The reaction of 2 equiv of the air- stable primary phosphine ( ferrocenylmethyl) phosphine ( PH(2)CH(2)Fc, 1) with [Pd- cod) Cl-2] (Fc) ferrocenyl; cod) 1,5- cyclooctadiene) at 298 K gave the phosphanido-bridged Pd(II) tetramer [ Pd(PH(2)CH(2)Fc) Cl(mu-PHCH(2)Fc)](4) (2), which shows an unprecedented arrangement of four Pd atoms embedded in an eight-membered Pd4P4 ring. An X-ray diffraction study showed that 2 crystallizes in the triclinic space group P (1) over bar with a = 17.607(7) angstrom b = 17.944( 7) angstrom c = 18.792(7) angstrom alpha = 107.120( 12)degrees, beta = 96.344(13)degrees, gamma = 117.087(15)degrees. Each molecule contains four palladium atoms in a distorted square- planar coordination formed by one chlorine and three phosphorus atoms. Two of the latter belong to bridging primary phosphanides and the remaining one is contributed by a terminal PH2CH2Fc ligand. The coordination environments of neighboring metal centers adopt an almost perpendicular mutual orientation. The reaction of 2 equiv of 1 with [Pt(cod)Cl-2] at 323 K yielded the analogous Pt(II) tetramer of formula [Pt(PH(2)CH(2)Fc) Cl(A-PHCH(2)Fc)](4) (3), which was fully characterized by multinuclear and dynamic NMR, IR, and elemental analyses. Single- crystal X-ray diffraction on 3 confirmed the tetranuclear arrangement in the solid state, but orientational disorder of the molecule precludes a more detailed discussion of the structure. Low-temperature NMR experiments in CD2Cl2 showed the presence of two slowly interconnecting conformers. Reaction of 1 and [M(cod) Cl-2] ( M) Pd or Pt) at lower temperatures (273 K for Pd, 295 K for Pt) in dichloromethane allowed the detection in solution of the mononuclear species cis-[M(PH(2)CH(2)Fc)(2)Cl-2] (M) Pd, 4; M) Pt, 5) which, upon heating, transformed into the tetramers 2 and 3, respectively. Solid samples of 4 and 5 could be isolated after workup at low temperature and were characterized by conventional spectroscopic methods.
|Titolo:||Reactivity of (Ferrocenylmethyl)phosphine towards Palladium and Platinum Chlorides. X-Ray Structure of [Pd(PH2CH2Fc)Cl(μ-PHCH2Fc)]4 (Fc = ferrocenyl), a Unique Complex Containing a Pd4P4 Cycle|
|Data di pubblicazione:||2006|
|Digital Object Identifier (DOI):||10.1021/ic060311w|
|Appare nelle tipologie:||1.1 Articolo in rivista|