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The stereochemistry of the title compound, C19H21N3, has been confirmed by a single-crystal X-ray analysis. The bicyclic ring system adopts a cis-deca­lin-like conformation, which presumably minimizes steric repulsion involving the bridgehead phenyl substituent. The conformation of the amino group appears to be dictated by a nitro­gen anomeric effect. [ABSTRACT FROM AUTHOR]

Abstract: The structures of four new alkaloids isolated from the bark of the rain forest trees Galbulimima belgraveana and Galbulimima baccata have been determined by a combination of NMR spectra and single crystal X-ray crystallography. Two of the alkaloids are simple oxygenated derivatives of himbacine, while the remaining two are based on a novel 7,19-cyclo-himbacine skeleton. [ABSTRACT FROM AUTHOR]

The crystal structures of three proton-transfer compounds of 5-sulfosalicylic acid (3-carboxy-4-hydroxybenzenesulfonic acid) with 4-X-substituted anilines (X = F, Cl and Br), namely 4-fluoroanilinium 5-sulfosalicylate (3-carboxy-4-hydroxyben- zenesulfonate) monohydrate, C6H7FN+·C7H5O6S¯·H2O, (I), 4-chloroanilinium 5-sulfosalicylate hemihydrate, C6H7C1-N+C7H5O6S¯0.5H2O, (II), and 4-bromoanilinium 5-sulfo-salicylate monohydrate, C6H7BrN+·C7H5O6S¯·H2O, (III), have been determined. The asymmetric unit in (II) contains two formula units. All three compounds have three-dimensional hydrogen-bonded polymeric structures in which both the water molecule and the carboxylic acid group are involved in structure extension. With both (II) and (III), which are structurally similar, the common cyclic R²2(8) dimeric carboxylic acid association is present, whereas in (I), an unusual cyclic R³3(8) association involving all three hetero- species is found. [ABSTRACT FROM AUTHOR]

2-Nitrobenzohydrazide was efficiently synthesized in two steps by the esterification of 2- nitrobenzoic acid followed by the treatment with hydrazine hydrate in methanol. The structure of 2- nitrobenzohydrazide was established by modern spectro-analytical techniques including FTIR, 1H and 13C-NMR spectroscopy and unequivocally confirmed by single crystal X-ray diffraction data. 2-Nitrobenzohydrazide crystallized in orthorhombic space group P 21 21 21 with unit cell dimensions a = 4.9764(4) Å, b = 12.5280 (3) Å, c = 12.8512(1) Å, α = β = γ = 90°. A combination of N-H...N and N-H...O hydrogen bonds stabilized the crystal packing of 3. The synthesized compound 3 was assessed as urease inhibitor against Jack bean urease and the results revealed good inhibitory potency with an IC50 value of 4.25 ± 0.08 μM. This inhibition strength was 5-fold higher compared to the reference inhibitor thiourea (IC50 = 21.00 ± 0.11 μM). The molecular docking studies of the synthesized inhibitor 3 inside the active pocket of urease revealed several important binding interactions. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis and crystal structure elucidation of two novel polymeric copper(II) complexes has led us to propose a mechanism for the formation of 2-picolinic acid (pic) from di-2-pyridyl ketone (dpk) and benzoic acid from acetophenone. During studies into the interaction of copper ions with the dpk-acetophenone system, two complexes Na2(NCS)2(H2O)[Cu(pic)2] (1) and Na2(H2O)2[Cu(pic)2(NCS)2] (2) which contain pic coordinated to copper were isolated. The occurrence of (1) and (2) has led us to consider the Baeyer–Villiger rearrangement as a possible mechanism for the formation of (1) and (2). [Copyright &y& Elsevier]

Abstract: The supramolecular interactions of the planar guanidinium cation () with benzenesulphonate (1), -phosphonate (2) and -arsonate (3) anions, and several of their 3- and 4-nitro-substituted derivatives is reported. In all cases well-defined crystalline materials, containing hydrogen-bonded networks with quasi-hexagonal sheet lattices were formed. However, the unsubstituted sulphonate (1) formed a 1:1 guanidinium:sulphonate bilayer structure, whilst the unsubstituted phosphonate (2) and arsonate (3) formed 2:1 guanidinium:phosphonate/arsonate single-layer structures with water occluded within the crystal voids. The additional H-bonding interactions resulting in distortion of the crystal voids in (2)/(3) as compared to the symmetrical hexagonal-form in (1). In the case of the nitro-substituted sulphonate derivatives, the 1:1 bilayer structure of the parent (1) was retained for the 3-nitrobenzenesulphonate (4), but transformed to a 1:1 single-layer system for the 4-nitrobenzenesulphonate (6). The reverse was observed for the nitrated phosphonic acids, whereby the 4-nitrobenzenephosphonate anion in (5) caused little disruption to the 2:1 single-layered structure and quasi-hexagonal sheet seen in (2), but the 3-nitrobenzenephosphonate caused a breakdown of the network forming a new, complex ribbon system (7). The greater complexity of the P/As (−2) structures compared to the S (−1) structure is attributed to the higher charge on the former anions providing additional opportunities for H-bonding. The observation of such interactions clearly indicates the likelihood of such species interacting with biologically-important arginine residues in vivo with concomitant unintended, but likely, toxic consequences. [Copyright &y& Elsevier]

