25791-35-9Relevant academic research and scientific papers
New chelating pyridyl-indenyl and quinolyl-indenyl ligands leading to C1 symmetrical complexes of zirconium via amine elimination. X-ray structure of [3-(2-pyridylmethyl) (indenyl) ]tris(dimethylamido) Zr(IV)
Ziniuk, Zeev,Goldberg, Israel,Kol, Moshe
, p. 441 - 446 (1997)
Two new chelating (1-) ligands, based on an indenyl group and either a pendant pyridylmethyl arm or a pendant quinolylmethyl arm were synthesized. The two ligands react cleanly with tetrakis(dimethylamido)zirconium by amine elimination reactions leading to complexes of C1 symmetry. The crystal structure of the pyridyl-indenyl zirconium complex 3 was determined. Compound C21H30N4Zr (3) crystallizes in the orthorhombic space group Pbca with a = 9.588(1), b = 14.858(12), c = 29.932(7) A, V = 4264.1 (A3), Z = 8. The structure refinement converged to R1 = 0.049 for 2363 F0 > 4σ(F0) and wR2 = 0.167 for all 3197 unique data, S = 1.04. The structure shows that the indenyl is bound in a η5 fashion blocking the top of the zirconium atom, and the pyridine is coordinated in an exceptionally long 2.536(5) A N-Zr bond, blocking the back of the zirconium atom.
Indenyl Compounds with Constrained Hapticity: The Effect of Strong Intramolecular Coordination
Mrózek, Ond?ej,Vinklárek, Jaromír,R??i?ková, Zdeňka,Honzí?ek, Jan
, p. 5250 - 5264 (2016/11/23)
A series of cyclopentadienyl and indenyl molybdenum(II) compounds with intramolecularly coordinated pyridine arms, including scorpionate-like species bearing two irreversibly coordinated arms on the indenyl core, were synthesized and characterized. All presented structural types were confirmed by X-ray diffraction analysis. Owing to the strong nucleophilicity of pyridine, the intramolecular interaction was found to be considerably stronger than that in analogous species bearing tertiary amines in the side chain. Although the starting compounds for the syntheses were isostructural, the reaction outcomes differed considerably. The cyclopentadienyl precursor gave a pentacoordinate η5:κN-compound, whereas the indenyl analogue produced a hexacoordinate species with the unprecedented η3:κN-coordination mode of the indenyl ligand and thus represents an unusual example of the so-called indenyl effect. The unusually high stability of the η3:κN-coordination compounds toward η3to η5haptotropic rearrangement was clarified by theoretical calculations. As the strong intramolecular interaction prevented rotation of the indenyl moiety, it could not reach the conformation suitable for the η3to η5rearrangement. As a result, the low hapticity was effectively locked.
