Copper phosphine compounds

Results from the same laboratory have appeared on carbon dioxide complexes with copper(I) compounds (124). Phosphine-containing copper(I) car-boxylate complexes, formed by the insertion of C02 into a copper-alkyl bond, take up additional C02. A complex, formulated as [(RC00)Cu(C02)-(PPh3)J has been isolated and the C02 shown to be labile, i.e., the C02 was lost on attempted recrystallization. The authors speculate that the car-... 

A variety of organophosphine transition-metal complexes have been used for the detection of SO2 [149]. Cook et al. used triphenyl- and tribenzyl phosphine compounds as ligands bound to Cu and Mn. Varying the ligand affects the Lewis acid strength of the metal complex, and hence, its ability to bind SO2. One complex (bis(tribenzylphosphine)copper(II) thiophenolate — [Cu(PBz3)2)SPh]) exhibited a reversible response to SO2 that was linear in the range of lO-KKK) mg/L. 

Complexes of Copper(i).— In most of the copper(i) complexes whose structures have been described during the period of this survey the co-ordination at the metal atom is close to tetrahedral co-ordination numbers of two or three are much less common, while values greater than four are found exclusively in cluster compounds. The structures of mono- and bi-nuclear copper(i)-phosphine complexes have aroused a great deal of interest, and an attempt has been made to explain the observed variations in the lengths of Cu -P bonds. Attention has also been directed at polymeric copper compounds containing bridging halide or pseudohalide ions a number of such systems are described in the section on mixed-valence copper(i)-copper(n) compounds. 

Synthesis of the chiral catalysts to introduce enantioselectivity in carbene transfer reactions is a subject of great interest. Often copper and rhodium chiral catalysts are of choice for the carbene transfer reactions. In some reports, immobilized chiral dirhodium (II) catalyst were employed successfully in asymmetric cyclopropanation reactions. Ubeda and coworkers reported the immobilization of chiral Rh2(02CR)2(PC)2 (PC = ort/io-metalated phosphine) compounds on cross-linked polystyrene (PS) resin by an... 

The enantioselective 1,4-addition addition of organometaUic reagents to a,p-unsaturated carbonyl compounds, the so-called Michael reaction, provides a powerful method for the synthesis of optically active compounds by carbon-carbon bond formation [129]. Therefore, symmetrical and unsymmetrical MiniPHOS phosphines were used for in situ preparation of copper-catalysts, and employed in an optimization study on Cu(I)-catalyzed Michael reactions of di-ethylzinc to a, -unsaturated ketones (Scheme 31) [29,30]. In most cases, complete conversion and good enantioselectivity were obtained and no 1,2-addition product was detected, showing complete regioselectivity. Of interest, the enantioselectivity observed using Cu(I) directly in place of Cu(II) allowed enhanced enantioselectivity, implying that the chiral environment of the Cu(I) complex produced by in situ reduction of Cu(II) may be less selective than the one with preformed Cu(I). 

Studies of the thermal decarboxylation of phenylpropiolates of copper, tin, and lead parallel those of the corresponding cyanoacetate compounds. Copper phenylpropiolate decarboxylated irreversibly in dmf at 35°C and reversibly in the presence of tertiary phosphines in dmf (52). Triorga-iio(phenylethynyl)tin and -lead compounds, R3MC=CPh [M=Sn, R = Ph or Bu (53) M = Pb, R = Ph (5/)], were isolated when the triorganotin or -lead phenylpropiolates, R3M02CC=CPh, were heated in vacuo. Triphenyllead phenylpropiolate also decarboxylated in refluxing toluene (54). 

The existence of the neutral rhenium carbonyl [Re(C0)4] was first claimed in 1965 206 but, although it is easily sublimed, it has not yet been characterized by mass spectrometry and the value of n is still not known. This colourless substance [v (CO) 2055 and 1995 cm-1 in CHC13] has been obtained as a by-product in the synthesis of Re2(CO)i0 starting from Re2S7, copper powder, and carbon monoxide at 85 atm, 200 °C206>. There has also been a report of the compound Re4(CO)10(PPh2Me)6, which can be considered to be a substitution product of the hypothetical species, Re4(CO)i6 it has been obtained by a photochemical reaction between Re2(CO)j0 and PPh2Me194. In both cases, and particularly in the phosphine derivative, a tetrahedral structure seems improbable because of steric constraints. 

The related zinc cuprates formed from diorganozinc reagents and copper(I) cyanide also undergo smooth SN2 substitution reactions with propargyl oxiranes in the presence of phosphines or phosphites (Scheme 2.12). These transformations can also be performed with catalytic amounts of the copper salt since no direct reaction between the organozinc reagent and the substrate interferes [31, 34], and therefore should also be applicable to functionalized organozinc compounds. 

Catalytic forms of copper, mercury and silver acetylides, supported on alumina, carbon or silica and used for polymerisation of alkanes, are relatively stable [3], In contact with acetylene, silver and mercury salts will also give explosive acetylides, the mercury derivatives being complex [4], Many of the metal acetylides react violently with oxidants. Impact sensitivities of the dry copper derivatives of acetylene, buten-3-yne and l,3-hexadien-5-yne were determined as 2.4, 2.4 and 4.0 kg m, respectively. The copper derivative of a polyacetylene mixture generated by low-temperature polymerisation of acetylene detonated under 1.2 kg m impact. Sensitivities were much lower for the moist compounds [5], Explosive copper and silver derivatives give non-explosive complexes with trimethyl-, tributyl- or triphenyl-phosphine [6], Formation of silver acetylide on silver-containing solders needs higher acetylene and ammonia concentrations than for formation of copper acetylide. Acetylides are always formed on brass and copper or on silver-containing solders in an atmosphere of acetylene derived from calcium carbide (and which contains traces of phosphine). Silver acetylide is a more efficient explosion initiator than copper acetylide [7],... 

Phosphine in small quantities in hydrogen containing over I per cent, of oxygen attacks copper, producing an acid liquid which has a most corrosive action on fabric. However, it does not appear under these circumstances to have any action on aluminium or zinc consequently any metal parts inside the envelope of an airship should be of aluminium. Phosphine under the above conditions attacks hemp and other textiles which have been treated with copper compounds, but it does not appear to have any action on fabrics free from copper compounds or copper or brass fastenings. 

Together with phosphine, noticeable amounts of diphosphine and higher phosphines are formed by the hydrolysis of calcium phosphide thus, this reaction can be used for the preparation of such compounds. Quesnel reported that the formation of diphosphine can be avoided when aqueous hydrochloric acid is added drop-wise to a mixture of calcium phosphide and copper chloride (proportions by weight, CaaPj CuClj = 10 1) in boiling alcohol, for example, methanol, or in dioxane. 

Organometallic reagents and catalysts continue to be of considerable importance, as illustrated in several procedures CAR-BENE GENERATION BY a-ELIMINATION WITH LITHIUM 2,2,6,6-TETRAMETHYLPIPERIDIDE l-ETHOXY-2-p-TOL-YLCYCLOPROPANE CATALYTIC OSMIUM TETROXIDE OXIDATION OF OLEFINS PREPARATION OF cis-1,2-CYCLOHEXANEDIOL COPPER CATALYZED ARYLA-TION OF /3-DICARBONYL COMPOUNDS 2-(l-ACETYL-2-OXOPROPYL)BENZOIC ACID and PHOSPHINE-NICKEL COMPLEX CATALYZED CROSS-COUPLING OF GRIG-NARD REAGENTS WITH ARYL AND ALKENYL HALIDES 1,2-DIBUTYLBENZENE. 

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