Diethylnicotinamide Research Articles

Crystal structure of trans-di-aqua-bis-(4-cyano-benzoato-κO)bis-(N,N-di-ethyl-nicotinamide-κN)cadmium.

The mononuclear title cadmium complex, [Cd(C10H14N2O)2(C8H4NO2)2(H2O)2], is centrosymmetric and contains two water mol-ecules, two 4-cyanobenzoate (CB) ligands and two di-ethyl-nicotinamide (DENA) ligands. All the ligands are coordinated to the CdII atom in a monodentate mode. The four nearest O atoms around the CdII atom form a slightly distorted square-planar arrangement, with the distorted octa-hedral coordination sphere being completed by the two pyridine N atoms of the DENA ligands at distances of 2.3336 (13) Å. The dihedral angle between the carboxyl-ate group and the adjacent benzene ring is 8.75 (16)°, while the benzene and pyridine rings are oriented at a dihedral angle of 57.83 (5)°. The water mol-ecules exhibit both intra-molecular [to the non-coordinating carboxyl-ate O atom, enclosing an S(6) hydrogen-bonding motif, where O⋯O = 2.670 (2) Å] and inter-molecular [to the amide carbonyl O atom, enclosing an R22(16) ring motif, where O⋯O = 2.781 (2) Å] O-H⋯O hydrogen bonds. The latter lead to the formation of supra-molecular chains propagating along [110].

Crystal structure of trans-di-aqua-bis-(4-cyano-benzoato-κO)bis-(N,N-di-ethyl-nicotinamide-κN)zinc(II).

In the title complex, [Zn(C8H4NO2)2(C10H14N2O)2(H2O)2], the ZnII cation, located on an inversion centre, is coordinated by two water mol-ecules, two 4-cyano-benzoate (CB) anions and two di-ethyl-nicotinamide (DENA) ligands in a distorted N2O4 octa-hedral geometry. In the mol-ecule, the dihedral angle between the planar carboxyl-ate group and the adjacent benzene ring is 9.50 (14)°, while the benzene and pyridine rings are oriented at a dihedral angle of 56.99 (5)°. The water mol-ecules exhibit both an intra-molecular hydrogen bond [to the non-coordinating carboxyl-ate O atom, enclosing an S(6) hydrogen-bonding motif, where O⋯O = 2.6419 (19) Å] and an inter-molecular hydrogen bond [to the amide carbonyl O atom, enclosing an R22(16) ring motif, where O⋯O = 2.827 (2) Å]; the latter lead to the formation of supra-molecular chains propagating along the [110] direction.

Crystal structure of diaquabis(N,N-diethylnicotinamide-κN1)bis(2,4,6-trimethylbenzoato-κO1)cobalt(II)

The centrosymmetric mol-ecule in the monomeric title cobalt complex, [Co(C10H11O2)2(C10H14N2O)2(H2O)2], contains two water mol-ecules, two 2,4,6-tri-methyl-benzoate (TMB) ligands and two di-ethyl-nicotinamide (DENA) ligands. All ligands coordinate to the Co(II) atom in a monodentate fashion. The four O atoms around the Co(II) atom form a slightly distorted square-planar arrangement, with the distorted octa-hedral coordination sphere completed by two pyridine N atoms of the DENA ligands. The dihedral angle between the planar carboxyl-ate group and the adjacent benzene ring is 84.2 (4)°, while the benzene and pyridine rings are oriented at a dihedral angle of 38.87 (10)°. The water mol-ecules exhibit both intra-molecular (to the non-coordinating carboxyl-ate O atom) and inter-molecular (to the amide carbonyl O atom) O-H⋯O hydrogen bonds. The latter lead to the formation of layers parallel to (100), enclosing R 4 (4)(32) ring motifs. These layers are further linked via weak C-H⋯O hydrogen bonds, resulting in a three-dimensional network. One of the two ethyl groups of the DENA ligand is disordered over two sets of sites with an occupancy ratio of 0.490 (13):0.510 (13).

