Inorganic Chemistry, Vol.35, No.1, 40-45, 1996
Synthesis, X-Ray Crystal-Structure Determination, and NMR Spectroscopic Investigation of 2 Homoleptic 4-Coordinate Lanthanide Complexes - Trivalent ((T)Bu(2)P(2))(2)La((Mu-P(T)Bu(2))(2)Li(THF)) and Divalent Yb((Mu-P(T)Bu(2))(2)Li(THF))(2)
La(OSO2CF3)(3) reacts with 4 equiv of LiP(t)Bu(2) in tetrahydrofuran to give dark red ((t)Bu(2)P)(2)La[(mu-P(t)Bu(2))(2)Li(thf)](2) (1). Yb(OSO2CF3)(3) reacts with LiP(t)Bu(2) in tetrahydrofuran in a 1:5 ratio to produce Yb[(mu-P(t)Bu(2))(2)Li(thf)](2) (2) and 1/2 an equiv of (t)Bu(2)P-P(t)Bu(2). Both 1 and 2 crystallize in the monoclinic space group P2(1)/c. Crystal data for 1 at 214 K : a = 11.562 (1) Angstrom, b = 15.914 (1) Angstrom, c = 25.373 (3) Angstrom, beta = 92.40 (1)degrees; V = 4664.5 Angstrom(3); Z = 4; D-calcd = 1.137 g cm(-3); R(F) = 2.61%. Crystal data for 2 at 217 K : a = 21.641 (2) Angstrom, b = 12.189 (1) Angstrom, c = 20.485 (2) Angstrom, beta = 109.01 (1)degrees; V = 5108.9 Angstrom(3); Z = 4; D-calcd = 1.185 g cm(-3); R(F) = 2.80%. The molecular structures of 1 and 2 show the four-coordinate lanthanide atoms in distorted tetrahedral environments. These complexes are the first representatives of the lanthanide elements surrounded by four only-phosphorus-containing substituents. The main features of the crystal structure of 1 are the shortest La-P distances (2.857(1) and 2.861(1) Angstrom) reported so far and a three-coordinate lithium cation. The molecular structure of 2 represents a divalent his "ate" complex with two three-coordinate lithium cations. Complex 2 shows photoluminescent properties. VT NMR spectra (Li-7 and P-31) are reported for 1 and 2.