Nicotinamide Ligands Research Articles

Poly[[bis-[μ4-3-(2-carboxyl-atophen-yl)propionato]{N-[2-(pyridine-3-amido)-eth-yl]nicotinamide}-dicopper(II)] penta-hydrate

In the title compound, {[Cu2(C10H8O4)2(C14H14N4O2)]·5H2O}n, the CuII cations are coordinated in a square-pyramidal fashion, with four 3-(2-carb-oxy-phen-yl)propionate (cpp) carboxyl-ate O-atom donors in the basal plane, along with an N-atom donor from a N-[2-(pyridin-3-yl-amino)-eth-yl]nicotinamide (pen) ligand in the apical position. [Cu2(cpp)2]n coordination polymer layer motifs with embedded {Cu2(OCO)4} paddlewheel clusters are thereby constructed. These layer motifs are connected into a three-dimensional [Cu2(cpp)2(pen)]n coordination polymer network by tethering pen ligands. Treating the {Cu2(OCO)4 paddelwheel clusters as 6-connected nodes reveals an underlying cross-pillared self-penetrated rob network with 48668 topology. The water mol-ecules of crystallization are held to the coordination polymer network by N-H⋯O and O-H⋯O hydrogen-bonding patterns.

New mixed ligand complexes of lanthanide metal cations containing acesulfame/nicotinamide. Synthesis and structural characterizations

The mixed ligand complexes containing acesulfame and nicotinamide ligands of rare earth metal cations Eu3+, Tb3+, Ho3+, Er3+ and Yb3+ were synthesized and their structural characterizations were examined. The complexes' thermal decomposition steps and structural properties were investigated by chemical analysis, infrared spectroscopy, mass analysis, and solid-state UV-vis spectroscopy and thermal analysis methods. According to the results obtained, it is suggested that the metal cations have six coordination sphere. It is recommended that the geometry of the complexes is distorted octahedral with two nicotinamide ligands that make neutral coordination over the nitrogen atom of the pyridine group, two aqua ligands and two monoanionic monodentate acesulfame ligands that coordinated via the acidic imine nitrogen. The coordination compounds perform charge balances with an anionic acesulfame situated the coordination sphere. Except for the Er3+ metal cation complex, it has been determined that all other structures have one hydrate water. From the thermal analysis curves, it was obtained that oxide derivatives of each metal cation were formed in the reaction pots as the last degradation products of Ho3+, Er3+ and Yb3+ complexes. It has been suggested that sulfate salts of related metal cations remain as thermal decomposition products in Eu3+ and Tb3+ metal cation-centered structures.

New mixed ligand complexes of alkaline earth metal cations containing nicotinamide and diphenic acid. Synthesis and structural properties

Mixed-ligand coordination compounds containing neutral nicotinamide and monoanionic diphenate organic molecules of alkaline earth metal cations, Mg2+ (C40H38MgN4O14) (I), Ca2+ (C40H34CaN4O2) (II), Sr2+(C40H34N4O2Sr) (III) and Ba2+(C40H34BaN4O2) (IV) were synthesised. Chemical composition analysis, single crystal XRD, spectroscopic, and thermal analysis methods were used to determine the structural properties of the compounds obtained. According to the data obtained from a single-crystal XRD analysis of the Mg2+ complex, the coordination environment of the metal cation was surrounded by four aqua and two nicotinamide ligands to form a distorted octahedral geometry. The charge balance of the complex sphere was provided by two diphenate ligands placed mono-anionically outside the coordination sphere. The structure is a salt-type complex. Since crystals suitable for single crystal structure analysis of other metal cations complexes (II, III and IV) could not be formed, the structural properties were tried to be explained by chemical composition analysis, spectroscopic, and thermal analysis methods. Accordingly, it is found that the coordination circles of metal cations are octahedral and all ligands (two aqua, two neutral nicotinamide, and two monoanionic-double-toothed diphenate) coordinate with the metal in the coordination sphere. The geometries of the complexes are detected to be of distorted cubic structure.

