Dry synthesis of triple cumulative double bonds (C=C=C=N) on Si(111)-7 x 7 surfaces.
The interactions of cyanoacetylene and diacetylene with a Si(111)-7 x 7 surface have been studied as model systems to mechanistically understand the chemical binding of unsaturated organic molecules to diradical-like silicon dangling bonds. Vibrational studies show that cyanoacetylene mainly binds to the surface through a diradical reaction involving both cyano and C[triple bond]C groups with an adjacent adatom-rest atom pair at 110 K, resulting in an intermediate containing triple cumulative double bonds (C=C=C=N). On the other hand, diacetylene was shown to the covalently attached to Si(111)-7 x 7 only through one of its C[triple bond]C groups, forming an enynic-like structure with a C=C-C[triple bond]C skeleton. These chemisorbed species containing triple cumulative double bonds (C=C=C=N) and C=C-C[triple bond]C may be employed as precursors (or templates) for further construction of bilayer organic films on the semiconductor surfaces.
Huang
Hai Gou
HG
Department of Chemistry, National University of Singapore, 10 Kent Ridge, Singapore 119260.
Xiang
Chao Li
CL
Ning
Yue Sheng
YS
Huang
Jing Yan
JY
Ang
Siau Gek
SG
Xu
Guo Qin
GQ