Crystal structure of (E)-4-benzyl-idene-6-phenyl-1,2,3,4,7,8,9,10-octa-hydro-phenanthridine.

The preparation of the title compound, C26H25N, was achieved by the condensation of an ethano-lic mixture of benzaldehyde, cyclo-hexa-none and ammonium acetate in a 2:1:1 molar ratio. There are two crystallographically independent mol-ecules in the asymmetric unit. The two cyclo-hexyl rings adopt an anti-envelope conformation with the benzyl moiety adopting a cis conformation with respect to the nitro-gen atom of the phenanthridine segment. In the crystal, mol-ecules are linked through C-H⋯N inter-actions into hydrogen-bonded chains that are further arranged into distinct layers by weak offset π-π inter-actions.

Crystal structure of diethyl 3,3'-{2,2'-(1E)-[1,4-phenyl-enebis(azan-1-yl-1-yl-idene)]bis-(methan-1-yl-1-yl-idene)bis-(1H-pyrrole-2,1-di-yl)}di-propano-ate.

The complete mol-ecule of the title compound, C26H30N4O4, is generated by crystallographic inversion symmetry. The dihedral angle between the planes of the benzene and pyrrole rings is 45.20 (11)°; the N atom bonded to the the benzene ring and the pyrrole N atom are in a syn conformation. The side chain adopts an extended conformation [N-C-C-C = 169.07 (17)° and C-O-C-C = -176.54 (17)°]. No directional inter-actions could be identified in the crystal packing.

Crystal structure of diethyl 2,2'-[((1E,1'E)-{[(1R,4R)-cyclo-hexane-1,4-di-yl]bis-(aza-nylyl-idene)}bis-(methanylyl-idene))bis-(1H-pyrrole-2,1-di-yl)]di-acetate.

The whole mol-ecule of the title compound, C24H32N4O4, is generated by inversion symmetry. The cyclo-hexane ring adopts a chair conformation and the conformation about the C=N bonds is E. The pyrrole rings have an anti confirmation with respect to the cyclo-hexane moiety and the ethyl acetate groups have extended conformations. In the crystal, mol-ecules are linked by pairs of C-H⋯O hydrogen bonds forming chains, enclosing R 2 (2)(10) ring motifs with inversion symmetry, propagating parallel to the (101) plane.

Comparison of the structural motifs and packing arrangements of six novel derivatives and one polymorph of 2-(1-phenyl-1H-1,2,3-triazol-4-yl)pyridine.

The crystal structures of a new polymorph and seven new derivatives of 2-(1-phenyl-1H-1,2,3-triazol-4-yl)pyridine have been characterized and examined along with three structures from the literature to identify trends in their intermolecular contact patterns and packing arrangements in order to develop an insight into the crystallization behaviour of this class of compound. Seven unique C-H···X contacts were identified in the structures and three of these are present in four or more structures, indicating that these are reliable supramolecular synthons. Analysis of the packing arrangements of the molecules using XPac identified two closely related supramolecular constructs that are present in eight of the 11 structures; in all cases, the structures feature at least one of the three most common intermolecular contacts, suggesting a clear relationship between the intermolecular contacts and the packing arrangements of the structures. Both the intermolecular contacts and packing arrangements appear to be remarkably consistent between structures featuring different functional groups, with the expected exception of the carboxylic acid derivative 4-(4-(pyridin-2-yl)-1H-1,2,3-triazol-1-yl) benzoic acid (L11), where the introduction of a strong hydrogen-bonding group results in a markedly different supramolecular structure being adopted. The occurrence of these structural features has been compared with the packing efficiency of the structures and their melting points in order to assess the relative favourability of the supramolecular structural features in stabilizing the crystal structures.

N,N'-Bis(di-phenyl-meth-yl)benzene-1,4-di-amine.

