Structural and Electronic Differences of Copper(I) Complexes with Tris(pyrazolyl)methane and Hydrotris(pyrazolyl)borate Ligands

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• 作者：Kiyoshi Fujisawa ; Tetsuya Ono ; Yoko Ishikawa ; Nagina Amir ; Yoshitaro Miyashita ; Ken-ichi Okamoto ; and Nicolai Lehnert
• 刊名：Inorganic Chemistry
• 出版年：2006
• 出版时间：February 20, 2006
• 年：2006
• 卷：45
• 期：4
• 页码：1698 - 1713
• 全文大小：353K
• 年卷期：v.45,no.4(February 20, 2006)
• ISSN：1520-510X

文摘

Copper(I) complexes with tripodal nitrogen-containing neutral ligands such as tris(3,5-diisopropyl-1-pyrazolyl)methane(L1') and tris(3-tertiary-butyl-5-isopropyl-1-pyrazolyl)methane (L3'), and with corresponding anionic ligands such ashydrotris(3,5-diisopropyl-1-pyrazolyl)borate (L1^-) and hydrotris(3-tertiary-butyl-5-isopropyl-1-pyrazolyl)borate (L3^-)were synthesized and structurally characterized. Copper(I) complexes [Cu(L1')Cl] (1), [Cu(L1')(OClO₃)] (2),[Cu(L1')(NCMe)](PF₆) (3a), [Cu(L1')(NCMe)](ClO₄) (3b), [Cu(L1')(CO)](PF₆) (4a), and [Cu(L1')(CO)](ClO₄) (4b) wereprepared using the ligand L1'. Copper(I) complexes [Cu(L3')Cl] (5) and [Cu(L3')(NCMe)](PF₆) (6) with the ligandL3' were also synthesized. Copper(I) complexes [Cu(L1)(NCMe)] (7) and [Cu(L1)(CO)] (8) were prepared using theanionic ligand L1^-. Finally, copper(I) complexes with anionic ligand L3^- and acetonitrile (9) and carbon monoxide(10) were synthesized. The complexes obtained were fully characterized by IR, far-IR, ¹H NMR, and ¹³C NMRspectroscopy. The structures of both ligands, L1' and L3', and of complexes 1, 2, 3a, 3b, 4a, 4b, 5, 6, 7, and 10were determined by X-ray crystallography. The effects of the differences in (a) the fourth ligand and the counteranion,(b) the steric hindrance at the third position of the pyrazolyl rings, and most importantly, (c) the charge of the N3type ligands, on the structures, spectroscopic properties, and reactivities of the copper(I) complexes are discussed.The observed differences in the reactivities toward O₂ of the copper(I) acetonitrile complexes are traced back todifferences in the oxidation potentials determined by cyclic voltammetry. A special focus is set on the carbonylcomplexes, where the ¹³C NMR and vibrational data are presented. Density functional theory (DFT) calculationsare used to shed light on the differences in CO bonding in the compounds with neutral and anionic N3 ligands. Incorrelation with the vibrational and electrochemical data of these complexes, it is demonstrated that the C-Ostretching vibration is a sensitive probe for the "electron richness" of copper(I) in these compounds.