Rhodium Derivatives Research Articles

ChemInform Abstract: Metalation of Carbaporphyrinoid Systems

AbstractReview: 79 refs.

N,N′-Bis(4-chlorophenyl)pentane-2,4-diiminato]dicarbonylrhodium(I)

The title compound, [Rh(C17H15Cl2N2)(CO)2], is a rhodium(I) derivative of a β-diketiminato moiety. It is an example of a new type of β-diketiminate derivative that has not yet been characterized via solid-state methods. The complex crystallizes with a distorted square-planar geometry about the RhI atom (m symmetry). A weak inter­molecular C—H⋯O contact is observed.

Carbosilane dendrimers peripherally functionalized with P-stereogenic diphosphine ligands and related rhodium complexes

The first carbosilane dendrimer functionalized with P-stereogenic diphosphine ligands was prepared along with its cationic rhodium derivative. A mononuclear rhodium model compound was also synthesized. Both species were used as catalysts in the hydrogenation of dimethylitaconate and the results compared with those obtained with the related rhodium-containing P-stereogenic monophosphine dendrimers.

Efficient Transfer Hydrogenation Using Iridium and Rhodium Complexes of Benzannulated N‐Heterocyclic Carbenes

AbstractBenzimidazol‐2‐ylidene(NHC) derivatives of iridium(I) and rhodium(I) bearing electron‐rich and/or functional substituents R and R′ at the nitrogen atoms of the heterocycle [IrBr(cod)(NHC)] (a) or [RhBr(cod)(NHC)] (b) (R = 2,3,5,6‐tetramethylbenzyl; R′ = methoxyethyl, 1a,b; R = R′ = 2,3,5,6‐tetramethylbenzyl, 2a,b; R = pentamethylbenzyl, R′ =methoxyethyl, 3a,b; R = R′ = pentamethylbenzyl, 4a,b) were prepared. All compounds were fully characterized by 1H and 13C NMR spectroscopy, mass spectrometry (MALDI), and elemental analysis. In addition, the molecular structures of 1a, 2a, and 3a were determined by single‐crystal X‐ray diffraction studies. All of the new benzimidazol‐2‐ylidene iridium(I) and rhodium(I) complexes were found to be effective catalysts for transfer hydrogenation with iridium(I) derivative 1a showing the highest catalytic activity.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Oxygenation of aromatic hydrocarbons with hydrogen peroxide catalyzed by rhodium carbonyl complexes

AbstractHexanuclear rhodium carbonyl cluster, Rh6(CO)16, catalyzes benzene hydroxylation with hydrogen peroxide in acetonitrile solution. Phenol and (at lower concentration) quinone are formed with the maximum attained total yield and turnover number 17% and 683, respectively. Certain other rhodium carbonyl complexes, containing cyclopentadienyl ligands, Rh2Cp2(CO)3 and Rh3(CpMe)3(CO)3, are less efficient catalysts. Cyclopentadienyl derivatives of rhodium which do not contain the carbonyl ligands, Rh(CpMe5)(CH2CH2)2, RhCp(cyclooctatetraene) and Rh2Cp2(cyclooctatetraene) turned out to be absolutely inactive in the benzene hydroxylation. Styrene is transformed into benzaldehyde and (at lower concentration) acetophenone and 1‐phenylethanol. Copyright © 2008 John Wiley & Sons, Ltd.

7-Azaindol-7-ylborate: A Novel Bidentate N^BH3Chelating Ligand

7-Azaindole (H-azain) reacts with sodium borohydride (NaBH4) to yield the sodium salt of the novel 7-azaindol-7-ylborate anion (7-azain-7)BH3−, two rhodium derivatives of which reveal distinct coordination modes — [Rh{κ2N,H-H3B(7-azain-7)}(CO)(PPh3)2] and [Rh{κ3N,H,H′-H3B(7-azain-7)}(PPh3)2]—thereby demonstrating how the variable denticity of the ligand may accommodate the varying electronic requirements of the metal center.