Abstract: The crystal structure and spectroscopic characteristics of n-octanohydroxamic acid and the potassium compound of that acid have been investigated by XRD, XPS, FTIR and Raman spectroscopy. XRD revealed that the acid is in the keto Z conformation with the alkyl chains oriented along the z-direction and hydrogen bonding between hydroxamate moieties. Vibrational spectra confirm this conclusion. Chemical analysis, XRD and XPS established that the potassium compound is the acid salt KH(C7H9CONO)2. The crystal structure showed that the hydroxamate groups are also in the keto Z conformation and this is supported by vibrational spectra. In the acid salt, the two hydroxamate moieties are connected by a symmetrical O–H–O short hydrogen bonded linkage between the two hydroxamate oxygen atoms and this explains the absence of a discernible O–H stretch band in the vibrational spectra. Identification of the vibrational bands displayed is supported by deuteration and 15N substitution. [Copyright &y& Elsevier]

Abstract: The complexes of 3-carboxy-4-hydroxybenzenesulfonic acid (5-sulfosalicylic acid, H3SSA) with rubidium(I), caesium(I) and lead(II) have been synthesized and characterized using single-crystal X-ray methods at 130K. The rubidium(I) complex 1, [Rb3(H2SSA)(HSSA)(H2O)4] n , is an unstable hydrate variant of a previously described complex [Rb(H2SSA)(H2O)] n , and comprises three independent and different seven-coordinate metal polyhedra interlinked through oxygen donors of the sulfonate, carboxylate and phenolate groups of the 5-sulfosalicylate ligands (one of which is dianionic, the other monoanionic), and one bridging water, giving a three-dimensional hydrogen-bonded framework polymer structure. The anhydrous caesium(I) complex 2 [Cs(H2SSA)] n , which has been previously described in a room-temperature determination, has a three-dimensional framework polymer structure based on an irregular Cs–O9 repeating unit. Complex 3 with lead(II), [Pb(H2SSA)2(H2O)] n , forms helical step-polymer ribbon substructures having an irregular Pb–O7 coordination centre comprising a single monodentate water and six sulfonate-O donors bridging three separate metals. The carboxylic acid and phenol substituent groups of the 5-sulfosalicylate ligand link the ribbons peripherally through hydrogen bonds, giving a three-dimensional layered framework polymer structure. [Copyright &y& Elsevier]

In the structure of the hydrated 1:1 compound of 4-chloroaniline withl-tartaric acid, C6H7ClN+·C4H5O6−·H2O, determined at 130 K, the asymmetric unit comprises two 4-chloroanilinium cations, two hydrogen tartrate anions and two water molecules of solvation, and forms a two-dimensional duplex substructure comprising head-to-tail C11(7) hydrogen-bonded hydrogen tartrate anions and water molecules. The π-associated 4-chloroanilinium cation pairs [ring centroid separation = 3.576 (4) Å; inter-ring dihedral angle = 0.5 (1)°] are accommodated within the channels of the substructure and are hydrogen-bonded to it peripherally. [ABSTRACT FROM AUTHOR]

In the title compound, C9H8N+·C6H7O7−, the dihydrogen citrate anions form a convoluted two-dimensional hydrogen-bonded substructure through head-to-tail interactions with the interstitial π-stacked quinolinium cations linked to it peripherally through cyclic R12(5) N+—H...O(carboxyl/hydroxyl) hydrogen-bond interactions. The loss of a proton from one of the β-carboxylic acid groups of the citric acid generates a chiral centre in the anion, but these form a racemate in the centrosymmetric crystal structure. [ABSTRACT FROM AUTHOR]

In the crystal structures of the proton-transfer compounds of strychnine with 3,5-dinitro­salicylic acid, namely strychninium 3,5-dinitro­salicylate, C21H23N2O2+·C7H3N2O7−, (I), and 5-nitro­salicylic acid, namely strychninium–5-nitro­salicylate–5-nitro­salicylic acid (1/1/2), C21H23N2O2+·C7H4NO5−·2C7H5NO5, (II), protonation of one of the N atoms of the strychnine mol­ecule occurs and this group is subsequently involved in inter­molecular hydrogen-bonding inter­actions. In (I), this is four-centred, the primary being with an adjacent strychninium carbonyl O-atom acceptor in a side-to-side inter­action giving linear chains. Other inter­actions are with the phenolate and nitro O-atom acceptors of the anionic species, resulting in a one-dimensional polymer structure. In (II), the N+—H inter­action is three-centred, the hydrogen bonding involving carboxyl O-atom acceptors of the anion and both acid adduct species, giving unique discrete hetero-tetramer units. The structure of (II) also features π-bonding inter­actions between the two acid adduct mol­ecules. [ABSTRACT FROM AUTHOR]

