Ferrocene and Transition Metal Bis(Dicarbollides) as Platform for Design of Rotatory Molecular Switches

Abstract

Design of rotatory molecular switches based on extremely stable sandwich organometallic complexes ferrocene and bis(dicarbollide) complexes of transition metals is reviewed. The “on”–“off” switching in these systems can be controlled by various external stimuli such as change of the solution pH, interactions with coordinating species or redox reactions involving the central atom or substituents in the ligands.

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

“…20,21 Recently, we suggested that cobalt bis(dicarbollide) can be used as a structural element in the design of molecular switches. 22 Molecular switches are molecules or supramolecular complexes that can exist in two or more stable forms that differ in the mutual orientation of their components and can be converted readily from one state to another by various external stimuli such as heat, light, chemicals, etc. 23 Indeed, when studying a series of isomeric B-methylthio derivatives of cobalt bis(dicarbollide), we found that in the 8,8 0 -isomer [8,8 0 -(MeS) 2 -3,3 0 -Co(1,2-C 2 B 9 H 10 ) 2 ] À stabilization of the transoid conformation is reached due to two pairs of intramolecular CH carb /S hydrogen bonds between the ligands, whereas in the 4,4 0isomer [4,4 0 -(MeS) 2 -3,3 0 -Co(1,2-C 2 B 9 H 10 ) 2 ] À two pairs of the CH carb /S hydrogen bonds stabilize the gauche conformation.…”

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

“…Surprisingly, the reaction of 3-methyl-6-nitro-1H-indazole with 1 resulting in the regioselective formation of desired compound 5 with almost a quantitative yield. Transition metal complexes with carborane ligands, or metallacarboranes, found application in a wide variety of fields including nuclear fuel reprocessing [40,41], catalysis [42], new material design [43][44][45][46], medicine [4,5,[47][48][49][50][51][52], etc. Therefore the obtained methoxy derivatives of nido-carborane K [3] and K [4] were used for synthesis the corresponding iron and cobalt bis(dicarbollide) complexes.…”

Coordination Ability of 10-EtC(NHPr)=HN-7,8-C2B9H11 in the Reactions with Nickel(II) Phosphine Complexes

“…One of the most interesting and promising tasks in this area is the synthesis of heterobifunctional nido-carborane-based ligands, that can give a firm bound to capture the metal center along with a weak bond, temporarily protecting a metal coordination site. This allows users to obtain labile complexes of transitional metal representing a promising new type of catalysts [5][6][7][8][9][10] and molecular switches [11,12]. There are several examples of such stable metal complexes based on nido-carborane with a side substituent coordinated through oxygen or nitrogen [5][6][7][8][13][14][15].…”