Synthesis, structure and reactivity of NHC–nickel complexes containing carbonato ligands

Nickel N-heterocyclic carbene complexes and their utility in homogeneous catalysis

“…In particular, the (533−534), [163] (535), [164] (536), [165] (543−544), [166] (545−546), [167] (548 [168]−557), [169] (558), [51] (559), [71] (560), [161] (561), [170] (562−563), [141] (565), [171] (566−567), [172] (568), [173] (569), [126d] (570−573), [174] (574), [175] (575−576), [176] (577), [177] (578), [178] (579), [106] (580−581), [179] (582−583), [151] (584−585), [180] (586−588), [181] (595−596), [182] (597−599), [183] (600−603), [184] (604), [185] (605−608), [186] (609), [185] (610−613), [187] (614−618), [188] (619−621), [189] (622−623), [185] (624−630), [190] (631), [191] (633−635), [192] (636), [193] (637), [194] (647) [195] and (648) [196] complexes were obtained by this pathway from the treatment of the free or the in situ generated NHC The third route is the oxidation method (Scheme 15) using which the (589−590), [197] (638) …”

“…The nickel complexes (124), [68] (128), [68] (622) [185] and (626) [190] were reported for the Kumada coupling of the fluoride and the chloride substrates, while the complex (756) [249] showed activity towards all of the three fluoride, chloride and the bromide substrates. Extending the substrate scope even further, the complexes (278) (319−320), [253] (322), [253] (324), [253] (391), [114] (392), [61] (586−587), [181] (604−605), [185] (609), [185] (623), [185] (624−625), [190] (627−630), [190] (684−685), [214] (691), [211] (708), [214] (711), [205] (722), [214] (741), [211] (755), [228] (757−760) [235] and (775−777) [238] have been reported of the Kumada coupling of only the chloride substrates. It is interesting to note that the compounds (129) and (132) are not analytically pure as they were found to be comprised of 70:30 mixture of Br/Cl atoms as observed in the single crystal X-ray diffraction studies [68].…”

“…The following complexes (116), [61] (121), [59] (293−294), [115] (299−301), [115] (370−371), [129] (439), [150] (543), [166] (546), [166] (548−557), [169] (588), [181] (682) [205] and (733−734) [231] were active for the chloride and bromide substrates, while the complexes (113), [60] (337), [121] (344), [150] (367−369), [129] (389), [129] (436−438) [150] and (440) [150] displayed catalytic activity toward only the bromide substrates.…”

Photo- and Thermoswitchable Half-Sandwich Nickel(II) Complex: [Ni(η5-C5H5)(IMes)(η1-NO2)]

“…Half-sandwich nickel­(II) complexes have recently gained much attention thanks to their easy synthesis and many interesting chemical and structural properties . In this Contribution we present a nitro analogue of a recently published nitrate compound, [Ni­(η 5 -Cp)­(IMes)­(NO 3 )] (Cp = cyclopentadienyl, C 5 H 5 ; IMes = 1,3-bis­(2,4,6-trimethylphenyl)­imidazol-2-ylidene), bearing the N-heterocyclic carbene (NHC) moiety . The original [Ni­(η 5 -Cp)­(IMes)­(NO 3 )] complex has been synthesized as a part of a larger project dedicated to finding the optimal catalyst facilitating the C–C bond formation in the polymerization of styrene, , polymerization of methyl methacrylate, or Suzuki–Miyaura cross-coupling reaction. , In turn, changing of the nitrate fragment to the nitro group, which leads to the formation of [Ni­(η 5 -Cp)­(IMes)­(η 1 -NO 2 )] (complex 2 , Scheme ), introduces a potential photoactive site.…”

Synthesis and Characterization of Heteroleptic Ni(II) Bipyridine Complexes Bearing Bis(N-heterocyclic carbene) Ligands

“…N-heterocyclic carbenes (NHCs) have been successfully used in place of phosphines in a variety of systems. − In the case of Ni­(II) bis-carbene complexes, both mono­(NHC) ligands and bis­(NHC) ligands have been shown to produce a variety of stable square-planar complexes of the Ni II (NHC 2 )­X 2 type, where X is a halide or pseudohalide. − These have been formed by direct reaction of NHC ligands or precursors with Ni­(II) halides , and by the oxidative addition of aryl halides, alkyl halides, and organonitriles to Ni(0) bis­(carbenes). In all cases, the NHC ligands orient trans to each other whenever possible.…”