Abstract

The symmetric d5 trans-bis-alkynyl complexes (n = 2, R = -CCTIPS (2a); n = 3, R = -CCTIPS (2b); n = 2, R = F (4); n = 3; -CCTIPS) were prepared by the reaction of [Mn(dmpe)2Br2] with two equivalents of the corresponding acetylide LiCCC6H4R (R = F, -CCTIPS). The reaction of compounds 2a, 2b and 4 with [Cp2Fe][PF6] yielded the corresponding d4 complexes [PF6] (n = 2, R = -CCTIPS, [2a]+; n = 3, R = -CCTIPS, [2b]+;n = 2, R = F, [4]+; n = 3; -CCTIPS). The unsymmetrically substituted trans-iodo-alkynyl complex [IMn(dmpe)2(CCC6H4-CCTIPS)] (5) was obtained by treating MeCpMn(dmpe)I with one equivalent of H-CCC6H4-CCTIPS in the presenceof dmpe. Deprotection of the TIPS group with TBAF gavecomplex [IMn(dmpe)2(CCC6H4CCH)] (6) in 94 % yield. The neutral dinuclear complexes MnII/MnII compounds (R = H, Me, n-pentyl, F) were prepared by the direct reaction of with the corresponding LiCCC6H4R (R = H, n-pentyl, F). These MnII/MnII dinuclear compounds were further oxidized to the mixed-valent complexes and the dicationic complexes using [Cp2Fe][PF6]. All complexes have been characterized by NMR, IR, and Raman spectroscopy. X-ray diffraction studies were carried out on complexes 1c, 2a, 4, [4]+, and 6.