Juan Gil-Rubio

Mono- and Dinuclear Ag(I), Au(I), and Au(III) Metallamacrocycles Containing N-Heterocyclic Dicarbene Ligands

Ag(I) dicarbene complexes [Ag(m)(L(n))m]X(m) (L(n) = Im(Me)(CH2)(n)Im(Me), Im(Me) = N-methylimidazol-N-yl-2-ylidene; n = 3, X = PF6, m = 2; n = 6-8, 10, X = AgBr2, m = 1, 2) were prepared by reacting Ag2O with 1 equiv of the corresponding bisimidazolium salt [H2L(n)]A2 (A = PF6, Br). The dibromoargentates react with 1 equiv of AgTfO to afford [Ag(m)(L(n))m](TfO)m (m = 1, 2). The room temperature transmetalation reaction of [Ag(m)(L(n))m][AgBr2]m (n = 3, 5, 6-8, 10) with [AuCl(SMe2)] and AgTfO (L(n):Au:TfO = 1:1:1) affords [Au2(μ-L(n))2](TfO)2 (n = 3, 5, 10), or mixtures of [Au(κ(2)-L(n))]TfO (main product for n = 7) and [Au2(μ-L(n))2](TfO)2 (main product for n = 6, 8). At room temperature, the equilibrium between [M2(μ-L(n))2](TfO)2 and [M(κ(2)-L(n))]TfO is fast for M = Ag, but slow for M = Au, in the NMR time scale. When n ≥ 7 and M = Ag or Au, the equilibrium is shifted toward the mononuclear complexes in the order 8 > 10 > 7, which proves that the (CH2)8 linker has the optimal length for trans chelation. Correspondingly, the high-temperature metalation of [H2L(n)]Br2 (n = 8, 10) with 1 equiv of [AuCl(SMe2)] and excess of NaAcO, affords [Au(κ(2)-L(n))]Br with a small amount of [Au2(μ-L(n))2]Br2. If AgTfO is added to the reaction mixture, [Au(κ(2)-L(8))]2[AgBr3] is isolated instead of the desired triflate, which can be obtained by reacting the mixture of [Au(κ(2)-L(8))]Br and [Au2(μ-L(8))2]Br2 with AgTfO. [Au(κ(2)-L(10))]TfO was isolated after thermal conversion of [Au2(μ-L(10))2](TfO)2. [Au(κ(2)-L(8))]TfO reacts with I2 to give trans-[AuI2(κ(2)-L(8))]TfO, which is the first Au(III) complex containing a trans-spanning bidentate ligand. We have determined the crystal structures of complexes [Ag2(μ-L(3))2](PF6)2, [Ag(κ(2)-L(7))]TfO, [Au2(μ-L(3))2](TfO)2, [Au(κ(2)-L(8))]Br, [Au(κ(2)-L(8))]2[AgBr3], and trans-[AuI2(κ(2)-L(8))]TfO.

Palladium-assisted formation of carbon-carbon bonds. Stoichiometric synthesis of indenols and indenones. Catalytic synthesis of an indenol

Reactions of diphenylacetylene or dimethylacetylenedicarboxylate with Q2[Pd2R2Cl2(μ-Cl)2] (1) [Q = (PhCH2)Ph3P; R = 2,3,4-trimethoxy-6-formylphenyl] give metallic palladium and 2,3-diphenyl-, or 2,3-dimethylcarboxylate-, 5,6,7-trimethoxyindenone (2 or 3), respectively whereas diphenylacetylene reacts with [PdR(bipy)(MeCN)]ClO4 (4), to give 2,3-diphenyl-5,6,7-trimethoxyindenol (5) and [Pd2 (OH)2(bipy)2](ClO4)2 (6). Catalytic synthesis of 5 is achieved by reaction of [HgR2], Ph2C2, and CuCl2 in the presence of (Me4N)2[Pd2Cl6] (molar ratios 1:2:2:0.1).