Toward Multistation Rotaxanes Using Metalloporphyrin Coordination Templating

This paper describes some approaches toward the templated synthesis of rotaxanes incorporating strapped metalloporphyrin moieties as the shuttle unit, with the thread component containing both a neutral diimide "station" and a functionalized pyridine moiety, the latter acting not only as a template but also as a second binding motif. In the first instance, the use of appropriately 3,5-difunctionalized pyridine esters and naphthoquinol-strapped rhodium(III) chloride porphyrins in a stoppering approach to rotaxanes produced only unlinked components: the flexibility of the strap allowed sufficient room for the potential thread unit to bind on the same face of the porphyrin as the strap, while not being interlocked through it. An alternative strategy involving a 1,3-dipolar cycloaddition reaction (a "click" reaction) between azides and alkynes, producing triazole linkers in the thread component of rotaxanes, was more successful. Both porphyrinic (zinc, free base, and rhodium(III) derivatives) and crown ether rotaxanes were successfully produced, with multifunctional (triazole and naphthodiimide) thread units. The potential for molecular motion through the use of stimuli such as acid, solvent, and competing ligands was investigated, with limited success. The same cycloaddition methodology was extended to pyridine-templated analogues of the thread components in the Rh(III)-strapped porphyrins, but again, only unlinked thread and porphyrin shuttle units were produced.

Rhodium Derivatives of Peroxoboronic Acids and Peroxoboric Acid: Formation of Metallatrioxaborolanes from an η2‐Peroxo Complex

Heterocyclische Peroxide mit fünfgliedrigen RhOOBO-Ringen werden bei den Reaktionen eines Rhodiumperoxokomplexes mit Phenylboronsäurederivaten erhalten. Die Produkte können als Rhodiumderivate von Perborsäure (siehe Schema) und Phenylperboronsäuren betrachtet werden.

Rhodium Derivatives of Peroxoboronic Acids and Peroxoboric Acid: Formation of Metallatrioxaborolanes from an η2‐Peroxo Complex

Rhodium Derivatives of Peroxoboronic Acids and Peroxoboric Acid: Formation of Metallatrioxaborolanes from an η²‐Peroxo Complex

Metalation of Carbaporphyrinoid Systems

Diverse carbaporphyrinoid systems have been synthesized using ‘3 + 1’ MacDonald condensations, LindseyRothemund reactions and other strategies. In common with the N-confused porphyrins (NCPs), these compounds have a CNNN core that can facilitate the generation of organometallic derivatives. Benzocarbaporphyrins and tropiporphyrins, with indene or cycloheptatriene units in place of a pyrrole ring, readily form silver(III) complexes and some gold(III) derivatives have also been prepared. On the other hand, benziporphyrins and azuliporphyrins, which have a benzene or azulene unit in place of a pyrrole moiety, are dianionic ligands that afford Ni, Pd and Pt complexes. Stable iridium and rhodium derivatives of azuliporphyrins can also be generated. 2-Methyl or 2-phenyl NCPs act as dianionic ligands forming Ni and Pd complexes but reactions with silver(I) acetate gave the aromatic 3-oxoNCP silver(III) derivatives. A related N-phenylpyrazole-containing porphyrinoid gave nickel(II) and palladium(II) complexes but these showed little or no aromatic character. Oxybenziporphyrins, which have a semiquinone subunit, can form Pd, Pt, Cu, Ag and Au derivatives and can therefore act as both dianionic and a trianionic ligands. Finally, a diazuliporphyrin has been used to prepare the first example of a palladium(II) dicarbaporphyrinoid complex. These investigations demonstrate that the unique characteristics of organometallic compounds derived from carbaporphyrins and related porphyrin analogues are starting to rival the significance of the better known metal complexes of N-confused porphyrins.