The complete mol-ecule of the title compound, C32H28N2, is generated by crystallographic inversion symmetry. The dihedral angles between the central aromatic ring and the pendant adjacent rings are 61.37 (16) and 74.20 (14)°. The N-H group does not participate in hydrogen bonds and there are no aromatic π-π stacking inter-actions in the crystal.

Co(II) and Cd(II) complexes derived from heterocyclic Schiff-Bases: synthesis, structural characterisation, and biological activity.

New monomeric cobalt and cadmium complexes with Schiff-bases, namely, N'-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]furan-2-carbohydrazide (L¹) and N'-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]thiophene-2-carbohydrazide (L²) are reported. Schiff-base ligands L¹ and L² were derived from condensation of 3-hydroxy-4-methoxybenzaldehyde (iso-vanillin) with furan-2-carboxylic acid hydrazide and thiophene-2-carboxylic acid hydrazide, respectively. Complexes of the general formula [M(L)2]Cl2 (where M = Co(II) or Cd(II), L = L¹ or L²) have been obtained from the reaction of the corresponding metal chloride with the ligands. The ligands and their metal complexes were characterised by spectroscopic methods (FTIR, UV-Vis, ¹H, and ¹³C NMR spectra), elemental analysis, metal content, magnetic measurement, and conductance. These studies revealed the formation of four-coordinate complexes in which the geometry about metal ion is tetrahedral. Biological activity of the ligands and their metal complexes against gram positive bacterial strain Bacillus (G+) and gram negative bacteria Pseudomonas (G-) revealed that the metal complexes become less resistive to the microbial activities as compared to the free ligands.

Metal complexes of macrocyclic schiff-base ligand: preparation, characterisation, and biological activity.

A new macrocyclic multidentate Schiff-base ligand Na4L consisting of two submacrocyclic units (10,21-bis-iminomethyl-3,6,14,17-tricyclo[17.3.1.1]tetracosa-1(23),2,6,8,10,12(24),13,17,19,21,-decaene-23,24-disodium) and its tetranuclear metal complexes with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) are reported. Na4L was prepared via a template approach, which is based on the condensation reaction of sodium 2,4,6-triformyl phenolate with ethylenediamine in mole ratios of 2 : 3. The tetranuclear macrocyclic-based complexes were prepared from the reaction of the corresponding metal chloride with the ligand. The mode of bonding and overall geometry of the compounds were determined through physicochemical and spectroscopic methods. These studies revealed tetrahedral geometries about Mn, Co, and Zn atoms. However, square planar geometries have been suggested for Ni(II) and Cu(II) complexes. Biological activity of the ligand and its metal complexes against Gram positive bacterial strain Staphylococcus aureus and Gram negative bacteria Escherichia coli revealed that the metal complexes become more potentially resistive to the microbial activities as compared to the free ligand. However, these metal complexes do not exhibit any effects on the activity of Pseudomonas aeruginosa bacteria. There is therefore no inhibition zone.

Electron-rich heteroaroylphosphonates and their reaction with trimethyl phosphite.

Dialkyl heteroaroylphosphonates based on thiophene, pyrrole or furan have been prepared and their reactions with trimethyl phosphite investigated. Deoxygenation of the carbonyl groups in these heteroaroylphosphonates occurs to give carbene intermediates, which then undergo further reaction. In the case of the furan-3-oylphosphonates and those systems containing a thiophene or pyrrole ring, the major reaction pathway involves intermolecular trapping of the carbene intermediates by the trimethyl phosphite, leading to the formation of ylidic phosphonates that can be readily converted into the corresponding 1,1-bisphosphonates. However, in some furan-2-oylphosphonates the carbenes generated undergo ring-opening to initially give acyclic alkynylphosphonates which may react further to give other novel phosphorus compounds. The effects of substituents on the extent to which intermolecular trapping of the initially formed carbene competes with intramolecular rearrangement has been investigated. The latter process appears to be suppressed by a substituent at the 5-position of the furan ring, the resulting ylidic phosphonates being a rare example of an efficient intermolecular trapping of a furan-2-yl carbene.