We have investigated the role of conjugation in attachment of multifunctional organic molecules to the Si(001) surface. The model molecules we have chosen are acrylonitrile (CH2=CHCdropN) and allyl cyanide (CH2=CHCH(2)CdropN) due to the electron-withdrawing nature of the cyano, group. X-ray photoelectron spectroscopy shows that significant difference in primary binding configuration exists. Infrared spectroscopy establishes that acrylonitrile attaches to the Si(001) surface primarily through a mechanism involving the cyano group, leading to a novel keteneimine structure that is evidenced by characteristic strong infrared absorbance at 1985 cm(-1). Allyl cyanide adsorbs in a way that principally utilizes the vinyl portion of the molecule, leading mainly to alkane infrared absorbance below 3000 cm(-1). These results show that conjugation can play an important role in controlling product distribution when attaching multifunctional organic molecules to the Si(001) surface. (C) 2002 Published by Elsevier Science B.V.