Crystallization of Mn(II) and Cd(II) Complexes in A Water-Methanol System: Tartrate vs Nicotinamide Ligand Selectivity

Ligand selectivity of tartrate vs nicotinamide in a water-methanol system has been observed in the crystallization of Mn(II) and Cd(II) complexes. These complexes were crystallized at room temperature by a layered solution technique using a water-methanol mixture solvent in a M(II):tartrate:nicotinamide (M = Mn, Cd) molar ratio of 1:1:2. Complexes of M(II)-nicotinamide and M(II)-tartrate were also prepared for data comparison. Analysis of the crystals by infrared spectroscopy, powder-X-ray diffraction and qualitative anion test showed that in a presence of both tartrate and nicotinamide, the Mn(II) forms neutral Mn(II)-tartrate hydrate complex, whereas the Cd(II) forms ionic Cd(II)-nicotinamide chloride complex. In the case of Mn(II) complex, tartrate tend to coordinate as ligand than the nicotinamide, although molar ratio of nicotinamide was doubled than that of tartrate ligand. In contrast, the neutral nicotinamide ligand is more predominant to coordinate in the Cd(II) complex than the anionic tartrate. The tartrate-nicotinamide ligand selectivity in the crystallization of Mn(II) and Cd(II) complexes is likely due to the use of tartrate salt as precursor and the choice of solvent mixture. In addition, powder-XRD analysis confirms that there was no indication of M(II)-tartrate and M(II)-nicotinamide that co-crystallized together at the same time by both metal ions.

New Nanosized Systems with Antitumor Activity Based on the Pt(IV) Complexes with Nicotinamide Ligands and Amphiphilic Copolymers of N-Vinylpyrrolidone and (Di)methacrylate

The nanosized systems involving Pt(IV) complexes with antitumor activity are obtained by their solubilization via amphiphilic copolymers of N-vinylpyrrolidone and (di)methacrylates synthesized by the radical copolymerization in toluene without any polymer chain growth terminating agents. The resulting systems are investigated by a complex of physico-chemical methods (IR spectroscopy, DLS, TEM, cyclic and square-wave voltammetry) and quantum chemical simulation. The Pt(IV) complexes are shown to have cytotoxic effects on A-172 tumor cells and the corresponding cytotoxicity indices (IC50) are determined. The amphiphilic copolymers under consideration are promising modern platforms and delivery vehicles for biologically active compounds.

Synthesis, characterization, X-ray structural analysis, DFT and BSA binding study of a Zn(II) complex, [Zn(II)Cl2(nia)2].2nia

A Zn(II) complex with two nicotinamide (nia) ligands, two chloride ions, and two co-crystallized nicotinamide molecules, [ZnCl2(nia)2].2nia, was synthesized and characterized on the basis of elemental analysis, spectroscopic techniques (UV-vis, FT-IR, 1H and 13C NMR), conductivity measurements, DFT and single-crystal X-ray crystallography. The complex crystallized in orthorhombic crystal system with pccn space group and cell dimensions: a = 27.1852(2), b = 7.6705(4), c = 12.7502(8) Å and α = β = γ = 90°. Single-crystal structural analysis revealed the presence of a neutral complex having tetrahedral geometry. In this complex, Zn(II) is coordinated to two chloride and two nicotinamide ligands in the coordination sphere and two nicotinamide molecules are co-crystallized. Hydrogen bonding interactions (N-H…O, C-H…O, N-H…N, C-H…Cl) along with π…π bonding interactions (between the coordinated nicotinamide and free nicotinamide moiety) stabilize the crystal lattice. The DFT studies consolidated the experimental findings and provided deeper insight into vibrational spectra, excitation spectra and hydrogen bonding interactions between nicotinamide molecules. The interactions and binding parameters of this complex with bovine serum albumin (BSA) have been probed through absorption and fluorescence spectroscopy which revealed the presence of static quenching mechanism and good binding propensity of the Zn complex.

