| Abstrakt: |
To further our understanding of the coordination chemistry of the heavy alkaline earth metals, we here report on a family of barium pyrazolates bearing various substitution patterns that illustrate the delicate balance between ligand bulk, donor size, stoichiometry, and hapticity, while emphasizing the importance of secondary interactions including π-bonding, agostic interactions, and hydrogen bonding to stabilize these heavy-metal complexes. The dimeric compounds [{Ba(Me2pz)2(pmdta)}2] (1), [{Ba(Phpz)2(pmdta)}2] (2), [{Ba(tBupz)2(pmdta)}2] (3), [{Ba(MePhpz)2(tmeda)}2] (5), [{Ba(Ph2pz)2(tmeda)}2]·TMEDA (6), the polymer [{Ba(tBupz)2(NH3)2}n] (4), and the monomer [Ba(Ph2pz)2(tmeda)2]·TMEDA (7), were prepared using a variety of synthetic methods and were characterized spectroscopically and structurally. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) |
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