Synthesis, structure, and properties of the Sc chloride complex coordinated by the tridentate bis(phenolate)-tethered NHC ligand

Sc3+ Chloro and Alkyl Complexes Coordinated by Pincer NHC‐Tethered Bis(phenolate) Ligands

“…This can be due to the widening of the NCN bond angle from 105.5(2)–108.2(2)° in five‐ to 116.4(2)–117.1(4)° in six‐membered cycles, although no significant elongation of the Sc−O bonds was detected. The O phenoxide −Sc−O phenoxide angles in L 2 ScCl ( THF ) 2 and L 2 ScCl ( py ) 2 are 159.25(5)° and 161.1(2)°, respectively, thus also being larger than in related scandium complex with five‐membered aliphatic L Im ScCl ( py ) 2 (156.06(6)°) [18] and aromatic linkers L 1 ScCl ( THF ) 2 (157.61(5)°). In case of the THF‐adduct L 2 ScCl ( THF ) 2 , the Sc−O phenoxide bonds are rather on the short side (1.957(2)–1.960(2) Å), while for the pyridine‐coordinated L 2 ScCl ( py ) 2 , the bond distances are somewhat longer (1.986(3) Å).…”

“…Selected structural features for L 1 ScCl ( THF ) 2 , L 2 ScCl(THF) 2 , L 2 ScCl(py) 2 and L Im ScCl(py) 2 (where L Im =bis[(2,4‐di‐tert‐butyl)phenolato]‐6,6′‐(4,5‐dihydroimidazole‐2‐ylidene)) [18] are summarized in Scheme 3.…”

“…To date, numerous pincer‐NHC transition metal complexes have been developed, [8–13] while the use of pincer NHC ligands in rare‐earth metal chemistry remains limited although growing [14–17] . Recently, we have reported two NHC‐based OCO pincer ligands featuring different ring size carbenes and their coordination to rare‐earth metals [18,19] . To gain a systematic insight into the principles of the precise tailoring of the metal coordination sphere, we were interested to prepare a series of NHC pincer ligands of different σ‐donor abilities and to explore their coordination to Sc 3+ having the smallest ionic radius among the rare‐earths.…”

“…[14][15][16][17] Recently, we have reported two NHC-based OCO pincer ligands featuring different ring size carbenes and their coordination to rare-earth metals. [18,19] To gain a systematic insight into the principles of the precise tailoring of the metal coordination sphere, we were interested to prepare a series of NHC pincer ligands of different σ-donor abilities and to explore their coordination to Sc 3 + having the smallest ionic radius among the rare-earths. Symmetrical (OCO)type NHC-donor systems, where a neutral carbene donor is tethered with two sterically demanding anionic phenolate functions, were chosen (Scheme 1).…”

“…[17,[33][34][35][36][37][38][39][40] The first scandium complex derived from a bis(phenolate) ligand with a dihydroimidazole-2ylidene linker, was described in our recent report. [18] We were interested in preparing anionic-tethered NHC ligands of different σ-donor abilities and attempting their coordination to Sc 3 + featuring the smallest ionic radius among all rare-earth metals.…”