Novel Mixed Ligand Complexes of Alkaline Earth Metals with Coumarilic Acid and Nicotinamide

Coordination compounds with mixed ligands were synthesized with 2A group (Mg2+, Ca2+, Ba2+, Sr2+) alkaline earth metal cations of coumarilic acid and nicotinamide ligands. Afterward, the structural properties of these new molecules were investigated by melting point, elemental analysis, infrared spectroscopy, thermal analysis (TGA / DTA) curves, powder X-ray diffraction (P-XRD) spectroscopy. It has been suggested that the complex structure with the Mg2+ metal center is different from the other three structures. In this structure, it was determined that four aqua and two nicotinamide ligands were located in the coordination sphere, and the coordination number was six, as expected. With two monoanionic coumarilic acids located outside the coordination sphere, complex charge equivalence was achieved. The other three molecules, Sr2+ and Ba2+, have iso-structural properties, and it is suggested that both structures contain a dinuclear metal center, and two aqua ligands are located in the bridging position between metal centers. Besides, the two coumarilate ligands involved in coordination are thought to coordinate with the primary metal cation through carbonyl and acidic oxygens while coordinating with the secondary metal cation through furan oxygen, providing the third bridge connection between metal centers. Metal cations with nine coordination numbers complete the coordination sphere with two terminal aqua and one nicotinamide ligands, each included in the structure. In the molecule with Ca2+ cation, which differs little from these metal cation structures, the difference according to these structures can be interpreted as the coordination of furan oxygen with the secondary metal center due to the octet coordination of the Ca2+ cation. From the thermal analysis curves, it was determined that only the Mg2+ cation complex contained hydrate. As a result of thermal decomposition, it was determined that relevant metal oxide residues remained in all structures, and this situation was defined by powder XRD.

Cobalt Werner hosts with nicotinamides: Characterisation of mixed ligand complexes and their selectivity towards ortho xylene

Cobalt host complexes which form novel Werner structures with nicotinamides were analysed and characterised, the formation of mixed ligand complexes by crystallisation with substitution of two nicotinamide ligands was achieved and selectivity toward a xylene isomer from a mixture was elucidated.Inter- and intra-molecular hydrogen bonding interactions which formed amide dimers, ring structures, discrete bonds and chains were described in this work. In some cases, the packing was stabilised by π⋯π interactions between the aromatic rings of the nicotinamides. Three mixed ligand crystal structures were formed when two nicotinamide ligands in host complexes were replaced with two DMSO molecules or two methanol molecules via oxygen bridging. This formation required an understanding of the strength of interaction between the ligand and the metal ion. The investigation of pKa, the dipole moment and electronegativity values for the interacting elements clarified the substitution process.A mixed ligand Werner clathrate [Co(NCS)2(isonic)2(C2H6OS)2]·2(ortho-C8H10), showing characteristics both of a mixed ligand structure and a clathrate, presented a preference towards ortho-xylene from a 50:50 mixture of ortho/meta-xylenes. The single crystal structure, its thermal behaviour and the Hirshfeld surfaces were used for confirmation of this finding.This study of cobalt Werner complexes with nicotinamides has explored mixed ligand complexes and the property of discrimination towards a xylene isomer from a mixture of two different isomers.

Structural elucidation, molecular modeling, and biological and antioxidant studies of phenanthroline/nicotinamide metals complexes

Three new cobalt (II), nickel (II), and copper (II) complexes [M (nicotinamide)(phenanthroline)(H2O)3]Cl2·3H2O (where M: Co (II), Ni (II) and Cu (II)) have been prepared and characterized by elemental analysis, Fourier transform infrared (FT‐IR), and ultraviolet/visible (UV–Vis) spectroscopy as well as thermal analysis. The molar conductance measurements proved that the complexes were electrolytes. The results obtained from FT‐IR confirm that the metal atoms were coordinated by one nitrogen atom from nicotinamide (NA) ligand, two nitrogen atoms from phenanthroline (Phen), and three oxygen atoms from three different water molecules. The complexes have octahedral structure. thermogravimetry (TGA) and its differential (DTG) analyses confirmed the suggested stereochemistry. Coats–Redfern and Horowitz–Metzger equations were used to calculate kinetic and thermodynamic parameters. Molecular modeling calculations confirm the structural geometry of the complexes, and the data indicate that the complexes are soft with respect to ligands where absolute softness (σ) varied from 5.34 to 13.33 eV, whereas σ for NA and Phen are 5.34 and 8.19 eV, respectively. The ligands and their complexes were assayed for their in vitro antimicrobial activities against some bacterial and fungal strains; the data showed that the complexes were active against some bacterial species compared with NA and Phen. Moreover, complexes and ligands revealed excellent antioxidant properties and could be useful in fighting the free radicals which occur in close connection with cancerous cells.

