Synthesis, Characterization, and Olefin/CO Exchange Reactions of Copper(I) Derivatives Containing Bidentate Oxygen Ligands

New hexafluoroacetylacetonate (hfacac) and trifluoroacetato olefin complexes of copper(I)
of the general formulas Cu(hfacac)(olefin) and Cu(CF3COO)(olefin) have been prepared from
Cu2O/hfacacH/olefin or Cu(CF3COO)(toluene)0.5/olefin systems. The structures of [Cu(hfacac)(coe)], [Cu(hfacac)(van)], [Cu(μ-CF3COO)(tbve)]n, and [Cu(μ-CF3COO)(van)]2·C7H8 have been
determined by X-ray diffraction methods, where coe = cyclooctene, van = 4-vinylanisole,
and tbve = tert-butyl vinyl ether. In the solid state, the 4-vinylanisole/trifluoroacetate complex
[Cu(CF3COO)(van)]2 is dimeric with two carboxylato groups symmetrically bridging two
copper atoms, while the tert-butyl vinyl ether derivative [Cu(μ-CF3COO)(tbve)]n is polymeric
with single [CF3COO]- bridges between adjacent copper atoms. Olefin hfacac complexes are
monomeric, and considering the two oxygen atoms and the midpoint of the double bond of
the coordinated olefin, the copper atom lies in a nearly trigonal-planar environment. The
carbonylation reactions of Cu(CF3COO)(olefin), (olefin = tbve, van; 2Cu(CF3COO)(olefin) +
2CO ⇆ [Cu(CF3COO)(CO)]2 + 2(olefin)) and of Cu(hfacac)(olefin) (olefin = coe, 1,5-cyclooctadiene (cod), norbornene (nbe), van; Cu(hfacac)(olefin) + CO ⇆ Cu(hfacac)(CO) +
olefin) have been studied gas volumetrically, and the equilibrium constants for the
displacement of the coordinated olefin by carbon monoxide have been determined at different
temperatures. Some hypotheses on the copper−olefin bond have been formulated on the
basis of structural, thermodynamic and spectroscopic (13C NMR) data.

本研究制备了通式为Cu(hfacac)(烯烃)与Cu(CF₃COO)(烯烃)的六氟乙酰丙酮根（hexafluoroacetylacetonate，hfacac）及三氟乙酸根（trifluoroacetato）合一价铜（copper(I)）烯烃配合物，其可通过Cu₂O/hfacacH/烯烃体系或半甲苯溶剂化三氟乙酸铜[Cu(CF₃COO)(toluene)₀.₅]/烯烃体系合成。通过X射线衍射法（X-ray diffraction）测定了[Cu(hfacac)(coe)]、[Cu(hfacac)(van)]、[Cu(μ-CF₃COO)(tbve)]ₙ以及[Cu(μ-CF₃COO)(van)]₂·C₇H₈的晶体结构，其中coe为环辛烯（cyclooctene）、van为4-甲氧基苯乙烯（4-vinylanisole）、tbve为叔丁基乙烯基醚（tert-butyl vinyl ether）。固态状态下，4-甲氧基苯乙烯/三氟乙酸根配合物[Cu(CF₃COO)(van)]₂为二聚体，两个羧酸根基团对称桥联两个铜原子；而叔丁基乙烯基醚衍生物[Cu(μ-CF₃COO)(tbve)]ₙ为聚合物，相邻铜原子间以单齿三氟乙酸根[CF₃COO]⁻作为桥联配体。六氟乙酰丙酮合铜烯烃配合物均为单分子结构，若以配位烯烃的双键中点与两个氧原子作为配位位点，铜原子处于近似平面三角配位的几何环境中。本研究采用气体体积法研究了两类羰基化反应：其一为Cu(CF₃COO)(烯烃)（烯烃为tbve、van，反应式为2Cu(CF₃COO)(烯烃) + 2CO ⇌ [Cu(CF₃COO)(CO)]₂ + 2烯烃）的羰基化反应；其二为Cu(hfacac)(烯烃)（烯烃为coe、1,5-环辛二烯（1,5-cyclooctadiene, cod）、降冰片烯（norbornene, nbe）、van，反应式为Cu(hfacac)(烯烃) + CO ⇌ Cu(hfacac)(CO) + 烯烃）的羰基化反应，并测定了不同温度下一氧化碳取代配位烯烃的平衡常数。基于晶体结构、热力学数据与13C核磁共振（13C NMR）光谱数据，本研究提出了若干关于铜-烯烃配位键的假说。