Enseñanza de las propiedades electrónicas y magnéticas de los compuestos de coordinación mediante fichas de actividad

En esta comunicación se describe el desarrollo de una metodología de enseñanza consistente en guiar a los estudiantes en su aprendizaje a través de la resolución de una serie de fichas proporcionadas por la profesora. En estas fichas se plantean diferentes actividades consistentes en lecturas y visualización de vídeos seguidos de cuestiones teóricas y ejercicios prácticos que los alumnos deben resolver en grupos de cuatro. Con este sistema, los alumnos pueden expresar sus opiniones y razonamientos en voz alta a la vez que escuchan lo que exponen sus compañeros. En todo momento el profesor se encuentra accesible para que ellos puedan consultar todas sus dudas ayudándoles, cuando es necesario, a reconducir sus razonamientos. En concreto se va a aplicar dicha metodología al estudio de las propiedades electrónicas y magnéticas de los compuestos de coordinación, un tema de gran complejidad para los estudiantes de grado en Química

Palladium-mediated Intramolecular Dearomatization of Ligated Dialkylterphenyl Phosphines

Aryl-Pd(ii) chlorides stabilized by dialkylterphenyl phosphine ligands undergo a thermal isomerization process, leading to the formation of allyl-Pd(ii)-chloride species. The transformation involves the intramolecular functionalization of a C-H bond of the terphenyl group mediated by the Pd(ii) center.Ministerio de Ciencia, Innovación y Universidades CTQ2017-82893-C2-2-

Boryl-assisted hydrogenolysis of a nickel–methyl bond

A stable Nickel(II) methyl complex containing a diphosphinoboryl (PBP) pincer ligand is described. Mechanistic studies on the hydrogenolysis of the Ni-Me bond suggest a metal ligand cooperation mechanism that involves the intermediacy of a - B‒H Ni(0) species that further undergoes B‒H oxidative addition to form a Ni(II) hydride complex

Electrophilic activation of alkynes promoted by a cationic alkylidene complex of Pt(II)

Pt(II) alkylidene 1a has been reacted with terminal alkynes to afford ylide complexes 3a-d, resulting from electrophilic activation of the C≡C bond and its insertion into the platinacyclic fragment of 1a that contains the carbene functionality. DFT calculations indicate that the observed regioselectivity is determined by the nucleophilic attack of the alkyne to the alkylidene carbon.MICINN/AEI/10.13039/501100011033/, “ERDF A way of making Europe” (CTQ2017-82893-C2-2-R), MICINN (CTQ2016-75193-P and PID2019-110856GA-I00), US/FEDER/JUNTA, UE (US126226), and Junta de Andalucía (P18-FR-4688

Different coordination modes of an aryl-substituted hydrotris(pyrazolyl) borate ligand in rhodium and iridium complexes

Complexes TptolRh(C2H4)2 (1a) and TptolRh(CH2C(Me)C(Me)CH2) (1b) have been prepared by reaction of KTptol with the appropriate [RhCl(olefin)2]2 dimer (Tptol means hydrotris(3-p-tolylpyrazol-1-yl)borate). The two complexes show a dynamic behaviour that involves exchange between κ2 and κ3 coordination modes of the Tptol ligand. The iridium analogue, TptolIr(CH2C(Me)CHCH2) (2) has also been synthesized, and has been converted into the Ir(III) dinitrogen complex [(κ4-N,N',N'',C-Tptol)Ir(Ph)(N2) (3) by irradiation with UV light under a dinitrogen atmosphere. Compound 3 constitutes a rare example of Ir(III)-N2 complex structurally characterized by X-ray crystallography. Its N2 ligand can be easily substituted by acetonitrile or ethylene upon heating and denticity changes in the Tptol ligand, from κ4-N,N',N'',C (monometallated Tptol, from now on represented as Tptol′) to κ5-N,N′,N″,C,C″ (dimetallated Tp tol ligand, represented as Tptol″) have been observed. When complex 3 is heated in the presence of acetylene, dimerization of the alkyne takes place to yield the enyne complex [(κ5-N,N′,N′′,C,C′-Tp tol)Ir(CH2CHCCH), 7̧ in which the unsaturated organic moiety is bonded to iridium through the carbon-carbon double bond.Ministerio de Educación y Ciencia CTQ2007-62814Consolider-Ingenio 2010 CSD2007-00006Junta de Andalucía FQM-3151, FQM-672CONACYT 22934

