Bis-phosphine dioxides

Structural and Physical Aspects. - The stability of the various conformers of the phosphines oxides (269)- 211) has received theoretical consideration. A new triclinic polymorph of triphenylphosphine sulfide has been structurally characterised, together with a related triclinic polymorph of triphenylphos-phine. Two reports of the solid state crystal structure of the phenolic phosphine oxide (272) have appeared. A crystallographic study has confirmed that the product of electrochemical oxidation of o-diphenylphosphinoben-zenethiol is the disulfide-bridged bis(phosphine oxide) (273). Solid-state structural studies of the dioxides (274), the (i )-(-I-)-isomer of (275), 1-hexynyl(diphenyl)phosphine oxide,tribenzylphosphine oxide, and tris(t-butyl)phosphine selenide," have also been reported. 

The bis(phosphine oxide) (48) was useful in the synthesis of 3-diphenylphos-phinsulfido-tetrahydrophosphinine sulfide (51) in which the same kind of intramolecular interactions found in the analogous dioxide derivative could be established (Scheme 23) [34],... 

Resorcinol carboxylation with carbon dioxide leads to a mixture of 2,4-dihydroxyben2oic acid [89-86-1] (26) and 2,6-dihydroxyben2oic acid [303-07-1] (27) (116). The condensation of resorcinol with chloroform under basic conditions, in the presence of cyclodextrins, leads exclusively to 2,4-dihydroxyben2aldehyde [95-01-2] (28) (117). Finally, the synthesis of l,3-bis(2-hydroxyethoxy)ben2ene [102-40-9] (29) has been described with ethylene glycol carbonate in basic medium (118), in the presence of phosphines (119). Ethylene oxide, instead of ethyl glycol carbonate, can also be used (120). 

Codeposition of silver vapor with perfluoroalkyl iodides at -196 °C provides an alternative route to nonsolvated primary perfluoroalkylsilvers [272] Phosphine complexes of trifluaromethylsilver are formed from the reaction of trimethyl-phosphme, silver acetate, and bis(trifluoromethyl)cadmium glyme [755] The per-fluoroalkylsilver compounds react with halogens [270], carbon dioxide [274], allyl halides [270, 274], mineral acids and water [275], and nitrosyl chloride [276] to give the expected products Oxidation with dioxygen gives ketones [270] or acyl halides [270] Sulfur reacts via insertion of sulfur into the carbon-silver bond [270] (equation 188)... 

Sulfur dioxide and carbon disulfide react with bis(bulky phosphine)platinum complexes to give monomeric trigonal planar [Pt(PR3)2(S02)] and trimeric complexes such as [Pt3(/u-S02)(PR3)2] and [Pt3(/i-CS2)(PR3)2] where R = Cy or But70 71... 

Darensbourg DJ, Wildeson JR, Yarbrough JC, Reibenspies JH (2000) Bis 2,6-difluorophen-oxide dimeric complexes of zinc and cadmium and their phosphine adducts lessons learned relative to carbon dioxide/cyclohexene oxide alternating copolymerization processes catalyzed by zinc phenoxides. J Am Chem Soc 122 12487-12496... 

Reaction of bis(trimethylsilyl)phosphines with carbon dioxide afforded adducts and addition-silatropy products instead of phosphaketene or 1,3-diphosphaallene (R—P=C=P—R ) (equation 33, compare with equations 72 and 91)52. Similarly, reaction of 3 with carbon disulfide resulted in the addition-silatropy product (equation 34, cf. equations 73 and 94)53. Successful preparations of phosphaallenes utilizing alkali metal silylphosphides bearing bulky substituents are described in Section V. 

Tellurium dioxide dissolved in hydrochloric acid reacted with sodium dialkyldithio-phosphinate to produce tellurium bis[dialkyldithiophosphinates]2. The reactions were carried out as described for the preparation of tellurium bis[0,0-dialkyl dithiophos-phates] (s. p. 41). 

Tellurium dioxide dissolved in hydrochloric acid, and sodium diethylchalcogenoselenolo-phosphinates produced tellurium bis[diethylchalcogenoselenolophosphinates] ... 

Fig. 15. RuCl(CO)(NO)(S02)(PPh3)2. (Reprinted, with permission, from Structure of Chloronitrosyl(i/ -sulfur dioxide)bis(triphenyl-phosphine)ruthenium-Dichloromethane, RuCl-(N0)(i7 -S02)(P(QH5)3)2 CHiQj, Wilson, R. D., Ibeis, J. A. Inorg. Chem. 17, 2136, Fig. 3, copyright, 1978, by the American Chemical Society)...

Attack on Unsaturated Carbon.- A versatile route to phosphinic acids (15) is the 1,4-addition of bis(trimethylsilyl) phosphonite (16) to a,p-unsaturated esters.The pyrophoric (16) was prepared in s/fu from triethylammonium phosphinate silylation and 1,4-addition can be repeated to give (17), or performed in one step if symmetrical phosphinic acids (17) are wanted. Tervalent phosphorus acid esters (18) react with dialkyl acetylenedicarboxylates in the presence of carbon dioxide to give 1,2-oxa-phospholenes (19) these reacted further with an excess of the phosphorus reagent to give different ylids, (20) or (21), dependant on the number of methoxy groups in (18). 

The Pd-catalyzed carbonylation of aryl halides (cf Section 2.1.2) occurs with high turnover numbers and reaction rates in SCCO2 as the solvent using standard precursor complexes and commercially available phosphine or phosphite ligands [30]. The generally better performance of the phosphite-based catalysts was attributed to their better solubility in the reaction mixture, but the formation of Pd carbonyl complexes was also mentioned as a possibility. The [Ni(cod)2]/dppb system (dppb = l,4-bis(diphenylphosphino)butane) was investigated in an early study as a catalyst for the synthesis of pyrones from alkynes and CO2 under conditions beyond the critical data of carbon dioxide [31]. Replacing dppb with PMcs results in a system with better solubility and catalytic performance, albeit catalyst deactivation remains a problem [3 c, 15]. 

Phosphine Chalcogenides as Ligands. - The complexation of lanthanide and actinide ions by phosphine oxide ligands remains an active area, and a theoretical assessment of the coordination of phosphine oxides (and phosphate esters) by trivalent lanthanide ions has appeared." Trivalent lanthanide complexes of the functionalised enol phosphine oxide (265), (and a related phosphonate), have been describedComplexes of thorium(iv) with bis(di-phenylphosphino) ethane dioxide and bis(diphenylphosphinoyl)amide have also been characterised." Calixarene systems which bear phosphine oxide... 

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