ChemInform Abstract: STABILITY OF DIPHOSPHACYCLOPROPANES

Prishchenko, A. A.; Novikova, Z. S.; Lutsenko, Iryna

doi:10.1002/chin.198030301

Cited by 5 publications

(5 citation statements)

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“…Young PTFE valves or rubber septa. Of the phosphines, dmpm and dppm were purchased from Strem and used as received, while depm was prepared by a literature method and stored under N 2 . Cl 2 (Matheson), Br 2 (Acros), and I 2 (AnalaR) were from commercial sources and used as received.…”

Section: Methodsmentioning

confidence: 99%

Solution Behavior and Structural Diversity of Bis(dialkylphosphino)methane Complexes of Palladium

et al. 2003

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The preparation of dipalladium complexes containing sterically nondemanding diphosphine (P-P) ligands of the type R(2)PCH(2)PR(2) where R = Me (dmpm) or Et (depm) is reported. Variable-temperature (1)H NMR spectra of the Pd(I)(2) complexes Pd(2)X(2)(dmpm)(2) (X = Cl, Br, or I; the P-P ligands in the Pd(2) complexes are always bridged, but for convenience, the micro -symbol is omitted) show the complexes to be fluxional in solution, the barriers to a ring-flipping process being DeltaG( double dagger ) = 37.9, 39.0, and 43.2 +/- 0.9 kJ mol(-)(1) for the chloro, bromo, and iodo complexes, respectively. Treatment of Pd(2)X(2)(P-P)(2) (X = Cl or Br) with X(2) generates the stable, face-to-face Pd(II)(2) derivatives trans-Pd(2)X(4)(P-P)(2), while oxidation of Pd(2)I(2)(P-P)(2) complexes with I(2) generates a new type of symmetrically di-iodo-bridged, five-coordinate complexes Pd(2)I(2)(micro -I)(2)(dmpm)(2) and Pd(2)I(2)(micro -I)(2)(depm)(2). The molecular crystal structures of four dipalladium(II) complexes are described: trans-Pd(2)Cl(4)(dmpm)(2).2CHCl(3), trans-Pd(2)Br(4)(dmpm)(2), trans-Pd(2)Cl(4)(depm)(2), and Pd(2)I(2)(micro -I)(2)(dmpm)(2). Solution NMR and UV-vis absorption spectra are consistent with the solid-state structures determined by X-ray diffraction. The stability of the dimeric Pd(II) complexes is attributed primarily to ligand steric factors.

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Section: Methodsmentioning

confidence: 99%

Solution Behavior and Structural Diversity of Bis(dialkylphosphino)methane Complexes of Palladium

et al. 2003

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“…70, 71 The preparations of diimidazolium salts used in this paper have been reported; 11,16,30,72 however, a general synthetic approach has been outlined below. Bis(diethylphosphino)methane (depm) was prepared using published procedures and used without further purification, 73 as was bis(cycloocta-1,5-diene)(m-dichloro)dirhodium ([Rh(m-Cl)(COD)] 2 ) and bis(cycloocta-1,5-diene)-(m-dichloro)diiridium ([Ir(m-Cl)(COD)] 2 ). 74,75 Bis(cycloocta-1,5diene)(m-diacetato)dirhodium ([Rh(m-OAc)(COD)] 2 ) was prepared as previously reported and recrystallized from ethyl acetate.…”

Section: General Commentsmentioning

confidence: 99%

Carbene-anchored/pendent-imidazolium species as precursors to di-N-heterocyclic carbene-bridged mixed-metal complexes

