Walter Baratta

• University of Udine

Recently, scientists have been developing sustainable processes, and in this context, mechanochemistry is commonly associated with green chemistry for its ability to reduce waste generation from chemical reactions. The well-known acetate complex, diacetate bis(triphenylphosphine) ruthenium(II) [Ru(OAc)2(PPh3)2], is a versatile precursor for prepari...

The amount of free ions, ion pairs, and higher aggregate of the possible species present in a solution during the gold(I)-catalyzed alkoxylation of unsaturated hydrocarbon, i.e., ISIP (inner sphere ion pair) [(NHC)AuX] and OSIP (outer sphere ion pairs) [(NHC)Au(TME)X] [NHC 1,3-bis(2,6-di-isopropylphenyl)-imidazol-2-ylidene; TME = tetramethylethylen...

The cyclometalated terpyridine complexes [Ru(η²-OAc)(NC-tpy)(PP)] (PP = dppb 1, (R,R)-Skewphos 4, (S,S)-Skewphos 5) are easily obtained from the acetate derivatives [Ru(η²-OAc)2(PP)] (PP = dppb, (R,R)-Skewphos 2, (S,S)-Skewphos 3) and tpy in methanol by elimination of AcOH. The precursors 2, 3 are prepared from [Ru(η²-OAc)2(PPh3)2] and Skewphos in...

The qualitative impact of pollutants on water quality is mainly related to their nature and their concentration, but in any case, they determine a strong impact on the involved ecosystems. In particular, refractory organic compounds represent a critical challenge, and several degradation processes have been studied and developed for their removal....

An N-alkylation procedure has been developed under very mild conditions using a known commercially available Ru-based catalyst. As a result, a wide range of aromatic primary amines has been selectively alkylated with several primary alcohols, yielding the corresponding secondary amines in high yields. The methodology also enables the methylation of...

The ion pairing structure of the possible species present in solution during the gold(III)-catalyzed hydration of alkynes: [(ppy)Au(NHC)Y]X2 and [(ppy)Au(NHC)X]X [ppy = 2-phenylpyridine, NHC = NHCiPr = 1,3-bis(2,6-di-isopropylphenyl)-imidazol-2-ylidene; NHC = NHCmes = 1,3-bis(2,4,6-trimethylphenyl)-imidazol-2-ylidene X = Cl–, BF4–, OTf–; Y = H2O an...

With the aim to design new water-soluble organometallic Ru(II) complexes acting as anticancer agents catalysing transfer hydrogenation (TH) reactions with biomolecules, we have synthesized four Ru(II) monocarbonyl complexes (1-4) featuring the 1,4-bis(diphenylphosphino)butane (dppb) ligand and different bidentate nitrogen (N^N) ligands, of general...

The selective oxidation of primary alcohols into their corresponding carbonyl compounds is challenging because of the easy over oxidization to acids and esters. The traditional reaction requires large amounts of solvent and oxidant, causing serious environmental issues. Recently, several efforts have been made to transform the reaction into a more...

The cyclometalated acetate ruthenium complexes [Ru(C^N)(η2-OAc)(dppb)] (dppb = 1,4-bis(diphenylphosphino)butane; HC^N = 2-phenylpyridine 1, benzo[h]quinoline 2, 1-phenylpyrazole 3, 2-phenyl-2-oxazoline 4) are easily obtained in 58-74% yield through a one-pot synthesis from...

The cationic achiral and chiral terpyridine diphosphine ruthenium complexes [RuCl(PP)(tpy)]Cl (PP=dppp (1), (R,R)‐Skewphos (2) and (S,S)‐Skewphos (3)) are easily obtained in 85–88 % yield through a one‐pot synthesis from [RuCl2(PPh3)3], the diphosphine and 2,2′:6′,2′′‐terpyridine (tpy) in 1‐butanol. Treatment of 1–3 with NaPF6 in methanol at RT aff...

The chiral cationic complex [Ru(η¹‐OAc)(CO)((R,R)‐Skewphos)(phen)]OAc (2R), isolated from reaction of [Ru(η¹‐OAc)(η²‐OAc)(R,R)‐Skewphos)(CO)] (1R) with phen, reacts with NaOPiv and KSAc affording [RuX(CO)((R,R)‐Skewphos)(phen)]Y (X=Y=OPiv 3R; X=SAc, Y=OAc 4R). The corresponding enantiomers 2S‐4S have been obtained from 1S containing (S,S)‐Skewphos....

