(Hexafluoroacetylacetonato-O,O')(1-hydroxy-2,2,6,6-tetramethylpiperidinato-O,N)palladium(II), [Pd(C5HF6O2)(C9H18NO)], a metal complex containing a reduced nitroxylradical

Abstract

[ PtC12(C6 H 13N)(CsH 11P)] The shortest intermolecular contact [3.46 (2)A], observed between N and Cl(2)[~+x, ~--y, - z ] , is probably due to an N - H . . . C 1 hydrogen bond. The packing arrangement is shown in Fig. 3. Thanks are due to Dr G. Consiglio (ETH, Zfirich) who kindly prepared the compound. The drawings were made by Mr M. Viola. References AMBUEHL, J., PREGOSIN, P. S., VENANZI, L. M., CONSIGLIO, G., BACHECHI, F. ~ ZAMBONELLI, L. (1979). J. Organomet. Chem. Fig. 3. Packing arrangement of the molecules viewed down a. It can be observed that the conformation of the unsubstituted pyrrolidine ring in (II) may be considered intermediate between the conformation of the ring in (IV) and that in (III), perhaps closer to the confor- mation in (IV) which has an envelope-like form with C(4) at the flap. Therefore the five structures seem to represent five phases of the pseudorotation of the pyrrolidine ring in the sequence (IV)--,(II)--,(III)--, (V)-,(I) or, to stress the influence of the methyl sub- stituents, (IV),-- (II)-,(III)--,(V) ~(I). BACHECHI, F., MURA, P. & ZAMBONELLI, L. (1980). Acta Cryst. B36, 2604-2608. BACHECHI, F., ZAMBONELLI, L. & MARCOTRIGIANO, G. (1977). J. Cryst. MoL Struct. 7, 11-20. CERRINI, S. & SPAGNA, R. (1977). 4th Eur. Crystallogr. Meet., Oxford. Abstracts, p. 7. CHATT, J. & VENANZI, L. M. (1955). J. Chem. So¢. pp. 3858-3864. CO'rTIN, H. (1966). Bull. Soe. Ch#n. Fr. p. 2731. International Tables for X-ray Crystallography (1974). Vol. 1V, Tables 2.2B and 2.3.1 Birmingham: Kynoch Press. (Present distributor D. Reidel, Dordrecht.) MCCANDLISH, L. E., STOUT, G. H. & ANDREWS, L. C. (1975). Aeta Cryst. A31, 245-249. NORTH, A. C. T., PHILLIPS, D. C. & MATHEWS, F. S. (1968). Acta Cryst. A24, 351-359. SPAGNA, R. & ZAMBONELLI, L. (1971). J. Chem. Soc. A, pp. Acta Cryst. (1985). C41, 838-840 (Hexafluoroacetylacetonato-O,O')(l-hydroxy-2,2,6,6-tetramethylpiperidinato- O,N)palladium(II), [Pd(C5 HF602) (C9H lsN O)], a Metal Complex Containing a Reduced Nitroxyl Radical BY LEIGH C. PORTER AND ROBERT J. DOEDENS* Department of Chemistry, University o f California, Irvine, California 92717, USA (Received 28 September 1984; accepted 10 December 1984) M r=469.7, monoclinic, P21/n, a= b=20.511(8), c=11.655(3)A, t= V = 1812 (1) A 3, Z = 4, Dx= 1.722 Mg m -3, 2(Mo Kct) = 0,71073 A, /t = 1.08 mm -1, F(000) = 936, T = 297 K, final R = 0.042 for 2498 observed reflections. The Pd atom is bound to a chelating hexafluoroacetylacetonato ligand and to a reduced nitroxyl radical coordinated in an r/2 fashion through its N and O atoms. Principal bond distances include P d - O ( F 6 a c a c ) = 2.058 (4), 2.078 (4), P d - O(nitroxyl) = 2.009 (4), P d - N = 1.985 (4), N - O = 1.346 (5) A. Abstract. * To whom correspondence should be addressed. Introduction. The title compound was prepared in the course of exploratory studies of the reactions of stable nitroxyl radicals with transition-metal complexes con- taining a strongly Lewis-acidic metal center. Previous studies in this series have yielded examples of various types of interactions of the nitroxyl group, including metal coordination of the nitroxyl radical through O (Dickman & Doedens, 1981; Porter, Dickman & Doedens, 1983; Porter & Doedens, 1985), bidentate N,O binding of the reduced radical (Dickman & Doedens, 1982), hydrogen bonding to coordinated water (Dickman & Doedens, 1983), and formation of a co-crystallized solid with no specific interactions involv- ing the nitroxyl group (Porter & Doedens, 1984). We © 1985 International Union of Crystallography