Angel Aguirre

Reactions of dirhodium(II) monometallated compounds with phosphines. Factors affecting the reactivity and the structure of the doubly-metallated compounds. Molecular structure of Rh2(O2CCH3)2[(C6H4)P(C6H5)2][(p-ClC6H3)P(p-ClC6H4)2] · (HO2CCH3)2·(C6H6), a compound with two different metallated phosphines

Abstract Monometallated compounds of formula Rh2(O2CCH3)3[(p-XC6H3)P(p-XC6H4)2](HO2CCH3)2 (X=CH3, Cl) have been prepared in good yield. The reactions with p-substituted triarylphosphines P(p-X′C6H4)3 (X′=CH3, H, Cl) have been studied. For X=X′ and [P]/[Rh2]=1 all the resulting doubly metallated compounds Rh2(O2CCH3)2[(p- XC6H3)P(p-XC6H4)2](HO2CCH3)2 (X=CH3, Cl) have head-to-tail (H-T) structure. For [P]/[Rh2]=3 reaction progress is observed at room temperature. When X=X′ a 1:1 mixture of H-T and H-H compounds is formed for X=Cl but only the H-H compound is obtained for X=CH3. For X ≠ X′ mixtures of H-T and H-H compounds are obtained. The entering phosphine, and to a less extent the phosphine in the monometallated compound, seems to influence the rate of the process and the product distribution. The crystal structure of Rh2(O2CCH3)2[(C6H4)P(C6H5)][(p-ClC6,H3)P(p-ClC6H4)2] (HO2CCH3)2· 1 2 (C6H6) a doubly metallated compound with two different metallated phosphines in a head-to-tail configuration, is also described.

Synthesis and crystal structure of [Cu3(μ3-η1-CCPh)(μ-dppm)3][BF4]2, a tricopper(I) complex containing a μ3-η1 acetylide group and three bis(diphenylphosphino)methane (dppm) bridging ligands

Abstract The synthesis of the cationic trinuclear copper(I) complex [Cu 3 (CCPh)(dppm) 3 ][BF 4 ] 2 is described. An X-ray structure determination shows a triangular array of copper atoms with three diphosphine ligands Ph 2 PCH 2 PPh 2 (dppm) bridging each edge of the triangle and a μ 3 -η 1 phenyl acetylide group bound to the Cu 3 unit.

Synthesis and electrochemical studies of new ferrocene-labelled dinuclear rhodium(II) complexes. Crystal structures of [Rh2(O2CMe)2{[(C6H4)PhP(C5H4)]Fe(C5H5)}2(HO2CMe)2] and [Rh2(O2CMe)2{[(C6H4)PhP(C5H4)]2Fe}(HO2CMe)]·CH2Cl2

The reaction of diphenylphosphinoferrocene and 1,1′-bis(diphenylphosphino)ferrocene with [Rh2(O2CMe)4(MeOH)2](1:1 and 1:2 molar ratio respectively) yields the monoadducts [Rh2(O2CMe)4{(Ph2PC5H4)Fe(C5H5)}]1 and [{Rh2(O2CMe)4(MeOH)}2{(Ph2PC5H4)2Fe}]2. By thermal treatment of 1 in refluxing toluene–acetic acid (10:3) the monometallated product [Rh2(O2CMe)3{[(C6H4)PhP(C5H4)]Fe(C5H5)}(HO2CMe)2]3 was obtained in practically quantitative yield. Compound 3 reacts with [Fe(C5H5)(C5H4PPh2)](1:1 molar ratio) giving the adduct [Rh2(O2CMe)3{[(C6H4)PhP(C5H4)]Fe(C5H5)}{(Ph2PC5H4)Fe(C5H5)}]4, which reacts thermally in toluene–acetic acid (10:3) yielding the doubly metallated product [Rh2(O2CMe)2{[(C6H4)PhP(C5H4)]Fe(C5H5)}2(HO2CMe)2]5 as a mixture of conformational isomers. An X-ray determination of 5 has been carried out: space group Pbca(orthorhombic), a= 18.065(3), b= 20.606(4), c= 26.242(5)A, Z= 8, and R= 0.038. The crystal structure shows that the two metallated phosphines are in a head-to-tail configuration. Thermal treatment of a mixture of [Rh2(O2CMe)4(MeOH)2] and [Fe(C5H4PPh2)2](1:1 molar ratio) in acetic acid yields the compound [Rh2(O2CMe)2{[(C6H4)PhP(C5H4)]2Fe}(HO2CMe)]·CH2Cl26 after purification and crystallization from a CH2Cl2–hexane–acetic acid mixture. An X-ray diffraction investigation showed that this compound crystallizes in space group P21/c(monoclinic) with a= 12.735(4), b= 16.811(5), c= 20.161(8)A, β= 95.17(4)°, Z= 4 and R= 0.089. The two PPh2 fragments of the ferrocene ligand act as bridging orthometallated ligands in a head-to-head configuration. Two well defined oxidation processes were detected by cyclic voltammetry for all the complexes in CH2Cl2 solution: the first one, in the range 0.6–0.7 V, is due to the couple Fe2+–Fe3+ while the second one, in the range 0.9–1.32 V, is due to the couple Rh24+–Rh25+.

