Building C(sp³) Molecular Complexity on 2,2′‐Bipyridine and 1,10‐Phenanthroline in Rhenium Tricarbonyl Complexes

Abstract

Ther eactions of [Re(N-N)(CO) 3 (PMe 3)]OTf (N-N = 2,2'-bipyridine, bipy;1 ,10-phenanthroline, phen) compounds with tBuLi andw ith LiHBEt 3 have been explored. Addition to the N-N chelate took place with different site-selectivity dependingo nb othc helate and nucleophile. Thus, with tBuLi, an unprecedenteda ddition to C5 of bipy,aregiochemistry not accessible for free bipy, was obtained, whereas coordinated phen underwent tBuLi addition to C2 and C4. Remarkably,when LiHBEt 3 reactedwith [Re(bipy)(CO) 3 (PMe 3)]OTf, hy-dride addition to the 4a nd 6p ositions of bipy triggered an intermolecularc yclodimerization of two dearomatized pyridyl rings. In contrast, hydride addition to the phen analog resultedi np artial reduction of one pyridine ring. The resulting neutral Re I products showedav aried reactivity with HOTf and with MeOTf to yield cationic complexes.T hese strategies rendereda ccess to Re I complexes containing bipy-and phen-derived chelatesw ith several C(sp 3)c enters.

Electrocatalyst Decomposition Pathways: Torsional Strain in a Second Sphere Proton Relay Shuts Off CO2RR in a Re(2,2’-bipyridyl)(CO)3X Type Electrocatalyst

“…Dearomatization of coordinated Re(bpy) type complexes has been seen before when the complexes are exposed to strongly nucleophilic reagents (tBuLi, LiBEt3H). 43 Partial hydrogenation of quinolines is also well known for a variety of homogeneous complexes, including group 7 carbonyl complexes but typically requires high pressures of H2 and elevated temperatures. [44][45][46] Milder conditions have also been reported although only with expensive catalysts or low functional group tolerance.…”

Metallated dihydropyridinates: prospects in hydride transfer and (electro)catalysis

“…18 As examples, the DHP − form of zinc-I 2 P complexes reacts with B(C 6 F 5 ) 3, 86 the cobalt pincer bis(diisopropylphenyl) imidazole pyridinate ligand complex, (HCNC − ) CoN 2 , reacts with trityl chloride to yield triphenyl methane, 109 and a rhenium-bipyridine-based DHP − reacts with methyl tri-ate to afford methane (Scheme 12). 110 These data suggest that the electron-withdrawing substituents (E) can inuence the electron density at the C 4 carbon. Furthermore B(C 6 F 5 ) 3 , Me + and H + all have a similar effect on electronic structure.…”

“… 18 As examples, the DHP − form of zinc–I 2 P complexes reacts with B(C 6 F 5 ) 3, 86 the cobalt pincer bis(diisopropylphenyl) imidazole pyridinate ligand complex, (HCNC − )CoN 2 , reacts with trityl chloride to yield triphenyl methane, 109 and a rhenium-bipyridine-based DHP − reacts with methyl triflate to afford methane ( Scheme 12 ). 110 Hydrogenation of alkenes with (CNC)CoCl was achieved under H 2 , but no mechanistic studies were available to elucidate the hydride source; it was possible for both a Co–H or M-DHP − species to transfer hydride to the alkene.…”

Electrocatalyst decomposition pathways: torsional strain in a second sphere proton relay shuts off CO2RR in a Re(2,2′-bipyridyl)(CO)3X type electrocatalyst

“…Dearomatization of coordinated Re(bpy) type complexes has been seen before when the complexes are exposed to strongly nucleophilic reagents (tBuLi, LiBEt 3 H). 46 Partial hydrogenation of quinolines is also well known for a variety of homogeneous complexes, including group 7 carbonyl complexes but typically requires high pressures of H 2 and elevated temperatures. [47][48][49] Milder conditions have also been reported although only with expensive catalysts or low functional group tolerance.…”