Separation of m/p‐Aminoacetophenone Using Hydrotropy

The aqueous solubilities of m/p‐aminoacetophenone in different concentrations (0‐3.0 mol/L) of hydrotropes such as diethyl nicotinamide, sodium pseudocumene sulfonate and sodium thiocyanate solutions at different system temperatures (303K to 333K) were studied. The percentage extraction (%E) of m‐ aminoacetophenone from m/p‐aminoacetophenone mixture increases with increase in hydrotrope concentration. A Minimum Hydrotrope Concentration (MHC) in the aqueous phase was required to initiate the significance of the %E of m‐aminoacetophenone. Percentage extraction (%E) is the ratio of moles of m‐aminoacetophenone extracted in presence and absence of a hydrotrope. The sensitivity and feasibility of the proposed process are examined by carrying out solubilization and equilibrium precipitation experiments with the mixtures of various compositions. The effectiveness of hydrotropes was measured in terms of Setschenow constant Ks. The extraction data are also fitted in a polynomial equation as the function of hydrotrope concentration. The solubilized material can be recovered by dilution with water.

Diaquabis(4-bromobenzoato-κO)bis(N,N-diethylnicotinamide-κN1)copper(II)

The title CuII complex, [Cu(C7H4BrO2)2(C10H14N2O)2(H2O)2], contains two 4-bromo­benzoate (PBB), two diethyl­nicotinamide (DENA) monodentate ligands and two water mol­ecules. The four O atoms in the equatorial plane around the CuII ion form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by two N atoms of the DENA ligands in the axial positions. Intra­molecular O—H⋯O hydrogen bonds link the water mol­ecules to the carboxyl­ate groups. The dihedral angles between the carboxyl­ate groups and the adjacent benzene rings are 3.1 (3) and 3.74 (17)°, while the pyridine rings and the benzene rings are oriented at dihedral angles of 6.81 (10) and 3.38 (12)°. In the crystal, inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into double chains along the b axis. C—H⋯O inter­actions are also observed. π–π contacts between pyridine rings [centroid–centroid distance = 3.485 (2) Å] may further stabilize the crystal structure.

Diaquabis(4-bromobenzoato-κO)bis(N,N-diethylnicotinamide-κN1)manganese(II)

In the crystal structure of the title MnII complex, [Mn(C7H4BrO2)2(C10H14N2O)2(H2O)2], the MnII cation is located on an inversion center and coordinated by two diethyl­nicotinamide (DENA) ligands, two 4-bromo­benzoate (PBB) anions and two water mol­ecules in a distorted octa­hedral geometry. The dihedral angle between the carboxyl­ate group and the adjacent benzene ring is 3.25 (14)°. In the mol­ecule, the pyridine ring and the benzene ring are oriented at a dihedral angle of 77.24 (5)°. In the crystal, inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into a two-dimensional network. Weak inter­molecular C—H⋯O hydrogen bonds and π–π inter­actions between the pyridine rings of neighbouring mol­ecules [centroid–centroid distance = 3.537 (1) Å] further consolidate the crystal packing.

Diaquabis(N,N′-diethylnicotinamide-κN1)bis(4-ethylbenzoato-κO)copper(II)

The title CuII complex, [Cu(C9H9O2)2(C10H14N2O)2(H2O)2], contains two 4-ethyl­benzoate (PEB) ligands, two monodentate diethyl­nicotinamide (DENA) ligands and two water mol­ecules. The four O atoms in the equatorial plane around the CuII ion form a slightly distorted square-planar arrangement, while the distorted octa­hedral coordination is completed by the two N atoms of the DENA ligands in the axial positions. Intra­molecular O—H⋯O hydrogen bonds link the water mol­ecules to the carboxyl­ate groups. The dihedral angles between the carboxyl­ate groups and the adjacent benzene rings are 4.6 (3) and 3.7 (2)°, while the pyridine rings and the benzene rings are oriented at dihedral angles of 6.82 (11) and 3.63 (14)°. In the crystal, inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into chains propagating along [010]. C—H⋯O inter­actions and a π–π contact between the pyridine rings [centroid–centroid distance = 3.469 (2) Å] are also observed.

