Stabilization of Heteroleptic Heavier Alkaline Earth Metal Complexes with an Encapsulating Dipyrromethene Ligand
Stabilization of Heteroleptic Heavier Alkaline Earth Metal Complexes with an Encapsulating Dipyrromethene Ligand
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DOI：
10.1002/ejic.201900743
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发表时间：
2019-08-12
影响因子：
2.3
通讯作者：
Harder, Sjoerd
中科院分区：
文献类型：
--
作者：
Ballmann, Gerd;Roesch, Bastian;Harder, Sjoerd
介绍了一种具有9-蒽基取代基的新型二吡咯甲烷配体，用于金属的空间屏蔽。配体(DPM)-D-Anth-H(3)直接与MN '(2) {M = Mg, Ca, Sr, Ba, Zn；N " = N(SiMe3)(2)}得到（(DPM)-D-Anth）MN "(4-8)，以高荧光物质的形式呈现，颜色从深红色到紫色。晶体结构在所有情况下都显示出与三配位金属的单体配合物。并介绍了3与KN′反应制备的（(DPM)-D-Anth）K的晶体结构。配合物4-8中金属的配位球进一步被M中心点中心点中心点相互作用饱和，这对较小的金属Mg和Zn来说是最重要的。对于较大的金属Ca-Ba，蒽基取代基有助于金属配位。这些次生金属相互作用导致非常高的热稳定性。最不稳定的配合物（(DPM)-D-Anth）BaN”在100℃左右分解，二吡咯甲烷配合物明显比相应的β -二氯胺酸配合物（(BDI)-B-DIPP）MN”{(BDI)-B-DIPP = CH[C(Me)N-DIPP](2), DIPP =2,6-二异丙基苯基}更稳定，后者在室温下部分分解。这些结构相似的异电配合物，金属的范围从Mg到Ba，形成了一个新的系列，对研究早期主族金属催化中的金属效应有潜在的用途。
A new dipyrromethene ligand with 9-anthracenyl substituents for steric shielding of the metal has been introduced. The ligand, (DPM)-D-Anth-H (3), was directly deprotonated with MN ''(2) {M = Mg, Ca, Sr, Ba, Zn; N '' = N(SiMe3)(2)} to give ((DPM)-D-Anth)MN '' (4-8) in the form of highly fluorescent substances that are intensively colored from deep-red to purple. Crystal structures reveal in all cases monomeric complexes with tricoordinate metals. Also the crystal structure of ((DPM)-D-Anth)K, prepared by reaction of 3 with KN '', is presented. The metal's coordination sphere in complexes 4-8 is further saturated by anagostic M center dot center dot center dot MeSi interactions which are most important for the smaller metals Mg and Zn. For the larger metals, Ca-Ba, the anthracenyl-substituents assist in metal coordination. These secondary metal pi-interactions result in very high thermal stabilities. The least stable complex ((DPM)-D-Anth)BaN '' decomposes at circa 100 degrees C. The dipyrromethene complexes are clearly more stable than the corresponding beta-diketiminate complexes ((BDI)-B-DIPP)MN '' {(BDI)-B-DIPP = CH[C(Me)N-DIPP](2), DIPP =2,6-diisopropylphenyl} which partially decompose at room temperature. These heteroleptic complexes of similar constitution, with metals ranging from Mg to Ba, form a new series that is potentially useful for investigations towards metal effects in early main group metal catalysis.