• We report complexes [Zn(Hal) 2 HL] (Hal = Cl, 1 ; Br, 2) and [Zn(NCS) 2 HL] (3) • Complexes were obtained from 2-formylpyridine nicotinoyl hydrazine (HL) • Crystal packing of 1 and 2 is mainly dictated by the H···Hal/H contacts • Crystal packing of 3 is mainly described by the H···H/N/C/S and C···C contacts In this work we report new discrete mononucler heteroleptic zinc(II) halido complexes of the type [Zn(Hal) 2 HL] (Hal = Cl, 1 ; Br, 2) and zinc(II) pseudohalido complex [Zn(NCS) 2 HL]·1.5MeOH (3 ·1.5MeOH) (HL = 2-formylpyridine nicotinoyl hydrazone). Single crystal X-ray diffraction revealed that in the structures of complexes 1–3 , the Zn(II) metal atom is in a five-coordinated coordination environment and adopts a distorted square pyramidal chromophore, formed by one N 2 O tridentate chelator HL and two halides or thiocyanates, respectively. All complexes display a very similar molecular structure and complexes 1 and 2 are fully isostructural. Crystal packing of 1 and 2 is mainly dictated by the bifurcated N–H···Hal and linear C–H···Hal hydrogen bonds, yielding 1D polymeric chains, which additionally stabilized by intermolecular stacking interactions of the types ZnOCNN···ZnOCNN, ZnOCNN···ZnNCCN and 2-Py···3-Py. These 1D chains are interlinked into a 3D network through C–H···Hal interactions. Crystal packing of 3 ·1.5MeOH is constructed from centrosymmetric dimers formed through linear N–H···O and O–H···N hydrogen bonds, yielding a hydrogen bonded synthon of motif R4 4 (16). These dimers are interlinked trough the C–S···ZnNCCN interactions, yielding 1D polymeric chains, which, in turn, are interlinked through the C–H···O bonds, and ZnNCCN···3-Py and 3-Py···3-Py stacking interactions into a 3D framework. Hirshfeld surface analysis, employed to gain additional insight into interactions responsible for the packing of complexes, and quantitative examination of 2D fingerprint plots revealed that the most important factors in the crystal packing are H···Hal and and H···H contacts in 1 and 2 , and H···H, H···N, H···C and H···S contacts in 3 , further supported by C···C contacts. Density function theory (DFT) calculations were performed to gather more information into structure and bonding since they play an important role in the construction of 3D supramolecular frameworks. A new series of three ZnII coordination compounds were assembled from the 2-formylpyridine nicotinoyl hydrazone ligand and ZnX 2 salts (X = Cl, Br, NCS). Their detailed structural analysis, including non-covalent interactions, is discussed. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The low-temperature (130 K) structure of the 1:1 proton-transfer compound of brucine with toluene-4-sulfonic acid (systematic name: 2,3-dimeth­oxy-10-oxostrychnidinium toluene-4-sulfonate trihydrate), C23H27N2O4+·C7H7O3S−·3H2O, has been determined. The asymmetric unit contains two cations, two anions and six molecules of water. Brucinium cations form the familiar undulating head-to-tail ribbon structures, which associate with the toluene-4-sulfonate anions and the water mol­ecules in the inter­stitial cavities through hydrogen-bonding associations involving all available donor and acceptor atoms on all species. The result is a framework polymer structure. [ABSTRACT FROM AUTHOR]

Guanidinium 4-nitro­anthranilate monohydrate, CH6N3+·C7H5N2O4−·H2O, determined at 130 K, forms a primary hydrogen-bonded ribbon structure through cyclic hydrogen-bonding inter­actions involving all six protons of the guanidinium cation with the amino N-atom and carboxyl­ate O-atom acceptors of the anion, and the water mol­ecule of solvation. Other inter­actions, including the water mol­ecule bridging the primary ribbons, give a three-dimensional structure. [ABSTRACT FROM AUTHOR]

The crystal structure of a non-centrosymmetric polymorphic modification of the title compound, C9H7NO4, determined at 130 K, shows the presence of 21 screw-generated one-dimensional zigzag chains formed through catemeric C(4) syn– anti carboxylic acid hydrogen-bonding associations. [ABSTRACT FROM AUTHOR]

The structures of two pseudopolymorphic hydrates of brucine, C23H26N2O4·4H2O, (I), and C23H26N2O4·5.25H2O, (II), have been determined at 130 K. In both (I) and (II) (which has two independent brucine mol­ecules together with 10.5 water mol­ecules of solvation in the asymmetric unit), the brucine mol­ecules form head-to-tail sheet substructures, which associate with the water mol­ecules in the inter­stitial cavities through hydrogen-bonding associations and, together with water–water associations, give three-dimensional framework structures. [ABSTRACT FROM AUTHOR]

The structure of the title, compound C23H27N2O4+·C8H5O4−·3H2O, has been determined at 130 K. The hydrogen isophthalate anions and the water mol­ecules (one of which is disordered over two approximately equal sites) associate through extensive hydrogen-bonded inter­actions, including those with the common undulating brucinium cation layer substructures, forming a three-dimensional framework structure. [ABSTRACT FROM AUTHOR]