Sterically Demanding Chelating Diamide Complexes of Yttrium and Lutetium

Abstract

Deprotonation of the bridged diamine ArHN(CH2)3NHAr (Ar = 2,6-iPr2C6H3) with n-butyllithium and potassium hydride, respectively, gives the corresponding alkali metal derivatives M2{ArN(CH2)3NAr} (M = Li (1a), K (1b)). 1a reacts with yttrium trichloride to form the metalate complex [Y{ArN(CH2)3NAr}(THF)2(μ-Cl)2Li(THF)2] (2). The coordination number of yttrium in 2 is six. The structure of 2 shows two bridging chloride ligands and an alkali metal bound by two solvate molecules. Further reaction of 2 with NaC5H5 in THF affords the complex [Y{ArN(CH2)3NAr}(η 5-C5H5)(THF)] (4). The structure of 4 in solution and in the solid state is best described as a distorted tetrahedron. Reaction of 1b with anhydrous lutetium trichloride leads to the unexpected ionic product [LuCl2(THF)5][Lu{ArN(CH2)3NAr}2] (5). 5 can be formally considered as a derivative of the ionic compound [LuCl2(THF)5][LuCl4(THF)2], in which all four chlorine atoms of the anion are substituted by 2 equiv of the {ArN(CH2)3NAr}2- ligand. As seen from all three structures, the steric demand of the {ArN(CH2)3NAr}2- ligand is less than that of two (C5Me5)- moieties.

(2,5‐Bis{[(2,6‐diisopropylphenyl)imino]methyl}pyrrolyl)yttrium and ‐lutetium Complexes – Synthesis and Structures

“…In contrast to compounds 1 and 2 , a splitting of the isopropyl CH 3 signals into two sets of doublets is observed, which is interpreted as a consequence of restricted rotation about the N–C ipso bond. Similar observations were made for other 2,6‐diisopropylaniline‐substituted yttrium complexes, such as [Y{ArN(CH 2 ) 3 NAr}(thf) 2 (μ‐Cl) 2 Li(thf) 2 ] (Ar = 2,6‐ i Pr 2 C 6 H 3 ) 10…”

Five‐ and Four‐Coordinate 1,3‐Diaza‐2‐yttria‐ and 1,3‐Diaza‐2‐scandia‐[3]ferrocenophanes

“…This also holds [23] for complex 5. The symmetry of 5 requires eclipsed cyclopentadienyl rings, which, however, are also forced out of the parallel orientation, and, in addition, the C-N vectors are shifted out of the C 5 planes (see angles [21] α and β in Table 2).…”

Cyclopentadienyl Yttrium Ene-Diamido Complexes: Coupling of the Ene-Diamido Ligand with Isocyanate

“…The Y− C Cp (average 2.708 Å), Y−N (average 2.234 Å), and Y−O (average 2.412 Å) bond distances in complex 2 are slightly longer than those (2.658, 2.171, and 2.372 Å) in the previously reported yttrium complex CpY(ArN(CH 2 ) 3 NAr)(THF). 7 The C1−C2 bond length of 1.359(3) Å in the N1−C1−C2−N2 framework of 2 is slightly lengthened, while the average C−N distance of 1.408(3) Å is shortened, in comparison to those observed in the corresponding free ene-diamine (C−C = 1.339(2), C−N = 1.431(2) Å), 8 indicating the noticeable electron delocalization of the N1−C1−C2−N2 framework. The short distances (2.632(2) and 2.627(2) Å) between the yttrium atom and the carbon atoms of the N−C−C−N framework and the folded N−C−C−N−Y five-membered ring (dihedral angle of the N−Y−N and N−C−C−N planes 123.4°) indicate the σ 2 ,π coordination mode of the DAB ligand in 2.…”