From the reactions of (CF 3) 2CHOH (hfip.H), (CF 3)Me 2COH (tftb.H) and (CF 3) 2MeCOH (hftb.H) with Y{N(SiMe 3) 2} 3 in benzene, thf or diethyl ether as solvents the following compounds have been isolated and characterized by elemental analysis, IR, NMR and mass spectroscopy : [Y{OCMe 2(CF 3)} 3] n ( 1), [Y{OCMe 2(CF 3)} 3(thf) 2.5] ( 2), [Y{OCMe(CF 3) 2} 3] n , ( 3), [Y{OCMe(CF 3) 2} 3(NH 3) 0.5] ( 4), [Y{OCMe(CF 3) 2} 3(NH 3) 3] ( 5), [Y{OCMe(CF 3) 2} 3(thf) 3] ( 6), [Y{OCMe(CF 3) 2} 3(Et 2O) 0.33] ( 7), [Y{OCMe(CF 3) 2} 3 (diglyme)] ( 8), [Y{OCMe(CF 3) 2} 3(Bu tOH) 3] ( 9), [Y{OCH(CF 3) 2} 3(NH 3) 0.5] ( 10) and [Y{OCH(CF 3) 2} 3(thf) 3] ( 11). Sublimation in vacuo is usually accompanied by loss of some of the neutral ligand, but 8 sublimes intact. Single-crystal X-ray structures of 6 and 8 showed that these mononuclear octahedral complexes have the facial configuration. 89Y NMR chemical shifts were obtained for 2, δ 93.66; 6, 66.44; 8, 78.63; and 11, 82.78.