646069-73-0Relevant academic research and scientific papers
The coordination chemistry of pentafluorophenylphosphino pincer ligands to platinum and palladium
Anderson, Bradley G.,Spencer, John L.
, p. 6421 - 6432 (2014/06/09)
The synthesis of electron-poor PCP pincer ligands 1,3-((C6F 5)2PO)2C6H4, 1,3-((C 6F5)2PCH2)2C 6H4, and 1-((C6F5) 2PO)-3-(tBu2PCH2)C6H4, and their coordination chemistry to platinum and palladium is described. The most electron-poor ligand 1,3-((C6F5)2PO) 2C6H4 (POCOPH) reacts with Group10 metal chloride precursors to form a range of unusual cis, trans-dimers of the type κ2-P,P-[(POCOPH)MCl(L)]2 (M=Pt, Pd; L=Cl, Me), which undergo metallation to form [(POCOP)MCl] pincer complexes only under prolonged thermolysis. The formation of such cis,trans-dimers during pincer complex formation can be mitigated through the use of starting materials with more strongly binding ancillary ligands, improving the overall rate of ligand metallation. Carbonyl complexes of the type [(PCP)M(CO)]+ were synthesised from the pincer chloride complexes by halide abstraction, and displayed large ν(C-O) values, from 2170-2111cm-1, confirming the electron-poor nature of the compounds. The [(PCP)Pd(CO)]+ complexes also demonstrated the ability to reversibly bind carbon monoxide both in solution and the solid state, with the rate of decarbonylation increasing with increasing wavenumber for the C-O stretch. Back and forth: The electron-poor P(C6F5)2 donor group was incorporated into the PCP pincer ligand motif to generate a range of poorly donating ligands. Palladium carbonyl complexes of these ligands demonstrated the ability to reversibly bind CO, with the ease of CO displacement increasing with increasing ν(CO) values (see figure). These ligands also displayed a reluctance to undergo metallation on Pt or Pd, which led to the formation of rare examples of cis,trans-dimers.
Catalytic synthesis of n-alkyl arenes through alkyl group cross-metathesis
Dobereiner, Graham E.,Yuan, Jian,Schrock, Richard R.,Goldman, Alan S.,Hackenberg, Jason D.
supporting information, p. 12572 - 12575 (2013/09/23)
n-Alkyl arenes were prepared in a one-pot tandem dehydrogenation/olefin metathesis/hydrogenation sequence directly from alkanes and ethylbenzene. Excellent selectivity was observed when (tBuPCP)IrH2 was paired with tungsten monoaryloxide pyrrolide complexes such as W(NAr)(C 3H6)(pyr)(OHIPT) (1a) [Ar = 2,6-i-Pr2C 6H3; pyr = pyrrolide; OHIPT = 2,6-(2,4,6-i-Pr 3C6H2)2C6H3O]. Complex 1a was also especially active in n-octane self-metathesis, providing the highest product concentrations reported to date. The thermal stability of selected olefin metathesis catalysts allowed elevated temperatures and extended reaction times to be employed.
Rational design of highly active "hybrid" phosphine-phosphinite pincer iridium catalysts for alkane metathesis
Nawara-Hultzsch, Agnieszka J.,Hackenberg, Jason D.,Punji, Benudhar,Supplee, Carolyn,Emge, Thomas J.,Bailey, Brad C.,Schrock, Richard R.,Brookhart, Maurice,Goldman, Alan S.
, p. 2505 - 2514 (2013/11/19)
Both the bisphosphine and bisphosphinite pincer complexes ( tBu4PCP)IrH2 and (tBu4POCOP)IrH2 can cocatalyze alkane metathesis in tandem with olefin metathesis catalysts, but the two complexes have different resting states during catalysis, suggesting that different steps are turnover-limiting in each case. This led to the hypothesis that a complex with intermediate properties would be catalytically more active than either of these two species. Accordingly, "hybrid" phosphine-phosphinite pincer ligands (PCOP) and the corresponding iridium complexes were synthesized (3c-e). In tandem with olefin-metathesis catalyst MoF12, (tBu4PCOP)IrH2 displays significantly higher activity for the metathesis of n-hexane than does (tBu4PCP)IrH 2 or (tBu4POCOP)IrH2. (tBu2PCOP iPr2)IrH4 (3d) is even more active (>30-fold more active than (tBu4POCOP)IrH2) and affords nearly 4.6 M alkane products after 8 h at 125 C.
Novel unsymmetrical PCP′ pincer ligands and their palladium(II) complexes
Eberhard, Michael R.,Matsukawa, Shiro,Yamamoto, Yohsuke,Jensen, Craig M.
, p. 185 - 189 (2007/10/03)
Synthetic routes towards novel PCP′ pincer ligands were devised. Ligand 1-(Pr2iPOCH2) -3-(Bu2tPCH2) (C6H4) is prepared in a three step synthesis from 1,3-benzenedimethanol and 1-(Pr2iPO)-3- (Bu2tPCH2)(C6H4) is accessible in three steps from 3-hydroxybenzylalcohol. Both their palladium(II) complexes are prepared in good yields but are distinctly different since [PdCl{(C6H3) (OPPr2i)-2-(CH2PBu2 t)-6}] possesses two five-membered palladacycles, whereas [PdCl{(C6H3)(CH2PBu2 t)-2-(CH2OPPr2i)-6}] is unusual for a pincer complex in that it contains both five- and six-membered palladacycles. Both compounds also represent the first examples of pincer complexes where one donor is a phosphinite and the other is a phosphine. The X-ray structures of these complexes were solved and are discussed. The data reveal that an increase in the metallacycle ring-size leads to changes in bond lengths, but more importantly to significant increases in the bond angles.
