Coordination Chemistry of N,N,N′,N′-Tetrakis(3,5-substituted benzyl-2-oxide)-2,2′-(ethylenedioxy)diethanamine Modified Group 4 Metal Alkoxides

Abstract

The coordination behavior of a set of (ethylenedioxy)diethanamine-based tetraphenol ligands with a series of Group 4 metal alkoxides ([M(OR)(4)]) was determined. The ligands were synthesized from a modified Mannich reaction and fully characterized as N,N,N',N'-tetrakis(3,5-tert-butyl-benzyl-2-hydroxy)-2,2'-(ethylenedioxy)diethanamine, termed H(4)-OEA-DBP(4) (1), and N,N,N',N'-tetrakis(3,5-chloro-benzyl-2-hydroxy)-2,2'-(ethylenedioxy)diethanamine, termed H(4)-OEA-DCP(4) (2). The reaction of 1 with a set of [M(OR)(4)] [M = Ti, Zr, or Hf; OR = iso-propoxide (OPr(i)), neo-pentoxide (ONep), or tert-butoxide (OBu(t))] precursors led to the isolation of [(OPr(i))(2)Ti](2)(μ-OEA-DBP(4)) (3), [(ONep)(2)Ti](2)(μ-OEA-DBP(4)) (4), and [(OBu(t))(2)M](2)(μ-OEA-DBP(4)) where M = Ti (5), Zr (6), or Hf (7). In addition, the [(ONep)(2)Ti](2)(μ-OEA-DCP(4)) (4a) derivative was isolated from the reaction of 2 and [Ti(ONep)(4)], demonstrating the similarity of coordination behavior between the two OEA-R(4) ligands. For 3-7, the metal center adopts a slightly distorted octahedral geometry by binding the two O atoms of the phenoxide moiety, as well as one N and one O atom from the OEA moieties, while retaining two of the original OR ligands. Solution NMR demonstrates inequivalent protons for the majority of the bound OEA ligands, which argues for retention of structure in solution. The synthesis and characterization of these compounds are presented in detail.

Synthesis, Characterization, and Nanomaterials Generated from 6,6′-(((2-Hydroxyethyl)azanediyl)bis(methylene))bis(2,4-di-tert-butylphenol) Modified Group 4 Metal Alkoxides

“…In contrast to what was reported for the [(OR)­Ti­( k 4 ( O,O′,O′′,N ))­AM-DBP 2 ] where R = OPr i or OBu t compounds, the angles around the Ti of 2 proved to adopt a fairly regular TBPY-5 geometry (τ = 0.981). The bond distances of 2 were found to be in general agreement with the other similarly constructed species. ,− …”

“…It is of note that several other ligands with similar constructs as AM-DBP 2 are available with a fur-2-ylmethyl or tetrahydrofur-2-yl moiety replacing the N- CH 2 CH 2 OH fragment or a methoxide replacing the N-CH 2 CH 2 O H . The more complex (ethylenedioxy)­diethanamine-based tetraphenoxide ligands, which possess two AM-DBP 2 submoieties linked by -[N–CH 2 CH 2 –O] 2 -, have also been used to modify group 4 compounds. , The coordination of the metal in the [(OR)­Ti­( k 4 ( O,O′,O′′,N )­AM-DBP 2 ] family of compounds were described as distorted trigonal bipyramidal ( TBPY-5 ) monomers, employing a tetradentate AM-DBP 2 and one parent alkoxide ligand. Similarly, when the 6,6′-(((2-hydroxyethyl)­azanediyl)­bis­(methylene))­bis­(2,4-dimethylphenol) (H 3 -AM-DMP 2 ), where Me groups replace the Bu t groups, was used, monomeric [(OR)­Ti­( k 4 ( O,O′,O′′,N )­AM-DMP 2 ] for OC 6 H 3 (R′) 2 -2,6 (where R′ = CH 3 , CH­(CH 3 ) 2 , C 6 H 5 ,) and dinuclear [(OR)­Ti­(μ-( O )­( k 3 ( O′,O′′,N )­AM-DMP 2 ] 2 for OR = OPr i , OBu t , OC 6 H 4 F-2, and OC 6 H 4 F 2 -2,6, OC 6 F 5 compounds were isolated.…”

“…a Averaged metrical data are shown without error bars. (57,58 The coordination of the metal in the [(OR)Ti(k 4 (O,O′,O′′,N)AM-DBP 2 ] family of compounds were described as distorted trigonal bipyramidal (TBPY-5) monomers, employing a tetradentate AM-DBP 2 and one parent alkoxide ligand. Similarly, when the 6,6′-(((2hydroxyethyl)azanediyl)bis(methylene))bis(2,4-dimethylphenol) (H 3 -AM-DMP 2 ), where Me groups replace the Bu t groups, was used, monomeric [(OR)Ti(k 4 (O,O′,O′′,N)AM-DMP 2 ] for OC 6 H 3 (R′) 2 -2,6 (where R′ = CH 3 ,59 CH(CH 3 ) 2 , 60 C 6 H 5 ,59 ) and dinuclear [(OR)Ti(μ-(O)(k 3 (O′,O′′,N)AM-…”

Uranyl Complexes of Alkyl-Bridged Ditopic Diaminotetraphenol Ligands and Their Use as Uranyl Ion Extractors

“…Dinuclear molybdenum(VI) complexes with diaminotetraphenols are linear, and they are active in oxo-transfer reactions because one coordination position is filled by a labile solvent molecule. A structural study of titanium(IV), zirconium(IV), and hafnium(IV) complexes with similar ether-bridged ligands has recently been reported . In general, very limited data of metal complexes with these types of ligands are available, but because of the fascinating results with these metals, we have extended our studies to the coordination chemistry of uranyl ions obtained with these ligands.…”

“…A structural study of titanium(IV), zirconium(IV), and hafnium(IV) complexes with similar ether-bridged ligands has recently been reported. 24 In general, very limited data of metal complexes with these types of ligands are available, but because of the fascinating results with these metals, we have extended our studies to the coordination chemistry of uranyl ions obtained with these ligands.…”