The diacetate complexes trans-[Ru(κ¹-OAc)2(PPh3)2(NN)] (NN = ethylenediamine (en) (1), 2-(aminomethyl)pyridine (ampy) (2), 2-(aminomethyl)pyrimidine (ampyrim) (3)) have been isolated in 76–88% yield by reaction of [Ru(κ²-OAc)2(PPh3)2] with the corresponding nitrogen ligands. The ampy-type derivatives 2 and 3 undergo isomerization to the thermodynam...

For the first time, NHC-Au-X [NHC = (1,3-bis(2,6-di-isopropylphenyl)-imidazol-2-ylidene, X⁻ = BF4⁻, OTf⁻, OTs⁻, TFA⁻] catalysts were tested in the cycloisomerization of N-(prop-2-yn-yl)benzamide to 2-phenyl-5-vinylidene-2-oxazoline in a wide set of green solvents. We found that most of these solvents (cyclohexanone, isopropyl acetate, MIBK, ethyl l...

The transfer hydrogenation of flavanones and ortho‐hydroxychalcones catalyzed by ruthenium pincer complexes RuCl(CNNPh)(disphosphine) has allowed the synthesis of ortho‐hydroxy 1,3‐diarypropanols in 80–88 % yield, under mild reaction conditions and short reaction times (1 h) in 2‐propanol. The amount of the co‐catalyst NaOiPr has been found crucial...

The employment of easily affordable ruthenium(II)-complexes as pre-catalysts in the transfer hydrogenation of carbonyl compounds in deep eutectic media is described for the first time. The eutectic mixture tetrabutylammonium bromide/formic acid = 1/1 (TBABr/HCOOH = 1/1) acts both as reaction medium and hydrogen source. The addition of a base is req...

Several mononuclear ruthenium complexes containing bulky diphosphines have been easily prepared from acetate ruthenium precursors. The cyclohexyl complex [Ru(η²-OAc)2(DCyPF)] (1-cy; DCyPF = 1,1′-bis(dicyclohexylphosphino)ferrocene) is synthesized from [Ru(η²-OAc)2(PPh3)2] and DCyPF in toluene at reflux, whereas the ethylenediamine (en) derivatives...

The mixed acetate acetylacetonate (acac) ruthenium(II) phosphine complexes Ru(OAc)(acac)P2 [P2=(PPh3)2, Ph2P(CH2)4PPh2 (dppb)] were prepared by protonation of Ru(OAc)2(PPh3)2 with acetylacetone in dichloromethane. Reaction of the dppb derivative with 2‐(aminomethyl)pyridine (ampy) affords the complex Ru(OAc)(acac)(ampy)(dppb), which converts to [Ru...

The cationic acetate ruthenium complex [Ru(η1-OAc)(CO)(dppb)(phen)]OAc (1) is easily prepared in 83% yield from [Ru(η1-OAc)(η2-OAc)(CO)(dppb)] (dppb = 1,4-bis(diphenylphosphino)butane) and 1,10-phenanthroline (phen) in MeOH. The derivative 1 undergoes easy substitution of the coordinated acetate by reaction with NaOPiv, KSAc, KSCN in MeOH, affordin...

The ligand HCNNOMe (6-(4-methoxyphenyl)-2-aminomethylpyridine) is easily prepared from the commercially available 6-(4-methoxyphenyl)pyridine-2-carbaldehyde by reaction of hydroxylamine and hydrogenation (H2, 1 atm) with Pd/C. The pincer complexes cis-[RuCl(CNNOMe)(PPh3)2] (1) and [RuCl(CNNOMe)(PP)] (PP = dppb, 2; dppf, 3) are synthesized from [RuC...

The ruthenium complex [Ru(OAc)(a-PC)2]Br (3) containing two abnormal NHC ligands is obtained by reaction of Ru(OAc)2(PPh3)2 (1) with 1-(2-diphenylphosphinoethyl)-3-mesitylimidazolium bromide in the presence of NaOAc. Complex 3 catalyzes the Oppenauer-type oxi-dation of a number of alcohols at unrivalled reaction rates reaching TOFs up to 550 000 h–...

