Mononuclear dpp-Bian Gallium Complexes: Synthesis, Crystal Structures, and Reactivity toward Alkynes and Enones

Treatment
of (dpp-Bian)­Ga–Ga­(dpp-Bian) (1)
(dpp-Bian = 1,2-bis­[(2,6-diisopropylphenyl)­imino]­acenaphthene) with
iodine gives (dpp-Bian)­Ga­(I)–Ga­(I)­(dpp-Bian) (2), which reacts in situ with K­(C5H4CH2CH2NMe2) (KCpDo) or K­(OCH2CH2NMe2) (KORDo) to produce the
monomeric species (dpp-Bian)­GaCpDo (3) and
(dpp-Bian)­GaORDo (4), respectively. Complex 3 reacts with PhCCH to give the paramagnetic derivative
(dpp-Bian)­Ga­(CCPh)2 (5), while compound 4 is inert toward this alkyne. In contrast, monomeric (dpp-Bian)­Ga­(S2CNMe2) (6) reacts with PhCCH
and HCCH to give the cycloaddition products [dpp-Bian­(PhCCH)]­Ga­(S2CNMe2) (7) and [dpp-Bian­(HCCH)]­Ga­(S2CNMe2) (8). The related compounds
[dpp-Bian­(MeCCC­(O)­OMe)]­Ga­(S2CNMe2) (9) and [dpp-Bian­(CH2CHC­(Me)­O)]­Ga­(S2CNMe2) (10) have been obtained in
the reactions of complex 6 with methyl 2-butynoate and
methyl vinyl ketone, respectively. New complexes have been characterized
by 1H NMR (3, 4, and 7–10) and ESR (5) spectroscopy; their
molecular structures have been established by single-crystal X-ray
analysis. The catalytic activity of complex 6 in the
hydroamination and hydroarylation of alkynes has been examined.

将(dpp-Bian)–Ga–Ga(dpp-Bian)（化合物1，其中dpp-Bian为1,2-双[(2,6-二异丙基苯基)亚氨基]苊）与碘单质反应，得到(dpp-Bian)–Ga(I)–Ga(I)(dpp-Bian)（化合物2）。该化合物可分别与二甲基氨基乙基环戊二烯基钾（K(C₅H₄CH₂CH₂NMe₂)，简称KCpDo）或二甲基氨基乙氧基钾（K(OCH₂CH₂NMe₂)，简称KORDo）发生原位反应，生成单核配合物(dpp-Bian)–GaCpDo（化合物3）与(dpp-Bian)–GaORDo（化合物4）。配合物3可与苯乙炔（PhC≡CH）反应，得到顺磁衍生物(dpp-Bian)–Ga(C≡CPh)₂（化合物5），而化合物4对该炔烃呈惰性。与之相对，单核配合物(dpp-Bian)–Ga(S₂CNMe₂)（化合物6）可分别与苯乙炔和乙炔发生环加成反应，生成环加成产物[dpp-Bian(PhC═CH)]–Ga(S₂CNMe₂)（化合物7）与[dpp-Bian(HC═CH)]–Ga(S₂CNMe₂)（化合物8）。配合物6分别与2-丁炔酸甲酯和甲基乙烯基酮反应，得到相关配合物[dpp-Bian(MeC≡CC(O)OMe)]–Ga(S₂CNMe₂)（化合物9）与[dpp-Bian(CH₂CH═C(Me)O)]–Ga(S₂CNMe₂)（化合物10）。上述新合成的配合物已通过¹H核磁共振波谱（针对化合物3、4及7–10）与电子顺磁共振波谱（针对化合物5）进行表征，其分子结构均通过单晶X射线衍射分析确定。此外，已考察配合物6在炔烃氢胺化反应与氢芳基化反应中的催化活性。