Dias H V Rasika, Flores Jaime A, Wu Jiang, Kroll Peter
Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, USA.
J Am Chem Soc. 2009 Aug 12;131(31):11249-55. doi: 10.1021/ja904232v.
A series of thermally stable, easily isolable, monomeric, and isoleptic coinage metal alkyne complexes have been reported. Treatment of [N{(C(3)F(7))C(Dipp)N}(2)]Li (the lithium salt of the 1,3,5-triazapentadiene [N{(C(3)F(7))C(Dipp)N}(2)]H) with AuCl, CF(3)SO(3)Ag or CF(3)SO(3)Cu in the presence of 3-hexyne led to the corresponding coinage metal alkyne complex [N{(C(3)F(7))C(Dipp)N}(2)]M(EtC[triple bond]CEt) in good yield (M = Au, Ag, Cu; Dipp = 2,6-diisopropylphenyl). X-ray crystal structures of the three coinage metal alkynes are remarkably similar, and show the presence of trigonal-planar metal sites with eta(2)-bonded 3-hexyne. The M-C and M-N bond distances vary in the order Cu < Au < Ag. The bending of the C-C[triple bond]C bond angle is largest for the gold, followed by Cu and Ag adducts. The gold adduct also shows the largest decrease in C[triple bond]C stretching frequency in Raman, while the Ag adduct shows the smallest change compared to that of the uncoordinated alkyne. DFT calculations on [N{(CF(3))C(Ph)N}(2)]M(EtC[triple bond]CEt) and the related ClM(EtC[triple bond]CEt) predict that the M-alkyne bond energy varies in the order Ag < Cu < Au. The gold adducts are also predicted to have the longest C[triple bond]C, largest deviation of C-C[triple bond]C bond angle from linearity, and smallest C[triple bond]C stretching frequency, followed by the Cu and Ag adducts. In these triazapentadienyl coinage metal adducts, the sigma-donation from alkyne --> M dominates over the M --> alkyne pi-back-donation.
已报道了一系列热稳定、易于分离的单体且均配型的铸币金属炔烃配合物。在3 - 己炔存在下，用AuCl、CF₃SO₃Ag或CF₃SO₃Cu处理[N{(C₃F₇)C(Dipp)N}₂]Li（1,3,5 - 三氮杂戊二烯[N{(C₃F₇)C(Dipp)N}₂]H的锂盐），以良好产率得到相应的铸币金属炔烃配合物[N{(C₃F₇)C(Dipp)N}₂]M(EtC≡CEt)（M = Au、Ag、Cu；Dipp = 2,6 - 二异丙基苯基）。三种铸币金属炔烃的X射线晶体结构非常相似，显示出具有η² - 键合3 - 己炔的三角平面金属位点。M - C和M - N键长按Cu < Au < Ag的顺序变化。C≡C键角的弯曲对于金配合物最大，其次是铜和银加合物。金加合物在拉曼光谱中C≡C伸缩频率的降低也最大，而与未配位炔烃相比，银加合物的变化最小。对[N{(CF₃)C(Ph)N}₂]M(EtC≡CEt)和相关的ClM(EtC≡CEt)进行的密度泛函理论计算预测，M - 炔烃键能按Ag < Cu < Au的顺序变化。还预测金加合物具有最长的C≡C键、C - C≡C键角与线性的最大偏差以及最小的C≡C伸缩频率，其次是铜和银加合物。在这些三氮杂戊二烯基铸币金属加合物中，从炔烃到M的σ - 给予作用比M到炔烃的π - 反馈给予作用占主导。