Synthesis, properties, and some rhodium, iridium, and platinum complexes of a series of bulky m-terphenylphosphine ligands

A series of sterically demanding aryl phosphine ligands (L) bearing terphenyl substituents, PR2Ar′ (R = hydrocarbyl, Ar′ = 2,6-diarylphenyl radical) has been prepared and characterized. The stability of these ligands towards oxidation in the air has been tested, and theoretical and experimental studies aimed to provide information on their electronic and steric properties have been performed. Treatment of the metal dimers [MCl(COD)]2(M = Rh, Ir; COD = 1,5-cyclooctadiene) with ligands PMe2ArXyl2(L1) and PMe2ArDipp2(L5), in a 1:1 metal:ligand ratio, afforded the expected square-planar 16-electron complexes [MCl(COD)(PMe2ArXyl2)] and [MCl(COD)(PMe2ArDipp2)], respectively. These compounds were readily converted into the corresponding dicarbonyl derivatives, [MCl(CO)2(PMe2ArXyl2)] and [MCl(CO)2(PMe2ArDipp2)], respectively. While the expected κ1-P coordination mode of the PR2Ar′ ligands is found for these rhodium and iridium species, the mononuclear Pt(II) derivative obtained by reaction of PtCl2with PMe2ArDipp2has composition [PtCl2(PMe2ArDipp2)], and exhibits a bidentate κ1-P, η1-arene coordination mode involving one of the ipso carbon atoms of a flanking terphenyl aryl ring. The corresponding carbonyl compound [PtCl2(CO)(PMe2ArDipp2)], was generated under a CO atmosphere and exhibits κ1-P coordination mode.Ministerio de Ciencia CTQ2013-42501-P, CTQ2014-51912-REDC, CTQ-2014-52769-C3-3-RJunta de Andalucía FQM-119 P09-FQM-4832, FQM-2126European Union 26722

A versatile approach to access trimetallic complexes based on trisphosphinite ligands

A straightforward method for the preparation of trisphosphinite ligands in one step, using only commercially available reagents (1,1,1-tris(4-hydroxyphenyl)ethane and chlorophosphines) is described. We have made use of this approach to prepare a small family of four trisphosphinite ligands of formula [CH3C{(C6H4OR2)3], where R stands for Ph (1a), Xyl (1b, Xyl = 2,6-Me2-C6H3), iPr (1c), and Cy (1d). These polyfunctional phosphinites allowed us to investigate their coordination chemistry towards a range of late transition metal precursors. As such, we report here the isolation and full characterization of a number of Au(I), Ag(I), Cu(I), Ir(III), Rh(III) and Ru(II) homotrimetallic complexes, including the structural characterization by X-ray diffraction studies of six of these compounds. We have observed that the flexibility of these trisphosphinites enables a variety of conformations for the different trimetallic species.European Research Council 756575Ministerio de Ciencia, Innovación y Universidades CTQ2017-92622-EX

Formation of C−X Bonds Through Stable Low-Electron Count Cationic Pt(IV) Alkyl Complexes Stabilized by N-Heterocyclic Carbenes

Cationic five-coordinate Pt(IV) alkyl complexes stabilized by bulky N-heterocyclic carbenes have been isolated and fully characterized. Related species have been postulated as key intermediates in carbon–heteroatom coupling reactions and most particularly in Shilov-type chemistry. The alkyl groups exhibit a pronounced electrophilic character and can undergo nucleophilic addition of pyridine, bromide, or iodide to form new carbon–heteroatom bonds. Nevertheless, direct reductive coupling to form C–X bonds can be operative in the absence of an external nucleophile source.Ministerio de Ciencia, Innovación y Universidades CTQ2013-45011Junta de Andalucía FQM-212

