S1 Structure and Reactivities of Rhenium and Technetium bisarene Sandwich Complexes [M( 6 arene) 2 ] + Giuseppe Meola, Henrik Braband, Sara Jordi, Thomas Fox, Oliver Blaque, Bernhard Spingler and Roger Alberto Department of Chemistry, University of Zurich, Winterthurerstr. 190, CH8057 Zurich Switzerland. Supplementary Information Table of Content 1. General Information 1.1 Materials 1.2 Characterization 2. Synthetic procedures 2.1 [ 99 Tc( 6 hmbz)( 6 C 6 H 5 NH 3 )](PF 6 ) 2 ([1H](PF 6 ) 2 ) and [ 99 Tc( 6 pmbz)( 6 C 6 H 5 NH 3 )](PF 6 ) 2 ([2H](PF 6 ) 2 ) 2.2 [ 99 Tc( 6 hmbz) 2 ](PF 6 ) ([3a](PF 6 )) and [ 99 Tc( 6 pmbz)( 6 hmbz)](PF 6 ) ([3b](PF 6 )) 2.3 [ 99 Tc( 6 hmbz)( 6 C 6 H 5 Br)](PF 6 ) ([4](PF 6 )) and [ 99 Tc( 6 pmbz)( 6 C 6 H 5 Br)](PF 6 ) ([5](PF 6 )) 2.4 [ 99 Tc( 6 hmbz)( ( 6 C 6 H 6 )](PF 6 ) and [ 99 Tc( 6 pmbz)( ( 6 C 6 H 6 )](PF 6 ) 2.5 [Re( 6 C 6 H 6 )( 6 napht)](OTF) ([6](OTf)) 2.6 [Re( 6 napht) 2 ](OTf) ([7](OTf)) 2.7 [Re( 6 C 6 H 6 )(tep) 3 ](OTf) ([8](OTf)) 2.8 [Re( 6 C 6 H 6 )(CN t Bu) 3 ](OTf) ([9](OTf)) 2.9 [Re( 6 C 6 H 6 )(HB(pyz) 3 )] (10) 2.10 [Re(η 6 napht)(tep) 3 ](PF 6 ) ([11](PF 6 )) 2.11 [Re(η 6 napht)(triphos)](PF 6 ) ([12](PF 6 )) 2.12 [Re(CN t Bu) 6 ](PF 6 ) ([13](PF 6 )) Electronic Supplementary Material (ESI) for Dalton Transactions. This journal is © The Royal Society of Chemistry 2017