Stogniy Marina Yu, Anufriev Sergey A, Shmal'ko Akim V, Antropov Sergey M, Anisimov Aleksei A, Suponitsky Kyrill Yu, Filippov Oleg A, Sivaev Igor B
A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Str., Moscow, 119991, Russia.
Dalton Trans. 2021 Feb 21;50(7):2671-2688. doi: 10.1039/d0dt03857a. Epub 2021 Feb 3.
An unusual reactivity of 9-iodo-nido-carborane [9-I-7,8-CBH] towards nucleophiles under strong basic conditions was revealed. The nucleophilic substitution of iodine with O- and N-nucleophiles results in [9-RO-7,8-CBH] (R = H, CHCHOMe) and [9-L-7,8-CBH] (L = Py, NEt, MeNCHCHNMe), respectively. Reaction of [9-I-7,8-CBH] with CoCl in 1,2-dimethoxyethane in the presence of t-BuOK, depending on the order of addition of the reagents, leads either to a diastereomeric mixture of diiodo derivatives cobalt bis(dicarbollide) rac-[4,4'-I-3,3'-Co(1,2-CBH)] and meso-[4,7'-I-3,3'-Co(1,2-CBH)] or to the corresponding mixture of 2-methoxyethoxy derivatives rac-[4,4'-(MeOCHCHO)-3,3'-Co(1,2-CBH)] and meso-[4,7'-(MeOCHCHO)-3,3'-Co(1,2-CBH)]. In the presence of accidental admixture of sodium thiosulfate, the reactions of 9-iodo-nido-carborane and 9-(2'-methoxyethoxy)-nido-carborane with CoCl in 1,2-dimethoxyethane were found to produce additionally unprecedented tricobalt tris(dicarbollide) cluster Na[4,4',4''-(MeOCHCHO)-3,3',3''-Co(μ-O)(μ-S)(1,2-CBH)], the central fragment of which is a trigonal bipyramid with apical oxygen and sulfur atoms, and the base is formed by the Co triangle flanked by three dicarbollide ligands. In addition, the 2-methoxyethoxy substituents of the dicarbollide ligands chelate the sodium cation in such a way that they form a helix whose rotation direction depends on the enantiomer of the parent ligand. Thus, in this case, induction of the helical chirality of the complex occurs due to the point chirality of the initial inorganic ligand. It is worth noting that in the case of symmetrically substituted 2-methoxyethoxy derivative of nido-carborane [10-MeOCHCHO-7,8-CBH] only formation of the corresponding cobalt bis(dicarbollide) complex [8,8'-(MeOCHCHO)-3,3'-Co(1,2-CBH)] was observed.
揭示了9-碘代巢式碳硼烷[9-I-7,8-CBH]在强碱性条件下对亲核试剂具有不寻常的反应活性。碘被O-和N-亲核试剂亲核取代分别生成[9-RO-7,8-CBH]（R = H，CHCHOMe）和[9-L-7,8-CBH]（L = Py，NEt，MeNCHCHNMe）。在叔丁醇钾存在下，[9-I-7,8-CBH]与CoCl在1,2-二甲氧基乙烷中的反应，根据试剂添加顺序的不同，会生成二碘代衍生物钴双（二碳硼烷）rac-[4,4'-I-3,3'-Co(1,2-CBH)]和内消旋-[4,7'-I-3,3'-Co(1,2-CBH)]的非对映异构体混合物，或者生成相应的2-甲氧基乙氧基衍生物rac-[4,4'-(MeOCHCHO)-3,3'-Co(1,2-CBH)]和内消旋-[4,7'-(MeOCHCHO)-3,3'-Co(1,2-CBH)]的混合物。在存在硫代硫酸钠意外杂质的情况下，发现9-碘代巢式碳硼烷和9-(2'-甲氧基乙氧基)-巢式碳硼烷与CoCl在1,2-二甲氧基乙烷中的反应会额外生成前所未有的三钴三（二碳硼烷）簇Na[4,4',4''-(MeOCHCHO)-3,3',3''-Co(μ-O)(μ-S)(1,2-CBH)]，其中心片段是一个具有顶端氧原子和硫原子的三角双锥，底部由一个被三个二碳硼烷配体包围的钴三角形构成。此外，二碳硼烷配体的2-甲氧基乙氧基取代基以这样一种方式螯合钠离子，即它们形成一个螺旋，其旋转方向取决于母体配体的对映体。因此，在这种情况下，由于初始无机配体的点手性，导致了配合物螺旋手性的诱导。值得注意的是，在巢式碳硼烷的对称取代2-甲氧基乙氧基衍生物[10-MeOCHCHO-7,8-CBH]的情况下，仅观察到相应的钴双（二碳硼烷）配合物[8,8'-(MeOCHCHO)-3,3'-Co(1,2-CBH)]的形成。