et al. 2009

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Reaction of a series of linked diimidazolium dibromide salts with one-half equivalent of [Rh(mu-OAc)(COD)](2) under reflux conditions generates a series of carbene-anchored/pendent-imidazolium complexes, [RhBr(COD)((R)C(H)-eta(1)-C(eth))][Br] ((Me)C(H)-eta(1)-C(eth) = ethylene[(N-methyl)imidazolium][(N-methyl)imidazole-2-ylidene] and (tBu)C(H)-eta(1)-C(eth) = ethylene[(N-tert-butyl)imidazolium][(N-tert-butyl)imidazole-2-ylidene]) via deprotonation of one end of the diimidazolium salt and coordination of the resulting carbene to Rh. Reaction of these complexes with carbon monoxide or the appropriate diphosphine yields either [RhBr(CO)(2)((R)C(H)-eta(1)-C(eth))][Br] (R = Me, (t)Bu) or [RhBr(P( intersection)P)((Me)C(H)-eta(1)-C(eth))][Br] (P( intersection)P = Ph(2)PCH(2)PPh(2), Ph(2)PCH(2)CH(2)PPh(2), Et(2)PCH(2)PEt(2)), respectively. The resulting diphosphine complexes readily decompose in solution. A series of palladium complexes [PdI(3-n)(PR(3))(n)(L)][I](n) (n = 1,2) and [PdI(P( intersection)P)(L)][I](2) (L = (tBu)C(H)-eta(1)-C(meth), (tBu)C(H)-eta(1)-C(eth); (tBu)C(H)-eta(1)-C(meth) = methylene[(N-tert-butyl)imidazolium][(N-tert-butyl)imidazole-2-ylidene]), containing the linked NHC-imidazolium moiety, have also been prepared by reacting the triiodo complexes, [PdI(3)((tBu)C(H)-eta(1)-C(meth))] and [PdI(3)((tBu)C(H)-eta(1)-C(eth))] with several mono- and diphosphines. Attempts to generate mixed Rh/Pd complexes using Pd(OAc)(2) to deprotonate the pendent arm of several of the above carbene-anchored/pendent-imidazolium complexes of Rh have proven unsuccessful. However, a targeted di-NHC-bridged heterobimetallic complex [PdI(2)(PEt(3))(mu-(tBu)CC(meth))RhI(COD)] ((tBu) CC(meth) = 1,1'-methylene-3,3'-di-tert-butyldiimidazol-2,2'-diylidene) can be generated by deprotonation of the imidazolium group in [PdI(2)(PEt(3))((tBu)C(H)-eta(1)-C(meth))][I] using half an equivalent of [Rh(mu-OAc)(COD)](2). The X-ray structure determination of this Pd/Rh complex confirms the dicarbene-bridged formulation and shows a metal-metal separation of approximately 6.2 A. Reaction of this Rh/Pd complex with CO yields the corresponding dicarbonyl product [PdI(2)(PEt(3))(mu-(tBu)CC(meth))RhI(CO)(2)] via replacement of the COD ligand. The related dicarbene-bridged Ir/Rh complex [IrBr(COD)(mu-(tBu)CC(meth))RhBr(COD)] can be generated by reaction of [IrBr(COD)((tBu)C(H)-eta(1)-C(meth) )][Br] with [Rh(mu-OAc)(COD)](2), while the Pd/Ir complexes [PdI(2)(PR(3))(mu-(tBu)CC(meth))IrI(COD)] (PR(3) = PPh(3), PMe(2)Ph) can be generated by reaction of the monometallic [PdI(2)(PR(3))((tBu)C(H)-eta(1)-C(meth))][I] species with K[N(SiMe(3))(2)] in the presence of [Ir(mu-Cl)(COD)](2). The carbonyl analogues, [PdI(2)(PR(3))(mu-(tBu)CC(meth))IrI(CO)(2)], can be generated via a gentle purge of CO gas. These di-NHC-bridged heterobimetallic species represent some of the first examples of this class and are the first involving palladium.

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“…By Cyclization of a P-C-P Unit This approach in eq 76 was very early proposed by Lutsenko. 124 The 3-membered ring was obtained as a 80:20 mixture with its dimer. Much more recently,…”

Section: Me3s»mentioning

confidence: 99%

Chemistry of 3-membered carbon-phosphorus heterocycles

Mathey¹

1990

Chem. Rev.

262

114

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ChemInform Abstract: STABILITY OF DIPHOSPHACYCLOPROPANES

Abstract: Die Methylen‐dialkyl‐phosphinig‐ säure‐dihalogenide (I) cyclisieren leicht zu den 1,2,4,5‐Tetra(alkylphospha)cyclohexanen (III).

Cited by 5 publications

References 0 publications

Solution Behavior and Structural Diversity of Bis(dialkylphosphino)methane Complexes of Palladium

Solution Behavior and Structural Diversity of Bis(dialkylphosphino)methane Complexes of Palladium

Carbene-anchored/pendent-imidazolium species as precursors to di-N-heterocyclic carbene-bridged mixed-metal complexes

Chemistry of 3-membered carbon-phosphorus heterocycles

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