Komplexe eines vierzehngliedrigen Tetraazadibenzo-Makrocyclus. Strukturen des freien und zweifach protonierten Liganden und seiner Nickel(II)-, Kupfer(II)-, Zink(II)- und Palladium(II)-Komplexe / Complexes of a 14-Membered N4 Dibenzo Macrocycle. Crystal Structures of the Free and Diprotonated Ligand and of its Nickel(II), Copper(II), Zink(II) and Palladium (II) Complexes

1996 ◽  
Vol 51 (6) ◽  
pp. 869-878 ◽  
Author(s):  
Ralf Feldhaus ◽  
Jens Köppe ◽  
Rainer Mattes

Abstract The synthesis and structural characterisation of complexes of the 14-membered macrocyclic trans-N4 dibenzo ligand 5,6,7,8,9,14.15,16,17,18-decahydrodibenzo[e,l][1,4, 8,11]-tetraazacyclotetradecine (L2) is described. The crystal structures of six compounds were determined by single crystal X-ray diffraction. The free ligand L2 has a saddle-shaped structure with short intramolecular hydrogen bonds. The N-N distances are 289 pm. The diprotonated species [H2L2]2+ has a different conformation due to intra- and intermolecular hydrogen bonds. The ligand is folded along an N-N axis in c/s-[Ni(L2)(H2O)2]2+, but displays a saddleshaped structure in the Cu(II), Zn(II) and Pd(II) complexes with a more or less planar arrangement of the four N donor atoms. The metal atoms are incorporated within the macrocyclic cavity in [Cu(L2)(CF3SO3)]+ and [Pd(L2)]2+. The metal-to-nitrogen bond lengths herein are rather small. Zn(II) is five-coordinate in [Zn(L2)(Cl)]+. The coordination polyhedron is intermediate between a trigonal bipyramid and a square pyramid. In all complexes the metalto- ligand distances originating at the nitrogen atoms in β-position (with respect to the aromatic ring) are significantly shorter then the donor bonds of the ‘anilinic’ N atoms

1985 ◽  
Vol 38 (3) ◽  
pp. 401 ◽  
Author(s):  
MJ O'Connell ◽  
CG Ramsay ◽  
PJ Steel

The colourless crystalline form of the benzoylpyrazolone (2) has molecules with the NH structure (2c) stabilized by intermolecular hydrogen bonds. At room temperature crystals are monoclinic: P21/c, a 13.508(5), b 9.124(4), c 11.451(3)Ǻ, β 90.80(3)°, Z4; the structure was refined to R 0.059, Rw 0.048. The acetoacetylpyrazolone (3) has the OH structure (3c) with two intramolecular hydrogen bonds. At 193 K crystals are triclinic: Pī , a 7.142(2), b 13.704(8), c 14.699(7)Ǻ, α 117.36(3), β 96.87(3), γ 93.73(3)°, Z 4; the structure was refined to R 0.049, Rw 0.054.


Molbank ◽  
10.3390/m1015 ◽  
2018 ◽  
Vol 2018 (3) ◽  
pp. M1015
Author(s):  
Jaqueline Heimgert ◽  
Dennis Neumann ◽  
Guido Reiss

(3-Ammonio-2,2-dimethylpropyl)carbamate dihydrate was synthesised. The title compound was characterised by single crystal X-ray diffraction and IR-/Raman-spectroscopy. It has been demonstrated that a mixture of dilute acetic acid and 2,2-dimethyl-1,3-diaminopropane is able to capture CO2 spontaneously from the atmosphere. An intramolecular hydrogen bond stabilises the conformation of the ylide-type title molecule. Intermolecular hydrogen bonds between all moieties connect them to a strand-type chain structure.


Author(s):  
Anna Brzuszkiewicz ◽  
Maciej Makowski ◽  
Marek Lisowski ◽  
Elżbieta Lis ◽  
Marta Otręba ◽  
...  

The present paper reports the crystal structures of two short phosphonotripeptides (one in two crystal forms) containing one ΔPhe (dehydrophenylalanine) residue, namely dimethyl (3-{[tert-butoxycarbonylglycyl-α,β-(Z)-dehydrophenylalanyl]amino}propyl)phosphonate, Boc0–Gly1–Δ(Z)Phe2–α-Abu3PO3Me2, C21H32N3O7P, (I), and diethyl (4-{[tert-butoxycarbonylglycyl-α,β-(Z)-dehydrophenylalanyl]amino}butyl)phosphonate, Boc0–Gly1–Δ(Z)Phe2–α-Nva3PO3Et2, as the propan-2-ol monosolvate 0.122-hydrate, C24H38N3O7P·C3H8O·0.122H2O, (II), and the ethanol monosolvate 0.076-hydrate, C24H38N3O7P·C2H6O·0.076H2O, (III). The crystals of (II) and (III) are isomorphous but differ in the type of solvent. The phosphono group is linked directly to the last Cαatom in the main chain for all three peptides. All the amino acids aretranslinked in the main chains. The crystal structures exhibit no intramolecular hydrogen bonds and are stabilized by intermolecular hydrogen bonds only.