Rhodium (III) derivative of dTTP and Ca2+ act interdependently to induce conformational changes in an RB69 DNA polymerase: primer/template complex

Rhodium (III) derivative of dTTP and Ca2+ act interdependently to induce conformational changes in an RB69 DNA polymerase: primer/template complex

Rhodium diphosphite pincer complexes. Rare preferred in-planeolefin conformation in square-planar compounds

Square-planar ethylene rhodium derivatives bearing pincer diphosphite ligands have been prepared and characterized, they display a rare in-plane coordination which, based on DFT calculations, has been mainly attributed to steric effects.

Carbonyl(3,7-dichlorotropolonato)(triphenylphosphine)rhodium(I)

The title compound, [Rh(C7H3Cl2O2)(C18H15P)(CO)], is a rhodium(I) derivative of chlorinated tropolonate. It crystallizes with a nearly square-planar geometry about the rhodium(I) metal centre. The most important bond distances and angles include: Rh—O(trans P) = 2.086 (2) Å, Rh—O(trans carbon­yl) = 2.056 (2) Å, Rh—P = 2.2377 (8) Å, Rh—C(carbon­yl) = 1.809 (2) Å, O—Rh—O = 76.60 (6)° and O—C—C—O = −3.0 (3)°.

Synthesis of 2-picolyl functionalized η 5-cyclopentadienyl derivatives of rhodium(I) and iridium(I) and preliminary study of their reaction with ruthenium(II) for assembling hetero-bimetallic complexes

The 2-picolylcyclopentadienyl derivatives of rhodium(I) and iridium(I) of formula [M{η 5-C 5H 4(2-CH 2C 5H 4N)}(η 4-C 8H 12)] ( 3) (M = Rh) and ( 4) (M = Ir) are obtained in good yields by reacting 2-picolylcyclopentadienyllithium ( 7) with [RhCl(η 4-C 8H 12)] 2 and [IrCl(η 4-C 8H 12)] 2, respectively. The corresponding dicarbonyl derivatives, [M{η 5-C 5H 4(2-CH 2C 5H 4N)}(CO) 2] ( 5) (M = Rh) and 6 (M = Ir), are obtained in good yields by reacting 2-picolylcyclopentadienylthallium(I) ( 8) with [RhCl(CO) 2] 2 and [IrCl(C 5H 5N)(CO) 2], respectively. 5 has already been reported in the literature. The new complexes were characterized by elemental analysis, mass spectrometry, 1H NMR, FT-IR, and UV–Vis (210–330 nm) spectroscopy. The UV–Vis spectra indicate the existence of some electronic interaction between the 2-picolinic chromophore and the cyclopentadienyl-metal moiety. The study of the electrochemical behaviour of 3– 6 by cyclic voltammetry (CV) allows the interpretation of the electrode processes and gives information about the location of the redox sites. Moreover, various synthetic strategies were tested in order to try to coordinate the complexes 3– 6 to a ruthenium(II) centre, but most of them failed. Instead, the hetero-bimetallic complex bis(2,2′-bipyridine)[(η 5-2-picolylcyclopentadienyl)(η 4-cycloocta-1,5-diene)rhodium(I)]chlororuthenium(II)-(hexafluorophosphate) ( 13), was obtained, although in poor yields (10%), by reacting the nitrosyl complex [RuCl(bipy) 2(NO)][PF 6] 2 14 (bipy = 2,2′-bipyridine) first with potassium azide and then with the rhodium(I) complex 3. The analogous complex bis(2,2′-bipyridine)(2-picoline)chlororuthenium(II)-(hexafluorophosphate) ( 15), that carries a ruthenium-bonded 2-picoline molecule instead of 3, has prepared in the same way. 13 and 15 were characterized by elemental analysis, mass spectrometry, and 1H NMR.

Functional Microporous Materials of Metal Carboxylate: Gas‐Occlusion Properties and Catalytic Activities

AbstractFor Abstract see ChemInform Abstract in Full Text.

Functional microporous materials of metal carboxylate: Gas-occlusion properties and catalytic activities

Copper(II) terephthalate is the first transition metal complex found capable of adsorbing gases. This complex has opened the new field of adsorbent complex chemistry. It is recognized as the lead complex in the construction of microporous complexes. This specific system has been expanded to a systematic series of derivatives of other isomorphous transition metals, molybdenum(II), ruthenium(II, III), and rhodium(II). These complexes with open frameworks are widely recognized as very useful materials for applications to catalysis, separation at molecular level, and gas storage.

