Polyhedral monocarbaborane chemistry. Carboxylic acid derivatives of the [closo-2-CB9H10]− anion

Reaction of B10H14 with para-(OHC)C6H4(COOH) in aqueous KOH gives the [nido-6-CB9H11-6-(C6H4-para-COOH)]− anion 1 which upon cluster closure with iodine in alkali solution gives the [closo-2-CB9H9-2-(C6H4-para-COOH)]− anion 2; an analogous procedure with B10H14 and glyoxalic acid OHCCOOH gives the [closo-2-CB9H9-2-(COOH)]− anion 4via the [arachno-6-CB9H13-6-(COOH)]− anion 3.