Volatile Donor-Functionalized Alkoxy Derivatives of Lutetium and Their Structural Characterization(1)

Reaction of beta-functionalized alcohols of type HOCR(2)CH(2)do (1a, do = OMe, R = Me; 1b, do = OMe, R = Et; 1c, do = NMe(2), R = Me) with Ln[N(SiMe(3))(3)](3) yields highly volatile (sublimation < 100 degrees C/10(-)(3) Torr) and n-hexane-soluble homoleptic alkoxide complexes [Ln(OCR(2)CH(2)do)(3)] (2a-d, Ln = Y, Lu). A single-crystal X-ray diffraction study of Lu(OCMe(2)CH(2)OMe)(3) (2a) revealed a dinuclear complex with significantly polarized metal centers originating from asymmetrical ligand association (triple-bridging). Unintentional employment of "water-contaminated" alcohol 1a resulted in the formation of n-hexane-soluble 3 exhibiting a substantially increased sublimation temperature (>220 degrees C/10(-)(3) Torr). Crystallization of 3 affords single crystals 3a featuring the tetranuclear constitution Lu(4)(O)(OH)(OCMe(2)CH(2)OMe)(9). 3a represents an unprecedented lanthanide alkoxide comprising both oxo and hydroxo units in addition to alkoxide ligands. The Lu(4)O(15)-core structure of 3a adopts a "butterfly" rather than a tetrahedral geometry. Potentially tridentate alcohols HOCtBu(CH(2)OiPr)(2) (4) and HOCiPr(2)CH(2)OCH(2)OMe (5) afford alkoxide complexes "Nd(OR)(3)" (6, 7) of reduced volatility. 2a crystallizes from n-hexane at ambient temperature in space group P2(1)/n with a = 13.510(1) Å, b = 15.130(1) Å, c = 38.953(4) Å, beta = 93.11(1) degrees, V = 7950 Å(3), and Z = 8. Least-squares refinement of the model based on 11 747 reflections (I > 2.0 sigma(I)) converged to a final R = 3.5%. 3a crystallizes from n-hexane at -35 degrees C in space group Cc with a = 21.63(1) Å, b = 14.49(3) Å, c = 21.04(2) Å, beta = 109.70(3) degrees, V = 6209 Å(3), and Z = 4. Least-squares refinement of the model based on 6057 reflections (I > 3.0 sigma(I)) converged to a final R = 6.7%.