Adducts of Cyclotriphosphorus Complexes with Cyclopentadienyl Ruthenium Fragments: Synthesis, Solid‐State Structure and Solution Behaviour

AbstractTreatment of the cyclo‐P3 complexes [(triphos)M(η3‐P3)]‐[triphos = 1,1,1‐tris(diphenylphosphanylmethyl)ethane; M = Co (1), Rh (2)] with stoichiometric amounts of [CpRu‐(CH3CN)2(PR3)]PF6 [R = Ph (3), Me (4), Cy (5)] in CH2Cl2 in the presence of CH3CN yields the bimetallic adducts [{(triphos)M}(μ,η3:1‐P3){CpRu(CH3CN)(PR3)}]PF6 [M = Co; R = Ph (6), Me (7), Cy (8); M = Rh; R = Ph, (9), Me (10), Cy (11)]. The rhodium derivatives 9 and 11, upon treatment with one equivalent of PMe3, form the complexes [{(triphos)Rh}(μ,η3:1‐P3){CpRu(PMe3)(PR3}]PF6 [R = Ph (12), Cy (13)]. On standing in CH2Cl2, the rhodium complexes 9 and 10 lose acetonitrile to yield compounds with the formula [{(triphos)Rh}(μ,η3:1,1'‐P3){CpRu(PR3)}]PF6 [R = Ph (14), Me (15)]. All the compounds have been characterised by elemental analyses and, in solution, by 31P and 1H NMR spectroscopy. The 31P{1H} EXSY NMR spectroscopic data at different temperatures of 11 and 14 have highlighted the occurrence of independent dynamic processes that exchange both the triphos and the cyclo‐P3 phosphorus nuclei. An X‐ray structural investigation carried out on 6 has confirmed the occurrence of the μ,η3:1‐ligating behaviour of the cyclo‐P3 ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

One-pot synthesis of the new dianionic ligand [Na] 2[C 5H 4CO 2(CH 2) 2NTs]; preparation and structures of two rhodium derivatives

The new dianionic ligand [Na] 2[C 5H 4CO 2(CH 2) 2NTs] ( 1) having an alkoxycarbonyl and an amide group in the same side chain has been prepared by a single step, high yield procedure. The synthesis of the related rhodium complexes [Rh{η 5-C 5H 4CO 2(CH 2) 2N(H)Ts}(NBD)] ( 3) and [Rh{η 5-C 5H 4CO 2 (CH 2) 2N(Me)Ts}(NBD)] ( 4) is reported as well as their X-ray molecular structures.

Mononuclear and heterodinuclear transition metal complexes of functionalized phosphinesCrystal and molecular structures of [Mo(CO)5(RPC6H4OCH2OCH3-o)] (R=Ph, C6H4OCH2OCH3-o), [Ru(Ph2PC6H4O-o)3], [Pd(Ph2PC6H4O-o)2] and [PdCl(Ph2PC6H4O-o)(Ph2PC6H4OH-o)

