Ein neutrales geminales frustriertes Zinn/Phosphor‐Lewis‐Paar

Abstract

Das geminale frustrierte Lewis-Paar (FLP) (F 5 C 2 ) 3 SnCH 2 P(tBu) 2 (2)w urdem ittels der Reaktion von (F 5 C 2 ) 3 SnCl mit LiCH 2 P(tBu) 2 hergestellt. Es ist ungeladen und enthält eine extrem elektronegativ substituierte,a ber relativ weiche (HSAB) Zinn-Säurefunktion. Seine FLP-artige Reaktivitätz eigte es in Reaktionen mit einer Vielzahl kleiner Moleküle (CO 2 ,S O 2 ,C S 2 ,P hNCO,H Cl, (Ph 3 P)AuCl);i n H/D-Austauschexperimenten mit H 2 /D 2 -Gemischen ist es jedochunreaktiv.Esbindet reversibel CO 2 ,was mit VT-NMR-Spektroskopie nachverfolgt wurde.V erbindung 2 und alle ihre Addukte wurden mittels Mehrkern-NMR-Spektroskopie,E lementaranalyse und Rçntgenbeugungsexperimenten vollständig charakterisiert.

Exploring the Reactivity of a Frustrated Sn/P Lewis Pair: The Highly Selective Complexation of the cis‐Azobenzene Photoisomer

“…Less surprisingly, no addition to the C−N but to the C−S bond was found, when reacting 1 with the heterocumulene homologue phenyl isothiocyanate PhNCS by forming adduct 5 in 79 % yield. The molecular structure of 5 reveals an envelope‐like CSSnCP‐heterocycle (Figure 5) and a C−S bond, which are well comparable to the related CS 2 adduct, and agrees well with expectations from the HSAB concept [9a, 20] . Compared to the corresponding PhOCN adduct 4 , compound 5 has a slightly widened Sn(1)‐C(7)‐P(1) angle of 117.2(1)°, close to that of the related CS 2 adduct (118.4(1)° [9a] ).…”

“…The molecular structure of 5 reveals an envelope‐like CSSnCP‐heterocycle (Figure 5) and a C−S bond, which are well comparable to the related CS 2 adduct, and agrees well with expectations from the HSAB concept [9a, 20] . Compared to the corresponding PhOCN adduct 4 , compound 5 has a slightly widened Sn(1)‐C(7)‐P(1) angle of 117.2(1)°, close to that of the related CS 2 adduct (118.4(1)° [9a] ). In addition, the molecular structure of 5 shows a slightly more distorted trigonal bipyramidally coordinate tin atom ( τ Sn =0.74, Table 1).…”

“…Since crystals of 4 show a phase transition at 100 K, data for X‐ray diffraction were recorded at 200 K. The molecular structure of 4 (Figure 4) in the crystal displays a five‐membered heterocycle with a N(1)−C(16) double bond of 1.227(6) Å and an exocyclic C‐O‐Ph unit. The Sn(1)‐C(7)‐P(1) angle of 110.3(3)° matches the angle of the corresponding constitutional isomeric phenyl isocyanate adduct (110.7(1)° [9a] ). Compound 4 shows a slightly distorted trigonal bipyramidal coordination at the tin atom, indicated by a τ Sn parameter of 0.77 (Table 1).…”

“…They differ significantly in their reactivities [7a,b, 9a] . Of these, Sn/P‐FLP (F 5 C 2 ) 3 SnCH 2 P( t Bu) 2 ( 1 ), is capable of reversibly binding CO 2 and turned out to be the most versatile FLP [9a] . Consequently, we set out to extend the scope with regard to binding nitrogen containing small molecules.…”

“…Recently, we reported on the tetrel‐based FLP systems (F 5 C 2 ) 3 ECH 2 P( t Bu) 2 (E=Si, Ge, Sn ( 1 )). They differ significantly in their reactivities [7a,b, 9a] . Of these, Sn/P‐FLP (F 5 C 2 ) 3 SnCH 2 P( t Bu) 2 ( 1 ), is capable of reversibly binding CO 2 and turned out to be the most versatile FLP [9a] .…”