Aryloxide-based multidentate ligands for early transition metals and f-element metals

Unique tripodal chiral tertiary amine, 2,6-trans-1,2,6-trisubstituted piperidine with pyridine and bis(phenol) donor groups: Its stereoselective coordination to titanium(IV) ion

“…Tripodal ligands, which are characterized by a facial coordination to metal ions, have recently gained considerable attention and found applications in various fields of research such as bioinorganic chemistry [1] and catalytic olefin polymerization [2]. As among the most reliable tactics to construct tetradentate ligands with a tripodal nature, trialkyl amine platforms have been long utilized as represented by tris (2-pyridylmethyl)amine [3], N,N 0 -bis(2-hydroxybenzyl)-2-picolylamine [4], and tris{2-(R)-4-phenyl-1,3-oxazolinylmethyl}amine [5] (Fig.…”

“…Since the isomers in Scheme 1 can be generally all accessible, an effective method to select an enantiomer with the desired C 1 -symmetry is required. To this end, chiral 2,6-trans-1,2,6-trisubstituted piperidine derivatives should be promising because they should favor a chair-like ring conformation for the piperidine backbone to dispose the substituent at C2 (6) in axial and the other one at C6 (2) in equatorial positions, leading to the desired cis(O Ù O)-and enantio-selective binding to the metal center ( Fig. 2).…”

“…TiO(4) 160.0(2) the first enantio-and cis(O phenolato -O phenolato )-selective chiral tripodal ligand of {A Ù (N Ù B) Ù A} type in the formation of an octahedral complex.Another characteristic point of view in the crystal structure of 7 is the Ti and the l-O atoms are deviated up and down by 0.46 Å and 0.37 Å on average, respectively, from the basal mean plane defined by the rest two Ti and two l-O atoms to constitute a very shallow six-membered chairlike conformation for the (Ti-l-O) 3 ring…”

A Family of 1,1,3,3‐Tetraalkylguanidine (H‐TAG) Solvated Zinc Aryloxide Precatalysts for the Ring‐Opening Polymerization of rac‐Lactide

“…[6,[10][11][12][13] To overcome this challenge, the use of bulky aryloxide ligands in conjunction with an auxiliary Lewis base has been proven useful. [11,14] Recently, we reported a detailed effort to outline the stoichiometric reactivity of hetero-ligated zinc systems involving aryloxide and guanidine ligand sets. [15] In this previous investigation, the use of the bulky aryloxide ligand 4MeDBP, in conjunction with 1,1,3,3-tetramethylguanidine (H-TMG) was found to assist in producing a well-defined metal aryloxide with a potential single site for reactions.…”

Polymerization of ε-caprolactone using bulky alkoxo-titanium complexes and structural analysis of [Ti(OBorneoxo)2Cl2(thf)2]

“…Bulky aryloxo or trialkylsiloxo of group 4 and 5 have extensively been used in organometallic chemistry [1][2][3][4]. Typically in the chemistry developed with these derivatives the metal centre is surrounded by two attendant RO ligands as found in the {Ti(ArO) 2 } fragment used as template for catalytic C-C coupling reactions [5].…”