Transition metal complexes of phosphine ethers (Ph2PC6H4OCH2OCH3-o and PhP(C6H4OCH2OCH3-o)2) and phosphinophenol, Ph2PC6H4OH-o are described. Phosphine ethers react with Group 6 metal carbonyls to form complexes of the type [M(CO)4L2] and [M(CO)5L] (M = Mo, Cr, W). The reaction of Ph2PC6H4OCH2OCH3-o with RuCl3 · 3H2O gave ruthenium(III) complex, [Ru(Ph2PC6H4O-o)3] through the elimination of CH3OCH2Cl whereas the reaction with CpRu(PPh3)2Cl resulted in the formation of [CpRu(Ph2PC6H4O-o)PPh3]. Treatment of Ph2PC6H4OCH2OCH3-o with rhodium(I) derivatives resulted in the formation of complexes with the phosphine exhibiting both mono- and bidentate modes of coordination involving the phosphorus center and the phenolic oxygen. The reaction of Ph2PC6H4OCH2OCH3-o with [PdCl2(COD)] led to the isolation of two mononuclear complexes, [PdCl(Ph2PC6H4O-o)(Ph2PC6H4OH-o)] cocrystallized with phosphonium salt, [Ph2P(CH2OCH3)C6H4OH-o]Cl and [Pd(Ph2PC6H4O-o)2] as confirmed by X-ray diffraction studies. The former shows extensive hydrogen bonding interactions between the complex and the phosphonium salt. The metalloligand, Cp2Zr(OC6H4PPh2-o)2 obtained by the reaction of Cp2ZrCl2 with Ph2PC6H4OH-o form heterobimetallic complexes with Mo(0), Re(I) and Ni(0) carbonyl derivatives. The reactions of Cp2Zr(OC6H4PPh2-o)2 with metal halides such as M(COD)Cl2 (M = Pd, Pt) and CpRuCl(PPh3)2 afforded metallacycles, [M(Ph2PC6H4O-o)2] and [CpRu(PPh2C6H4OH-o)(PPh2C6H4O-o)], respectively via transmetallation.

Mononuclear and heterodinuclear transition metal complexes of functionalized phosphines: Crystal and molecular structures of [Mo(CO) 5(RPC 6H 4OCH 2OCH 3- o)] (R = Ph, C 6H 4OCH 2OCH 3- o), [Ru(Ph 2PC 6H 4O- o) 3], [Pd(Ph 2PC 6H 4O- o) 2] and [PdCl(Ph 2PC 6H 4O- o)(Ph 2PC 6H 4OH- o)

Transition metal complexes of phosphine ethers (Ph 2PC 6H 4OCH 2OCH 3- o and PhP(C 6H 4OCH 2OCH 3- o) 2) and phosphinophenol, Ph 2PC 6H 4OH- o are described. Phosphine ethers react with Group 6 metal carbonyls to form complexes of the type [M(CO) 4L 2] and [M(CO) 5L] (M = Mo, Cr, W). The reaction of Ph 2PC 6H 4OCH 2OCH 3- o with RuCl 3 · 3H 2O gave ruthenium(III) complex, [Ru(Ph 2PC 6H 4O- o) 3] through the elimination of CH 3OCH 2Cl whereas the reaction with CpRu(PPh 3) 2Cl resulted in the formation of [CpRu(Ph 2PC 6H 4O- o)PPh 3]. Treatment of Ph 2PC 6H 4OCH 2OCH 3- o with rhodium(I) derivatives resulted in the formation of complexes with the phosphine exhibiting both mono- and bidentate modes of coordination involving the phosphorus center and the phenolic oxygen. The reaction of Ph 2PC 6H 4OCH 2OCH 3- o with [PdCl 2(COD)] led to the isolation of two mononuclear complexes, [PdCl(Ph 2PC 6H 4O- o)(Ph 2PC 6H 4OH- o)] cocrystallized with phosphonium salt, [Ph 2P(CH 2OCH 3)C 6H 4OH- o]Cl and [Pd(Ph 2PC 6H 4O- o) 2] as confirmed by X-ray diffraction studies. The former shows extensive hydrogen bonding interactions between the complex and the phosphonium salt. The metalloligand, Cp 2Zr(OC 6H 4PPh 2- o) 2 obtained by the reaction of Cp 2ZrCl 2 with Ph 2PC 6H 4OH- o form heterobimetallic complexes with Mo(0), Re(I) and Ni(0) carbonyl derivatives. The reactions of Cp 2Zr(OC 6H 4PPh 2- o) 2 with metal halides such as M(COD)Cl 2 (M = Pd, Pt) and CpRuCl(PPh 3) 2 afforded metallacycles, [M(Ph 2PC 6H 4O- o) 2] and [CpRu(PPh 2C 6H 4OH- o)(PPh 2C 6H 4O- o)], respectively via transmetallation.