Polycyclic Compounds of Manganese

Abstract

<p>This dissertation focuses on the synthesis, characterization and reactivity of several types of arene manganese systems.</p> <p>The reaction of potassium tert-butoxide with [(ɳ6-trindane)Mn(CO)3][BF4], 58c, was investigated in attempts to funtionalize 58c at the benzylic positions. It was demonstrated that complex 58c undergoes three C-H insertions and a haptotropic shift when treated with potassium tert-butoxide. As well, other trindane complexes including [(ɳ6-trindane)Mn(CO){O(OMe)3}2][BF4], 98, and [(ɳ6-trindane)Re(CO)3][PF6], 99, have been synthesized in hopes of alkylating the exo benzylic positions and develop an organometallic route to sumanene, a key fragment of C60 that has not yet been synthesized. The former compound, 98, was characterized by X-ray crystallography.</p> <p>In order to probe the generality of the novel reaction exhibited by the trindane system, other [(arene)Mn(CO)3]+ systems were studied in which the arene is bicyclic or tricyclic and possesses attached 5-, 6- or 7-membered rings. In particular, the syntheses of [(ɳ6-indane)Mn(CO)3][BF4], 84, [(ɳ6-tetralin)Mn(CO)3][PF6], 103, and [(ɳ6-dibenzosuberane)Mn(CO)3][BF4], 102, and their reactions with potassium tert-butoxide in the presence of donor ligands are presented. The products of these reactions were characterized by infrared and 1H, 13C and 31P NMR spectroscopy and mass spectrometry.</p> <p>The molecular dynamics of two hexaethylbenzene (HEB) complexes, [(ɳ6-HEB)Mn(CO)3][BF4], 147, and (ɳ6-HEB)Mn(CO)2Br, 148, were examined using low-temperature NMR spectroscopy. The activation barrier (ΔG≠) for ethyl rotation for 147 was determined to be ~ 11.5 kcal mol-1. Crystallographic data was obtained for 148, which demonstrated the 1,3,5-distal-2,4,6-proximal geometry, a feature common to transition metal HEB complexes.</p> <p>Finally, extended Hückel molecular orbital (EHMO) calculations were carried out for four polycyclic frameworks ligated to organometallic fragments: anti-dibenzpentalene, 157, and syn-dibenzpentalene, 158; fluoradenyl, 159, and fluoranthene, 160. Each of these systems exhibited unique dynamic behaviour, which are interpreted using a molecular orbital rationale.</p>