Cristina Tejel

Deprotonation induced ligand-to-metal electron transfer: Synthesis of a mixed-valence Rh(-I,I) dinuclear compound and its reaction with dioxygen

Treatment of bis(2-picolyl)amine (bpa) with [{Rh(nbd)(mu-OMe)}2] leads to the unexpected and unique redox asymmetric dinuclear Rh-I,Rh+I complex [{Rh(nbd)}2(bpa-2H)] (2) with a pi-coordinating imine bound to a tetrahedral low valent rhodate(-I). Mono-oxygenation of the deprotonated bpa ligand in 2 by O2 leads to the mononuclear carboxamido complex [Rh(nbd)(bpam-H)] (3) (bpam = N-(2-picolyl)picolinamide). The second O atom of O2 ends up as a hydroxo fragment in [{Rh(nbd)(mu-OH)}2].

Rhodium wires based on binuclear acetate-bridged complexes

Abstract The synthesis, properties, structure and conductivity of a new class of one-dimensional, mixed valence Rh(I)–Rh(II) complexes { Rh 2 ( μ-O 2 CMe ) 2 ( N – N ) 2 ][ BX 4 ]} n ( N – N =bipyridine, phenanthroline; X=F, Ph) are described.

Rhodium(III)-Catalyzed Dimerization of Aldehydes to Esters

The generous financial support from MICINN/FEDER (Project CTQ2008-03860) and G.A. (Gobierno de Aragon, Project: PM 036/2007) is gratefully recognized. V.P. thanks C.S.I.C. for an I3P postdoctoral contract.

Rhodium and Iridium Pyrazolato Blues

The staggered arrangement of the two dimers in 1 facilitates the formation of an almost linear chain of four metal centers that is held together by a nonsupported metal-metal bond. The intense color of the compounds and the fractional oxidation states of the metal atoms can be explained by electron delocalization along the chain. M=Rh, Ir.

Catalysis and Organometallic Chemistry of Rhodium and Iridium in the Oxidation of Organic Substrates

The purpose of this chapter is to present a survey of the organometallic chemistry and catalysis of rhodium and iridium related to the oxidation of organic substrates that has been developed over the last 5 years, placing special emphasis on reactions or processes involving environmentally friendly oxidants. Iridium-based catalysts appear to be promising candidates for the oxidation of alcohols to aldehydes/ketones as products or as intermediates for heterocyclic compounds or domino reactions. Rhodium complexes seem to be more appropriate for the oxygenation of alkenes. In addition to catalytic allylic and benzylic oxidation of alkenes, recent advances in vinylic oxygenations have been focused on stoichiometric reactions. This review offers an overview of these reactions as well as some comments on key questions related to achieving the desired C – O bond formation.

Terminal Phosphanido Rhodium Complexes Mediating Catalytic P-P and P-C Bond Formation

Complexes with terminal phosphanido (M-PR2) functionalities are believed to be crucial intermediates in new catalytic processes involving the formation of P-P and P-C bonds. We showcase here the isolation and characterization of mononuclear phosphanide rhodium complexes ([RhTp(H)(PR2)L]) that result from the oxidative addition of secondary phosphanes, a reaction that was also explored computationally. These compounds are active catalysts for the dehydrocoupling of PHPh2 to Ph2P-PPh2. The hydrophosphination of dimethyl maleate and the unactivated olefin ethylene is also reported. Reliable evidence for the prominent role of mononuclear phosphanido rhodium species in these reactions is also provided.

1,2,4-Triazolate (tz) complexes of rhodium(I), iridium(I), and palladium(II). Crystal structure of [Rh3(µ3-tz)(µ-Cl)Cl(η4-tfbb)(CO)4]·0.5CH2Cl2(tfbb = tetrafluorobenzobarrelene), a trinuclear complex with extended metal–metal interactions

New binuclear complexes of formula [M2(µ-tz)2(L2)2][tz = triazolate; M = Rh or Ir, L2= diolefin, (CO)2, or (CO)(PPh3); M = Pd, L2=η3-C3H5 or η3-C4H7] have been prepared. These binuclear complexes, having unco-ordinated N atoms from the triazolate ligands, react with [M2(µ-Cl)2(L2)2](M = Rh, Ir, or Pd) to give tetranuclear compounds of formula [Rh2M2(µ3-tz)2Cl2(L2)4]. The latter complexes can also be prepared by reacting triazole and [Rh(acac)(CO)2] with [M2(µ-Cl)2(L2)2]. The heteronuclear rhodium–gold complex [Rh2Au2(µ3-tz)2Cl2(cod)2](cod = cyclo-octa- 1,5-diene) has been synthesized. Trinuclear complexes of formula [Rh2M(µ3-tz)(µ-X)ClL2(CO)4](X = Cl or OH) have been isolated by several routes starting from the above mentioned tetra-, bi-, or mononuclear complexes. In general, these trinuclear complexes show metallic lustre and marked dichroism, suggesting metal–metal interactions which were confirmed by the X-ray determination of [Rh3(µ3-tz)(µ-Cl)Cl(tfbb)(CO)4](tfbb = tetrafluorobenzobarrelene). This complex shows a stacking arrangement of centred rhodium units with an intermetallic separation of 3.425(4)A.

Developing synthetic approaches with non-innocent metalloligands: Easy access to Ir I/Pd 0 and Ir I/Pd 0/Ir I cores

Guilty as charged is the verdict for anionic Ir complex [Ir(bpa−2 H)(cod)]− in its reactions with PdII compounds. The net transfer of two electrons from the Ir complex to Pd allows easy preparation of di‐ and trinuclear π‐imine‐coordinated Pd0 compounds such as [{Ir(PyCH2NCHPy)(cod)}2Pd] (see picture; C white, Ir red, N blue, Pd yellow). bpa−2 H: doubly deprotonated form of N,N‐bis(2‐picolyl)amine (bpa); cod: 1,5‐cyclooctadiene.

Formation of a bridging-imido d6 rhodium compound by nitrene capture. insertion and cycloaddition reactions.

The first d (6) rhodium imido complex, [{(C 5Me 5)Rh(mu-NSO 2C 6H 4Me- p)} 2] ( 2), has been obtained from the reaction of [(C 5Me 5)Rh(C 2H 4) 2] with chloramine-T. Carbon monoxide inserts into the N-Rh bonds in 2 to give the dinuclear ureylene complex [(C 5Me 5)Rh(mu-{(Ts) N-CO-N(Ts)}Rh(CO)(C 5Me 5)], while the azide C 6F 5N 3 adds to 2 to give the mononuclear tetrazene complex [(C 5Me 5)Rh{( p-MeC 6H 4SO 2)N 4(C 6F 5)}].

N-Substituted imidazole derivatives of rhodium(I) and iridium(I) with and without metal-metal interaction. Crystal structure of cis-(CO)2RhCl(N-methylimidazole)

Bridge splitting reactions with N-methylimidazole (Rim, R = Me) or N-benzylimidazole (Rim, R = PhCH2) gave cis-L2MCl(Rim) complexes (M = Rh, Ir, L2 = (CO)2, 1,5-cyclooctadiene; M = Rh, L2 = (p-tosylmethyl isocyanide)2 or (CO)(PPh)3). M … M interactions in the dicarbonyl complexes are revealed by an X-ray diffraction study of cis-(CO)2RhCl(N-methylimidazole). The molecular units pack in the crystal as infinite chains along the c-axis with intermetallic distances Rh ⋯ Rh of 3.2833(5) A.