Synthesis, characterisation and some chemistry of C- and B-substituted carboxylic acids of cobalt bis(dicarbollide)

0428161 - ÚACH 2015 RIV GB eng J - Článek v odborném periodiku
Nekvinda, Jan - Šícha, Václav - Hnyk, Drahomír - Grüner, Bohumír
Synthesis, characterisation and some chemistry of C- and B-substituted carboxylic acids of cobalt bis(dicarbollide).
Dalton Transactions. Roč. 43, č. 13 (2014), s. 5106-5120. ISSN 1477-9226. E-ISSN 1477-9234
Grant CEP: GA AV ČR IAAX00320901
Institucionální podpora: RVO:61388980
Klíčová slova: BORON-CLUSTER COMPOUNDS * EFFICIENT EXTRACTANTS * ACTINIDE EXTRACTIONS
Kód oboru RIV: CA - Anorganická chemie
Impakt faktor: 4.197, rok: 2014

Low temperature reactions of lithiated cobalt bis(1,2-dicarbollide)(1-) (1(-)) in DME with carbon dioxide leads to the substitution of 1(-) at the C-atoms by carboxy function(s). This results in a good yield formation of monosubstituted and disubstituted products of formulations [(1-HOOC-1,2-C2B9H10)(1', 2'-C2B9H11)3,3'-Co)](-) (2(-)) and [(HOOC)(2)-(1,2-C2B9H10)(2)-3,3'-Co](-)(3a, b(-)), respectively. Indeed, the latter compound is in fact a mixture of two diastereoisomers, denoted here as 1,1'-anti (3a(-)) and 1,2'-syn-isomer (3b(-)), from which only the former major species (3a(-)) could be isolated in pure form. Considerations about stereochemistry of these species are supported by geometry optimizations and calculations of 11B NMR shifts at the GIAO-DFT level. In addition, three monocarboxylic acids with three different linear spacers between the carboxy groups and the cage are reported. The first one of the formula [(1-HOOC-CH2-1,2-C2B9H10)(1', 2'-C2B9H11)-3,3'-Co]-(5-) results in a lithiation followed by reaction with BrCH2COOEt and hydrolysis of the respective ethyl ester (4-). Another one with ethylene chain [(1-HOOC-(CH2) 2-1,2-C2B9H10)( 1', 2'-C2B9H11)-3,3'-Co]-(6-) was prepared by the oxidation of a hydroxypropyl derivative of the ion 1(-). The sole representative of B-substituted species of the formulation [8-(HOOC-CH2-O-1,2C(2)B(9)H(10))(1', 2'-C2B9H11)-3,3'-Co]-(7(-)) is prepared by alkylation of the known 8-hydroxy derivatives of the ion 1-by BrCH2COOEt and alkaline hydrolysis. A synthetic route to active nitrofenyl esters (8(-), 9(-) and 10(-)) is described here based on the respective acids 5(-) to 7(-). As verified, the nitrophenyl esters provide easy access to the formation of amidic bonds between the boron cage and organic primary amino functions.
Trvalý link: http://hdl.handle.net/11104/0233571