Dimethyloxonium and Methoxy Derivatives of nido-Carborane and Metal Complexes Thereof

Abstract

9-Dimethyloxonium, 10-dimethyloxonium, 9-methoxy and 10-methoxy derivatives of nido-carborane (9-Me2O-7,8-C2B9H11, 10-Me2O-7,8-C2B9H11, [9-MeO-7,8-C2B9H11]−, and [10-MeO-7,8-C2B9H11]−, respectively) were prepared by the reaction of the parent nido-carborane [7,8-C2B9H12]− with mercury(II) chloride in a mixture of benzene and dimethoxymethane. Reactions of the 9 and 10-dimethyloxonium derivatives with triethylamine, pyridine, and 3-methyl-6-nitro-1H-indazole result in their N-methylation with the formation of the corresponding salts with 9 and 10-methoxy-nido-carborane anions. The reaction of the symmetrical methoxy derivative [10-MeO-7,8-C2B9H11]− with anhydrous FeCl2 in tetrahydrofuran in the presence of t-BuOK results in the corresponding paramagnetic iron bis(dicarbollide) complex [8,8′-(MeO)2-3,3′-Fe(1,2-C2B9H10)2]−, whereas the similar reactions of the asymmetrical methoxy derivative [9-MeO-7,8-C2B9H11]− with FeCl2 and CoCl2 presumably produce the 4,7′-isomers [4,7′-(MeO)2-3,3′-M(1,2-C2B9H10)2]− (M = Fe, Co) rather than a mixture of rac-4,7′- and meso-4,4′-isomers.

Synthesis and study ofC-substituted methylthio derivatives of cobalt bis(dicarbollide)

“…27,28 However, in some cases, e.g. in a similar reaction with [9-MeO-7,8-C 2 B 9 H 11 ] − only one isomer is formed, 29 that could be explained by lower stability of second isomer under synthesis and/or isolation conditions. It should be noted that all our attempts to synthesize cobalt and iron bis(dicarbollide) complexes based on 7,8-di(methylthio)- nido -carborane [7,8-(MeS) 2 -7,8-C 2 B 9 H 10 ] − failed.…”

Synthesis and Structure of Methylsulfanyl Derivatives of Nickel Bis(Dicarbollide)

“…Therefore, by analogy with the corresponding derivatives of cobalt bis(dicarbollide) [18], column chromatography was used to separate the nickel(III) diastereomeric complexes. The 11 B NMR spectra of all the obtained paramagnetic complexes (Figures S1-S3) are quite characteristic; however, unlike the similar derivatives of paramagnetic iron bis(dicarbollide) [19,26,27], their interpretation is not possible. Therefore, an X-ray diffraction study is crucial to determine the structure of the diastereomers.…”

Synthesis and Reactivity of Cyclic Oxonium Derivatives of nido-Carborane: A Review

“…The molecular structure of the 1,4-dioxane derivative of nido-carborane was determined by single crystal X-ray diffraction [71] (Figure 1). It should be noted that, in addition to cyclic oxonium derivatives of nido-carborane, some acyclic oxonium derivatives such as the dimethyloxonium 9-Me 2 O-7,8-C 2 B 9 H 11 and 10-Me 2 O-7,8-C 2 B 9 H 11 [72] and the diethyloxonium 9-Et 2 O-7,8-C 2 B 9 H 11 [73]…”

“…The charge-compensated nido-carborane-based conjugates with mitonafide were prepared in mild conditions by the ring-opening reactions of 1,4-dioxane and tetrahydropyran derivatives of nido-carborane with dimethylamino group of mitonafide [63] (Scheme 15). The dimethyl-and diethyloxonium derivatives of nido-carborane are also easily reacted with nucleophiles with the loss of the methyl or ethyl group, respectively, and can be used as alkylating agents [72,73]. ).…”