作者:Patrick Bösing、Alexander Willner、Tania Pape、Alexander Hepp、Norbert W. Mitzel
DOI:10.1039/b718268f
日期:——
Reactions of bishydroxylamines of the type HON(R)CH2CH2N(R)OH (R = Me, tBu) with trimethyl- and triisopropylgallium gave bicyclic metalla cages of the formula R′2GaO(R)NCH2CH2N(R)OGaR′2 [R′ = Me, R = Me (3a), tBu (3b); R′ = iPr, R = Me (4a), tBu (4b)] with six-membered Ga2O2N2-rings. While the complexes show the same core constitution in the solid state, NMR spectra reveal the steric influence of the isopropyl substituent of the compounds 4a/4b on its behaviour in solution. The reaction of the sterically more demanding substituted tri-tert-butylgallium with HON(Me)CH2CH2N(Me)OH yielded a heterodimeric complex O′-[HON(Me)CH2CH2NH(Me)O(tBu2Ga)]-cyclo-(tBu2Ga)-O,N′-[ON(Me)CH2CH2N(Me)O] (5) with two gallium atoms of different surrounding and two different bishydroxylamine ligands, one doubly deprotonated and one protonated, but at one end in its tautomeric aminoxide form. Further condensation of 5 was observed to give a tricyclic compound cyclo-[(tBuGa)ON(Me)CH2CH2N(Me)O]2 (6) with a central Ga2O2N2 ring resulting from two Ga–N donor–acceptor bonds.
HON(R)CH2CH2N(R)OH(R=Me,tBu)型双羟胺与三甲基镓和三异丙基镓反应,得到式 R′2GaO(R)NCH2CH2N(R)OGaR′2 [R′=Me, R=Me (3a), tBu (3b)]的双环金属笼;R′ = iPr, R = Me (4a), tBu (4b)]具有六元 Ga2O2N2 环。虽然这些复合物在固态下显示出相同的核心结构,但核磁共振光谱显示,化合物 4a/4b 的异丙基取代基对其在溶液中的行为有立体影响。立体要求更高的取代三叔丁基镓与 HON(Me)CH2CH2N(Me)OH 反应生成了异二聚体 O′-[HON(Me)CH2CH2NH(Me)O(tBu2Ga)]-cyclo-(tBu2Ga)-O、N′-[ON(Me)CH2CH2N(Me)O](5)具有两个不同环绕的镓原子和两个不同的双羟胺配体,一个双去质子化,一个质子化,但一端为同分异构体氨基氧化物形式。观察到 5 的进一步缩合生成了环-[(tBuGa)ON(Me)CH2CH2N(Me)O]2 (6)三环化合物,其中心是由两个 Ga-N 供体-受体键形成的 Ga2O2N2 环。