Study On The Synthesis, Structure And Reactivity Of Organolanthanide Complexes Supported By Anionic Functionalized-NHC Ligand

Different aryloxo-functionalized N-heterocyclic carbene （NHC） precursors, phenol-functionalized imidazolium salts, such as bis（phenol）-functionalized imidazolium salt, amido-phenol-functionalized imidazolium salt, salicylaldimino-functionalized imidazolium salt and mono（phenol）-functionalized imidazolium salt have been synthesized by modified literature procedures. A series of aryloxo-functionalized NHC lanthanide complexes have been synthesized and characterized by X-ray structure determination, for example discrete ion-pair complexes,“ate”complexes supported by bis（aryloxo）-functionalized NHC, the first cationic NHC lanthanide complexes supported by amido-aryloxo-functionalized and salicylaldimino-functionalized NHC, the first anionic functionalized NHC-Ln（II） complexes.1. Bis（phenol）-functionalized imidazolium salt [1,3-bis[HO-4,6-^tBu₂-C₆H₂-2-CH₂]- [CH（NCHCHN）]]Cl （B） has been synthesized, a series of discrete ion-pair complexes [[1,3-bis-[O-4,6-^tBu₂-C₆H₂-2-CH₂][C（NCHCHN）]]₂Ln]-[Li（DME）₃]+ （Ln = Sm （1）, Er （2）, Yb （3））,“ate”complexes {（Sol）M{μ-[1,3-bis-[O-4,6-^tBu₂-C₆H₂-2-CH₂][C（NCH- CHN）]]}}Ln[1,3-bis-[O-4,6-^tBu₂-C₆H₂-2-CH₂][C（NCHCHN）]] （Ln = Sm, M = Li, Sol = THF （4）; Ln = Sm, M = Na, Sol = Et2O （5）; Ln = Y, M = Li, Sol = THF （6）） have been synthesized by amine-elimination reaction. Bis（aryloxo）-functionalized NHC-Yb amide complex [1,3-bis-[O-4,6-^tBu₂-C₆H₂-2-CH₂][C（NCHCHN）]]Yb[N（SiMe₃）C6H3iPr₂- 2,6][（μ-Cl）Li（THF）₃] （7） has been synthesized by one-pot reaction. Tried to synthesize the bis（NHCs）-bis（metals） complex by the reaction of complex 1 with SmCl3 are unsuccessful, and the 1,2-benzyl migration rearrangement aryloxy-substituted imidazole lanthanide complex （8） was isolated. Reaction of complex 3 with TiCl4 didn’t give the expected heterobimetallic product, but （THF）₂YbCl₂（μ-Cl）₂Li（THF）₂ （9）. Complexes 1 and 4 displayed catalytic activities in ring-opening polymerization ofε-caprolactone, and complexes 1 and 3 can catalyse the reaction of amidation of aldehydes with amines, addition of alkyne to carbodiimides.2. Two dimeric amido-aryloxo-functionalized NHC-Li complexes （[3,5-^tBu₂-2-（O）C₆H₂CH（nBu）NH（CH₂）₂（C（NCHCHNR））]Li）₂ （R = iPr 10, C₆H₂-Me₃-2,4,6 11） have been synthesized by the reaction of salicylaldimino-functionalized imidazolium salt with nBuLi. Three cationic NHC-Ln complexes supported by amido-aryloxo-functionalized NHC ligand [（3,5-^tBu₂-2-（O）C₆H₂CH（nBu）NH（CH₂）₂（C（NCHCHNiPr）））₂Ln]+[Br]- （Ln = Y （12）, Lu （13）, Er （14）） were synthesized by the reaction of compelx 10 with LnCl3. The cationic NHC-Yb bromide [（3,5-^tBu₂-2-（O）C₆H₂CH=N（CH₂）₂（C（NCHCHNiPr）））₂YbTHF)]+- [Br]- （15） was also synthesized by the reaction of [3,5-^tBu₂-2-（OH）C₆H₂CH= N（CH₂）₂（CH（NCHCHNiPr））]Br with Li（THF）Yb（NiPr₂）4. They are the first examples of cationic NHC-Ln complexes. [3,5-^tBu₂-2-（O）C₆H₂CH=N（CH₂）₂（C（NCHCHNiPr））]₂YBr （16） was synthesized by the one-pot reaction of salicylaldimino-functionalized imidazolium salt, NaN（SiMe₃）₂ and YCl3.3. The amido-aryloxo-functionalized NHC-Yb（II） complex [3,5-^tBu₂-2-（O）C₆H₂- CH（nBu）NH（CH₂）₂（C（NCHCHNiPr））]₂Yb （17） was synthesized by the the reaction of Na/K alloy with the cationic complex [（3,5-^tBu₂-2-（O）C₆H₂CH（nBu）NH（CH₂）₂（C（NCH- CHNiPr）））₂Yb]+[Br]-; salicylaldimino-functionalized NHC-Eu（II） complex [3,5-^tBu₂-2- （O）C₆H₂CH=N（CH₂）₂（C（NCHCHNiPr））]₂Eu （18） was synthesized by the the reaction of EuI2 with in-situ salicylaldimino-functionalized NHC-Na. One discrete ion-pair complex [nBu（μ-Li）[1,3-bis-[O-4,6-^tBu₂-C₆H₂-2-CH₂][C（NCHCHN）]]₂Eu]₂-- [Li（DME）₃]+2（ICl）₂ （19） was isolated by the reaction of bis（phenol）-functionalized imidazolium salt, nBuLi and EuI2 in 1:3:1 molar ratio by chance. They are the first anionic functionalized NHC-Ln（II） complexes.4. By the reaction of [O-4,6-^tBu₂-C₆H₂-2-CH₂（C（NCHCHNiPr））]₂LnNiPr₂ （Ln = Nd, Y） with CO2, we didn’t isolate the CO2 inserted complex, but the trimer of o-quinone methide （20）, which from the cleavage of the ligand [O-4,6-^tBu₂-C₆H₂-2-CH₂（C（NCHCHNiPr））]+. We also didn’t isolate the NHC bimetal complexes by the reaction of [O-4,6-^tBu₂-C₆H₂-2-CH₂（C（NCHCHNiPr））]₂YbNiPr₂ with NiCl₂（DME）₂ （or NiCl₂（PPh3）₂）, but the black metal Ni. Three complexes [4,6-^tBu₂-（O）C₆H₂-2-CH₂（C（NCHCHNMe））]₂NdN（SiMe₃）₂ （21）, [4,6-^tBu₂- （O）C₆H₂-2-CH₂（N（CHCHN（Me）C））]₃Ln （Ln = Yb （22）, Y （23）） were isolated by the reaction of [4,6-_tBu₂-（OH）C₆H₂-2-CH₂{CH（NCHCHNMe）}]Cl with Ln[N（SiMe₃）₂]₃- （μ-Cl）Li（THF）₃ （Ln = Nd, Yb） and Y[N（SiMe₃）₂]₃, respectively. Tried to synthesize the aryloxo-functionalized NHC lanthanide bis-amine complex, unsuccessful, but the [O-4,6-^tBu₂-C₆H₂-2-CH₂（C（NCHCHNiPr））]₂YbCl（THF） （24）.