Synthesis and crystal structure of {Rh2(O2CCH3)4·P(o-CH3OH6H4)Ph2}2. A novel dirhodium(II) monoadduct with intermolecular μ-oxo interactions

Abstract We have investigated the reaction of dirhodium tetraacetate with the phosphine P( o -CH 3 OH 6 H 4 )Ph 2 (P) under different experimental conditions. From these reactions we have been able to isolate the dirhodium tetraacetate phosphine mono-adduct. The crystal structure shows that in the solid state this compound forms a centrosymmetric dimer of the dimer, {Rh 2 (O 2 CCH 3 ) 4 ·P(0-CH 3 OC 6 H 4 )Ph 2 } 2 , in which we oxygen atom from one acetate group in one Rh 2 (O 2 CCH 3 ) 4 ·P unit is axially coordinating one Rh atom on another Rh 2 (O 2 CCH 3 ) 4 · P unit (Rh⋯) 2.347(3) A intermolecular versus Rh⋯O 2.455(3) A intermolecular), and vice versa. The RhRh bond distance is 2.414(1) A while the intermolecular Rh⋯Rh distance is 3.45592) A.

Rhenium carbonyl complexes with bis(diphenyl phosphino)methane. X-ray crystal structure of [ReBr(CO)2(Ph2PCH2PPh2)(Ph2PCH2P′Ph2)·0.43[ReBr(CO)2(Ph2PCH2PPh2)(Ph2PCH2P(O)Ph2)]

The reaction of fac-[ReBr(CO)3(dppm)] (dppm=Ph2PCH2PPh2) with dppm in refluxing xylene gave the dicarbonyl cis-mer-[ReBr(CO)2(dppm-P)(dppm-P,P′)] (Id) in which one dppm is monodentated. This compound reacted with oxygen in xylene at room temperature to give first the P-oxide derivative cis-mer-[ReBr(CO)2(dppm-P)(dppm-P,PO)] (II), that subsequently decomposes with formation of Ph2P(O)CH2P(O)PPh2. The X-ray structure of I has been determined in a crystal containing 30% of II. The reaction of I with TlPF6 in CH2Cl2 gave the cationic cis-[Re(CO)2(dppm-P)2]PF6 (III).

Mononuclear Biscarbene Complexes by Direct Nucleophile Addition to a CO Ligand of Fischer Arylcarbene Complexes

Mononuclear Group 6 Fischer biscarbene complexes I, which are organometallic compounds that have two carbene ligands bonded to the same transition-metal atom, have been much less investigated than the corresponding Fischer monocarbene complexes II (Figure 1). Only very few examples of this class of compounds I have been reported and characterized by reactivity and/or X-ray studies, and their synthetic potential remains to be explored. In addition, there is a lack of a general method to produce such complexes.

An expeditious synthesis of highly substituted 1,4-diazepines and their rearrangement into 2H-1,3-oxazines

3-lminoprop-1-enylamines 1 react successively with diethylgermanium dichloride and diethyl oxomalonate to afford 1,3-dihydro-1,4-diazepin-2-ones 4; the crystal structure of 4a has been determined and its thermal behaviour leading to 2H-1,3-oxazines 5 studied.

Intramolecular nucleophilic attack on cationic iron(II) vinylidene complexes: Synthesis and crystal structure of the alkenyl [Fe(CCMetBu)(η-C5H5)(Ph2PCCMetBu)(η-C5H5)(Ph2P)2CH] containing an unprecedented bicyclopentane ring system

Abstract Reaction between [Fe(CCMetBu)(η-C5H5)(dppm)][CF3SO3] (dppm = bis(diphenylphosphino) methane) and NaOMe at − 20°C resulted in the deprotonation of dppm followed by the intramolecular nucleophilic attack of the methanide group on the vinylidene α-carbon to give [ Fe(CCMe t Bu)(η-C 5 H 5 )(Ph 2 P CCMe t Bu)(η-C 5 H 5 ){(Ph 2 P) 2 C H}]. An X-ray single-crystal structure determination shows that the complex contains a novel 1-ferra-2,4-diphosphabicyclo[1.1.1]pentane ring system.