Hydration and alkoxylation of alkynes are key processes for the industrial production of carbonyl derivatives. In this review, the pivotal role of ion pairing in the mechanism of hydration and alkoxylation of alkynes promoted by gold(I) catalysts L-Au-X is deeply analyzed and discussed, that has been elucidated by means of experimental findings sup...

The monocarbonyl complexes [RuCl2(CO)(PR3)(NN)] (R = Cy, NN = en 1, ampy 2; R = iPr; NN = en 3) have been prepared in a one pot reaction from [RuCl2(CO)(dmf)(PPh3)2], PR3 and the NN ligand in CH2Cl2. Treatment of the [Ru(OAc)2(CO)(PPh3)2] with NN ligands in methanol gives the cationic derivatives [Ru(OAc)(CO)(PPh3)(NN)]OAc (NN = en 4, ampy 5) in wh...

The mitochondrial F-ATP synthase is the principal energy-conserving nanomotor of cells that harnesses the proton motive force generated by the respiratory chain to make ATP from ADP and phosphate in a process known as oxidative phosphorylation. In the energy-converting membranes, F-ATP synthase is a multisubunit complex organized into a membrane-ex...

The dinuclear ruthenium(ii) phosphine complexes Ru 2 Cl(O 2 CCH x F 3−x ) 3 (PPh 3 ) 4 (μ-H 2 O) (x = 0, 1, 2), containing fluoroacetate ligands, were prepared from RuCl 2 (PPh 3 ) 3 and NaO 2 CCH x F 3−x in t BuOH. The X-ray characterization of these complexes reveals a bridging water molecule, stabilized by hydrogen bonds with the fluoroacetate l...

The bidentate HCNN dicarbonyl ruthenium complexes trans,cis-[RuCl 2 (HCNN)(CO) 2 ] (1-3) and trans,cis-[RuCl 2 (ampy)(CO) 2 ] (1a) were prepared by reaction of [RuCl 2 (CO) 2 ] n with 1-[6-(4′-methylphenyl)pyridin-2-yl]methanamine, benzo[h]quinoline (HCNN), and 2-(aminomethyl)pyridine (ampy) ligands. Alternatively, the derivatives 1-3 were obtained...

The cationic abnormal N-heterocyclic carbene complex [Ru(OAc)(dppe)(PC)]Br (2b) (PC = bidentate phosphine-carbene ligand) has been obtained by treatment of the neutral derivative RuBr(OAc)(PPh3)(PC) (2a) with dppe in THF. Reaction of 2b with Ag2O afforded the heterobimetallic complex Ru(OAc)(dppe)(PC)AgBr (2c) which can be easily transmetallated wi...

This review provides a brief overview of advances on ruthenium(II) N-heterocyclic carbene complexes (NHCs) applied for hydrogenation reactions undertaken during the last five years. Several structural motifs, containing mono-, bi-, tri- and tetradentate binding modes of the NHCs are discussed in combination with a variety of different wingtip subst...

The dicarbonyl complex RuCl2(L)2(CO)2 (1) was easily prepared by reaction of ruthenium chloride hydrate with formic acid and L (L = (2,6-Me2C6H3)PPh2) in ethanol at reflux, via the [RuCl2(CO)2]n intermediate. Alternatively, 1 was obtained from [RuCl2(CO)3]2 and L by CO elimination. Reaction of 1 with NEt3 in toluene at reflux afforded the cyclometa...

NHC-Au-OTf [NHC = (1,3-bis(2,6-di-isopropylphenyl)-imidazol-2-ylidene] catalyst was tested in the alkoxylation and hydration of alkynes in a wide set of neoteric solvents for the first time. We found that most of these solvents (ethyl lactate, glycerol, propylene carbonate, d-limonene, γ-valerolactone, p-cymene) are comparable or better solvents wi...

The osmium complex trans-[OsCl2(PPh3)2(en)] (2) was prepared by reaction of [OsCl2(PPh3)3] (1a) with ethylenediamine (en), whereas the diphosphine derivatives trans-[OsCl2(dppf)(NN)] (NN = en (3), bn (4; bn = 1,4-butanediamine)) and trans-[OsCl2(dpbp)(en)] (5) were obtained from 1a, dppf or dpbp, and the corresponding NN ligand in CH2Cl2 or toluene...

