Xantphos as cis- and trans-chelating ligand in square-planar platinum(II) complexes. Hydroformylation of styrene with platinum–xantphos–tin(II)chloride system

Efficient Platinum(II) Catalyzed Hydroformylation Reaction in Water: Unusual Product Distribution in Micellar Media

“…The system shows catalytic activity comparable, and in some cases better, than traditional Pt-Sn systems, [26] with good l/b selectivities that can rival with the best Rh catalysts. When styrenes are employed as substrates the unusual formation of significant amounts of benzaldehydes is observed via a b-aryl elimination step.…”

“…Pt(II) complexes have emerged in recent years as valuable hydroformylation catalysts with interesting results [24,25,26] in terms of enantioselectivity even if with a lower catalytic activity compared to rhodium species. [27] All Pt(II) catalysts reported were monomeric chloro derivatives bearing a diphosphine or two monophosphines or other ligands [28] activated with SnCl 2 always tested in organic media or in ionic liquids.…”

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

“…This is not surprising as the 2:1 ligand to metal ratio may lead to the blocking of coordination sites, thereby reducing the activity, [5,42] and increase the steric hindrance at the metal, thus improving the regioselectivity. [5,44] Role of SnCl 2 Given that cationic Pt II species are normally invoked in the catalytic cycle, and the role of the SnCl 2 is widely believed to be the generation of such cationic species by abstraction of Cl -to form SnCl 3 -, we tested the mono-and dinuclear cationic complexes 4a and 5 in the catalysis and were surprised to find that these complexes gave much lower activity and productivity than 2 (27 % and 32 % yield of nonanals after 3.5 h for 4a and 5, respectively, see en-tries 14 and 15 of Table 1) even though SnCl 2 was present in the reactions. The similar catalytic activities exhibited by 4a and 5 suggest the formation of the same active species from these cationic precursors, i.e.…”

“…[1] On the other hand, there is an increasing interest in platinum-catalysed olefin hydroformylation, mainly devoted to the optimisation of chemo-and regioselectivity of the reaction and the synthesis of linear aldehydes. [2] Since Parshall's pioneering work using PtCl 2 in the ionic liquid [(NEt 4 )SnCl 3 ], [3] many catalytic systems, [4][5][6][7] including some specifically suited to enantioselective catalysis, [8][9][10][11][12][13][14][15] have been developed. A common feature of all these systems is the use of SnCl 2 in combination with the Pt II salt or complex.…”

A new xantphos-type ligand and its gold(I) complexes: Synthesis, structure, luminescence

“…The xanthene skeleton is not fully rigid [3,4], the dihedral angle characterizing its folding and the torsion angle characterizing its twisting, and thereby the PP distance and the P-M-P chelating angle vary in xantphos complexes, depending on the central metal atom and the counter ligands [5]. This explains the structural variety of xantphos complexes, demonstrated by studies on its Pd [6], Pt [7], Rh [5] and Ir [8] complexes, in which it acts as a monodentate, a bidentate (P,P with cis or trans coordination mode) or a tridentate (P,O,P) ligand. Many of its Pd, Ru, Rh complexes proved to be efficient catalysts in homogeneous catalytic reactions [9,10].…”