The metalcarbon bond in vinylidene, carbonyl, isocyanide and ethylene complexes

Abstract Density functional theory (DFT) calculations were carried out for trans-[RhX(L)(PMe3)2] (L=CCH2, CCHC6H5, CO, 2,6-Me2C6H3NC, C2H4) which served as model compounds for the analysis of the vibrational spectra of related complexes. The characterization of the metalcarbon stretching mode allowed to study the trans influence of a series of ligands on the metalcarbon bond in vinylidene, carbonyl and isocyanide complexes. Furthermore, the comparison of the FT-Raman spectra of the complexes trans-[RhF(CO)(PiPr3)2] and trans-[RhF(13C13CH2)(PiPr3)2] which possess the same reduced mass (13C13CH2 vs. CO) allowed for an evaluation of the RhC bond strength free of any mass effects and therefore only showing effects of electronic nature.

Synthesis of rhodium(I) and rhodium(III) perfluoroalkyl complexes from [Rh(μ-OH)(COD)]2

Complexes [Rh(RF)(PMexPh3-x)3] (RF = CF3, x = 1 ( 2); RF = n-C3F7, x = 1 ( 3), x = 2 ( 4)) are quantitatively generated in situ when [Rh(-OH)(COD)]2 ( 1) is reacted with the corresponding Me3SiRF and PMexPh3-x. In contrast, the reaction of 1 with Me3SiCF3 and PMe2Ph gives mixtures containing [Rh(CF3)(PMe2Ph)3] ( 5), [Rh(CF3)(PMe2Ph)4] ( 6), [Rh(CF3)(COD)(PMe2Ph)2] ( 7) and [Rh(CF3)(COD)(PMe2Ph)] ( 8), the relative amounts of which depend on the Rh:PMe2Ph molar ratio. [Rh(CF3)(2-O2)(PMePh2)3] ( 9) was isolated after bubbling air through a solution of 2 in THF. Reactions of in situ generated 2-5 with L = CO, XyNC (Xy = 2,6-dimethylphenyl) gives pentacoordinate complexes [Rh(RF)L(PMexPh3-x)3] (L = CO, x = 1, RF = CF3 ( 10), n-C3F7 ( 11); L = XyNC, RF = CF3, x = 1 ( 12), 2 ( 13); L = XyNC, RF = n-C3F7, x = 2 ( 14)). Oxidative addition of MeI (i) to 2 gives (PMe2Ph2)[OC-6-43]-[Rh(CF3)(Me)I2(PMePh2)2] ( 15), which reacts with Tl(acac) (acac = acetylacetonato) to give [OC-6-14]-[Rh(CF3)(Me)(acac)(PMePh2)2] ( 16), (ii) to 5 gives [Rh(CF3)(Me)I(PMe2Ph)3] as a ca. 5 : 1 mixture of the isomers OC-6-34 ( 17) and OC-6-43 ( 17), and (iii) to 12 or 14 leads to [OC-6-52]-[Rh(CF3)(Me)I(CNXy)(PMePh2)2] ( 18) or [OC-6-52]-[Rh(n-C3F7)(Me)I(CNXy)(PMe2Ph)2] ( 19), respectively. Oxidative addition of iodotrifluoroethene to 12 affords [OC-6-32]-[Rh(CFCF2)(CF3)I(CNXy)(PMePh2)2] ( 20). The crystal structures of 10, 15 and 19 were determined.

Vibrational spectroscopy studies and density functional theory calculations on square-planar vinylidene, carbonyl and ethylene rhodium(I) complexes

Abstract Density functional theory (DFT) calculations have been carried out for trans-[RhF(CCH2)(PMe3)2] (5), trans-[RhF(CO)(PMe3)2] (6) and trans-[RhF(C2H4)(PMe3)2] (7) which serve as model compounds for the analysis of the vibrational structure of related rhodium (I) compounds. The calculated structures were in good agreement with the geometries determined from the experimental data of related compounds. The calculated vibrational modes have been used to classify the bands found in the Raman spectra of the rhodium (I) complexes: trans-[RhF(CCH2)(PiPr3)2] (1), trans-[RhF(13C13CH2)(PiPr3)2] (2), trans-[RhF(CO)(PiPr3)2] (3) and trans-[RhF(C2H4)(PiPr3)2] (4). The comparison of the vibrational behavior of the vinylidene complexes 1 and 2 allow for a characterization of the RhC stretching mode. The IR and FT-Raman spectra of complexes 1–4 exhibit one vibrational mode between 425 and 465 cm−1 with strong to medium intensity. This band can be assigned to the ν(RhF) mode.