The acetate complex Ru(OAc)2(DiPPF) (2) obtained from Ru(OAc)2(PPh3)2 (1) and 1,1'-bis(diisopropylphosphino)ferrocene (DiPPF) reacts cleanly with formaldehyde affording Ru(OAc)2(CO)(DiPPF) (3) in high yield. The monocarbonyl complex 3 (0.4-2 mol %) efficiently catalyzes the N-alkylation of primary and secondary alkyl and aromatic amines using prima...

Three Ru(II) and two Os(II) CNN pincer complexes are synthesized and tested in the title reaction.

Aldehydes were chemoselectively reduced to primary alcohols by using HCOONH4 as the hydrogen donor through transfer hydrogenation catalyzed by benzo[h]quinoline pincer complexes RuCl(CNNPh)(PP) at substrate to catalyst molar ratios of 2000 to 20 000. This practical reaction performed with aldehydes of commercial-grade purity in a water/toluene biph...

CNN pincer ruthenium(II) and osmium(II) complexes of general formula RuCl(CNN)(dppb) (1 a-c) and OsCl(CNN)(dppb) (2 a,b) (dppb=Ph2P(CH2)4PPh2, HCNN=[6-(p-tolyl)-2-pyridyl]methylamine (4), N-methyl-[6-(p-tolyl)-2-pyridyl]methylamine (7) and N,N-dimethyl-[6-(p-tolyl)-2-pyridyl]methylamine (8)) were prepared and assessed as catalysts in the hydrogenat...

A hetero-bimetallic Pd–Ru N-Heterocyclic Dicarbene (NHDC) complex was synthesized from a Ag–Ru complex by transmetalation. The Pd–Ru system displays high catalytic activity in tandem Suzuki–Miyaura cross-coupling/transfer hydrogenation reaction of bromoaryl ketones with boronic acids in toluene and 2-propanol in the presence of KOH.

The chemoselective reduction of commercial-grade aldehydes (97–99 %) to primary alcohols is achieved with cis-[RuCl2(ampy)(PP)] [ampy=2-(aminomethyl)pyridine; PP=1,4-bis(diphenylphosphino)butane, 1,1′-ferrocenediyl-bis(diphenylphosphine)] and pincer [RuCl(CNNR)(PP)] [PP=1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,1′-ferro...

Reaction of 1-naphthylamine with ethyl benzoylacetate gives the corresponding benzoyl acetamide derivative 1, which undergoes cyclization to 4-phenylbenzo[h]quinolin-2(1H)-one (2) in the presence of H2SO4. Bromination with POBr3, followed by reaction with n-BuLi and DATE, gives 4-phenylbenzo[h]quinoline-2-carbaldehyde (4), which is converted to the...

Two novel di(N-heterocyclic carbene) complexes of formula (-PyrIm-CH2-ImPyr)[IrCp*Cl](2)(PF6)(2) (1) and -MeIm-CH2(p-C6H2)CH2-ImMe[IrCp*Cl](2) (2) (Im = imidazol-2-ylidene) have been synthesised by transmetallation of the dicarbene ligand from the corresponding dicarbene silver complex, using [IrCp*(-Cl)Cl](2) as an iridium precursor. The structure...

Reaction of [Ru(OAc)2(PPh3)2] with a P-functionalized imidazolium bromide easily affords a cationic abnormal carbene Ru system. Metalation with Ag2O yields a Ru-Ag complex containing an anionic dicarbene ligand, while subsequent transmetalation with Au(tht)Cl leads to the corresponding Ru-Au system. The bimetallic complexes were characterized by si...

This account focuses on the application in catalysis of ruthenium and osmium complexes containing 2-(aminomethyl)pyridine (Ampy)-based ligands. The combination of these aminoalkylpyridine ligands with appropriate phosphines affords ruthenium and osmium systems displaying unprecedented high catalytic activity and productivity in a variety of organic...

Conspectus A current issue in metal-catalyzed reactions is the search for highly efficient transition-metal complexes affording high productivity and selectivity in a variety of processes. Moreover, there is also a great interest in multitasking catalysts that are able to efficiently promote different organic transformations by careful switching of...