Complexes of N- and O-Donor Ligands as Potential Urease Inhibitors.

We report five new transition-metal complexes that inhibit the urease enzyme. Barbituric acid (BTA), thiobarbituric acid (TBA), isoniazid (INZ), and nicotinamide (NCA) ligands were employed in complexation reactions. The resulting complexes were characterized using a variety of analytical techniques including infra-red and UV–vis spectroscopy, 1H NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction analysis. We describe two mononuclear complexes with a general formula {[M(NCA)2(H2O)4](BTA)2(H2O)}, where M = Co (1) and Zn (2), a mononuclear complex {[Ni(NCA)2(H2O)4](TBA)2(H2O)} (3), and two polymeric chains of a general formula {[M(INZ) (H2O)3](BTA)2(H2O)3}, where M = Co (4) and Zn (5). These complexes displayed significant urease enzyme inhibition with IC50 values in the range of 3.9–19.9 μM.

Werner clathrates with enhanced hydrogen bonding functionality

The role of hydrogen bonding to generate molecular frameworks for selective enclathration of selected, closely related alcohols, carbonyls and water by three Ni(II) isothiocyanate based Werner hosts was scrutinized and their generation of crystal structures elucidated.Structures of host:guest compounds of H1, Ni(NCS)2(nicotinamide)4, with five alcohols were compared with five guests with carbonyl functionalities. In both cases, host columns formed by interaction via hydrogen bonded amide tetramers. However, the hydrogen bond between the guest alcohol functional group and thiocyanato sulphur showed a more robust structure than those with intercalated carbonyl guests found in layers between sheets of host molecular bands. A predictable framework of H1 host led to architectures with analogous patterns. Physical properties differed according to their hydrogen bonding capabilities. Selectivity was achieved for the separation of a pair of alcohols (1-butanol and 2-pentanol) and a pair of carbonyls (3- and 4-methylcyclohexanone), both difficult to separate due to similar physical properties. The positive discrimination characteristics of host H1 towards one of a pair of alcohols and carbonyl isomers have given possibilities for future industrial prospects.Host H2, Ni(NCS)2(isonicotinamide)4, presented three different tubulate packing arrangements, with the guests (H2O, ethanol and self-included ligand isonicotinamide) occupying channels in the structure. Hydrogen bonding between host carbonyl oxygens and amides formed molecular frameworks into which the guest was included.Mixed-ligand host H3, Ni(NCS)2(nicotinamide)2(isonicotinamide)2 with inclusion of water and methanol, confirmed our findings of hydrogen bonded frameworks with the two different ligands in H1 and H2; nicotinamide ligands formed amide tetramers, whereas the isonicotinamide ligands formed a variety of discrete hydrogen bonds with neighbouring molecules.The host networks formed porous materials for inclusion, giving the advantage of ‘tunability’, and pores with different size and nature available to accommodate guest molecules and to separate isomers.

