Syntheses, characterizations, and reactivities of new 1,4,7-trimethyl-l,4, 7-triazacyclononane (Me 3 tacn) molybdenum and tungsten complexes

摘要

The reported complexes of [(Me(3)tacn)M-0(CO)(3)] (Me(3)tacn = 1,4,7-trimethyl-1,4,7-triazacyclononane; M = W, 1a; Mo, 1b), [(Me(3)tacn)M-II(CO)(3)I](PF6) (M = W, 2a; Mo, 2b), [(Me(3)tacn)MVOCl2](PF6) (M = W, 3a; Mo, 3b), and [(Me(3)tacn)(MIO3)-I-V]center dot 4H(2)O (M = W, 4a; Mo, 4b) were synthesized as tungsten and molybdenum precursors according to the works by Wieghardt [20,21,24]. Reaction of 2a with sodium dialkyl dithiocarbamate afforded complexes [(Me(3)tacn)W-II(CO)(2)(S2CNR2)]I (R = Me, 5a; P-i(r), 6a). Similar reaction using 2b gave rise to the isolations of complexes [(Me(3)tacn)Mo-II(CO)(2)(S2CNR2)](PF6) (R = Me, 5b; P-i(r), 6b; P-n(r), 7). Hydrolysis of 3b in acetonitrile gave a dimeric molybdenum complex [{(Me(3)tacn)(MoO)-O-V(OH)}(2)(mu-O)](PF6)(2)center dot 2MeCN (8). Treatment of 4b with sodium diisopropyl dithiocarbamate in the presence of HPF6 yielded [(Me(3)tacn)(MoO2S)-O-VI] (9), while the similar reaction with S-8 powder yielded the oxotetrasulfido complex [(Me(3)tacn)(MoO)-O-IV(S-4)] (10). All complexes are well characterized by electronic, infrared, and NMR spectroscopies, and the solid-state structures of 1a/b, 2a, 3b, 4a/b, 5a/b, 6a/b, and 7-10 have been also established by single-crystal X-ray diffraction. The electrochemical properties of these molybdenum and tungsten complexes were also investigated in the paper.