Palladium POCOP-pincer hydride complexes[2,6-(R_(2)PO)_(2)C_(6)H_(3)]PdH(R=tBu,2a;R=^(i)Pr,2b;R=^(c)Pe,2c,^(c)Pe=cyclopentyl)have been synthesized from[2,6-(R_(2)PO)_(2)C_(6)H_(3)]PdCl(1a-c)and LiAlH_(4) or LiBEt_(3)H...Palladium POCOP-pincer hydride complexes[2,6-(R_(2)PO)_(2)C_(6)H_(3)]PdH(R=tBu,2a;R=^(i)Pr,2b;R=^(c)Pe,2c,^(c)Pe=cyclopentyl)have been synthesized from[2,6-(R_(2)PO)_(2)C_(6)H_(3)]PdCl(1a-c)and LiAlH_(4) or LiBEt_(3)H.These hydride complexes react with phenylacetylene to afford H2,[2,6-(R_(2)PO)_(2)C_(6)H_(3)]PdCuCPh(3a-c)and a small amount of styrene.When the R groups are isopropyl groups,a second palladium species is generated,and it has been identified as an alkenyl complex(E)-[2,6-(^(i)Pr_(2)PO)_(2)C_(6)H_(3)]PdCHvCHPh(4b).Mechanistic studies have shown that decomposition of these palladium pincer complexes and related palladium methyl complexes[2,6-(R_(2)PO)_(2)C_(6)H_(3)]PdCH_(3)(5a-c)occurs at room temperature in the presence of H_(2)(1 atm or lower),resulting in the leaching of palladium particles.These particles have been shown to catalyze the hydrogenation of phenylacetylene and diphenylacetylene to their alkene and alkane products.A mechanism for the formation of palladium particles has been proposed.The structures of 1a,1c,2a,2c,3a,4b and 5b have been studied by X-ray crystallography.展开更多
A(POCOP)-supported palladium complex was used to catalyse the dehydrogenative borylation of terminal alkynes to form alkynylboronates.Competing hydrogenation reactions could be mitigated through the use of additives s...A(POCOP)-supported palladium complex was used to catalyse the dehydrogenative borylation of terminal alkynes to form alkynylboronates.Competing hydrogenation reactions could be mitigated through the use of additives such as phosphines or elemental mercury.展开更多
基金the National Science Foundation(CHE-0952083)Alfred P.Sloan Foundation(research fellowship to H.G.)the University of Cincinnati Honors Program for supporting this research.
文摘Palladium POCOP-pincer hydride complexes[2,6-(R_(2)PO)_(2)C_(6)H_(3)]PdH(R=tBu,2a;R=^(i)Pr,2b;R=^(c)Pe,2c,^(c)Pe=cyclopentyl)have been synthesized from[2,6-(R_(2)PO)_(2)C_(6)H_(3)]PdCl(1a-c)and LiAlH_(4) or LiBEt_(3)H.These hydride complexes react with phenylacetylene to afford H2,[2,6-(R_(2)PO)_(2)C_(6)H_(3)]PdCuCPh(3a-c)and a small amount of styrene.When the R groups are isopropyl groups,a second palladium species is generated,and it has been identified as an alkenyl complex(E)-[2,6-(^(i)Pr_(2)PO)_(2)C_(6)H_(3)]PdCHvCHPh(4b).Mechanistic studies have shown that decomposition of these palladium pincer complexes and related palladium methyl complexes[2,6-(R_(2)PO)_(2)C_(6)H_(3)]PdCH_(3)(5a-c)occurs at room temperature in the presence of H_(2)(1 atm or lower),resulting in the leaching of palladium particles.These particles have been shown to catalyze the hydrogenation of phenylacetylene and diphenylacetylene to their alkene and alkane products.A mechanism for the formation of palladium particles has been proposed.The structures of 1a,1c,2a,2c,3a,4b and 5b have been studied by X-ray crystallography.
基金the US National Science Foundation(grant CHE-1300299 to O.V.O.)the Welch Foundation(grant A-1717 to O.V.O.).
文摘A(POCOP)-supported palladium complex was used to catalyse the dehydrogenative borylation of terminal alkynes to form alkynylboronates.Competing hydrogenation reactions could be mitigated through the use of additives such as phosphines or elemental mercury.
