Sigma-aromaticity and sigma-antiaromaticity in saturated inorganic rings.
The magnetic properties of a series of inorganic saturated rings, (SiH2)n, (GeH2)n, (NH)n, (PH)n, (AsH)n, On, Sn, and Sen (n = 3-6), exhibit zigzag behavior with ring size resembling that of aromatic and antiaromatic Hückel pi-systems and (CH2)n rings. Computed GIAO-SCF nucleus-independent chemical shifts (NICS) and localized (LMO) NICS analysis indicate that the sigma-ring electrons are chiefly responsible for this zigzag behavior. This evidence for sigma-aromaticity is further supported by theoretical strain energy (TSE). The Hückel 4n + 2/4n aromaticity/antiaromaticity rule for pi-electron systems applies well to the smaller saturated rings.
Li
Zhen-Hua
ZH
Center for Theoretical Chemical Physics, Laboratory of Molecular Catalysis & Innovative Material Department of Chemistry, Fudan University, Shanghai 200433, China.
Moran
Damian
D
Fan
Kang-Nian
KN
Schleyer
Paul von Ragué
Pv