Abstract:A 1:1 adduct of hexamethylenetetramine oxide and thiourea (C6HI2NgO.CH4N2S)has been prepared and subjected to crystal-structure analysis. The crystals are orthorhombic, space group Pbca, with a = 7.698 (5), b = 12.03 (1), c = 23.09 (2) ,~, and Z = 8. The structure was solved by direct methods and refined with 1426 observed Cu Ka film data to R = 0.099. In the crystal lattice each (CH2)6N40 molecule is linked by O---H-N hydrogen bonds to three thiourea molecules and vice versa, giving rise to corrugated layers … Show more
“…It is notable that the N−O bond length is particularly short at 1.3951(12) Å, where the normal range for the N−O distance in hydroxylammonium cations is 1.396−1.436 Å. , It is a neutral molecule, though there is a formal charge separation between nitrogen and oxygen. The structure of several adducts of urotropine- N -oxide have also been reported; − we note that the molecular and crystal structure of 1 was first determined by Mak in 1978, from data accumulated at room temperature. , 1 Molecular structure of urotropine- N -oxide.…”
The crystal structure of urotropine-N-oxide.formic acid, as determined from multiple temperature single-crystal X-ray diffraction experiments in the range 123-295 K and from neutron diffraction at 123 K, is reported. There is a strong hydrogen bonding interaction between the OH of formic acid and the N-oxide of urotropine, with the oxygen-oxygen distance ranging from 2.4300(10) to 2.4469(10) A. The electron density of the hydrogen atom associated with this interaction was located in the Fourier difference maps of the spherical atom refinement after all heavy atom positions were determined. The maximum of the electron density associated with the hydrogen bond is located approximately 1.16 A from the formate segment, though the distribution of electron density is very broad. The electron density associated with the H atom is thus shown by these accurate X-ray diffraction experiments to be approximately centered at all temperatures studied. This was conclusively confirmed by single-crystal neutron diffraction data obtained at 123 K, from which statistically equivalent O-H distances of 1.221(7) and 1.211(7) A were obtained.
“…It is notable that the N−O bond length is particularly short at 1.3951(12) Å, where the normal range for the N−O distance in hydroxylammonium cations is 1.396−1.436 Å. , It is a neutral molecule, though there is a formal charge separation between nitrogen and oxygen. The structure of several adducts of urotropine- N -oxide have also been reported; − we note that the molecular and crystal structure of 1 was first determined by Mak in 1978, from data accumulated at room temperature. , 1 Molecular structure of urotropine- N -oxide.…”
The crystal structure of urotropine-N-oxide.formic acid, as determined from multiple temperature single-crystal X-ray diffraction experiments in the range 123-295 K and from neutron diffraction at 123 K, is reported. There is a strong hydrogen bonding interaction between the OH of formic acid and the N-oxide of urotropine, with the oxygen-oxygen distance ranging from 2.4300(10) to 2.4469(10) A. The electron density of the hydrogen atom associated with this interaction was located in the Fourier difference maps of the spherical atom refinement after all heavy atom positions were determined. The maximum of the electron density associated with the hydrogen bond is located approximately 1.16 A from the formate segment, though the distribution of electron density is very broad. The electron density associated with the H atom is thus shown by these accurate X-ray diffraction experiments to be approximately centered at all temperatures studied. This was conclusively confirmed by single-crystal neutron diffraction data obtained at 123 K, from which statistically equivalent O-H distances of 1.221(7) and 1.211(7) A were obtained.
“…This mode of packing, in which the (CHz)6N4 moiety is not involved in hydrogen bonding and relegated to a space-filling role, has been observed for (CH2)6N40.H202.H20 and (CHz)~N40. (NHz)2CS (Yu & Mak, 1978), and appears to be a structural feature common to molecular complexes of (CHE)6N4 O.…”
Section: Structure Determination and Refinement Discussionmentioning
confidence: 93%
“…Recently we isolated and studied hexamethylenetetramine oxidet (I) and a number of its molecular adducts Yu & Mak, 1978;Mak, Ladd & Povey, 1979, and references therein). In the present work, the title compound was prepared and subjected to analysis to elucidate the nature of the molecular association.…”
ExperimentalA 1:1 adduct of hexamethylenetetramine oxide and hydroquinone, (CH2)6N40.C6H4(OH)2, has been prepared and subjected to crystal structure_analysis. The crystals are triclinic, space group P1, with a = 9.532(2), b = 6.521(1), c = 10.399(2) A, a= 102.13 (2), fl = 83.09 (2), y = 92.09 (2) °, and Z = 2. The structure was solved by a combination of direct phasing with packing considerations and refined to R = 0.053 for 2334 Mo Ka diffractometer data. The C6H4(OH)2 molecules occupy two non-equivalent sites of symmetry [, and are linked by hydrogen bonds to form infinite zigzag chains. Two centrosymmetrically related (CH2)6N40 molecules are attached to every other C6Ha(OH) 2 molecule in each chain through hydrogen bonding involving their N-oxide functions.
“…3 H 2 0 (37), (CH2)6N40. (NH2)2CS (9), and (CH2)6N40.H202.H20 (8). The hydrogen bonding features of hydrated N,N1-dioxides 1-111 are described in the following sections.…”
“…A research program on the structural chemistry of polycyclic tertiary amine N-oxides has been pursued in our laboratory. A series of preparative and X-ray crystallographic studies on the adducts of hexamethylenetetramine N-oxide (HMTO) have shown that all these structures involve hydrogen bonding between the terminal 0 atom of the N + 0 dative bond and the proton donor molecule(s) (7)(8)(9)(10). We now report the synthesis and structural characterization of a series of heterocyclic tertiary amine N,N '-dioxide hydrates, namely N, N '-di(o-toly1)piperazine N,N '-dioxide tetrahydrate, I, N, N '-di(p-toly1)piperazine N, N '-dioxide tetrahydrate, 11, and N,N '-di(p-chloropheny1)piperazine N,Nr-dioxide tetrahydrate, 111.…”
The synthesis and X-ray structure determination of N,N′-di(o-tolyl)piperazine N,N′-dioxide tetrahydrate, I, N,N′-di(p-tolyl)piperazine N,N′-dioxide tetrahydrate, II, and N,N′-di(p-chlorophenyl)piperazine N,N′-dioxide tetrahydrate, III, are described. Compound I crystallizes in space group [Formula: see text] with a = 7.778(1), b = 7.915(2), c = 8.919(2) Å, α = 106.25(2), β = 99.56(1), γ = 108.80(2)°, and Z = 1. Compound II crystallizes in space group [Formula: see text] with a = 6.558(1), b = 7.134(2), c = 11.610(3) Å; α = 73.23(2), β = 78.08(2), γ = 72.67(2)°, and Z = 1. Compound III crystallizes in space group P21/c with a = 9.159(3), b = 12.390(4), c = 8.339(4) Å, β = 97.38(3)°, and Z = 2. The structures of I–III were solved by the direct method and refined to R = 0.049 (1749 observed MoKα reflections), 0.055 (2651 observed reflections), and 0.035 (1827 observed reflections), respectively. In each case, the N,N′-dioxide molecule occupies a site of symmetry [Formula: see text]. The piperazine ring takes the chair form, with two N—O bonds oriented axially in a trans configuration. The structures are characterized by strong hydrogen bonding between the water molecules, as well as between the N-oxide groups and water molecules, giving rise to puckered layers composed of various combinations of edge-sharing four-membered, six-membered, ten-membered, and twelve-membered rings. The aryl rings, which protrude on both sides of each puckered layer, constitute hydrophobic regions separating the hydrophilic layers in the crystal packing.
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