Synthesis, immobilization, and solid-state NMR of new phosphine linkers with long alkyl chains

Monodentate and chelating phosphines with long alkyl chains, incorporating ethoxy- or chlorosilane functions for immobilizations, have been synthesized and fully characterized. The new compounds (EtO)3Si(CH2)xPPh2, Cl2Si(CH2CH2PPh2)2, and (EtO)2Si[(CH2)xPPh2]2 (x = 7, 11) could be prepared in high yields from cheap starting materials, and they have been characterized by multinuclear NMR spectroscopy and X-ray crystallography. The phosphines have been immobilized on silica in a well-defined manner, and the modified silicas have been studied by 31P and 29Si solid-state NMR of the dry materials and of the suspensions.