Diaquabis(N,N-diethylnicotinamide-κN1)bis(4-ethylbenzoato-κO)cobalt(II)

The title CoII complex, [Co(C9H9O2)2(C10H14N2O)2(H2O)2], contains two 4-ethyl­benzoate (PEB), two monodentate diethyl­nicotinamide (DENA) ligands and two water mol­ecules. The four O atoms in the equatorial plane around the CoII ion form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by the two N atoms of the DENA ligands in the axial positions. Intra­molecular O—H⋯O hydrogen bonds link the water mol­ecules to the carboxyl­ate groups. The dihedral angles between the carboxyl­ate groups and the adjacent benzene rings are 4.52 (18) and 4.56 (18)°, while the pyridine rings and the benzene rings are oriented at dihedral angles of 7.76 (10) and 5.67 (13)°. In the crystal, inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into chains propagating along [010]. C—H⋯O inter­actions and a π–π contact between the pyridine rings [centroid–centroid distance = 3.476 (2) Å] are also observed.

Diaquabis(2-bromobenzoato-κO)bis(N,N-diethylnicotinamide-κN1)cobalt(II)

In the mononuclear title compound, [Co(C7H4BrO2)2(C10H14N2O)2(H2O)2], the CoII ion is located on a crystallographic inversion center. The asymmetric unit is completed by one 2-bromo­benzoate anion, one diethyl­nicotinamide (DENA) ligand and one coordinated water mol­ecule; all ligands are monodentate. The four O atoms in the equatorial plane around CoII form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by the two pyridine N atoms of the DENA ligands in axial positions. The dihedral angle between the carboxyl­ate group and the attached benzene ring is 84.7 (1)°; the pyridine and benzene rings are oriented at a dihedral angle of 43.64 (6)°. In the crystal structure, inter­molecular O—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network.

Diaquabis(N,N-diethylnicotinamide-κN1)bis[4-(dimethylamino)benzoato-κO]cobalt(II)

The title CoII complex, [Co(C9H10NO2)2(C10H14N2O)2(H2O)2], is centrosymmetric. It contains two dimethyl­amino­benzoate (DMAB) and two diethyl­nicotinamide (DENA) ligands and two water mol­ecules, all of them being monodentate. The four O atoms in the equatorial plane around the Co atom form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by the two pyridine N atoms of DENA ligands with the Co—N distance of 2.1519 (11) Å in the axial positions. The Co atom is displaced out of the least-squares plane of the carboxyl­ate group by −0.781 (1) Å. The dihedral angle between the carboxyl­ate group and the adjacent benzene ring is 5.05 (7)°, while the pyridine and benzene rings are oriented at a dihedral angle of 71.48 (5)°. In the crystal structure, inter­molecular O—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network. Two weak C—H⋯π inter­actions are also present.

Diaquabis(N,N-diethylnicotinamide-κN1)bis[4-(dimethylamino)benzoato-κO]nickel(II)

The centrosymmetric title NiII complex, [Ni(C9H10NO2)2(C10H14N2O)2(H2O)2], contains two dimethyl­amino­benzoate (DMAB), two diethyl­nicotinamide (DENA) ligands and two water mol­ecules, all of them monodentate. The four O atoms in the equatorial plane around the NiII atom form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by the two pyridine N atoms of the DENA ligands in axial positions. The NiII atom is displaced by 0.681 (1) Å out of the least-squares plane of the carboxyl­ate group. The dihedral angle between the carboxyl­ate group and the adjacent benzene ring is 5.61 (7)°, while the pyridine and benzene rings are oriented at a dihedral angle of 73.20 (4)°. An intra­molecular O—H⋯O hydrogen bond results in the formation of a six-membered ring with a twisted conformation. In the crystal structure, inter­molecular O—H⋯O and C—H⋯O hydrogen bonds link mol­ecules into a three-dimensional network. Two weak C—H⋯π inter­actions are also present.