Synthesis, Structure and Nickel Carbonyl Complexes of Dialkylterphenyl Phosphines

The experimental and computational characterization of a series of dialkylterphenyl phosphines, PR2Ar′ is described. The new P‐donors comprise five compounds of general formula PR2Arurn:x-wiley:09476539:media:chem201803598:chem201803598-math-0001 (R=Me, Et, iPr, c‐C5H9 and c‐C6H11); Arurn:x-wiley:09476539:media:chem201803598:chem201803598-math-0002 = 2,6‐C6H3‐(3,5‐C6H3‐(CMe3)2)2), and another five PR2Ar′ phosphines containing the bulky alkyl groups iPr, c‐C5H9 or c‐C6H11, in combination with Ar′=Arurn:x-wiley:09476539:media:chem201803598:chem201803598-math-0003 , Arurn:x-wiley:09476539:media:chem201803598:chem201803598-math-0004 , or Arurn:x-wiley:09476539:media:chem201803598:chem201803598-math-0005 (L1–L10). Steric and electronic parameters have been determined computationally and from IR and X‐ray data obtained for the phosphines and for some derivatives, including tricarbonyl and dicarbonyl nickel complexes, Ni(CO)3(PR2Ar′) and Ni(CO)2(PR2Ar′). In the solid state, the free phosphines PR2Ar′ adopt one of the three possible structures formally related by rotation around the Cipso−P bond. Details on their relative energies and on the influence of the free phosphine structure on its coordination chemistry towards Ni(CO)n (n = 2, 3) fragments has been obtained by experimental and computational methods.Ministerio de Economía y Competitividad CTQ2013-42501-P, CTQ2016-75193-P, CTQ2017-82893-C2-2-

An Unsaturated Four-Coordinate Dimethyl Dimolybdenum Complex with a Molybdenum–Molybdenum Quadruple Bond

We describe the synthesis and the molecular and electronic structures of the complex [Mo2Me2{μ‐HC(NDipp)2}2] (2; Dipp=2,6‐iPr2C6H3), which contains a dimetallic core with an Mo–Mo quadruple bond and features uncommon four‐coordinate geometry and has a fourteen‐electron count for each molybdenum atom. The coordination polyhedron approaches a square pyramid, with one of the molybdenum atoms nearly co‐planar with the basal square plane, in which the trans coordination position with respect to the Mo−Me bond is vacant. The other three sites are occupied by two trans nitrogen atoms of different amidinate ligands and the methyl group. The second Mo atom occupies the apex of the pyramid and forms an Mo–Mo bond of length 2.080(1) Å, consistent with a quadruple bond. Compound 2 reacts with tetrahydrofuran (THF) and trimethylphosphine to yield the mono‐adducts [Mo2Me(μ‐Me){μ‐HC(NDipp)2}2(L)] (3⋅THF and 3⋅PMe3, respectively) with one terminal and one bridging methyl group. In contrast, 4‐dimethylaminopyridine (dmap) forms the bis‐adduct [Mo2Me2{μ‐HC(NDipp)2}2(dmap)2] (4), with terminally coordinated methyl groups. Hydrogenolysis of complex 2 leads to the bis(hydride) [Mo2H2{μ‐HC(NDipp)2}2(thf)2] (5⋅THF) with elimination of CH4. Computational, kinetic, and mechanistic studies, which included the use of D2 and of complex 2 labelled with 13C (99 %) at the Mo–CH3 sites, supported the intermediacy of a methyl‐hydride reactive species. A computational DFT analysis of the terminal and bridging coordination of the methyl groups to the Mo≣Mo core is also reported.Ministerio de Ciencia e Innovación CTQ2010-15833, CTQ2013-42501-P, CTQ2014-52769-C3-3-R, CTQ2015-64579-C3-1-P, Consolider-Ingenio 2010 CSD2007-00006Junta de Andalucía FQM-119, P09-FQM-5117Ministerio de Educación AP-4193Ministerio de Ciencia e Innovación BES-2011-04764