Organoamido- and Aryloxo-Lanthanoids. XI. Syntheses and Crystal Structures of Nd(Odpp)3, Nd(Odpp)3(thf) and [Nd(Odpp)3(thf)2].2(thf) (Odpp-=2,6-Diphenylphenolate): Variations in Intramolecular π-Ph-Nd Interactions

The X-ray crystal structure of Nd (Odpp)3 ( Odpp- = 2,6-diphenylphenolate), obtained by sublimation of Nd ( Odpp )3( thf )2 ( thf = tetrahydrofuran ) [triclinic, Pi , a 15.835(5), b 13.499(10), c 10.955(11) ?, a 116.25(7), ß 92.87(7), ? 101.66(6)°, V 2031 ?3, Z2, No 5726 'observed' data (I > 3s(I)) refined to conventional R 0.047 shows a near triangular array of oxygens surrounding neodymium { Nd -O} 2.169 ?, ? O- Nd -O 353.2° with additional, intramolecular Nd-?6-Ph chelate interactions { Nd -C} 3.046 ? and Nd-?1-Ph ( Nd -C 2.964(7)?). There is a pseudotrigonal bipyramidal arrangement of the oxygens, the centroid of the ?6-Ph, and the ?1-carbon. The complex Nd ( Odpp )3( thf ), obtained by crystallization of Nd ( Odpp )3( thf )2 from toluene (monoclinic, P21/c, a 12.213(4), b 21.447(4), c 17.744?, ß 104.25(2)°, V 4505 ?3, Z 4, R 0.042 for No 8014) also has pseudotrigonal bipyramidal stereochemistry, with a triangular equatorial array of aryl oxide oxygens { Nd -O} 2.193 ?; ? O- Nd -O 358.7°, an apical thf oxygen (Nd -O 2.446(3)?), and an apical intramolecular chelating phenyl group. As the last has three Nd -C contacts (3.094(5), 3.144(5), 3.010(5)?) significantly shorter than the other three (3.300(5), 3.427(5), 3.377(5)?), an ?3-Ph-Nd interaction seems likely. For [ Nd ( Odpp )3( thf )2].2( thf ), obtained by crystallization from tetrahydrofuran without drying of the crystals, the X-ray structure (monoclinic, P21, a 10.230(2), b 21.919(5), c 13.411(4) ?, ß 101.15(2)°, V 2950 A3, Z2, R 0.058 for No 3237) reveals a distorted trigonal bipyramidal arrangement of three aryl oxide oxygens (two equatorial 2.208(9), 2.16(1) ?; one axial 2.203(9) ?) and two thf oxygens (one equatorial 2.44(1) ?; one axial (significantly distant) 2.62(1) ?). The X-ray structure of [La( Odpp )3( thf )2].2( thf ) shows it to be isostructural with the neodymium analogue.