Agnieszka Czapik

On the bioreactivity of triorganotin aminobenzoates. Investigation of trialkyl and triarylyltin(IV) esters of 3-amino and 4-aminobenzoic acids.

The synthesis and study of trimethyl-, tributyl- and triphenyltin esters of the 3- and 4-aminobenzoic acids are reported. The triorganotin derivatives are characterized by elemental analyses, FT-IR and solution (1)H and (13)C NMR spectra. The structure of the trimethyltin 4-aminobenzoate is solved by X-ray diffraction and proves to be polymeric in nature with bridging carboxylates and trigonal bipyramidal tin(IV) environment. However, all the compounds become monomeric in solution with a tetrahedral tin coordination environment in chloroform and trigonal bipyramidal in DMSO due to coordination of the solvent as the NMR spectra have revealed. The compounds exhibit variable cytotoxic activity when tested against Kappa562 myelogenous leukaemia, HeLa cervical cancer and HepG2 hepatocellular carcinoma cell lines, with the butyl derivatives being the more effective and the methyl ones the less. Interestingly, their antibacterial action was significantly lower when tested against Escherichia coli, while not appreciable direct interaction with DNA has been observed. The above observations account for a mode of action that may be related to their potential interaction with cell membranes and the subsequent inhibition of various signaling processes.

A new polymorph of benzene‐1,2‐diamine: isomorphism with 2‐aminophenol and two‐dimensional isostructurality of polymorphs

A new crystalline form of benzene-1,2-diamine, C(6)H(8)N(2), crystallizing in the space group Pbca, has been identified during screening for cocrystals. The crystals are constructed from molecular bilayers parallel to (001) that have the polar amino groups directed to the inside and the aromatic groups, showing a herringbone arrangement, directed to the outside. The known monoclinic form and the new orthorhombic polymorph exhibit two-dimensional isostructurality as the crystals consist of nearly identical bilayers. In the monoclinic form, neighbouring bilayers are generated by a unit translation along the a axis, whereas in the orthorhombic form they are generated by a c-glide. Moreover, the new form of benzene-1,2-diamine is essentially isomorphous with the only known form of 2-aminophenol.

p-Phenyl­enediamine and its dihydrate: two-dimensional isomorphism and mechanism of the dehydration process, and N—H⋯N and N—H⋯π inter­actions

p-Phenylenediamine can be obtained as the dihydrate, C(6)H(8)N(2) x 2 H(2)O, (I), and in its anhydrous form, C(6)H(8)N(2), (II). The asymmetric unit of (I) contains one half of the p-phenylenediamine molecule lying about an inversion centre and two halves of water molecules, one lying on a mirror plane and the other lying across a mirror plane. In (II), the asymmetric unit consists of one molecule in a general position and two half molecules located around inversion centres. In both structures, the p-phenylenediamine molecules are arranged in layers stabilized by N-H...pi interactions. The diamine layers in (I) are isostructural with half of the layers in (II). On dehydration, crystals of (I) transform to (II). Comparison of their crystal structures suggests the most plausible mechanism of the transformation process which requires, in addition to translational motion of the diamine molecules, in-plane rotation of every fourth p-phenylenediamine molecule by ca 60 degrees. A search of the Cambridge Structural Database shows that the formation of hydrates by aromatic amines should be considered exceptional.

Synthesis and structural characterization of heteroleptic Cu(I) complexes with α-diimines derived from pyridinyliminobenzoic acids

The synthesis and molecular and electronic structure of heteroleptic univalent copper compounds [Cu(L)(PPh3)X] are reported where X is a halide and L represents 3-pyridinylimino, 4-pyridinylimino or 3,5-dipyridinylimino-substituted benzoic acid, hereafter abbreviated as L1, L2, and L3, respectively. The crystal structures of two iodide and one bromide complexes are described. All compounds are hydrogen-bonded dimers. The electronic excitation spectra of the compounds are dominated by intraligand bands of ligands while characteristic MLCT transitions are observed at 430–480 nm. No emission is observed from the compounds either in the solid state or in solution; on the contrary a photodecomposition is observed resulting in triphenylphosphane ligand elimination and formation of halogen-bridged dimmers.

trans-Dichloro(η 2-ethylene) (N-3-pyridinylmethanesulfonamide)platinum(II). Crystal structure, spectroscopic, and thermoanalytical characterization, and cytotoxicity assays

The organometallic complex, trans-[PtCl2(η 2-C2H4)(PMSA)] (1), where PMSA = N-3-pyridinylmethanesulfonamide, has been synthesized and characterized by elemental analysis, molar electric conductivity, IR, electronic, and NMR (1H, 13C, and 195Pt) spectroscopy, and thermal analysis. X-ray crystallography revealed that in 1 [monoclinic, P21 c, a = 5.1260(1), b = 19.1600(4), c = 12.7990(3) Å, β = 97.242(2)°, Z = 4] Pt(II) shows planar coordination geometry with PMSA coordinated via the pyridine. The ethylene is virtually perpendicular to the PtCl2N plane with the pyridine ring twisted relative to this plane by 47°. In in vitro assays, PMSA, K[PtCl3(η 2-C2H4)] · H2O, and 1 do not exhibit appreciable cytotoxic activity against human K562 and HepG2 tumor cell lines.