Reaction of [RuCl(CNN)(dppb)] (1-Cl) (HCNN=2-aminomethyl-6-(4-methylphenyl)pyridine; dppb=Ph2P(CH2)4PPh2) with NaOCH2CF3 leads to the amine-alkoxide [Ru(CNN)(OCH2CF3)(dppb)] (1-OCH2CF3), whose neutron diffraction study reveals a short RuO⋅⋅⋅HN bond length. Treatment of 1-Cl with NaOEt and EtOH affords the alkoxide [Ru(CNN)(OEt)(dppb)]⋅(EtOH)n (1-OE...

A cationic phthalimido-functionalized N-heterocyclic carbene (NHC) palladium(II) complex has been synthesized from [3-methyl-1-(2′-phthalimidoethyl)imidazolium] hexafluorophosphate ([NHCMe,PhtH]PF6) by transmetalation and isolated in 67 % yield. The title complex has been applied as catalyst in the Suzuki–Miyaura cross-coupling reaction under benig...

A new class of ligands derived from benzo[h]quinoline are described and these ligands are used to prepare several novel transition metal complexes. The complexes are preferably of the group VIII transition metals iron, ruthenium or osmium, with the benzo[h]quinoline ligands acting as tridentate ligands. The complexes described are proved to be very...

The monocarbonyl hydride complexes [RuH(CO)(dppp)(NN)]Cl (dppp = Ph2P(CH2)3PPh2; NN = ethylenediamine (en), 1; NN = 2-aminomethylpyridine (ampy), 3) have been isolated in high yield by reaction of RuHCl(CO)(PPh3)(dppp) with en and ampy, respectively, in toluene at reflux. The chloride complexes [RuCl(CO)(dppp)(NN)]Cl (NN = en, 2; NN = ampy, 4) have...

The bifunctional phosphine-abnormal N-heterocyclic carbene ruthenium(II) complex RuBr(OAc)(PPh3)(P-aNHC) (1) has been synthesized in high yield by reaction of Ru(OAc)(2)(PPh3)(2) with a phosphine imidazolium bromide (P-NHC X HBr) and characterized by X-ray diffraction. This compound shows high catalytic activity for the transfer hydrogenation of ke...

The cationic [RuCl(η6-p-cymene)(HCNNa)]Cl (1a) (HCNNa = 1-(6-arylpyridin-2-yl)methanamine) and the neutral RuCl2(η6-p-cymene)(HCNNb) (1b) (HCNNb = 2-aminomethylbenzo[h]quinoline) complexes have been obtained by reaction of the precursor [RuCl(μ-Cl)(η6-p-cymene)]2 with the corresponding nitrogen ligand (HCNNa and HCNNb) in THF. Complex 1a reacts cle...

The easily accessible complexes [MCl2(dppf)(ampy)] (M = Ru (cis-1), Os (trans-2); dppf = 1,1′-bis(diphenylphosphino)ferrocene; ampy = 2-aminomethylpyridine) in the presence of base (NaOiPr, KOtBu) are efficient catalysts for several reactions involving carbonyl compounds and alcohols. The derivatives 1 and 2 catalyze the selective transfer hydrogen...

The complexes [MCl2(dppf)(NN)] (M: Ru, Os, NN: ethylenediamine, 2-(aminomethyl)pyridine), containing 1,1'-bis(diphenylphosphino)ferrocene (dppf), have been found to catalyse the acceptorless dehydrogenation of alcohols and 5-en-3β-hydroxy steroids. The Ru and Os ampy derivatives display also high catalytic activity for related C-H bond activation r...

The pincer complexes [MX(CNN)(PP)] (M = Ru, Os; X = Cl, OTf; HCNN = 1-(6-arylpyridin-2-yl)methanamine; PP = diphosphine) have proven to efficiently catalyze both racemization and deuteration of alcohols in the presence of a base. Chiral alcohols have been racemized at 30-50 °C using 1 mol% of Ru or Os pincer complexes and 5 mol% of KOtBu in 2-propa...