Novel mixed ligand complexes of acesulfame / nicotinamide with some transition metals. Synthesis, crystal structural characterization, and biological properties

The salt type mixed ligand metal complexes of CoII (I), NiII (II), CuII (III), ZnII (IV) and MnII (V) were synthesized using neutral ligand nicotinamide and anionic ligand acesulfame. The structural characterizations of complexes were performed by using elemental analysis, magnetic susceptibility, solid-state UV–Vis, FTIR spectra, thermoanalytic TG-DTG/DTA, and single crystal X-ray diffraction methods. The complexes of I, III, IV, and V were obtained suitable crystal form for single crystal analysis by SC-XRD diffraction. The complexes of II was believed that the others structures so, the spectroscopic results of all the complexes are suitable for each other. The complexes are salt type compounds, and they have 2 mol nicotinamide ligands as monodentate coordination to metal center by pyridine N atoms and 4 mol aqua ligands in coordination sphere and 2 mol anionic acesulfamate ligands located outside of coordination unit as a counter ion. The metal(II) cationic atoms in complexes have octahedral geometry. Thermal decomposition steps of compounds are started with dehydration.

Synthesis, crystal structure and Hirshfeld surface analysis of a 1D coordination polymer catena-poly[[di-aqua-bis-(nicotinamide-κN1)nickel(II)]-μ-fumarato-κ2O1:O4

The reaction of NiCl2 with fumaric acid and nicotinamide in basic solution produces the title polymeric complex, [Ni(C4H2O4)(C6H6N2O)2(H2O)2] n . The NiII cation, located on an inversion centre, is coordinated by two O atoms of the fumarate dianions, two N atoms from nicotinamide ligands and two water mol-ecules in a distorted octa-hedral fashion. In the crystal, the fumarate dianions bridge the NiII cations, forming polymeric chains propagating along the [101] direction; the polymeric chains are further linked by O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular architecture. Hirshfeld surface analyses and two-dimensional fingerprint plots were used to analyse the inter-molecular inter-actions present in the crystal, indicating that the most important contributions for the crystal packing are from H⋯O/O⋯H (35.9%), H⋯H (31.7%) and C⋯C (10.4%) inter-actions.

Supramolecular assembled networks in crystal structure built up of copper(II) dipicolinates with pyrazine- and pyridinecarboxamides connected through hydrogen bonds

New copper(II) dipicolinate complexes containing pyrazine- or pyridinecarboxamides, namely {[Cu(pca)(dipic)(H2O)]·H2O} (1), [Cu(nia)(dipic)(H2O)] (2), {[Cu(mnia)(dipic)(H2O)]·2H2O} (3), {[Cu(inia)(dipic)]n·2nCH3OH} (4) {[Cu(hmnia) (dipic)(H2O)]2·2[Cu(hmnia)(dipic)(H2O)2]·4H2O} (5) and [Cu(denia)(dipic)(H2O)] (6) (dipic = dipicolinate, anion derived from pyridine-2,6-dicarboxylic acid, pca = pyrazinecarboxamide, nia = nicotinamide, mnia = N-methylnicotinamide, inia = isonicotinamide, hmnia = N-(hydroxymethyl)nicotinamide and denia = N,N-diethylnicotinamide) were synthesized, structurally characterised by single-crystal X-ray diffraction analysis and their properties were studied using IR, UV–Vis and EPR spectroscopic techniques. The Cu(II) compounds are of square-pyramidal (1–4 and 6) or square-bipyramidal geometry (5), in which copper(II) centres are coordinated by N donor atom of a nicotinamide or its derivatives, one N donor atom and two O donor atoms of dipicolinate anions and the coordination sphere around the Cu(II) atoms is completed by terminal aqua ligands (besides 4). The complex 4 is a polymer, in which are dipicolinate ligands bridging via O atoms of their carboxylate groups neighbouring Cu(II) atoms. The compound 5 is made up of two different types of complex molecules, dinuclear [Cu(hmnia)(dipic)(H2O)]2 and mononuclear [Cu(hmnia)(dipic)(H2O)2], and lattice solvent molecules in the ratio of 1:2:4. Copper(II) atoms in the dinuclear complex molecules of 5 [Cu(hmnia)(dipic)(H2O)]2 are interconnected through carboxamide O donor atoms of bridging N-(hydroxymethyl)nicotinamide ligands. In most cases are complex molecules to each other and solvent molecules linked together via NH⋯O and OH⋯O hydrogen bonds and form 2D or 3D supramolecular networks. The X-band EPR spectra of six copper(II) complexes were recorded at room and low temperature (98 K). The g-factor relation g// > g⊥ > 2.0023 is consistent with the dx2-y2 ground electronic state.

