have been prepared with the halides of manganese (II), cobalt(II), nickel(II) (except the iodide), zinc(II), cadmium(II) and iron(II) and copper(II) chlorides and also with the thiocyanates of cobalt(II), nickel(II) and zinc(II). These complexes have been characterized by analysis, vibrational and electronic spectra and magnetic moments.

A Comparative Study of Quinoline and Hexamethylene Tetramine Complexes with Ethereal Blue Perchromate in Relation to the Constitution of Blue and Red Perchromates

A Comparative Study of Quinoline and Hexamethylene Tetramine Complexes with Ethereal Blue Perchromate in Relation to the Constitution of Blue and Red Perchromates

Infra-red spectra of molecular complexes of hexamethylenetetramine with bromine and iodine

Infra-red spectra of molecular complexes of hexamethylenetetramine with bromine and iodine

The crystal structure of the complex of hexamethylenetetramine with manganous chloride

The crystal structure of the complex of hexamethylenetetramine with manganous chloride