Diboration of Dialkynes with [2]Boraferrocenophanes

A series of new [4]diboradicarbametalloarenophanes was synthesized via transition-metal-mediated diboration of selected dialkynes by [Fe{η5-C5H4B(NMe2)}2] (3) and [Fe{η5-C5H4B(NMe2)}2Pt(PEt3)2] (18), respectively. Hereby, we have found three different structural motifs: (i) single diboration of the dialkynes to afford [Fe{η5-C5H4B(NMe2)}2{R}CC–X–CC–R] (R = Me, no X; R = Ph, no X; R = SiMe3, X = C2H2; R = SiMe3, X = 1,4-C6H4), (ii) single diboration with additional coordination of the pendent CC triple bond to a [Pt(PEt3)2] fragment affording the dinuclear complexes [(3,4-η2-Fe{η5-C5H4B(NMe2)}2{R}CC–CC–R)Pt(PEt3)2] (R = Me; R = Ph), and (iii) double diboration of one dialkyne yielding [1,4-(Fe{η5-C5H4B(NMe2)}2{Me3Si}CC)2C6H4]. Additionally, a series of mononuclear and dinuclear platinum alkyne complexes, [(Et3P)2Pt(1,2-η2-R–CC–X–CC–R)] and [{(Et3P)2Pt}2(μ-1,2-η2-3,4-η2-R–CC–X–CC–R)] (R = Me, no X; R = Ph, no X; R = SiMe3, X = 1,4-C6H4), and the platinum alkene complex [(Et3P)2Pt(3,4-η2-E-R–CC–C{H}C{H}–CC–R)] (R = SiMe3) were derived from the reaction of [Pt(PEt3)3] (11) with the corresponding dialkynes. All compounds thus obtained were fully characterized by high-resolution NMR spectroscopy and, in selected cases (that is 14, 24, 26a, 27b, and 29), additionally by X-ray diffraction analysis.

本研究分别通过二(η⁵-4-二甲基氨基硼基环戊二烯基)合铁([Fe{η⁵-C₅H₄B(NMe₂)}₂]，编号3)与二(η⁵-4-二甲基氨基硼基环戊二烯基)铁铂双核配合物([Fe{η⁵-C₅H₄B(NMe₂)}₂Pt(PEt₃)₂]，编号18)介导的过渡金属二硼化反应，由选定的二炔类底物合成了一系列新型[4]二硼二碳金属环芳烷([4]diboradicarbametalloarenophanes)。本研究中我们发现了三类不同的结构基元：(i) 二炔类底物的单二硼化反应得到通式为[Fe{η⁵-C₅H₄B(NMe₂)}₂{R}C=C–X–C≡C–R]的产物，其中取代基参数为：R=Me时无X；R=Ph时无X；R=SiMe₃时X=C₂H₂；R=SiMe₃时X=1,4-亚苯基(1,4-C₆H₄)；(ii) 经单二硼化反应后，其悬挂的C≡C三键还可与[Pt(PEt₃)₂]片段发生配位，最终得到双核配合物[(3,4-η²-Fe{η⁵-C₅H₄B(NMe₂)}₂{R}C=C–C≡C–R)Pt(PEt₃)₂]，其中R=Me、R=Ph；(iii) 单分子二炔的双二硼化反应则得到产物[1,4-(Fe{η⁵-C₅H₄B(NMe₂)}₂{Me₃Si}C=C)₂C₆H₄]。此外，通过三(三乙基膦)合铂([Pt(PEt₃)₃]，编号11)与对应二炔类底物的反应，我们还得到了一系列单核及双核铂炔配合物：[(Et₃P)₂Pt(1,2-η²-R–C≡C–X–C≡C–R)]与[{(Et₃P)₂Pt}₂(μ-1,2-η²-3,4-η²-R–C≡C–X–C≡C–R)]（取代基参数为：R=Me时无X；R=Ph时无X；R=SiMe₃时X=1,4-亚苯基(1,4-C₆H₄)），以及铂烯配合物[(Et₃P)₂Pt(3,4-η²-E-R–C≡C–CH=CH–C≡C–R)]（R=SiMe₃）。所有合成得到的化合物均通过高分辨核磁共振波谱完成了完整表征，其中14、24、26a、27b及29号化合物还额外通过X射线衍射分析进行了结构确证。