Crystal structure and Hirshfeld surface analysis of aqua-bis-(nicotinamide-κN1)bis-(2,4,6-tri-methyl-benzoato-κ2O,O')cadmium(II).

The asymmetric unit of the title complex, [Cd(C10H11O2)2(C6H6N2O)2(H2O)], contains one half of the complex mol-ecule, with the CdII cation and the coordinated water O atom residing on a twofold rotation axis. The CdII cation is coordinated in a bidentate manner to the carboxyl-ate O atoms of the two symmetry-related 2,4,6-tri-methyl-benzoate (TMB) anions and to the water O atom at distances of 2.297 (2), 2.527 (2) and 2.306 (3) Å to form a distorted penta-gonal arrangement, while the distorted penta-gonal-bipyramidal coordin-ation sphere is completed by the two pyridine N atoms of the two symmetry-related monodentate nicotinamide (NA) ligands at distances of 2.371 (3) Å in the axial positions. In the crystal, mol-ecules are linked via inter-molecular N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds with R22(12), R33(8), R33(14), R33(16), R33(20), R33(22), R44(22), R55(16), R66(16) and R66(18) ring motifs, forming a three-dimensional architecture. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are H⋯H (56.9%), H⋯C/C⋯H (21.3%) and H⋯O/O⋯H (19.0%) inter-actions.

Cu(II) and Ni(II) 4-cyanobenzoate complexes with nicotinamide: Synthesis, spectral, structural and optical characterization and thermal behavior

Two new copper(II) and nickel(II) complexes [M(NCC6H4COO)2(C6H6N2O)2(H2O)2] (where M:Cu and Ni) have been synthesized and characterized by elemental analysis, FT-IR and UV–Vis spectroscopy, spectroscopic ellipsometer (SE), X-ray crystallography, thermal analysis and molar conductivity. X-ray measurements showed that both of the complexes crystallized in triclinic system with the space group P-1. The isostructure complexes have distorted octahedral geometry around the metal atom center. In both of the crystal structures, the metal atoms are coordinated by two nitrogen atoms from two different nicotinamide ligands, two carboxyl oxygen atoms from two different 4-cyanobenzoate anions and two oxygen atoms from two different water molecules. From the linear absorption spectra and spectroscopic ellipsometer measurements, it was observed that these complexes showed different optical behaviors.

Crystal structure and Hirshfeld surface analysis of aqua-bis-(nicotinamide-κN1)bis-(2,4,6-tri-methyl-benzoato-κO)zinc.

The asymmetric unit of the title complex, [Zn(C10H11O2)2(C6H6N2O)2(H2O)], contains one half of the complex mol-ecule, and the ZnII cation and the water O atom lie on a twofold rotation axis. The ZnII cation is coordinated by two carboxyl-ate O atoms of the two symmetry-related 2,4,6-tri-methyl-benzoate (TMB) anions and by the water O atom at distances of 2.0311 (16) and 2.076 (2) Å to form a slightly distorted trigonal-planar arrangement, while the distorted trigonal-bipyramidal coordination sphere is completed by the two pyridine N atoms of the two symmetry-related monodentate nicotinamide (NA) ligands at distances of 2.2066 (19) Å in the axial positions. In the crystal, mol-ecules are linked via inter-molecular N-H⋯O and O-H⋯O hydrogen bonds with R22(12), R33(10) and R33(16) ring motifs, forming a double-column structure running along the c-axis direction. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (58.4%), H⋯C/C⋯H (20.3%) and H⋯O/O⋯H (18.3%) inter-actions.

Crystal structure of di-aqua-bis-(4-tert-butyl-benzoato-κO)bis-(nicotinamide-κN (1))cobalt(II) dihydrate.

