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Yttrium and Lanthanide Diphosphanylamides: Syntheses and Structures of Complexes with one {(Ph 2 P) 2 N} − ligand in the Coordination Sphere
Author(s) -
Roesky Peter W.,
Gamer Michael T.,
Marinos Nicolas
Publication year - 2004
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200305745
Subject(s) - chemistry , lanthanide , cyclooctatetraene , yttrium , ligand (biochemistry) , crystallography , coordination sphere , tetrahydrofuran , crystal structure , protonolysis , anhydrous , pentagonal bipyramidal molecular geometry , stereochemistry , medicinal chemistry , inorganic chemistry , molecule , catalysis , organic chemistry , ion , biochemistry , receptor , solvent , oxide
Treatment of the recently reported potassium salt [K(thf) n ][N(PPh 2 ) 2 ] ( n =1.25, 1.5) with anhydrous yttrium or lanthanide trichlorides in THF leads after crystallization from THF/ n ‐pentane (1:2) to the monosubstituted diphosphanylamide complexes [LnCl 2 {(Ph 2 P) 2 N}(thf) 3 ] (Ln=Y, Sm, Er, Yb). The single‐crystal X‐ray structures of these complexes show that the metal atoms are surrounded by seven ligands in a distorted pentagonal bipyramidal arrangement, in which the chlorine atoms are located in the apical positions. The diphosphanylamide ligand is always η 2 ‐coordinated through the nitrogen atom and one phosphorus atom. Further reaction of [SmCl 2 {(Ph 2 P) 2 N}(thf) 3 ] with K 2 C 8 H 8 or reaction of [LnI(η 8 ‐C 8 H 8 )(thf) 3 ] with [K(thf) n ][N(PPh 2 ) 2 ] in THF gives the corresponding cyclooctatetraene complexes [Ln{(Ph 2 P) 2 N}(η 8 ‐C 8 H 8 )(thf) 2 ] (Ln=La, Sm). The single crystals of these compounds contain enantiomerically pure complexes. Both compounds adopt a four‐legged piano‐stool conformation in the solid state. The structures of the A and the C enantiomers were established by single‐crystal X‐ray diffraction. The more soluble bistrimethylsilyl cyclooctatetraene complex [Y{(Ph 2 P) 2 N}(η 8 ‐1,4‐(Me 3 Si) 2 C 8 H 6 )(thf) 2 ] was obtained by transmetallation of Li 2 [1,4‐(Me 3 Si) 2 C 8 H 6 ] with anhydrous yttrium trichloride in THF followed by the addition of one equivalent of [K(thf) n ][N(PPh 2 ) 2 ]. The 89 Y NMR signal of the complex is split up into a triplet, supporting other observations that the phosphorus atoms are chemically equivalent in solution and, thus, dynamic behavior of the ligand in solution can be anticipated.