(Diphosphane monosulfide)platinum(II) Complexes for Hydroformylation Reactions: Their Catalytic Activity and a High‐Pressure NMR Mechanistic Study

Abstract

The neutral complexes of formula [κ 2 P,S-(dppmS)Pt(CH 3 )- (3) [dppmS = Ph 2 PCH 2 P(S)Ph 2 ; dppeS = Ph 2 P(CH 2 ) 2 P(S)Ph 2 ; dpppS = Ph 2 P(CH 2 ) 3 P(S)Ph 2 ] are active catalyst precursors for the hydroformylation of 1-octene in methyl isobutyl ketone. The order of reactivity found is 3 Ͼ 2 Ͼ 1. Surprisingly, the cationic complexes [κ 2 P,S-(dppeS)Pt(CH 3 )(CH 3 CN)]BF 4 (4a) and [{κP,µ-κS-(dppeS)-Pt(CH 3 )} 2 ][BF 4 ] 2 (5) are less active than the analogous neutral complex 2. High-pressure NMR studies revealed that, at 20°C under 1 to 50 bar of syngas, and in the presence of SnCl 2 , both 2 and 4a react immediately to form the same acetyl complex (8). However, in the absence of SnCl 2 , the methyl

Epimerization, diastereoselectivity and hemilability in dicationic chiral ruthenium complexes with bidentate (P∧S) bisphosphine monosulfide ligands

“…This phosphorus is coupled through the metal to the phosphorus nucleus of the arene-tethered ligand ( 2 J P-P = 35.7 Hz), as well as to the phosphine sulfide with J P-P = 19.7 Hz. This latter coupling is decreased with respect to the free ligand (49 Hz) [18], which is the usual observation [18][19][20][21][22] and is indicative of a spin coupling contribution of opposite sign through the metal and thus indicates the coordination of the sulfur to the metal. Likewise, the phosphine of the arene-tethered ligand shows a coupling to the directly coordinated phosphine of diphos(S), but an additional smaller 3 J coupling of 19.7 Hz to the phosphorus atom (the P V ) bound to the sulfur is observed.…”

Regioselectivity and memory effects in palladium catalyzed allylic alkylations with bidentate P^PS donor ligands

“…The exchange observed may be due to dissociation of the P]S moiety. This behavior has been observed previously with dppp(S) (d) [47,48]. Therefore, the fluxional processes that are available to each individual ligand may further influence branched selectivity, reaction rate and memory effect.…”

Alternative Metalle für die homogen katalysierte Hydroformylierung

“…[98] Hydroformylierungen mit alternativen Metallen werden nicht nur durch Phosphinliganden gefçrdert -Arsine, Aminoder schwefelhaltige Analoga zeigen ebenfalls positive Einflüsse. [100] Tatsächlich wurde aus Arbeiten von van Leeuwen und Mitarbeitern zur synthesechemischen Anwendung von Arsinliganden mit weiten Koordinationswinkeln deutlich, dass diese -besonders in Form des gemischten Xantphosarsinliganden 85 -zu einer Zunahme von Aktivität und Selektivität bei der Pt/Sn-katalysierten Hydroformylierung von 1-Octen führten (Schema 35). [101] Die Umwandlung des terminalen Alkens zu seinem C 1 -verlängerten Aldehyd wurde Schema 32.…”