Structures and Dynamics of Secondary and Tertiary Alkylphosphine Oxides Adsorbed on Silica

Abstract

Abstract The three secondary phosphine oxides [CH 2 =CH(CH 2 ) 4 ] 2 HPO ( 1 ), [CH 2 =CH(CH 2 ) 5 ] 2 HPO ( 2 ), and [CH 2 =CH(CH 2 ) 6 ] 2 HPO ( 3 ), and two diphosphine dioxides, {[CH 2 =CH(CH 2 ) 6 ] 2 PO(CH 2 ) 7 } 2 ( 4 ) and {[CH 2 =CH(CH 2 ) 6 ] 2 PO(CH 2 ) 4 } 2 ( 5 ), incorporating long methylene chains, are described. The single crystal X‐ray structures of 1 , 2 , and 5 have been determined. The phosphine oxides 3 , 4 , and 5 have been adsorbed on silica in submonolayer quantities to give 3 a – 5 a . The 1 H, 13 C, and 31 P solid‐state NMR spectra of polycrystalline 3 – 5 have been analyzed and compared with those of 3 a – 5 a . The changes of the solid‐state NMR characteristics upon adsorption and the surface mobilities of the phosphine oxides are discussed.