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The deprotonation of the nido-anion [B 11 H 14 ] ± by two equivalents of LitBu yields the anion [B 11 H 12 ] 3± . Three observed 11 B NMR shifts of this anion in the ratio 1 : 5 : 5 are in agreement with shifts calculated by the GIAO method on the basis of the ab initio computed geometry. The deprotonation can be reversed, giving back [B 11 H 14 ] ± via [B 11 H 13 ] 2± . The thermolysis of [Li(thp) x ] 3 [B 11 H 12 ] in thp at 80°C leads to the closo-borate [Li(thp) 3 ] 2 [B 11 H 11 ] under elimination of LiH. Anhydrous air transforms [B 11 H 12 ] 3± into the known oxa-nido-dodecaborate [OB 11 H 12 ] ± . The rhoda-closo-dodecaborate [L 2 RhB 11 H 11 ] 3± is formed from [B 11 H 12 ] 3± and RhL 3 Cl (L = PPh 3 ). Dodecahydro-nido-undecaborat [B 11 H 12 ] 3± Inhaltsu È bersicht. Das nido-Anion [B 11 H 14 ] ± la È ût sich mit zwei Øquivalenten LitBu zum Anion [B 11 H 12 ] 3± deprotonieren. Drei 11 B-NMR-Verschiebungen im Verha È ltnis 1 : 5 : 5 stimmen mit Verschiebungen u È berein, die mit der GIAOMethode auf der Grundlage der ab initio ermittelten Geometrie berechnet wurden. Protoniert man umgekehrt [B 11 H 12 ] ± , so gelangt man u È ber [B 11 H 13 ] 2± zu [B 11 H 14 ] ± zuru È ck. Die Thermolyse von [Li(thp) x ] 3 [B 11 H 12 ] in thp bei 80°C fu È hrt unter Abspaltung von LiH zum closo-Borat [Li(thp) 3 ] 2 [B 11 H 11 ]. Wasserfreie Luft oxidiert [B 11 H 12 ] 3± zum bekannten Oxa-nido-dodecaborat [OB 11 H 12 ] ± . Aus [B 11 H 12 ] 2± und RhL 3 Cl bildet sich das Rhoda-closo-dodecaborat [L 2 RhB 11 H 11 ] 3± (L = PPh 3 ).

The Lewis base SMe2 in 7‐B11H13(SMe2) (1a) can be replaced by the amines L = NH2(CH2tBu), NH2Cy, NH2Ph, NH2(4‐C6H4Me), py, chinoline or the phosphanes L = PPh3, PMePh2, yielding 7‐B11H13L (1b‐i). The borane 1a can be deprotonated by certain amines, alkanides, or hydrides to give the anion 7‐B11H12(SMe2)‐ (2a). Replacing the base SMe2 in the anion 2a by weak bases gives B11H12L‐ (L = PPh3, MeCN; 2h, j). Upon reaction of 1a with the amine NH2(CH2tBu) in the ratio 1:2, a deprotonation and the substitution of SMe2 by the amine are observed, 7‐B11H12[NH2(CH2tBu)]‐ (2b) being formed. At 170 °C, the 7‐isomers 1b, f are isomerized into a mixture of the corresponding 1‐ and 2‐isomers (1b′, f′ and 1b″, f″, respectively).

organic chemistry, review organic chemistry, review Z 0200 -322Reactivity of the closo-Azaboranes R-NB9H9 and R-NB11H11 -(19 refs.). -(DIRK, W.; LEUSCHNER, E.; LOMME, P.; PAETZOLD, P.; ROTH, M.; Spec. Publ. -R.

Reactions of the Undecaborate Anion [B11 H 11 ] 2− -[15 refs.]. -(VOLKOV, O.; DIRK, W.; ENGLERT, U.; PAETZOLD, P.; Spec. Publ. -R.

2002 boron, B boron, B I 0055 08 -010 Dodecahydro-nido-undecaborate [B 11 H 12 ] 3− . -The formation of the [B 11 H 12 ] 3− anion from [B 11 H 14 ] − is reinvestigated and some of its properties are studied. -(DIRK, W.; PAETZOLD, P.; RADACKI, K.; Z. Anorg. Allg.

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Undecaborates M 2 [B 11 H 11 ]: Facile Synthesis, Crystal Structure, and Reactions. -Crystal structure analysis of (III) (space group P2 1 /c, Z = 4) reveals a rather distorted octahedron for the [B 11 H 11 ] 2− anion, whereas the corresponding octahedron in (VIIb) (space group P2 1 2 1 2 1 , Z = 4) exhibits a structure close to C 2c symmetry. Protonation of the [B 11 H 11 ] 2− anion at low temp. gives [B 11 H 12 ] − , which is apparently formed by opening of the B1-B4 edge in the course of the known degenerate skeletal rearrangement (NMR), followed by protonation of this edge. Addition of BH 3 to [B 11 H 11 ] 2− yields closo-[B 12 H 12 ] 2− under loss of H 2 . Fusion of two [B 11 H 11 ] 2− units with the aid of FeCl 3 produces the known [B 22 H 22 ] 2− anion, whose 11 B NMR signals could completely assigned on the basis of Cs symmetry. [Et 3 BnN][(Ph 3 P) 2 N] [B 22 H 22 ] crystallizes in the space group Pna2 1 with Z = 4. -(VOLKOV, O.; DIRK, W.; ENGLERT, U.; PAETZOLD, P.; Z.