1992 ◽  
Vol 47 (8) ◽  
pp. 1141-1153 ◽  
Author(s):  
Sven M. Jessen ◽  
Horst Küppers ◽  
Dean C. Luehrs

Four acid salts of pyromellitic acid (benzene-1,2,4,5-tetracarboxylic acid) have been synthesized and studied by X-ray diffraction and IR spectroscopy. (1) Dilithium dihydrogen pyromellitate pentahydrate, Li2[C6H2(COO)4H2]· 5H2O; monoclinic, P21/m, a = 6.214(2), b = 19.647(7), c = 6.592(2)Å, β = 115.90(2)°, Ζ = 2, R = 0.068, Rw = 0.067. (2) Hexaaquanickel dihydrogen pyromellitate, [Ni(H2O)6][C6H2(COO)4H2]; monoclinic, P2/m, a = 6.528(1), b = 9.927(2), c = 6.472(1)Å, β = 115.57(1)°, Z = 1, R = 0.044, Rw = 0.039. (3) Tetrabutylammonium trihydrogen pyromellitate, [(C4H9)4N][C6H2(COO)4H3]; monoclinic, P21/c, a = 9.719(4), b = 18.823(8), c = 15.795(5)Å, β = 107.42(3)°, Z = 4, R = 0.059, Rw = 0.039. (4) Diammonium dihydrogen pyromellitate, [NH4]2[C6H2(COO)4H2]; monoclinic, P21/c, a = 4.7665(6), b = 11.681(3), c = 10.149(2)Å, ß = 102.19(2)°, Z = 2, R = 0.045, Rw = 0.039. Compounds 1, 2, and 3 show very short intramolecular hydrogen bonds between adjacent carboxylic groups (O ••• O distances 2.384(6), 2.386(5), 2.387(3)Å, respectively). Compound 4 forms intermolecular hydrogen bonds (O ··· O distance 2.642(2) A). The different hydrogen bonding modes are also evident in the IR spectra.


Author(s):  
Agnieszka Czapik ◽  
Marcin Kwit

The structure of N-triphenylacetyl-L-tyrosine (C29H25NO4, L-TrCOTyr) is characterized by the presence of both donors and acceptors of classical hydrogen bonds. At the same time, the molecule contains a sterically demanding and hydrophobic trityl group capable of participating in π-electron interactions. Due to its large volume, the trityl group may favour the formation of structural voids in the crystals, which can be filled with guest molecules. In this article, we present the crystal structures of a series of N-triphenylacetyl-L-tyrosine solvates with chloroform, namely, L-TrCOTyr·CHCl3 (I) and L-TrCOTyr·1.5CHCl3 (III), and dichloromethane, namely, L-TrCOTyr·CH2Cl2 (II) and L-TrCOTyr·0.1CH2Cl2 (IV). To complement the topic, we also decided to use the racemic amide N-triphenylacetyl-DL-tyrosine (rac-TrCOTyr) and recrystallized it from a mixture of chloroform and dichloromethane. As a result, rac-TrCOTyr·1.5CHCl3 (V) was obtained. In the crystal structures, the amide molecules interact with each other via O—H...O hydrogen bonds. Noticeably, the amide N—H group does not participate in the formation of intermolecular hydrogen bonds. Channels are formed between the TrCOTyr molecules and these are filled with solvent molecules. Additionally, in the crystals of III and V, there are structural voids that are occupied by chloroform molecules. Structure analysis has shown that solvates I and II are isostructural. Upon loss of solvent, the solvates transform into the solvent-free form of TrCOTyr, as confirmed by thermogravimetric analysis, differential scanning calorimetry and powder X-ray diffraction.


1999 ◽  
Vol 54 (3) ◽  
pp. 321-328 ◽  
Author(s):  
Rainer Mattes ◽  
Ulrich Voet

The syntheses and structural characterizations of complexes of two 14-membered macrocyclic trans-N4 dibenzo ligands, 5,7,8,9,14,16,17,18-octahydrodibenzo[e,1]-[1,4,8,11-tetraazacyclotetradecine- 6,15-dimethyl (L3) resp. -6,15-diacetamide (L4), are presented. The crystal structures of five compounds have been determined by single crystal X-ray diffraction. The free ligand L3 has a saddle-shaped structure with intramolecular hydrogen bonds. This conformation of the ligand exists also in the Zn(II) complex in which the metal ion is five-coordinated with the metal center outside the cavity. The coordination polyhedron is intermediate between a trigonal bipyramid and a square pyramid. In cis-[Ni(L3)(NCS)2] the ligand is folded along an N ⋯ N axis. The nickel ion in this complex shows an approximate octahedral geometry. For Ni(II) and Cu(II) complexes of ligand L the overall geometry is also distorted octahedral. The folding of the ligand causes a cis-N4O2 coordination.


