DIVALENT LANTHANIDE CHEMISTRY; BIS (PENTAMETHYLCYCLOPENTADIENYL) EUROPIUM(II) AND YTTERBIUM(II) DERIVATIVES: CRYSTAL STRUCTURE OF BIS(PENTAMETHYLCYCLOPENTADIENYL) YTTERBIUM (II)TETRAHYDROFURAN HEMI (TOLUENE) AT 176K
Red, paramagnetic ({mu}{sub B} = 7.99 B.M., 5-50K) bis(pentamethylcyclopentadienyl) europium (II)(tetrahydrofuran)(diethylether), (Me{sub 5}C{sub 5}){sub 2}Eu(THF)(Et{sub 2}O) is isolated from reaction of three molar equivalents of sodium pentamethylcyclopentadienide and europium trichloride in refluxing tetrahydrofuran, after crystallization from diethyl ether. The monotetrahydrofuran complex, (Me{sub 5}C{sub 5}){sub 2}Eu(THF), may be isolated by use of toluene rather than diethyl ether as the crystallization solvent. Red, diamagnetic bis(pentamethylcyclopentadienyl)ytterbium(II)(tetrahydrofuran) is isolated from the reaction of ytterbium dichloride and sodium pentamethylcyclopentadienide in refluxing tetrahydrofuran. The diethyl ether complex, (Me{sub 5}C{sub 5}){sub 2}Yb(OEt{sub 2}), may be isolated by crystallization of the tetrahydrofuran complex from diethylether, The hemi-toluene complex, (Me{sub 5}C{sub 5}){sub 2} Yb(THF) {center_dot} 1/2 toluene, can be isolated by recrystallization of the tetrahydrofuran complex from toluene. As these divalent metallocenes are the first hydrocarbon-soluble lanthanide derivatives to be isolated we have examined the latter complex by X-ray crystallography. Crystals of (Me{sub 5}C{sub 5}){sub 2}Yb(OC{sub 4}H{sub 8}) {center_dot} 1/2(C{sub 6}H{sub 5}cH{sub 3}) crystalline in the monoclinic system, P2{sub 1}/n, with a = 11.358(8) {angstrom}, b = 21.756(19) {angstrom}, c = 10.691(7) {angstrom}, and {beta} = 101.84(5){sup o} at 176K. For Z = 4 the calculated density is 1.37 g cm{sup -3}. The ytterbium atom is coordinated to the oxygen atom of a tetrahydrofuran molecule and to two pentamethyl cyclopentadienyl rings. The molecule has approximate c{sub 2} symmetry about the Yb-0 bond. The Yb-0 distance is 2.41 {angstrom}, the Yb-C distances average 2.66 {angstrom}, and the Yb-Cp (centroid) distances average 2.37 {angstrom}. The Me{sub 5}C{sub 5} rings are in a staggered configuration with respect to each other. The methyl groups of the Me{sub 5}C{sub 5} groups are displaced by .03 to .21 {angstrom} from the planes of the five-membered rings away from the ytterbium atom. The toluene molecule is not coordinated to the complex and is on a center of symmetry in a disordered configuration. The 3466 data with F{sup 2} > 3{sigma} refined by full matrix least-squares to a conventional R factor of 0.036.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- Materials Sciences Division
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 1030602
- Report Number(s):
- LBL-10490; INOCAJ; TRN: US201124%%349
- Journal Information:
- Inorganic Chemistry, Vol. 19, Issue 10; ISSN 0020-1669
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
A CENTERS
ATOMS
CHEMISTRY
CONFIGURATION
CRYSTAL STRUCTURE
CRYSTALLIZATION
CRYSTALLOGRAPHY
ETHYL ETHER
EUROPIUM
OXYGEN
R FACTORS
RARE EARTHS
RECRYSTALLIZATION
SODIUM
SYMMETRY
TETRAHYDROFURAN
TOLUENE
YTTERBIUM