Grüner Bohumír, Šícha Václav, Hnyk Drahomír, Londesborough Michael G S, Císařová Ivana
†Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Hlavní 1001, CZ-250 68 Řež, Czech Republic.
‡Department of Inorganic Chemistry, Faculty of Natural Sciences, Charles University, Hlavova 2030, 128 42 Prague 2, Czech Republic.
Inorg Chem. 2015 Apr 6;54(7):3148-58. doi: 10.1021/ic502450t. Epub 2015 Mar 26.
The cobalt bis(dicarbollide) anion (1,2-C2B9H11)2-3,3'-Co (1(-)) is an increasingly important building block for the design of new biologically active compounds. Here we report the reactions of lithiated 1(-) with N-(ω-bromoalkyl)phthalimides Br-(CH2)n-N(CO)2NC6H4 (where n = 1 to 3) that give a number of new compounds substituted at dicarbollide carbon atom positions. For n = 2 and 3, substitution of the cobalt bis(dicarbollide) anion is accompanied by cyclocondensation of the organic moieties to give polycyclic ring structures attached to the cage. Predominant products correspond to oxazolo[2,3-a]isoindol-5(9bH)-1,2,3-dihydro-9b-yl)-(1-cobalt(III) bis(1,2-dicarbollide)(1(-)) (2(-)) and 1-(2H-[1,3]-oxazino[2,3-a]isoindol-6(10bH)-1,3,4-dihydro-10b-yl)-(1-cobalt(III) bis(1,2-dicarbollide)(1(-)) (4(-)) ions with isoindolone functions containing either five- or six-membered lateral oxazine rings. Additionally, products (tetrahydro-2-benzo[4,5]furan-1(3H)-1-[3,3]-yl-)-1,1'-μ-cobalt(III) bis(1,2-dicarbollide)(1(-)) (3(-)) and (2-(azetidin-yl-carbonyl)benzoyl-)-1-cobalt(III) bis(1,2-dicarbollide)(1(-)) (5(-)) were isolated, which display unusual cyclic structures featuring a bicyclic benzofuranone ring attached in a bridging manner by a quarternary carbon to two skeletal carbon atoms and a ketobenzoic acid amide substituent with a side azetidine ring. However, in the case of n = 1, only the anticipated methylene amine derivative (1-NH2CH2-1,2-C2B9H11)(1',2'-C2B9H11)2-3,3'-Co (6(-)) was isolated in low yield after cleavage of the phthalimide intermediate species. The molecular structures of all isolated cyclic products 2(-) to 5(-) were confirmed by single-crystal X-ray diffraction studies, and the structure of cobalt bis(dicarbollide)-1-CH2NH2 6(-) was delineated using density functional theory applied at BP86/AE1 level in combination with NMR spectroscopy. Thus, the synthetic method described herein presents a facile route to new cobalt bis(dicarbollide) derivatives substituted by polycyclic structural motifs with potential biological activity.
双（二碳硼烷）钴阴离子[（1,2 - C₂B₉H₁₁）₂ - 3,3'-Co]⁻（1⁻）是设计新型生物活性化合物中越来越重要的结构单元。在此，我们报道了锂化的1⁻与N - （ω - 溴代烷基）邻苯二甲酰亚胺Br - （CH₂）ₙ - N（CO）₂NC₆H₄（其中n = 1至3）的反应，该反应生成了一些在二碳硼烷碳原子位置被取代的新化合物。对于n = 2和3，双（二碳硼烷）钴阴离子的取代伴随着有机部分的环缩合，形成连接到笼状结构上的多环结构。主要产物对应于恶唑并[2,3 - a]异吲哚 - 5（9bH） - 1,2,3 - 二氢 - 9b - 基） - （1 - 钴（III）双（1,2 - 二碳硼烷）（1⁻）（2⁻）和1 - （2H - [1,3] - 恶嗪并[2,3 - a]异吲哚 - 6（10bH） - 1,3,4 - 二氢 - 10b - 基） - （1 - 钴（III）双（1,2 - 二碳硼烷）（1⁻）（4⁻）离子，其异吲哚酮官能团含有五元或六元侧向恶嗪环。此外，还分离出了产物（四氢 - 2 - 苯并[4,5]呋喃 - 1（3H） - 1 - [3,3] - 基） - 1,1'-μ - 钴（III）双（1,2 - 二碳硼烷）（1⁻）（3⁻）和（2 - （氮杂环丁烷基 - 羰基）苯甲酰基） - 1 - 钴（III）双（1,2 - 二碳硼烷）（1⁻）（5⁻），它们具有不寻常的环状结构，其特征是一个双环苯并呋喃酮环通过一个季碳原子以桥连方式连接到两个骨架碳原子上，以及一个带有侧氮杂环丁烷环的酮基苯甲酸酰胺取代基。然而，在n = 1的情况下，在邻苯二甲酰亚胺中间体物种裂解后，仅以低产率分离出了预期的亚甲基胺衍生物[（1 - NH₂CH₂ - 1,2 - C₂B₉H₁₁）（1',2'-C₂B₉H₁₁）₂ - 3,3'-Co]⁻（6⁻）。所有分离出的环状产物2⁻至5⁻的分子结构通过单晶X射线衍射研究得到证实，并且使用在BP86/AE1水平应用的密度泛函理论结合核磁共振光谱确定了双（二碳硼烷）钴 - 1 - CH₂NH₂ 6⁻的结构。因此，本文所述的合成方法为具有潜在生物活性的多环结构基序取代的新型双（二碳硼烷）钴衍生物提供了一条简便的途径。
