A Neutral Geminal Tin/Phosphorus Frustrated Lewis Pair

Abstract

The geminal frustrated Lewis pair (FLP) (F 5 C 2 ) 3 SnCH 2 P(tBu) 2 (2)w as prepared by reacting (F 5 C 2 ) 3 SnCl with LiCH 2 P(tBu) 2 .I ti sn eutral and contains an extremely electronegatively substituted, but relatively soft (hard-soft acid-base,H SAB) acidic tin function. Its FLPtype reactivity was proven by reaction with av ariety of small molecules (CO 2 ,S O 2 ,C S 2 ,P hNCO,H Cl, (Ph 3 P)AuCl). However,itshows no reaction in H/D scrambling experiments with H 2 /D 2 mixtures and binds CO 2 reversibly,aswas observed by VT-NMR spectroscopy. Compound 2 and all its adducts were completely characterized by means of multinuclear NMR spectroscopy, elemental analysis,and X-ray diffraction experiments.

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

“…The S−O bond lengths in 2 between 1.604(5) and 1.615(4) Å are unusually long: more than 0.1 Å longer than in gaseous SO ( r e =1.481(1) Å, determined by high‐resolution IR spectroscopy), gaseous SO 2 ( r e =1.430793(4) Å determined by gas electron diffraction), and also longer than the endocyclic S−O bond in the corresponding adduct 1 ⋅SO 2 (1.524(1) Å) . The latter correlates with significantly shorter Sn−O (2.122(4)–2.131(4) Å) and P−S (2.082(2)–2.089(2) Å) bonds in 2 compared to 1 ⋅SO 2 at 2.239(1) and 2.331(1) Å, respectively …”

“…[8] Despite these activities in SO chemistry, the trapping of a complete S-O unit by a main group metal system has not been achieved so far, but occurred when we reacted our recently reported Sn/P FLP (F 5 C 2 ) 3 SnCH 2 P(tBu) 2 (1) with Nsulfinylaniline PhNSO. [9] FLP 1 is the heaviest congener of a series of tetrel-based FLP systems (F 5 C 2 ) 3 ECH 2 P(tBu) 2 (E = Si, Ge, Sn (1)), with large differences in their reactivity. [9,10] Due to its relatively soft Lewis acid binding site, the Sn/P FLP 1 is, for instance, capable of reversibly binding CO 2 .…”

“…[9] FLP 1 is the heaviest congener of a series of tetrel-based FLP systems (F 5 C 2 ) 3 ECH 2 P(tBu) 2 (E = Si, Ge, Sn (1)), with large differences in their reactivity. [9,10] Due to its relatively soft Lewis acid binding site, the Sn/P FLP 1 is, for instance, capable of reversibly binding CO 2 . [9] Its affinity towards oxygen atoms is obviously less pronounced than in systems with much harder acid sites like those based on boron, aluminum, or silicon.…”

Ein Schwefelmonoxid‐Addukt eines frustrierten Sn/P‐Lewis‐Paares

“…Trotz dieser Aktivitäten in der SO‐Chemie ist es bisher nicht gelungen, eine intakte S‐O‐Einheit durch ein Hauptgruppenmetallsystem einzufangen. Dies erreichten wir nun, als wir unser kürzlich vorgestelltes Sn/P‐FLP (F 5 C 2 ) 3 SnCH 2 P( t Bu) 2 ( 1 ) mit N ‐Sulfinylanilin, PhNSO, umsetzten . FLP 1 ist das schwerste Homologe einer Reihe Tetrel‐basierter FLP‐Systeme (F 5 C 2 ) 3 ECH 2 P( t Bu) 2 (E=Si, Ge, Sn ( 1 )), die große Differenzen in ihrer Reaktivität aufweisen .…”

“…Aufgrund seiner relativ weichen Lewis‐Säurebindungsstelle ist das Sn/P‐FLP 1 z. B. in der Lage, CO 2 reversibel zu binden . Seine Affinität zu Sauerstoffatomen ist offensichtlich weniger ausgeprägt als in Systemen mit deutlich härteren Säurefunktionen wie solchen auf Bor‐, Aluminium‐ oder Silicium‐Basis.…”