Diaquabis(2-bromobenzoato-κO)bis(N,N-diethylnicotinamide-κN1)nickel(II)

In the monomeric centrosymmetric title NiII complex, [Ni(C7H4BrO2)2(C10H14N2O)2(H2O)2], the NiII ion is located on an inversion center. The asymmetric unit contains one 2-bromo­benzoate ligand, one diethyl­nicotinamide (DENA) ligand and one coordinated water mol­ecule. The four O atoms in the equatorial plane around the NiII ion form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by two N atoms of two DENA ligands in the axial positions. The dihedral angle between the benzene ring and the attached carboxyl­ate group is 87.73 (15)°, while the pyridine and benzene rings are oriented at a dihedral angle of 42.48 (7)°. In the crystal structure, O—H⋯O hydrogen bonds link the mol­ecules into a two-dimensional network parallel to (10). In addition, C—H⋯O hydrogen bonds are observed.

Diaquabis(2-chlorobenzoato-κO)bis(N,N-diethylnicotinamide-κN1)nickel(II)

In the monomeric and centrosymmetric title NiII complex, [Ni(C7H4ClO2)2(C10H14N2O)2(H2O)2], the NiII ion is located on an inversion center. The asymmetric unit contains one 2-chloro­benzoate ligand, one diethyl­nicotinamide (DENA) ligand and one coordinating water mol­ecule, the ligands being monodentate. The four O atoms in the equatorial plane around the NiII ion form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by two N atoms of the DENA ligands in axial positions. The dihedral angle between the benzene ring and the attached carboxyl­ate group is 87.36 (10)°, while the pyridine and benzene rings are oriented at an angle of 41.90 (5)°. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into a two-dimensional network parallel to (10).

Diaquabis(2-bromobenzoato-κO)bis(N,N-diethylnicotinamide-κN1)manganese(II)

The title MnII complex, [Mn(C7H4BrO2)2(C10H14N2O)2(H2O)2], is centrosymmetric. The mol­ecule contains two 2-bromo­benzoate (BB) and two diethyl­nicotinamide (DENA) ligands and two water mol­ecules, all ligands being monodentate. The four O atoms in the equatorial plane around the Mn atom form a slightly distorted square-planar arrangement, while the distorted octa­hedral coordination is completed by the two N atoms of the DENA ligands in the axial positions. The dihedral angle between the carboxyl group and the adjacent benzene ring is 79.95 (11)°, while the pyridine and benzene rings are oriented at a dihedral angle of 45.66 (6)°. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into infinite chains.

Diaquabis(2-chlorobenzoato-κO)bis(N,N-diethylnicotinamide-κN1)manganese(II)

In the monomeric title complex, [Mn(C7H4ClO2)2(C10H14N2O)2(H2O)2], the MnII atom is located on a crystallographic centre of inversion. The asymmetric unit contains one 2-chloro­benzoate (CB) ligand, one diethyl­nicotinamide (DENA) ligand and one coordinated water mol­ecule, all ligands being monodentate. The four O atoms in the equatorial plane around the Mn atom form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by the two pyridine N atoms of the DENA ligands in the axial positions. The dihedral angle between the carboxyl group and the adjacent benzene ring is 77.9 (11)°, while the pyridine and benzene rings are oriented at a dihedral angle of 45.94 (5)°. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into infinite chains.

Diaquabis(2-bromobenzoato-κO)bis(N,N-diethylnicotinamide-κN1)zinc(II)

In the centrosymmetric title complex, [Zn(C7H4BrO2)2(C10H14N2O)2(H2O)2], the ZnII atom is located on an inversion center. The asymmetric unit contains one 2-bromo­benzoate (BB), one diethyl­nicotinamide (DENA) ligand and one coordinating water molecule. The four O atoms in the equatorial plane around the Zn atom form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by the two N atoms of the DENA ligands in the axial positions. The dihedral angle between the carboxyl group and the adjacent benzene ring is 85.51 (12)°, while the pyridine and benzene rings are oriented at a dihedral angle of 44.07 (6)°. In the crystal structure, O—H⋯O hydrogen bonds link the mol­ecules into infinite chains.

