Crystal structure of di-chlorido-{2,6-bis-[(3-phenyl-1H-pyrazol-1-yl)meth-yl]pyridine}cobalt(II).

In the title complex, [CoCl2(C25H21N5)], the Co(II) atom is coordinated by two Cl atoms and two N atoms, provided by a tridentate pyrazolylpyridyl ligand, forming a slightly distorted tetra-hedral geometry [range of angles: 96.51 (10) (chelate ring) to 118.60 (9)°]. The dihedral angle between Cl/Co/Cl and N/Co/N planes is 86.83 (7)°. The chelate ring has the conformation of a distorted boat. The dihedral angle between pyridyl ring and the coordinated pyrazolyl ring is 56.16 (12)°. The uncoordinated pyrazolyl ring is almost perpendicular to the pyridyl ring with the dihedral angle of 87.49 (10)°. In the crystal packing, inter-molecular phenyl-C-H ⋯π(pyrid-yl) inter-actions generate dimeric aggregates. These are connected into a zigzag supra-molecular chain along the c-axis direction via π-π inter-actions [inter-centroid distance between pyridyl and phenyl rings = 3.664 (2) Å].

Highly active chromium(III) complexes based on tridentate pyrazolyl pyridyl ligands for ethylene polymerization and oligomerization.

A set of new chromium(III) [Cr(III)] complexes based on the tridentate ligand HC(Pz)2Py (Pz = pyrazole; Py = pyridine) and its derivatives were prepared, characterized, and evaluated for ethylene polymerization/oligomerization. X-ray single-crystal analyses of the Cr(III) complexes showed tridentate coordination on the fac-octahedral Cr sphere. Upon activation with methylaluminoxane (MAO), the precatalysts and the ligands L1-L3 mixed in situ with Cr(acac)3 were highly active and generally produced polyethylene as a major product. Their catalytic performances were markedly affected by the substituents on the methine carbon atom of the ligands and reaction conditions.

Crystal structure of chlorido-penta-kis(dimethyl sulfoxide-κO)chromium(III) dichloride.

In the complex cation of the title salt, [CrCl(C2H6OS)5]Cl2, the Cr(III) ion is coordinated by one chloride ligand and five O atoms from dimethyl sulfoxide (DMSO) ligands, leading to a slightly distorted octa-hedral coordination environment [O-Cr-O angles range from 86.69 (16) to 92.87 (16)°]. In the crystal, complex cations are arranged in hexa-gonally packed rows parallel to [010], with the chloride counter-anions situated in between. The inter-actions between cations and anions are mainly ionic in nature.

Crystal structure of 2,6-bis-[(1H-pyrazol-1-yl)meth-yl]pyridine.

In the title compound, C13H13N5, the planes of the pyrazolyl groups are nearly perpendicular to that of the central pyridine ring, making dihedral angles of 87.77 (8) and 85.73 (7)°. In the crystal, weak C-H⋯N hydrogen bonds link the mol-ecules into layers extending parallel to (10-1).