An Adduct of Sulfur Monoxide to a Frustrated Sn/P Lewis Pair

The geminal frustrated Lewis pair (F5C2)(3)SnCH2P(tBu)(2)(1) reacted with N-sulfinylaniline PhNSO to afford the first sulfur monoxide adduct of a main group metal, (F5C2)(3)SnCH2P(tBu)(2).SO (2), which contains a SnCPSO ring. The second product is a phenylnitrene adduct of1. The surprising stability of2was compared with the stabilities of the so far inaccessible O(2)and S(2)adducts of1. Attempts to prepare these from1and the elemental chalcogens (O-2, S-8, Se-infinity, Te-infinity) led to four-membered SnCPE ring systems. Quantum-chemical investigations of2demonstrate the bond polarity of the SO unit to stabilize2.