Copper(II) Halide Complexes of 2-Aminopyrimidines: Crystal Structures of [(2-aminopyrimidine) n CuCl2] (n=1,2) and (2-amino-5-bromopyrimidine)2CuBr2

Crystal structure, Hirshfeld surface analysis and physicochemical characterization of bis-[4-(di-methyl-amino)-pyridinium] di-μ-chlorido-bis[di-chlorido-mercurate(II)]

The title mol-ecular salt, (C7H11N2)2[Hg2Cl6], crystallizes with two 4-(di-methyl-amino)-pyridinium cations (A and B) and two half hexa-chlorido-dimercurate(II) anions in the asymmetric unit. The organic cations exhibit essentially the same features with an almost planar pyridyl ring (r.m.s. deviations of 0.0028 and 0.0109 Å), which forms an inclined dihedral angle with the dimethyamino group [3.06 (1) and 1.61 (1)°, respectively]. The di-methyl-amino groups in the two cations are planar, and the C-N bond lengths are shorter than that in 4-(di-methyl-amino)-pyridine. In the crystal, mixed cation-anion layers lying parallel to the (010) plane are formed through N-H⋯Cl hydrogen bonds and adjacent layers are linked by C-H⋯Cl hydrogen bonds, forming a three-dimensional network. The analyses of the calculated Hirshfeld surfaces confirm the relevance of the above inter-molecular inter-actions, but also serve to further differentiate the weaker inter-molecular inter-actions formed by the organic cations and inorganic anions, such as π-π and Cl⋯Cl inter-actions. The powder XRD data confirms the phase purity of the crystalline sample. Furthermore, the vibrational absorption bands were identified by IR spectroscopy and the optical properties were studied by using optical UV-visible absorption spectroscopy.

CuII and ZnII β-diketonate coordination polymers based on pyrimidin-2-amine, pyrazine and 1,2-bis(4-pyridyl)ethane

Copper(II) and zinc(II) bis(4,4,4-trifluoro-1-phenylbutane-1,3-dionato) compounds with pyrimidin-2-amine (pyr2a), pyrazine (pyz) and 1,2-bis(4-pyridyl)ethane (dpet) were prepared and solid-state structures of coordination polymers [M(tfpb)₂(pyr2a)]_∞ [M = Cu (1), Zn (2); tfpb = 4,4,4-trifluoro-1-phenylbutane-1,3-dionate], [M(tfpb)₂(pyz)]_∞ [M = Cu (3), Zn (4a, 4b)] and [Cu(tfpb)₂(dpet)]_∞ (5), respectively, were determined by single-crystal X-ray analysis. The coordination of metal centers in all compounds is octahedral with nitrogen ligands occupying the axial positions. Compound (1) crystallizes in the triclinic space group P\bar 1, whereas (2) crystallizes in the monoclinic space group P2/n. Differences are due to the different orientation of adjacent M(tfpb)₂ units, whereas the orientation of pyrimidin-2-amine is the same in both compounds. Polymeric chains in (1) and (2) contain intramolecular N-H...O hydrogen bonding between amino and carbonyl groups. Room-temperature structures (3) and (4a) are isomorphous adopting the monoclinic space group C2/m; however, on cooling crystals (4a) to 150 K a single-crystal-to-single-crystal transformation to (4b) possessing the triclinic space group P\bar 1 was observed. Compound (5) crystallizes in the triclinic space group P\bar 1 and contains a parallel aggregation of chains in contrast to the known structure of the non-fluorinated benzoylacetonato ligand, where chains aggregate in a perpendicular fashion. In the compounds studied intramolecular C-H...O and/or C-H...F interactions are present. The neighboring chains are linked by π...π interactions and in some compounds also by C-H...π interactions [(1), (4b), (5)].

(2-Amino-pyrimidine-κN)diaqua(pyridine-2,6-dicarboxyl-ato-κO,N,O)-nickel(II) monohydrate

The reaction of Ni(NO₃)₂·6H₂O with pyridine-2,6-dicarboxylic acid, NaOH and 2-amino­pyrimidine in aqueous solution leads to the formation of the title complex, [Ni(C₇H₃NO₄)(C₄H₅N₃)(H₂O)₂]·H₂O. The Ni^II ion is coordinated by one N and two O atoms of the tridentate chelating pyridine-2,6-dicarboxyl­ate anion, one heterocyclic N atom of the 2-amino­pyrimidine ligand, and two water mol­ecules. The resulting geometry for the [NiN₂O₄] coordination environment can be described as distorted octa­hedral. One uncoord­inated water mol­ecule completes the asymmetric unit. Extensive O—H⋯O and N—H⋯O hydrogen-bonding inter­actions between the NH₂ group of 2-amino­pyrimidine, carboxyl­ate groups, and coordinated and uncoordinated water mol­ecules contribute to the formation of a three-dimensional supra­molecular structure.

1-(2-Pyrid-yl)-N,N'-dipyrimidin-2-ylmethane-diamine

In the title compound, C₁₄H₁₃N₇, inter­molecular N—H⋯N and C—H⋯N hydrogen bonds link the mol­ecules into infinite one-dimensional chains along (100). A C—H⋯π inter­action also occurs in the crystal.