Conformational flexibility of 2,6-bis(pyrazol-1-ylmethyl)pyridine (L5) in [(L5)CoII(H2O)3]Cl2 and [(L5)NiII(H2O)2Cl]Cl·H2O. Molecular structures and non-covalent interactions

Synthesis, characterization and molecular structures of Ni(II) complexes derived from Schiff base pyridylimine ligands

“…The NiL1 (15) Å] is close to those observed in other aqua nickel complexes [17,18,[25][26][27][28][29][30][31], lengths for Ni-N imine and Ni-N pyridyl bonds are in accordance with other structurally similar complexes [15,[17][18][19]32,33].…”

Synthesis and selected lanthanide coordination chemistry of new ((1H-pyrazol-1-yl)methyl)pyridine and -pyridine 1-oxide ligands

“…The previously reported functionalized pyridine compound, 1, and several of its closely related derivatives, have been demonstrated to behave as tridentate chelating ligands toward a number of transition metal ions [6,7,29], and CPK model building suggests that 2, 4 and 5 should also be able to adopt tridentate chelate binding modes on lanthanide cations. In order to confirm this expectation and to more fully assess the impact of ligand steric energetics upon coordination, the reorganization energy of …”

“…As mentioned in the Introduction, the lanthanide coordination chemistry of numerous derivatives of 1-bpp (A) and 3-bpp (B) ligands has been extensively developed [6][7][8][9]. Based upon single crystal X-ray structure analyses, it is generally found that these bis-(pyrazole)pyridine ligands bind in a tridentate N pyrz N pyrz N pyrd manner on Ln(III)ions.…”

Synthesis, characterization, and ethylene polymerization behavior of Cr(III) catalysts based on bis(pyrazolylmethyl)pyridine and its derivatives

“…The organic phase was washed with saturated aqueous NaCl solution and distilled water and dried over Na 2 SO 4 ; the solvent was removed in vacuo to afford 2,6-pyridinedimethylene-ditosylate (0.79 g, 88%) as a white powder. 1 [33,[36][37][38] At 0 • C, a solution of pyrazole (0.22 g, 3.2 mmol) in dry THF (5 mL) was added dropwise to a suspension of NaH (0.08 g, 3.2 mmol) in dry THF (5 mL). After 15 min of stirring, a clear solution of NaPz was obtained.…”

“…8, solid-state structure of Cr2 revealed that coordination sphere of the Cr center adopts an octahedral geometry with a tridentate ligand and three chlorines. In the molecular structure of Cr2, the donor nitrogen atoms form a mer configuration; the basal plane consists of the three nitrogen atoms from the pyridine and pyrazoles and one equatorial chloride, with the remaining chlorides occupying the apical positions [37]. The structure can be compared to that of 2,6-bis(2-benzimidazolyl) pyridine Cr(III) complex reported by Zhang et al [16] Similarities include the fact that the bond lengths between the Cr and the mutually trans-disposed chlorine atoms, Cr1-Cl2 and Cr1-Cl2 i (2.3329(16) Å), are longer than the bond length of Cr1-Cl3 (2.303(2) Å).…”