The reactivity of the geminal frustrated Lewis pair (FLP) (F5C2)3SnCH2P(tBu)2 (1) was explored by reacting it with a variety of small molecules (PhOCN, PhNCS, PhCCH, tBuCCH, H3CC(O)CH=CH2, Ph[C(O)]2Ph, PhN=NPh and Me3SiCHN2), featuring polar or non‐polar multiple bonds and/or represent α,β‐unsaturated systems. While most adducts are formed readily, the binding of azobenzene requires UV‐induced photoisomerization, which results in the highly selective complexation of cis‐azobenzene. In the case of benzil, the reaction does not lead to the expected 1,2‐ or 1,4‐addition products, but to the non‐stereoselective (tBu)2PCH2‐transfer to a prochiral keto function of benzil. All adducts of 1 were characterised by means of multinuclear NMR spectroscopy, elemental analyses and X‐ray diffraction experiments.

The geminal frustrated Lewis pair (F5C2)3SnCH2P(tBu)2 (1) reacted with N‐sulfinylaniline PhNSO to afford the first sulfur monoxide adduct of a main group metal, (F5C2)3SnCH2P(tBu)2⋅SO (2), which contains a SnCPSO ring. The second product is a phenylnitrene adduct of 1. The surprising stability of 2 was compared with the stabilities of the so far inaccessible O2 and S2 adducts of 1. Attempts to prepare these from 1 and the elemental chalcogens (O2, S8, Se∞, Te∞) led to four‐membered SnCPE ring systems. Quantum‐chemical investigations of 2 demonstrate the bond polarity of the SO unit to stabilize 2.

Die Reaktion des geminalen frustrierten Lewis‐Paares (F5C2)3SnCH2P(tBu)2 (1) mit N‐Sulfinylanilin PhNSO ergab das erste Schwefelmonoxid‐Addukt eines Hauptgruppenmetalls (F5C2)3SnCH2P(tBu)2⋅SO (2). Es enthält einen SnCPSO‐Ring. Das zweite Produkt ist ein Phenylnitren‐Addukt von 1. Die überraschende Stabilität von 2 wurde mit denen der bisher unzugänglichen O2‐ und S2‐Addukte von 1 verglichen. Versuche, diese aus 1 und den elementaren Chalkogenen (O2, S8, Se∞, Te∞) herzustellen, führten zu viergliedrigen SnCPE‐Ringsystemen. Quantenchemische Untersuchungen von 2 zeigen den Beitrag der Bindungspolarität der SO‐Einheit zur Stabilisierung von 2.