The ruthenium and osmium complexes [MCl(2)(diphosphane)(L)] (M=Ru, Os; L=bidentate amino ligand) and [MCl(CNN)(dppb)] (CNN=pincer ligand; dppb=1,4-bis-(diphenylphosphino)butane), containing the N−H moiety, have been found to catalyze the acceptorless dehydrogenation of alcohols in tBuOH and in the presence of KOtBu. The compounds trans-[MCl(2)(dppf...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A series of chiral HCNN ligands ((S)-1b-g) (S)-2-(1-aminoethyl)-6-(aryl) pyridine (aryl = 4-MeO-phenyl, 1b; 4-CF3-phenyl, 1c; 3,5-di-Me-phenyl, 1d; 3,5-di-CF3-phenyl, 1e; 1-naphthyl, 1f; 2-naphthyl, 1g) were synthesized starting from commercial 2-acetyl-6- bromopyridine (2), by a chemoenzymatic method involving the dynamic kinetic resolution of the...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Stereoselective decomposition of the α-diazo carbonyl compounds N2CHCOR [R = Me, Prn, Pri, (CH2)10CH3] catalysed by [RuCl(η5-C5H5)(PPh3) 2] (0.1 mol%) in toluene at 65°C affords quantitatively RCOCH=CHCOR carbene dimers, the cis isomers being formed in 95-97% yield; under the same experimental conditions N2CHCOEt gives diethyl maleate in a purity o...

The osmium complexes trans-[OsCl(2)(dppf)(diamine)] (dppf: 1,1'-bis(diphenylphosphino)ferrocene; diamine: ethylenediamine in 3, propylenediamine in 4) were prepared by the reaction of [OsCl(2)(PPh(3))(3)] (1) with the ferrocenyl diphosphane, dppf and the corresponding diamine in dichloromethane. The reaction of derivative 3 with NaOCH(2)CF(3) in to...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Chiral orthometalated osmium complexes [OsCl(CN′N)(PP)] {PP = (S,R)-Josiphos type diphosphane} based on 2-aminomethylbenzo[h]quinoline ligands (HCN′N) were prepared by reaction of [OsCl2(PPh 3)3] with a Josiphos diphosphane and a HCN′N ligand in the presence of NEt3. Ruthenium and osmium complexes [MX(CN′N)(PP)] {M = Ru, Os; X = Cl, OCH(p-C6H 4F)2;...

The pincer complexes [RuX(CNN)(dppb)] (5−11: X = carboxylate, phenoxide, alkoxide, silanolate, triflate; HCNN = 1-[6-(4′-methylphenyl)pyridin-2-yl]methanamine; dppb = Ph2P(CH2)4PPh2), containing the Ru−NH2 functionality and a monodentate oxygen donor ligand, have been prepared in high yield starting from [RuCl(CNN)(dppb)] (1) via substitution of th...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Chiral, nonracemic pincer ligands based on the 6-phenyl-2-aminomethylpyridine and 2-aminomethylbenzo[h]quinoline scaffolds were obtained by a chemoenzymatic approach starting from 2-pyridyl and 2-benzoquinolyl ethanone. In the enantiodifferentiating step, secondary alcohols of opposite absolute configuration were obtained by a baker's yeast reducti...

Chiral pincer ruthenium complexes of formula [RuCl(CNN)(Josiphos)] (2-7; Josiphos = 1-[1-(dicyclohexylphosphano)ethyl]-2-(diarylphosphano)ferrocene) have been prepared by treating [RuCl(2)(PPh(3))(3)] with (S,R)-Josiphos diphosphanes and 1-substituted-1-(6-arylpyridin-2-yl)methanamines (HCNN; substituent = H (1 a), Me (1 b), and tBu (1 c)) with NEt...

Novel as well as known C,N-palladacyclic neutral complexes were tested as precatalyst in the Heck reaction between bromobenzene and styrene under aerobic conditions. The catalytic system Pd(II) complex/K2CO3/EGME–H2O (EGME=ethylene glycol monomethyl ether) showed to be highly efficient. Best performances of the catalysts were achieved by controllin...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The results of a ligand-free Pd(OAc)2-catalyzed Suzuki–Miyaura C–C coupling performed at room temperature under aerobic conditions are presented. It was found that the use of an ethylene glycol monomethyl ether/H2O mixture as the solvent resulted in very rapid reactions of aryl bromides with arylboronic acids. As a matter of fact, under optimized c...

New benzo[h]quinoline ligands (HCN'N) containing a CHRNH2 (R=H (a), Me (b), tBu (c)) function in the 2-position were prepared starting from benzo[h]quinoline N-oxide (in the case of ligand a) and 2-chlorobenzo[h]quinoline (for ligands b and c). These compounds were used to prepare ruthenium and osmium complexes, which are excellent catalysts for th...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

This Microreview focuses on the development of novel ruthenium complexes displaying high performance in the catalytic asymmetric transfer hydrogenation of ketones with 2-propanol, providing this procedure alternative to the hydrogenation with dihydrogen. The key role is played by 1-(pyridin-2-yl)methanamine (Pyme) type ligands which in combination...