Diaquabis(N,N-diethylnicotinamide-κN1)bis(4-formylbenzoato-κO)cobalt(II)

In the crystal structure of the title CoII complex, [Co(C8H5O3)2(C10H14N2O)2(H2O)2], the metal centre is located on an inversion center and is coordinated by two 4-formyl­benzoate (FOB), two diethyl­nicotinamide (DENA) ligands and two water mol­ecules in a slightly distorted CoO4N2 octa­hedral geometry. In the crystal structure, O—H⋯O hydrogen bonds link the mol­ecules into infinite chains. π–π contacts between the parallel pyridine rings of neighboring DENA ligands [centroid–centroid distance = 3.652 (3) Å] further stabilize the crystal structure.

Diaquabis(N,N-diethylnicotinamide-κN1)bis(4-formylbenzoato-κO)nickel(II)

In the title centrosymmetric mononuclear NiII compound, [Ni(C8H5O3)2(C10H14N2O)2(H2O)2], the central NiII atom is coordinated by two O atoms from two 4-formyl­benzoate (FOB) ligands, two O atoms from two water mol­ecules and two N atoms from two diethyl­nicotinamide (DENA) ligands. The coordination geometry is slightly distorted octa­hedral, with four O atoms in the equatorial plane and two N atoms in axial positions. Intra­molecular O—H⋯O hydrogen bonds are observed. In the crystal structure, mol­ecules are linked into chains along the a axis by inter­molecular O—H⋯O hydrogen bonds. The structure is further stabilized by π–π inter­actions between the pyridine rings of DENA units, with a centroid–centroid distance of 3.668 (2) Å.

Paclitaxel-loaded microparticles and implants for the treatment of brain cancer: Preparation and physicochemical characterization

The aim of this study was to prepare different types of paclitaxel-loaded, PLGA-based microparticles and lipidic implants, which can directly be injected into the brain tissue. Releasing the drug in a time-controlled manner over several weeks, these systems are intended to optimize the treatment of brain tumors. The latter is particularly difficult because of the blood–brain barrier (BBB), hindering most drugs to reach the target tissue upon systemic administration. Especially paclitaxel (being effective for the treatment of ovarian, breast, lung and other cancers) is not able to cross the BBB to a notable extent since it is a substrate of the efflux transporter P-glycoprotein. Both, biodegradable microparticles as well as small, cylindrical, glycerol tripalmitate-based implants (which can be injected using standard needles) were prepared with different paclitaxel loadings. The effects of several formulation and processing parameters on the resulting drug release kinetics were investigated in phosphate buffer pH 7.4 as well as in a diethylnicotinamide (DENA)/phosphate buffer mixture. Using DSC, SEM, SEC and optical microscopy deeper insight into the underlying drug release mechanisms could be gained. The presence of DENA in the release medium significantly increased the solubility of paclitaxel, accelerated PLGA degradation, increased the mobility of the polymer and drug molecules and fundamentally altered the geometry of the systems, resulting in increased paclitaxel release rates.

Superexchange Interactions through Quasi-Linear End-to-End Azido Bridges: Structural and Magnetic Characterisation of a New Two-Dimensional Manganese–Azido System [Mn(DENA)2(N3)2]n (DENA = diethylnicotinamide)

Reaction of sodium azide with manganese(II) and diethylnicotinamide (DENA) leads to the two-dimensional system trans-[Mn(DENA)2(N3)2]n. The compound crystallises in the P2/c (monoclinic) group. Structural determination shows layers of manganese atoms bridged by means of single µ1,3-azido bridges. The polymeric structure is achieved by means of two different µ1,3-azide bridges, one of them with Mn–N–N bond angles of 148.4(2)°, whereas the second nonequivalent azido bridge has the unusual feature of quasi-linear coordination with Mn–N–N bond angles of 171.7(2)°. Molecular orbital calculations and susceptibility data show antiferromagnetic interaction and similar constant coupling values for the two superexchange pathways, in spite of the structural differences. Susceptibility, magnetisation, and EPR properties are compared with related azido systems.