The asymmetric unit of the mononuclear cobalt complex, [Co(C11H13O2)2(C6H6N2O)2(H2O)2]·2H2O, contains one half of the complex mol-ecule, one coordinating and one non-coordinating water mol-ecule, one 4-tert-butyl-benzoate (TBB) ligand and one nicotinamide (NA) ligand; the Co atom lies on an inversion centre. All ligands coordinating to the Co atom are monodentate. The four nearest O atoms around the Co atom form a slightly distorted square-planar arrangement, with the distorted octa-hedral coordination completed by the two pyridine N atoms of the NA ligands at distances of 2.1638 (11) Å. The coordinating water mol-ecules are hydrogen bonded to the carboxyl O atoms [O ⋯ O = 2.6230 (17) Å], enclosing an S(6) hydrogen-bonding motif, while inter-molecular O-H⋯O hydrogen bonds link two of the non-coordinating water mol-ecules to the coordinating water mol-ecules and NA anions. The dihedral angle between the planar carboxyl-ate group and the adjacent benzene ring is 29.09 (10)°, while the benzene and pyridine rings are oriented at a dihedral angle of 88.53 (4)°. In the crystal, O-H⋯O and N-H⋯O hydrogen bonds link the mol-ecules, enclosing R 2 (2)(8), R 2 (2)(10) and R 4 (4)(12) ring motifs, forming layers parallel to (001). The C and H atoms of the tert-butyl group of the TBB ligand are disordered over two sets of sites with an occupancy ratio of 0.631 (5):0.369 (5).

Diphenic acid/nicotinamide complexes of CoII, CuII and ZnII. Synthesis and structural investigation

The complexes of diphenic acid with CoII and CuII metals and diphenic acid/nicotinamide mixed ligand with CoII and ZnII metals were synthesized and characterized of structural properties by elemental analysis, FT-IR spectra, thermo analytic TG-DTG/DTA and crystal X-ray diffraction methods. The pure ligand complexes of diphenic acid (C14H16O8Co (1), C14H16O8Cu (2)) and mixed ligand complexes of diphenic acid/nicotinamide (C40H38N4O14Co (3), C40H38N4O14Zn (4)) are similar to each other and they have P21, P21/n and P1¯ space groups. The diphenic acid ligands in 1 and 2 complexes were coordinated to metal cations as dianionic bridge and in the others complexes (3 and 4) it was involved as monoanionic counter ion. The complexes of 1 and 2 are linked into sheets by a combination of O–H⋯O hydrogen bonds and the others complexes of 3 and 4 are linked into sheets by a combination of O–H⋯O, N–H⋯O and C–H⋯O hydrogen bonds. All of the complexes structures have distorted octahedral geometry. According to TG/DTG-DTA analysis, thermal decomposition of complexes starts with dehydration of coordinated aqua ligands. After the dehydration, neutral nicotinamide ligands start to decompose in mixed ligand complexes. Lastly, anionic diphenic acid ligands decompose and corresponding metal oxides remain as residual products of thermal degradation in reaction vessel.

Crystal structure of trans-di-aqua-bis-(nicotinamide-κN (1))bis-(4-nitro-benzoato-κO)manganese(II).

The asymmetric unit of the title compound, [Mn(C7H4NO4)2(C6H6N2O)2(H2O)2], contains one Mn(II) atom, one 4-nitro-benzoate (NB) anion, one nicotinamide (NA) ligand and one water mol-ecule; NA and NB each act as a monodentate ligand. The Mn(II) atom, lying on an inversion centre, is coordinated by four O atoms and two pyridine N atoms in a distorted octa-hedral geometry. The water mol-ecules are hydrogen bonded to the carboxyl-ate O atoms. The dihedral angle between the carboxyl-ate group and the adjacent benzene ring is 24.4 (3)°, while the benzene and pyridine rings are oriented at a dihedral angle of 86.63 (11)°. In the crystal, O-H⋯O and N-H⋯O hydrogen bonds link the mol-ecules, forming a layer parallel to the ab plane. The layers are further linked via weak C-H⋯O hydrogen bonds, a π-π stacking inter-action [centroid-centroid distance = 3.868 (2) Å] and a weak C-H⋯π inter-action, resulting in a three-dimensional network.