Palladium-assisted formation of carboncarbon bonds Part 2. Stoichiometric synthesis of spirocyclic compounds. X-ray structure of a π-allylic palladium intermediate

Abstract Stoichiometric reactions of arylpalladium compounds with alkynes give spirocyclic organic and organometallic compounds. The compound bis{ k 2 -C-O-(2,3,4-trimethoxy-6-acetyl-phenyl)}di(μ-chloro)dipalladium(II) reacts with diphenyl-acetylene or ethyl 3-phenylpropiolate giving 6-acetyl-1,2,3,4-tetraphenyl-9,10-dimethoxy-spiro[4.5] 1,3,6,9-decatetraen-8-one and 6-acetyl-1,3-dicarboxyethyl-2,4-diphenyl-9,10-dimethoxy-spiro[4,5]1,3,6,9-decatetraen-8-one, respectively. A π-allylpalladium complex, η 3 -{6-acethyl-1,2,3,4-tetraphenyl-8,9,10-trimethoxy-spiro[4,5] 1,3,9-decatrien-6-enyl} (2,2′-bipyridine)palladium(II) trifluoromethylsulfonate solvated, with one molecule of 1,2-dichloroethane, has also been isolated and its structure determined by X-ray diffraction studies.

The Coordination and Supramolecular Chemistry of Gold Metalloligands

This review article deals with the use of gold metalloligands as building blocks for the assembly of heterometallic complexes. Several families of gold complexes decorated with crown-ether, amide, pyridine, bipyridine, terpyridine, carboxylato, amino acid or π-alkyne binding sites have been reported. Adducts of these metalloligands with alkaline or transition-metal cations, or with transition-metal or lanthanide complexes, have been isolated and structurally characterized. The reported heterometallic species range from simple dinuclear complexes to self-assembled supramolecules, coordination polymers, or solids. New structural motifs have been found in these complexes. Most of these metalloligands and complexes are photoluminescent and some of them show switchable emissions based on the formation and rupture of metallophilic contacts. Potential applications as sensors, sensitizers, in vivo imaging agents, and anticancer drugs are envisaged.

Preparation, molecular structure, and fundamental vibrational modes of the dinuclear complexes trans-[{RhX(PiPr3)2}2{μ-1,3-(CN)2C6H4}]

Abstract The reaction of [RhCl(C8H14)2]2 with 4 equiv. of PiPr3 and an equimolar amount of 1,3-C6H4(NC)2 in benzene–ether led to the formation of the dinuclear diisonitrile complex trans-[{RhCl(PiPr3)2}2{μ-1,3-(CN)2C6H4}] (2) in 75% yield. The related iodo compound trans-[{RhI(PiPr3)2}2{μ-1,3-(CN)2C6H4}] (3) was obtained from 2 and NaI by salt metathesis. Density functional theory (DFT) calculations have been carried out for the model complexes trans-[RhX(CNC6H5)(PMe3)2] (X=F, Cl) and trans-[{RhF(PMe3)2}2{μ-1,3-(CN)2C6H4}] in order to assign the vibrational modes of compounds 2 and 3. Moreover, the FT-Raman spectrum of the free ligand m-diisocyanobenzene has been measured and analyzed based on the calculation of the Raman intensities for the normal modes using the BPW91/6-31+G(d) method. The most noteworthy result is that the RhC stretching mode of 2 appears at almost the same wavenumber as that of the vinylidene complex trans-[RhCl(CCHC6H5)(PiPr3)2]. The crystal and molecular structure of 2 has been determined by X-ray crystallography.