Structure of bis(tri-tert-butylphosphine)palladium(0)

Abstract

Abstract. [Pd(flzn27P) The molecule is centrosymmetric with Pd located at a center of symmetry. The structure is compared with similar bulky tertiary phosphine-coordinated complexes of zero-valent Pd and Pt.Experimental. A colorless single crystal was obtained by a procedure similar to that described previously (Otsuka, Yoshida, Matsumoto & Nakatsu, 1976). A crystal with approximate dimensions of 0.1 x 0.1 x 0.1 mm was mounted in a glass capillary. All measurements were made on a Rigaku AFC5R diffractometer with graphite-monochromated Mo Ka radiation and a 12 kW rotating anode generator. Cell constants were obtained from a least-squares refinement using 25 reflections in the range 8 < 20 < 26 °. The data were collected at a temperature of 296 _ 1 K using the w-2O-scan technique to a maximum 20 value of 55.0 ° (sin0/A = 0.63 A-~) corresponding to the range 0___h_<18, 0_<k___17, -12_l___12. Scans of (1.10 + 0.14tan0) ° were made at a speed of 8.0 ° min-~ (in oJ). The weak reflections [I < 10.00"(/)] were rescanned (maximum of two rescans) and the counts were accumulated to assure good counting statistics. Stationary background counts were recorded on each side of the reflection. The ratio of peak counting time to background counting time was 2:1. Of the 3181 reflections collected, 2995 were unique (Rin t = 0.1153 based on F2). Since intensities of three standard reflections measured after very 150 reflections indicated -5.5% decline, a decay correction was made. An empirical absorption correction, based on azimuthal scans of several reflections, was applied with transmission factors ranging from 0.9457 to 1.00. The data were corrected for Lorentz and polarization effects.The structure was solved by direct methods, MITHRIL (Gilmore, 1984) followed by DIRDIF (Beurskens, 1984). The non-H atoms were refined anisotropically. H atoms were included in the calcu-

One‐Electron Oxidation of [M(PtBu3)2] (M=Pd, Pt): Isolation of Monomeric [Pd(PtBu3)2]+ and Redox‐Promoted C−H Bond Cyclometalation

“…Complex 2 a crystallizes in the high‐symmetry cubic space group Pa with the palladium atom on a center of inversion (Figure ). In comparison to 1 a , the Pd−P bond length is significantly elongated, from 2.285(3) to 2.3469(6) Å (Δ(Pd−P)=+0.062(4) Å); the P‐Pd‐P angles in both cases are symmetry enforced at 180° . To the best of our knowledge, this is the first example of an unsupported two‐coordinate Pd I complex.…”

Cationic Two-Coordinate Complexes of Pd(I) and Pt(I) Have Longer Metal-Ligand Bonds Than Their Neutral Counterparts

“…5 Å , ruling out coordination of these moieties to the metal center. The M-P distances (2.3466(5) Å in 3 and 2.3362(6) Å in 4) are considerably longer than the M-P distances in the neutral 1 (2.285(3) Å ) 45 and 2 (2.249(3) Å ). 46 The Pd-P distance in 3 in the present work is indistinguishable from the Pd-P distance (2.3470(6) Å ) in Chaplin's [( t Bu 3 P) 2 Pd][PF 6 ].…”

New insights into the palladium‐catalysed synthesis of δ‐lactones from 1,3‐dienes and carbon dioxide

“…In contrast, the ligand Xlg, which has a nearly identical sterical demand to lla, forms a complex with a P-Pd-P angle of 177".2' The latter observation was confirmed independently by Otsuka et u L .~, More recently, a 1'-Pd-P angle of 180" has been reported for the corresponding complex of llk. 26 Obviously, the P-Pd-P angle in the solid-state structures of complexes R,P-Pd-PR, depends considerably on the ligand structure and we were interested to see whether this ligand-structure relationship correlates in some respect with the observed ligand effects on the catalytic activity. This consideration is supported from the theoretical and experimental work by Hofmann, who has demonstrated the importance of the P-M-P angle for binding of 01efins~~ and heterocumulenes2R to coordinatively unsaturated complexes of the nickel triad metals in the zero oxidation state.…”