The reaction of [RuCl(CNN)(dppb)] (1; HCNN=6-(4-methylphenyl)-2-pyridylmethylamine) with NaOiPr in 2-propanol/C6D6 affords the alcohol adduct alkoxide [Ru(OiPr)(CNN)(dppb)].n iPrOH (5), containing the Ru-NH2 linkage. The alkoxide [Ru(OiPr)(CNN)(dppb)] (4) is formed by treatment of the hydride [Ru(H)(CNN)(dppb)] (2) with acetone in C6D6. Complex 5 i...

We describe the isolation of the first CNN pincer osmium complexes [OsX(CNN)P₂] to display high catalytic activity and productivity in the reduction of ketones by either TH or HY (TOFand TON up to 10⁶ h¹ and 10⁵, respectively). A high enantioselectivity (up to 98% ee ) is possible in both reactions with a...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The osmium compound trans,cis-[OsCl2(PPh3)2(Pyme)] (1) (Pyme=1-(pyridin-2-yl)methanamine), obtained from [OsCl2(PPh3)3] and Pyme, thermally isomerizes to cis,cis-[OsCl2(PPh3)(2)(Pyme)] (2) in mesitylene at 150 degrees C. Reaction of [OsCl2(PPh3)3] with Ph2P(CH2)(4)PPh2 (dppb) and Pyme in mesitylene (150 degrees C, 4 h) leads to a mixture of trans-[...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Ruthenium complexes of the general formula [RuCl2(PPh3)(PNN‘)] have been obtained from tridentate PNN‘ ligands containing phosphine (P), amine or imine (N), and pyridyl donor groups (N‘). The imino ligand Ph2P(o,o‘-C6H4CHNCH2C5H4N) (a) has been synthesized from Ph2P(2-C6H4CHO) and 2-(aminomethyl)pyridine, whereas amino Ph2P(o,o‘-C6H4CH2NHCH2C5H4N)...

(Chemical Equation Presented) Jumping Josiphos! Ruthenium cis-dichloro complexes with matched chiral diphosphane and aminopyridine ligands (see structure) are easily obtained by a one-pot reaction of [RuCl 2(PPh3)3] with a Josiphos diphosphane and racemic 1-substituted 1-(pyridin-2-yl)methanamine ligands. These complexes are highly active catalysts...

The catalytic activity of the terdentate complex [RuCl(CNN)(dppb)] (A) [dppb=Ph(2)P(CH(2))(4)PPh(2); HCNN=6-(4'-methylphenyl)-2-pyridylmethylamine] in the transfer hydrogenation of acetophenone (S) with 2-propanol has been found to be dependent on the base concentration. The limit rate has been observed when NaOiPr is used in high excess (A/base mo...

Aromatic, aliphatic and α,β‐unsaturated aldehydes are quickly, quantitatively and chemoselectively reduced to primary alcohols with 2‐propanol using 0.05–0.01 mol % of the terdentate CNN ruthenium complex RuCl(CNN)(dppb) ( 1 ) [HCNN=6‐(4′‐methylphenyl)‐2‐pyridylmethylamine; dppb=Ph 2 P(CH 2 ) 4 PPh 2 ] in the presence of potassium carbonate (K 2 CO...

The complexes cis-[RuCl2(ampy){R1N(CH2PPh2)2}] [ampy = (2-aminomethyl)pyridine, R1 = C6H5 or (CH3CH2O)3Si(CH2)3] showed very high catalytic activity in the homogeneous transfer hydrogenation of acetophenone (TOF > 300000 h–1) with the use of 2-propanol as the hydrogen donor and in the presence of sodium isopropoxide. The ligand (CH3CH2O)3Si(CH2)3N(...

The Vaska-type iridium(I) complex [IrCl(CO){PPh(2)(2-MeC(6)H(4))}(2)] (1), characterized by an X-ray diffraction study, was obtained from iridium(III) chloride hydrate and PPh(2)(2,6-MeRC(6)H(3)) with R=H in DMF, whereas for R=Me, activation of two ortho-methyl groups resulted in the biscyclometalated iridium(III) compound [IrCl(CO){PPh(2)(2,6-CH(2...

