Reactions of the metallocene dichlorides [M(Cp)2Cl2] (M = Zr, Hf) and [Ti(MeCp)2Cl2] with the pyridine-2,6-dicarboxylate(−2) ligand: Synthesis, spectroscopic characterization and X-ray structures of the products |
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Authors: | Theocharis C StamatatosSpyros P Perlepes Catherine P RaptopoulouVassilis Psycharis Nikolaos Klouras |
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Institution: | a Department of Chemistry, University of Patras, 265 00 Patras, Greece b Institute of Materials Science, NCSR “Demokritos”, 153 10 Aghia Paraskevi Attikis, Greece |
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Abstract: | The reactivity pattern of the 16-electron species M(Cp)2Cl2] (M = Zr, Hf; Cp− = η5-C5H5−) and Ti(MeCp)2Cl2] (MeCp− = η5-C5H4CH3−) towards the dipicolinate(−2) (dipic2−) ligand under mild (ambient temperature) and convenient (aerobic reactions, aqueous media) conditions have been investigated. The syntheses, molecular structures and spectroscopic (IR, 1H NMR) characterization are reported for the 18-electron products Zr(Cp)2(dipic)] (1), Hf(Cp)2(dipic)] (2) and Ti(MeCp)2(dipic)] (3). The dipic2− ion behaves as N,O,O′-chelating ligand in the three complexes, while the centroids of the Cp− (1, 2) and MeCp− (3) rings formally occupy the fourth and fifth coordination sites about the central metal. The two identical/very similar bite angles of only ∼70° make the dipic2− ligand particularly suited to form stable metallocene derivatives with 5-coordinate geometry. IR and 1H NMR data are discussed in terms of the known structures and the tridentate chelating mode of the dipic2− ligand. |
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Keywords: | Bis(η5-cyclopentadienyl)hafnium(IV)/pyridine-2 6-dicarboxylate complex Bis(η5-cyclopentadienyl)zirconium(IV)/pyridine-2 6-dicarboxylate complex Bis(η5-methylcyclopentadienyl)titanium(IV)/pyridine-2 6-dicarboxylate complex Crystal structures Group 4 metal complexes Reactivity studies |
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