No abstract

No abstract

A convenient electrochemical method for the synthesis of 8,8´ dihalogen derivatives of bis(1,2 dicarbollyl)cobalt(III) anion [8,8´ X 2 3,3´ Co(1,2 C 2 B 9 H 10 )] -(X = Cl, Br, I) was developed. The method includes the electrolysis of a solution of alkaline metal halide and tetramethylammonium salt of bis(1,2 dicarbollyl)cobalt(III) in methanol at 50 °С in a one compartment electrochemical cell with a nickel cathode and platinum anode.Bis(dicarbollyl)cobalt derivatives 1 found wide use for the liquid extraction of radionuclides. 2,3 . Many both ra dioactive and stable nuclides (Li + , Na + , K + , Rb + , Cs + , Tl + ; Ca 2+ , Ba 2+ , Ra 2+ , Pd 2+ ; lanthanides, etc.) can suc cessfully be separated and isolated using bis(dicarbol lyl)cobalt and its derivatives. 4-7 In addition, bis(dicarbol lyl)cobalt derivatives turned out to be promising compo nents of ion selective electrodes and phase transfer catalysts. 1 The introduction of a halogen into the [3,3´ Co(1,2 C 2 B 9 H 11 ) 2 ] -framework enhances its resistance to strong acids, oxidants, and intense radioactive radiation, 3,8,9 which extends possibilities of practical use of these com pounds. Hence, the halogen derivatives of bis(dicarbol lyl)cobalt can thus be challenging extracting agents for decontamination of radioactive waste. 7,10-14The syntheses of halogen derivatives of bis(1,2 di carbollyl)cobalt by treatment with halogens, 9,15,16 iodine chloride, 17,18 hypochlorous acid, 9 and chloro or bromo succineimide are described in the literature. 9 It was shown that substitution occurs stepwise in these cases: first, hy drogen atoms were displaced from positions 8 and 8´ ad jacent to the metal atom followed by substitutions of fur ther halogens at positions 9, 9´, 12, and 12´ most remote from the carbon atoms. 15 A drawback of all listed methods is a necessity to use expensive halogenating agents and the formation by prod ucts (in particular, highly corrosive gaseous hydrogen halide).In this work, we attempted to prepare Me 4 N[8,8´ X 2 3,3´ Co(1,2 С 2 В 9 Н 10 ) 2 ] (Х = Cl, Br, I) by the coupled electrolysis of Me 4 N[3,3´ Co(1,2 С 2 В 9 Н 10 ) 2 ] (1) and al kaline metal halide in methanol. Results and DiscussionCompound 1 was halogenated with a halogen species produced by the anodic oxidation of a halide ion. The reaction of 1 with halogen affords a halogen derivative of bis(1,2 dicarbollyl)cobalt and halide ion. The electro chemical halogenation of 1 is presented in Scheme 1.The halide ions formed by the chemical reaction un dergo anodic oxidation, which makes possible regenera tion of the halogenating agent to form a target product in a preparative yield.It is known 19 that the separation of mixtures of the mono and dihalogen substituted products and their iso lation in the individual state are labor consuming pro cesses. The dihalogen derivatives are chemically, ther mally, and radiationally more stable than the unsubstituted and monohalogenated bisdicarbollyl complexes of transi tion metals. Therefore, the purpose of our work was to find conditions f...

ChemInform Abstract The reaction between the camphor analogue (I) and methyllithium (II) affords the title compound (III). The Ritter reaction with acetonitrile (IV) gives an inseparable 2:1 mixture of the isomeric amides (V) and (VI). Their formation probably proceeds via non-classical carbocations, which undergo Wagner-Meerwein rearrangements. The structures of (V) and (VI) are further confirmed by spectral characterization of the corresponding amines, which are prepared by LiAlH4 reduction.

No abstract