6533b826fe1ef96bd1284596

RESEARCH PRODUCT

Amino‐Substituted Ferra‐bis(tricarbollides) − Metallatricarbaboranes Designed for Linear Molecular Constructions

subject

description

Reactions between high purity FeCl2 and the anion [nido-7-(tBuHN)-7,8,9-C3B8H10)]− (1−) have been used for efficient syntheses of the twelve-vertex double-cluster metallatricarbollide complexes of the para,para (p,p) type [closo-9,9′(RHN)2-commo-2,2′-FeII-1,7,9-(C3B8H10)-1′,7′,9′-(C3B8H10)] (2) (2a, R = tBu and 2b, R = H) (yields 42−45% for 2a). Compound 2b, which contains two reactive amino substituents conveniently attached to the tricarbollide subclusters in p-positions with respect to the metal center, was prepared via facile cleavage of the tBu substituent in 2a either by AlCl3 or by thermal means. The structure of 2b constitutes a good setting for the synthesis of building blocks for constructing linear metallatricarbollide rods of high stability. Two isomeric compounds of the para,meta (p,m) type 3, [closo-9,10′-(RHN)2-commo-2,2′-Fe-1,7,9-(C3B8H10)-1′,7′,10′-(C3B8H10)] (where R = tBu 3a and/or H 3b), were isolated in smaller yields from reactions of high purity FeCl2 with 1− at higher temperatures. Also reported is the characterization of the m,m-type complex, [closo-10,10′-(tBuHN)2-commo-2,2′-FeII-1,7,10-(C3B8H10)-1′,7′,10′-(C3B8H10)] (4a), and the two zwitterionic species of the new 7-L-7,8,10-C3B8H10 type (6) [L = Me3N 6a and tBu(Me)HN 6b] isolated in moderate yields from the reaction of reagent grade FeCl2 with 1−. The molecular structures of 2b, 3a, and 6b were determined by single-crystal X-ray diffraction studies. Multinuclear (1H and 11B), two-dimensional [11B-11B]-COSY, and 1H{11B(selective)} magnetic resonance measurements enabled complete assignments of all resonances for all compounds and are in excellent agreement with the structures proposed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)