Fast reaction studies of rhenium carbonyl complexes: the pentacarbonylrhenium(0) radical

Photochemically Enabled Iodine Degenerative Transfer Controlled Radical Homo- and Block Copolymerization of Vinylidene Fluoride at Ambient Temperatures with Mn2(CO)10and Visible Light

“…Qualitatively, the order of their ability to abstract halides (83) (k act of ATRP) is Re(CO) 5 • > Mn(CO) 5 • > CpW(CO) 3 • > CpMo(CO) 3 • > CpFe(CO) 2 • > Co(CO) 4 • . However, while Re(CO) 5 • does indeed abstract Cl from CCl 4~6 5 times faster than Mn(CO) 5 • (69,84), the stronger Re-Re (85) bond dissociation energy and its higher price, render the relatively inexpensive Mn 2 (CO) 10 (86,87) the most popular reagent in the series (62). The dimer is stable at room temperature, in the dark (K eq < 2.4 x 10 -19 ) (88), but as the Mn-Mn BDE is relatively small (30-40 kcal/mol) (62,89,90), and further decreased by extra ligands (91), Mn 2 (CO) 10 easily dissociate thermally (6 0-90°C) (92), and respectively, photolytically at rt.…”

“…5, 6), the reactivity of fluorinated radicals (i.e. more branched, more electrophilic) (141), and by the preferential activation of primary vs. secondary or tertiary halides (84) with Mn(CO) 5 • . As such, depending of the amount of Mn 2 (CO) 10 required for activation (i.e.…”

“…Indeed, while UV leads to CO loss to Mn 2 (CO) 9 and Mn(CO) 5 Mn(CO) 5 • easily abstracts hydrides and halide from e.g. Bu 3 SnH (97), and respectively from RX halides with moderate to high BDEs (< 310 kJ/mol) (98) such as CCl 4 (99), I 2 (85), polyhalides (84), allyl and benzyl halides (84,85), and even CH 3 I (100) and other inactivated alkyl iodides. Remarkably, unlike other radical abstractors, Mn(CO) 5 • reacts faster with primary rather than secondary or tertiary halides, due to the sterics of the CO ligands (84).…”

“…Bu 3 SnH (97), and respectively from RX halides with moderate to high BDEs (< 310 kJ/mol) (98) such as CCl 4 (99), I 2 (85), polyhalides (84), allyl and benzyl halides (84,85), and even CH 3 I (100) and other inactivated alkyl iodides. Remarkably, unlike other radical abstractors, Mn(CO) 5 • reacts faster with primary rather than secondary or tertiary halides, due to the sterics of the CO ligands (84). Moreover, prior to our work (50)(51)(52)(53), there were no examples of Mn 2 (CO) 10 mediated activation of perfluoroalkyl or sulfonyl halides, or trifluoromethylations with CF 3 -I or CF 3 -SO 2 -I.…”

Gehinderte Ligandbewegungen in Übergangsmetallkomplexen, XXXVII [1]: Photoreaktion von Dekacarbonyldirhenium mit Phenylallen / Hindered Ligand Motions in Transition Metal Complexes, XXXVII [1]: Photoreaction of Decacarbonyldirhenium with Phenylallene

“…Das Reaktionsgeschehen bei der Umsetzung von 1 mit 2 kann mit den bekannten Prim ärpro dukten aus der Bestrahlung von 1 [31][32][33][34][35][36][37][38][39][40] [ 14,15,17].…”