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11‐Vertex arachno ‐Clusters with an NB 10 , SNB 9 , and SeNB 9 Skeleton
Author(s) -
Paetzold P.,
Englert U.,
Hansen H.P.,
Meyer F.,
Leuschner E.
Publication year - 2001
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/1521-3749(200103)627:3<498::aid-zaac498>3.0.co;2-7
Subject(s) - deprotonation , chemistry , medicinal chemistry , decaborane , sulfur , protonation , lewis acids and bases , ion , stereochemistry , boron , organic chemistry , catalysis
One of the two bridging protons of the aza‐ nido ‐decaboranes RNB 9 H 10 X can be removed by certain bases to give nido ‐anions [RNB 9 H 9 X] – [R/X = H/H ( 1 a ), Ph/H ( 1 b ), p ‐MeC 6 H 4 /H ( 1 c ), Bzl/H ( 1 d ), H/N 3 ( 1 ′ a )]; the stericly demanding base 1,8‐bis(dimethylamino)naphthalene (“proton sponge”, ps) is ideal. In the case of t Bu anion, the deprotonation (→ C 4 H 10 ) may be accompanied by a hydridation (→ C 4 H 8 ), yielding the arachno ‐anions [RNB 9 H 11 X] – ( 2 a , b , d , 2 ′ a ); these are the main products, when stericly non‐demanding bases like H – are applied. The Lewis acid BH 3 is added to 1 a and 1 ′ a to give the aza‐ arachno ‐undecaborates HNB 10 H 12 X [X = H ( 3 a ), N 3 (in position 2) ( 3 ′ a )]. Thia‐ and selenaaza‐ arachno ‐undecaborates, [S(RN)B 9 H 10 ] – ( 4 b , c ) and [Se(RN)B 9 H 10 ] – ( 4 ′ b , c ), are obtained from 1 b , c by the addition of sulfur or selenium, respectively. The methylation of the anions 4 c and 4 ′ c gives the thia‐ and selenaaza arachno ‐undecaboranes (MeS)(RN)B 9 H 10 ( 5 c ) and (MeSe)(RN)B 9 H 10 ( 5 ′ c ), respectively. The action of HBF 4 on the arachno ‐borates [HNB 10 H 12 X] – ( 3 a , 3 ′ a ) leads to a mixture of nido ‐HNB 9 H 10 X and nido ‐HNB 10 H 11 X by the elimination of BH 3 or H 2 , respectively; the aza‐ nido ‐decaborane predominates in the case of 3 ′ a and the aza‐ nido ‐undecaborane in the case of 3 a . The action of HBF 4 on the anion 4 c yields the hypho ‐undecaborate [S(RN)B 9 H 10 F 2 ] – ( 6 c ). The structures of the products are elucidated on the basis of 1 H and 11 B NMR spectra, supported by 2D COSY and HMQC techniques. Two types of 11‐vertex‐ arachno structures and an 11‐vertex‐ hypho structure are found for the products. The crystal structures of 5 c and [Hps] 6 c · CH 2 Cl 2 are reported.