Shashank Mishra, L. G. H. Pfalzgraf, E. Jeanneau
Jan 2, 2007
Citations
0
Influential Citations
11
Citations
Journal
Polyhedron
Abstract
The reaction between BaI 2 · 2H 2 O and NaHFIP [HFIP = OCH(CF 3 ) 2 ] in a 1:1 stoichiometry gave the heterometallic compound NaBaI 2 (HFIP)(H 2 O)(THF) 0.5 ( 1 ). Attempts to recrystallize 1 in the presence of N- or O-donor ligands lead to redistribution reactions. Barium iodide adducts such as BaI 2 (DME) 3 ( 2 ), trans -BaI 2 (DME)(triglyme) ( 3 ) and cis -BaI 2 (DME)(tetraglyme) ( 4 ) were isolated with DME as solvent. A similar behavior was observed for the reaction between BaI 2 · 2H 2 O and NaTFA (TFA = O 2 CCF 3 ) in a 1:1 stoichiometry in THF, and [Ba(tetraglyme) 2 ]I 2 · C 7 H 8 ( 6 ) was isolated in the presence of excess tetraglyme. All compounds have been characterized by elemental analysis, IR and 1 H NMR as well as single crystal X-ray studies for 3 , 4 and 6 . Compounds 3 and 4 are covalent adducts with eight- and nine-coordinate barium, respectively. Compound 6 is an ionic compound where two tetraglyme ligands wrap the 10-coordinate barium cation in a helical fashion. The presence of DME actually allows the coordination number of barium in the mixed-ligand adducts 3 and 4 to be tuned. The average Ba–O bond lengths (2.80 for 3 to 2.87 A for 6 ) reflect the coordination number of the metal. The same observation is valid for the average Ba–I bond distance, 3.442 for 3 vs. 3.536 A for 4 .