Crystal structures of (MeC/sub 5/H/sub 4/)/sub 3/M(L) (M = uranium or cerium; L = quinuclidine or P(OCH/sub 2/)/sub 3/ CEt). Evidence for uranium to phosphorus. pi. -back-bonding

Journal Article · Wed Jun 01 00:00:00 EDT 1988 · Organometallics; (United States)

DOI:https://doi.org/10.1021/om00096a016· OSTI ID:6742774

Brennan, J G; Stults, S D; Andersen, R A; Zalkin, A

The synthesis and X-ray crystal structure of (MeC/sub 5/H/sub 4/)/sub 3/M(L), where M is Ce or U and L is N(CH/sub 2/CH/sub 2/)/sub 3/CH or P(OCH/sub 2/)/sub 3/CEt, are described. Crystals of (MeC/sub 5/H/sub 4/)/sub 3/U(N(CH/sub 2/CH/sub 2/)/sub 3/CH) and (MeC/sub 5/H/sub 4/)/sub 3/Ce(N(CH/sub 2/CH/sub 2/)/sub 3/CH) are triclinic of space group P anti 1 with Z = 2. for the uranium complex, a = 10.604 (4) A, b = 13.552 (6) A, c = 8.333 (4) A, ..cap alpha.. = 100.20 (4)/sup 0/, ..beta.. = 74.78 (4)/sup 0/, and ..gamma.. = 104.13 (4)/sup 0/ at 23/sup 0/C; the calculated density is 1.751 g/cm/sup 3/. For the cerium compound, a = 10.609 (4) A, b = 13.586 (5) A, c = 8.348 (5) A, ..cap alpha.. = 100.15 (4)/sup 0/, ..beta.. = 74.75 (4)/sup 0/, and ..gamma.. = 104.01 (3)/sup 0/ at 23/sup 0/C; the calculated density is 1.451 g/cm/sup 3/. The uranium(III) and cerium(III) atoms are each bonded to three cyclopentadienyl rings; the average U-C and Ce-C distances are 2.82 +/- 0.03 and 2.85 +/- 0.03 A, respectively. The U-N and Ce-N distances are 2.764 (4) and 2.789 (3) A, respectively. Crystals of (MeC/sub 5/H/sub 4/)/sub 3/U(P(OCH/sub 2/)/sub 3/CEt) and (MeC/sub 5/H/sub 4/)/sub 3/Ce(P(OCH/sub 2/)/sub 3/CEt) are orthorhombic of space group P2/sub 1/2/sub 1/2/sub 1/ with Z = 4. The structure of the two isomorphous complexes were determined by single-crystal X-ray diffraction methods. For the uranium complex, a = 13.122 (5) A, b = 16.363 (5) A, c = 10.922 (4) A at 23/sup 0/C; the calculated density is 1.806 g/cm/sup 3/. For the cerium complex, a = 13.163 (7) A, b = 16.443 (7) A, and c = 10.976 (4) A at 23/sup 0/C; the calculated density is 1.509 g/cm/sup 3/. The metal atom is tetrahedrally bound to the three cyclopentadienyl rings and a phosphorus atom. The U-P and Ce-P distances are 2.988 (6) and 3.086 (3) A, respectively; the average U-C and Ce C distances are 2.80 +/- 0.05 and 2.82 +/- 0.03 A, respectively.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6742774
• Journal Information: Organometallics; (United States), Vol. 7:6
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
CERIUM COMPOUNDS
CHEMICAL PREPARATION
CRYSTAL STRUCTURE
ORGANIC COMPOUNDS
PHOSPHORUS COMPOUNDS
URANIUM COMPOUNDS
BOND ANGLE
BOND LENGTHS
CHEMICAL BONDS
EXPERIMENTAL DATA
SPACE GROUPS
X-RAY DIFFRACTION
ACTINIDE COMPOUNDS
COHERENT SCATTERING
DATA
DIFFRACTION
DIMENSIONS
INFORMATION
LENGTH
NUMERICAL DATA
RARE EARTH COMPOUNDS
SCATTERING
SYNTHESIS
400702* - Radiochemistry & Nuclear Chemistry- Properties of Radioactive Materials