Charles H. Van Dyke

Preparation and properties of rhodium(I) complexes of phosphinated poly(methylsiloxanes)

Abstract A series of poly(methylsiloxanes) that contain carbon-functional diphenylphosphine groups were prepared and subsequently treated with RhCl(CO)(PPh 3 ) 2 to produce polymer-attached chlorocarbonylrhodium(I) complexes. The materials are soluble in a variety of organic solvents, and are easily precipitated from solution by the addition of excess methanol. The polymer complex A derived from a phosphinated silicone polymer containing one PPh2 group per 60 siloxy units has a molecular weight of 21000 daltons and contains 0.8% Rh. In accord with its formulation, the polymer shows a ν(CO) at 1970 cm -1 and an ultraviolet absorption at 3625 A. Similar rhodium(I) complexes derived from phosphinated silicones containing one PPh 2 group per 20 (complex B) and 8 (complex C) siloxy units were also investigated. Complexes A and B catalyze the hydroformylation of hex-1-ene at 100°C, 1000 psi CO/H 2 pressure yielding the linear/branched heptaldehyde in a ratio of 0.9 with 95% selectivity and an overall conversion of 97% to products in 3 h. Although the hydroformylation conditions do not lead to depolymerization, both Rh and P are lost from the polymers and the actual catalyst appears to be a free rhodium carbonyl species. Complex C is a less active hydroformylation catalyst (14% aldehyde conversion, normal/branched ratio 1.7) and the polymer undergoes extensive degradation in the reaction.

The interaction of organosilanes with triphenylmethyl tetrafluoroborate

Abstract Under mild conditions, Ph 3 CBF 4 readily fluorinates the SiH bond(s) of trialkylsilanes and dialkylsilanes. The use of this reagent in the successful fluorination of HSiMe 2 CH 2 Fe(CO) 2 Cp suggests that the reaction can be used to fluorinate silicon compounds that possibly would not survive more vigorous fluorination reactions. A convenient preparation of diorganofluorosilanes that have both hydrogen and fluorine bonded to silicon is described.

The preparation and catalytic hydroformylation activity of some halocarbonylrhodium(I) complexes containing phosphinoalkylorganosilicon ligands

The synthesis and properties of a series of trans-halocarbonylrhodium(I) complexes containing the phosphinoalkylorganosilicon ligands Me3SiCH2PPh2, Me3Si(CH2)3PPh2, and PPh2CH2(Me)Si(OSiMe2)3O have been investigated. The complexes could be prepared by an exchange reaction involving RhCl(CO)(PPh3)2 and the organosilicon ligands or in better yields by the reaction of Rh2Cl2(CO)4 with the ligands. Iodorhodium derivatives were obtained as the exclusive products in the latter reaction if a small amount of LiI was present. The catalytic activity of RhCl(CO)(PPh2CH2SiMe3)2 was similar to that of RhCl(CO)(PPh3)2 in the hydroformylation of hex-1-ene at 100°C and 1000 psi pressure of H2/CO. The catalytic properties of the iodo derivatives RhI(CO)L2 [L = Me3SiCH2PPh2, Me3Si(CH2)3PPh2, and PPh2CH2(Me)Si(OSiMe2)3O] varied considerably, with RhI(CO)(PPh2CH2SiMe3)2 producing an unexpectedly low linear/branched aldehyde product ratio.

Some Calorimetric Measurements on Adducts of Organotin Halides with Nitrogen Bases

Considerable interest has developed over the past few years concerning the nature and constitution of complexes of organotin halides. The use of infrared, nuclear magnetic resonance, Mossbauer, and X-ray crystallographic techniques has provided much information about the unique structures and bonding of these complexes. Pyridine was used as the donor ligand in most of the early work with these compounds, however, gradually other ad- ducts which involve more complex ligands have been studied. Surprisingly, little work has been done with the methyl, amino, and other related substituted pyridine series of donor ligands. These systems offer some excellent examples of how steric, electronic, and other fundamental factors influence the formation, stability and structures of the complexes. We have initiated a study of some of these systems and the various structural and stability factors which go along with them. We now report the results of our calorimetric measurements on various organic nitrogen base adducts of (CH3)3SnCl and (CH3)2SnCl2. Bases chosen for study include: pyridine, 2-picoline, 3-picoline, 4-picoline, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 4-cyanopyridine, aniline, and 2,2′dipyridyl

Partially fluorinated derivatives of disiloxane

The synthesis of FSiH2OSiH3 and (FSiH2)2O has been achieved by the reaction of (SiH3)2O with PF5 at low temperatures.