1996 ◽  
Vol 51 (10) ◽  
pp. 1449-1458 ◽  
Author(s):  
Ralf Feldhaus ◽  
Jens Köppe ◽  
Rainer Mattes ◽  
Ulrich Voet

The synthesis and structural characterisation of complexes of the 14-membered macrocyclic trans-N4 dibenzo ligand 7,8,9,16,17.18-hexahydrodibenzo[e,l][1,4, 8.11]-tetraazacyclotetradecine (L1) is described. The crystal structures of six compounds were determined by single crystal X-ray diffraction. In [CuL1]2+ the metal atom is tightly bound within the macrocyclic cavity. The Cu-N bonds [201.2(3) and 191.8(3) pm] are rather short. Zn(II) is penta-coordinated in [Zn(L1)Cl]+ with the metal center outside the cavity. L1 is deprotonated at one or both secondary amine functions in the complexes [Ni(L1-H)]+, [Co(L1-2H)]+, [VO(L1-2H)] and [Pd(L1-2H)]. With the exception of [VO(L1-2H)] the metal ions assume nearly square planar N4-coordination, which is very rare for Co(III). Salts of [Co(L1-2H)]+ display a temperature independent magnetic moment of 0,64 B. M. The nickel, cobalt and palladium complexes show remarkably short metal-nitrogen bond distances: Ni-N [183.8(8)], Co-N [181.8(2)] and Pd-N [194.5(6) pm], respectively. The UV/Vis and EPR spectra, and the electrochemical behaviour of some of these complexes are also discussed.


Holzforschung ◽  
2018 ◽  
Vol 72 (10) ◽  
pp. 829-837 ◽  
Author(s):  
Yangmei Chen ◽  
Yu Jiang ◽  
Jinquan Wan ◽  
Qitang Wu ◽  
Zebin Wei ◽  
...  

AbstractThe supramolecular structure of eucalyptus pulp cellulose was studied by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and water retention value (WRV) after subjecting the pulp to pressures of 0.1, 0.2, 0.3, 0.4 and 0.5 MPa. It was interpreted from the FTIR spectra of the sheets after pressing that the amount of intermolecular hydrogen bonds (HBinter) first increased and then decreased as a function of increasing pressure, while the number of the intramolecular hydrogen bonding (HBintra) exhibited an opposite trend. In the pressed fibers, the number of HBintraO(6)H· · ·O(3′) increased by 16% compared to the un-pressed fibers, while the number of HBinterO(2)H· · ·O(6) and O(3)H· · ·O(5) decreased by 23% at 0.3 MPa. XRD analysis showed that the crystallite size corresponding to the diffraction peaks for (002) lattice planes and the crystallinity of eucalyptus fibers were the lowest at a pressure of 0.3 MPa. Pressing produced an irreversible reduction of fiber pore volume, which was manifested by reduced WRV data.


2013 ◽  
Vol 68 (3) ◽  
pp. 214-222 ◽  
Author(s):  
Jörg Hübscher ◽  
Michael Günthel ◽  
Robert Rosin ◽  
Wilhelm Seichter ◽  
Florian Mertens ◽  
...  

Two new linker-type molecules 1a and 1b composed of o-hydroxyacetophenone coordinative groups attached to linear ethynylene or 1,4-phenylenediethynylene spacer units have been synthesised and structurally characterised. An X-ray crystallographic study for both compounds has shown structures with strong intramolecular hydrogen bonds fitting in the model of ‘Intramolecular Resonance Assisted Hydrogen Bond (IRHAB)’. Initial coordination experiments with Cu(II) were performed and the resulting materials characterised by PXRD. The similarity of the copper coordination between these compounds and copper(II) acetylacetonate complexes was demonstrated by XPS measurements. Based on the evidence of these studies, and on elemental analysis, the formation of the corresponding coordination polymers comprising Cu(II) and the linkers has been proposed


1982 ◽  
Vol 37 (11) ◽  
pp. 1393-1401 ◽  
Author(s):  
Beatrix Milewski-Mahrla ◽  
Hubert Schmidbaur

Reactions of pentamethylantimony (CH3)5Sb with carboxylic acids in the molar ratio 1:2 afford one equivalent of methane and essentially quantitative yields of crystalline tetramothylstibonium hydrogendicarboxylates. Six new compounds of this series have been synthesized using benzoic, o-phthalic, salicylic, 4-ethoxy-salicylic, oxalic, and malic acid, and characterized by analytical and spectroscopic data. An ionic structure with strong hydrogen bonds in the anionic components is proposed.The crystal structures of the hydrogen-dibenzoato (1), hydrogen-ortho-plithalato (2) and 4-ethoxy-hydrogen-salicylate (3) were determined by single crystal X-ray diffraction. The compounds can be described as having ionic lattices with some donor-acceptor inter­actions between the stibonium centers and the carboxylate oxygen atoms. The anions are characterized by strong hydrogen bonds O...H...O. Thus, the (CH3)4Sb-tetrahedron in 1 is distorted by two benzoate oxygon atoms (at 304(2) and 340(2) pin). The cation in 2 is largely undistorted and the anion has a hydrogenphthalate hydrogen bond of d(O...H...O) = 232 pm. The cation-anion contact in 3 is as short as d(Sb-O) = 289 pm rendering the Sb atom pentacoordinate.


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