Aggregation of Hydrogen Bonded Dimeric Tri-Organotin Amino Substituted Pyrimidine-2-Thiolates

The synthesis of six tri-organotin compounds with 4-amino and 4,6-diaminopyrimidine-2-thiolate is described. The compounds have the general formula R3Sn(thiolate) where R = Me, Bu, or Ph. The compounds are investigated by a variety of spectroscopic techniques both in solution and in the solid state. The environment around the tin centres proves to be tetrahedral with monodentate thiolate anions as is inferred from the infrared and NMR spectra. The coordination sphere is not affected even by the presence of DMSO as solvent. In the solid state, the crystal structure determination of the trimethyl and triphenyltin derivatives of the 4,6-diaminopyrimidine-2-thiolate ligand, reveal an association into centrosymmetric dimers through N–H⋯N hydrogen-bonding interactions leaving the organotin site practically unaffected. However, in addition to the classical hydrogen bonding, weaker N–H⋯RS and N–H⋯Rπ interactions are also present and play an important role in determining further aggregation of these dimers which gives rise to a three-dimensional polymeric structure in the case of the trimethyltin and a layer of dimers in the case of the triphenyltin derivative, respectively.

Phenazine-naphthalene-1,5-diamine-water (1/1/2).

The asymmetric unit of the title compound, C12H8N2·C10H10N2·2H2O, contains one half-molecule of phenazine, one half-molecule of naphthalene-1,5-diamine and one water molecule. The phenazine and naphthalene-1,5-diamine molecules are located on inversion centers. The water molecules serve as bridges between the naphthalene-1,5-diamine molecules and also between the naphthalene-1,5-diamine and phenazine molecules. The naphthalene-1,5-diamine and water molecules are connected via N—H⋯O and O—H⋯N hydrogen bonds, forming a T4(2) motif. They are arranged into a two-dimensional polymeric structure parallel to (10) in which the water molecule is a single donor and a double acceptor, whereas the amino group is a double donor and a single acceptor in the hydrogen bonding. These two-dimensional assemblies alternate with the layers of phenazine molecules arranged into a herringbone motif. Each phenazine molecule is hydrogen bonded to two water molecules and thus a three-dimensional framework of hydrogen-bonded molecules is generated.

Cocrystals of 2,3,5,6-tetrafluorobenzene-1,4-diol with diaza aromatic compounds

2,3,5,6-Tetrafluorobenzene-1,4-diol easily forms cocrystals with heteroaromatic bases containing the pyrazine unit. In the 1:1 complexes with pyrazine, C(6)H(2)F(4)O(2) x C(4)H(4)N(2), (I), and quinoxaline, C(6)H(2)F(4)O(2) x C(8)H(6)N(2), (II), the crystal components are linked via O-H...N hydrogen bonds into one-dimensional chains. With the largest base, phenazine, the 1:2 benzenediol-phenazine complex, C(6)H(2)F(4)O(2) x 2 C(12)H(8)N(2), (III), was obtained, with the molecules linked via O-H...N interactions into a discrete heterotrimer. In all three cocrystals, the two types of molecules are organized into layers via softer C-H...O and C-H...F interactions and pi-pi stacking interactions, with stronger hydrogen bonds linking molecules of adjacent layers. In (II) and (III), molecules are arranged into heterostacks, whereas in (I) separate stacks are formed by the heterocyclic base and the benzenediol molecule.

Carbonato-kappa2 O, O’) bis(di-2-pyridylamine- kappa2 N,N’)cobalt(III) bromide

In the title compound, [Co(CO3)(C10H9N3)2]Br, a distorted octahedral coordination of the CoIII atom is completed by four N atoms of the two chelating di-2-pyridylamine ligands and two O atoms of the chelating carbonate anion. The di-2-pyridylamine ligands are nonplanar and the dihedral angles between the 2-pyridyl groups are 29.11 (9) and 37.15 (12)°. The coordination cation, which has approximate C 2 symmetry, is connected to the bromide ion via an N—H⋯Br− hydrogen bond. The ionic pair thus formed is further assembled into a dimer via N—H⋯O interactions about an inversion centre. A set of weaker C—H⋯O and C—H⋯Br− interactions connect the dimers into a three-dimensional network.

(Carbonato-κ2O,O′)bis(di-2-pyridylamine-κ2N,N′)cobalt(III) bromide

In the title compound, [Co(CO3)(C10H9N3)2]Br, a distorted octahedral coordination of the CoIII atom is completed by four N atoms of the two chelating di-2-pyridylamine ligands and two O atoms of the chelating carbonate anion. The di-2-pyridylamine ligands are nonplanar and the dihedral angles between the 2-pyridyl groups are 29.11 (9) and 37.15 (12)°. The coordination cation, which has approximate C 2 symmetry, is connected to the bromide ion via an N—H⋯Br− hydrogen bond. The ionic pair thus formed is further assembled into a dimer via N—H⋯O interactions about an inversion centre. A set of weaker C—H⋯O and C—H⋯Br− interactions connect the dimers into a three-dimensional network.