6956 process, slow on the pmr time scale, has also been established for mixtures of (n-methallyl)Pd(SDBM) and (a-allyl)Pd(DBM). These conclusions are sustained by comparison with studies of other asymmetric T allyl-Pd systems. I Acknowledgments. This work was supported by a grant from the donors of the Petroleum Research Fund, administered by the American Chemical Society. We 488,
wish to thank Miss Janet Sadownick for experimental assistance, Dr. K. Wiithrich of the Bell Telephone Laboratories for obtaining the 220-MHz pmr spectra, Drs. M. C. Woods, R . Grubbs, and Mr. Howard Heitner for valuable discussions, and Dr. B. G. Segal, Miss V. Parmakovich, and Mr. I. Miura for technical assistance. S. J. L. expresses his appreciation t o the Alfred P. Sloan Foundation for a Research Fellowship (1968-1970).
Crystal and Molecular Structure of Monothiodibenzoylmethanato-n-syn-1-tert-butyl-2-methallylpalladium( I1) Stephen J. Lippard" and Sheila M. Morehouse'
Contribution from the Department of Chemistry, Columbia University, New York, New York 10027. Received December 17, 1971 Abstract: The structure of the title compound, 1,2,3-h3-[(tert-C4Hs)CHC(CH3)CH2]Pd(C~H~COCHCSC~H~), has been determined in a single-crystal X-ray diffraction study. The tert-butyl substitbent syn to the methyl group in the r-allyl ligand is trans to the sulfur atom of theochelating monothiodibenzoylmethane anion (SDBM). The Pd-S and Pd-0 distances are 2.297 (3) and 2.047 (7) A, respectively, and the S-Pd-0 angle is 94.4 (2)". The trans influenceoof the sulfur atom m,ay be judged by the nonequivalence ofathebond lengths Pd-C(1) (trans to sulfur), 2.18 (1) A, Pd-C(2),02.141 (9) A, and Pd-C(3) (cis to sulfur), 2.05 (1) A. Both the C(l)-C(2) and C(2)-C(3) bond lengths are 1.39 (1) A. The geometry of the SDBM ligand is comparable to that found in the r-methallyl analog. The complex crystallizes in the triclinic system, space group Pi,with unit cell dimensions of u = 12.251 (6) A, b = 11.524 (9) A,c = 8.514 (5) A, Q: = 112.89 ( 5 ) " , p = 107.61 ( 2 ) O , y = 90.31 (5)", 2 = 2. From 2363 independent observed reflections collected by diffractometer. the structure was solved and refined to a final value for the discrepancy index R1 = 0.073.
T
he solid-state structure of monothiodibenzoylmethanato-7i.-methallylpalladium(II), I, has been
H
A H
H
type (vally1)PdXY. In conjunction with our study of the solution behavior of (n-allyl)Pd(SDBM) complexes,* a number of compounds of this kind were synthesized, for which structures IIa-d are possible. As discussed previously,8 structure IIa predominates at Rz
H
R2
I
described previously, and several other structural studies of (7r-ally1)PdXY complexes containing a symmetric n-allylic group bonded t o a palladium atom in a nonsymmetric ligand environment have been carried out. 3--6 The geometries of various asymmetrically substituted A-allyl palladium complexes have also been but there has not yet been a structural investigation of an asymmetrically substituted T-allyl group coordinated t o palladium in a compound of the
IIa, syn/trans
IIb, anti/trans
(1) National Institutes of Health Predoctoral Fellow, 1967-1970.
(2) S. J. Lippard and S. M. Morehouse, J . Amer. Chem. SOC.,91, 2504 (1969). (3) R . Mason and D. R. Russell, Chem. Commun., 26 (1966). (4) A. E. Smith, Acta Crystallogr., Sect. A , 25, S161 (1969). ( 5 ) (a) R. Mason, G. E.Robertson, P. 0. Whimp, and D. A. White, Chem. Commun., 1655 (1968); (b) R. Mason and P. 0. Whimp, J . Chem. Soc. A , 2709 (1969).
low temperatures in solution, a conclusion facilitated by the present solid-state structural determination. It
(6) For references see Table VI, ref 2. (7) I
