Heterogenizing homogeneous catalysis using molecular self-assembly of longalkane chain phosphines bound to Rh(I) complexes

Long alkane chain hydrocarbons terminated with OH and PPh2 groups, HO-(CH2) (n)-PPh2 (n = 10-12) were self-assembled on inorganic oxide surfaces via ac id-base hydrolysis of surface-anchored [Si]-NEt2 groups with terminal OH mo ieties and subsequently used to covalently anchor Rh(I) complexes. Similar thin films can also be prepared from [Si]-NEt2 and RhCl(1,5-C8H12)[PPh2(CH2 )(n)OH]. The functionalized surfaces were characterized using solid-state N MR, contact angle goniometry, ellipsometry, X-ray photoelectron spectroscop y, and FT-IR. The self-assembled organometallic thin films were found to be highly active in catalyzing hydrogenation of tolan. Surface-bound Rh(I) ca talyst is stable and can be recycled, while the homogeneous analogue decomp oses under similar catalytic reaction conditions.