B ‐Substituted (Arene)ruthenacarborane–Sulfonium, –Thioether and–Mercaptan Complexes: Mild Single and Double Dealkylation and Structural Implications in the Antipodal Distance

Reactions of [RuCl 2 (η 6 ‐arene)] 2 (arene = benzene, p ‐cymene) with nido ‐[7‐R‐10‐L‐7,8‐C 2 B 9 H 9 ] – in THF at room temperature for 3 d give the (arene)ruthenacarborane complexes closo ‐[3‐Ru(η 6 ‐arene)‐1‐R‐8‐L‐1,2‐C 2 B 9 H 9 ] + {arene = benzene, R = H [L = Me 2 S ( 1a ), THT ( 1b ), EtPhS ( 1c )], R = Me [L = Me 2 S ( 2a )]; arene = p ‐cymene, R = H [L = Me 2 S ( 3a )]} and mercaptan closo ‐[3‐Ru(η 6 ‐ arene)‐1‐R‐8‐HS‐1,2‐C 2 B 9 H 9 ] [arene = benzene, R = H ( 4 ), Me ( 5 ); arene = p ‐cymene, R = H ( 6 )] in yields of 20–40 % and 22–29 %, respectively. The asymmetric ligand nido ‐[9‐Me 2 S‐7,8‐C 2 B 9 H 10 ] – leads to the thioether complex closo ‐[3‐Ru(η 6 ‐benzene)‐7‐MeS‐1,2‐C 2 B 9 H 10 ] ( 8 ) in 34 % yield under the same reaction conditions. The crystal structure of 1a is described and compared with those of 4 and 8 . The fully assigned 11 B NMR spectroscopic data for a whole series of ruthenacarboranes having B ‐substituted sulfonium, thioether and mercaptan groups are presented. These data show a relation between antipodal cluster atom distances (antipodal distance) and antipodal effect (AE) in the crystal structures of these complexes and for other families of heteroboranes such as closo ‐[EB 11 H 11 ] and closo ‐[EB 9 H 9 ]. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)