POLYHEDRAL NONABORANE CHEMISTRY - AN UNSUSPECTED NEW ISOMERIC TYPE INTHE 9-VERTEX ARACHNO-B9H13L SYSTEM

NMR spectroscopy reveals that the preparation of conventionally-struct ured 4-(ligand)-arachno-B9H13 species 1 by ligand exchange on 4-(SMe2) -arachno-B9H13 1a is often accompanied by the formation of their hithe rto unsuspected and unreported 5-(ligand)-arachno-B9H13 isomers 2, whi ch can be isolated by chromatography. 5-(4'-PhC5H4N)-arachno-B9H13 2c is characterised by a single-crystal X-ray diffraction analysis that a lso reveals an interesting stacking of the organic aromatic residues i n the solid state. (C) 1998 Elsevier Science S.A.