Kohlenstoff‐Extrusion/Cluster‐Kontraktion: Synthese des fluorierten Cyano‐closo‐undecaborats K₂[3‐NC‐closo‐B₁₁F₁₀]

Abstract

Aus dem Käfig befreit: Die Deprotonierung der Aminogruppe im [1‐H2N‐closo‐CB11F11]−‐Ion löst eine Clusterumwandlung des Carba‐closo‐dodecaborats in ein closo‐Undecaborat aus. Die Umlagerung wird von einer Fluoridabspaltung begleitet, und das C‐N‐Fragment wandelt sich in einen Cyanoliganden um (siehe Schema).

Synthesis and Characterization of 2‐Mono‐ and 1,2‐Diaminocarba‐closo‐dodecaborates M[1‐R‐2‐H2N‐closo‐CB11H10] (R=H, Ph, H2N, CyHN)

“…Similar insertion reactions of boron have been described previously, [16][17][18] but the groups attached to the boron atom in the 2-position of the resulting carba-closo-dodecaborate anions (e. g. F, Ph, Me 2 N, OA C H T U N G T R E N N U N G (CH 2 ) 4 Cl) are not useful for further derivatizations. Recently, we reported on investigations of the [1-H 2 N-2-F-closo-CB 11 H 10 ] À ion, which was obtained from 7-H 3 N-7-nido-CB 10 H 12 and BF 3 ·OEt 2 , in an analogous reaction to those presented in Scheme 4, [42] and comparable reactions of zwitterionic carboranes 7-RH 2 N-7-nido-CB 10 H 12 are standard procedures for the preparation of amino-substituted 12-vertex closo-metallacarboranes. [51] After aqueous work up, 2-H 3 N-closo-CB 11 The carboranes 1-H 2 N-2-H 3 N-closo-CB 11 H 10 (H-3) and 1-CyHN-2-H 3 N-closo-CB 11 H 10 (H-4) were isolated in a purity of 90 and 70 %, respectively.…”

“…[38,41] Recently, we reported on the fluorination of the [1-H 2 Ncloso-CB 11 H 11 ] À ion (7) with elemental fluorine in anhydrous hydrogen fluoride, which results in salts of the amino-functionalized undecafluorinated anion [1-H 2 N-closo-CB 11 F 11 ] À . [14] Double deprotonation of this anion resulted in a carbon extrusion/cluster contraction reaction yielding the cyano-closo-undecaborate dianion [3-NC-closo-B 11 F 10 ] 2À , [42] which takes part in further unprecedented reactions. [42,43] These unexpected findings tempted us to investigate the chemistry of other, especially fluorinated, aminocarba-closododecaborate anions.…”

“…[14] Double deprotonation of this anion resulted in a carbon extrusion/cluster contraction reaction yielding the cyano-closo-undecaborate dianion [3-NC-closo-B 11 F 10 ] 2À , [42] which takes part in further unprecedented reactions. [42,43] These unexpected findings tempted us to investigate the chemistry of other, especially fluorinated, aminocarba-closododecaborate anions. Since the starting materials for these studies-the non-fluorinated amines-are unknown or they are only available in trace amounts, their preparation was attempted.…”

Salts with the Triborate Anion [B3O3F2(OH)2]–: A Combined Experimental and Theoretical Study

“…[1] It is obtained from the fluorinated monocarba-closo-dodecaborate anion [1-H 2 N-closo-CB 11 F 11 ] - [2] by an unusual carbon extrusion/cluster contraction reaction. [1] Major degradation products of K 2 [3-NC-closo-B 11 F 10 ] are salts of the difluorodihydroxytriborate anion [B 3 O 3 F 2 (OH) 2 ] -(1) (Figure 1).…”

“…[1] It is obtained from the fluorinated monocarba-closo-dodecaborate anion [1-H 2 N-closo-CB 11 F 11 ] - [2] by an unusual carbon extrusion/cluster contraction reaction. [1] Major degradation products of K 2 [3-NC-closo-B 11 F 10 ] are salts of the difluorodihydroxytriborate anion [B 3 O 3 F 2 (OH) 2 ] -(1) (Figure 1). To the best of our knowledge, anion 1 is unknown and only a small number of other partially fluorinated borates with boron oxygen rings have been reported so far: [Ph 3 [3] [(iPr 3 PAu) 6 4 ).…”