Ruthenium compounds of general formula Cp‘RuX(PR2R‘)2 (Cp‘ = η5-C5H5 (Cp), η5-C9H7 (Ind), η5-C5(CH3)5 (Cp*); X = Cl, CF3C(O)O; R = C6H5 (Ph), C6H4(CH3) (m-tolyl); R‘ = C6H5, C6H11 (Cy), C6H4(CH3) (m-tolyl, o-tolyl)) are examined as catalysts for the aldehyde olefination starting from diazo compounds, phosphanes, and aldehydes. Cp*RuCl(PPh3)2 is hig...

Terdentate ruthenium(II) complexes of general formula RuX(CNN)(dppb) (X = chloride, hydride, alkoxide; dppb = Ph2P(CH2)4PPh2), where CNN is a deprotonated 2-aminomethyl-6-arylpyridine ligand, have been prepared. The orthometalated derivative RuCl(b)(dppb) (1) has been obtained by reaction of RuCl2(PPh3)(dppb) with N,N-dimethyl-2-aminomethyl-6-(4-me...

NiII, PdII and PtII cationic complexes of the general formula [MCl(PNN)]PF6, where PNN is the terdentate ligand N-[2-(diphenylphosphanyl)benzylidene][2-(2-pyridyl)ethyl]amine, have been synthesised and fully characterised in solution by NMR spectroscopy. The diamagnetic NiII complex 1 shows fluxionality, which can be attributed to a conformational...

The free carbene 1,3,4-triphenyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene reacts with trans,cis-RuHCl(PPh3)(2)(ampy) (ampy= 2-(aminomethyl)pyridine) affording an orthometalated N-heterocyclic carbene complex characterized by an X-ray diffraction study. This compound in presence of NaOH shows very high catalytic activity for the transfer hydrogenation...

Reduction of enantiopure N-p-toluenesulfinyl ketimines derived from 2-pyridyl ketones affords N-p-toluenesulfinyl amines with good yields and diastereoselectivities.

(Chemical Equation Presented) Very low loading and short reaction times are characteristic features of the quantitative reduction of different ketones using 2-propanol and terdentate [RuX(CNN)-(dppb)] (X = H, Cl (see structure); dppb = Ph2P(CH2)4PPh2) complexes prepared from 6-(4′-methylphenyl)-2-pyridyl-methylamine. The reduction apparently takes...

The complexes [Pd(acac)2] 1, [Pd(hfa)2] 2 (hfa=hexafluoroacetylacetonate), [Pd(CF3CO2)2] 3 and [Pd3(CH3CO2)6] 4 exhibit very different catalytic efficiency in the reaction between secondary amines and activated alkenes. Complexes 1 and 4 generally show an enhanced activity when catalytic amounts of NH4X salts (X−=low-coordinating anion) are added t...

The ruthenium(II) chemistry of the ampy ligand in combination with various phosphines as catalysts in transfer hydrogenation was investigated. The preparation and characterization of a new series of complexes of formulas RuCl2(PPh3) (ampy) and RuCl2(PP)(ampy) (PP double bonded with diphosphine), including a structural analysis by X-ray diffraction...

The five-coordinate complex RuCl{(2-CH2-6-MeC6H3)PPh2}(CO)(L*) (2; L* = (2,6-Me2C6H3)PPh2) was prepared in high yield by reaction of the 14-electron complex RuCl2(L*)(2) (1) with formaldehyde in the presence of NEt3 via cyclometalation of an ortho methyl group and aldehyde decarbonylation. Alternatively, 2 can be obtained from RuCl3 hydrate, L*, H2...

The five-coordinate complex RuCl{(2-CH2-6-MeC6H3)PPh2}(CO)(L*) (2; L* = (2,6-Me2C6H3)PPh2) was prepared in high yield by reaction of the 14-electron complex RuCl2(L*)2 (1) with formaldehyde in the presence of NEt3 via cyclometalation of an ortho methyl group and aldehyde decarbonylation. Alternatively, 2 can be obtained from RuCl3 hydrate, L*, H2CO...

Complexes of general formula (η5-L)RuCl(PR3)2 are shown to be active and highly selective catalysts for the olefination of aldehydes in the presence of phosphines and diazoacetate at moderate temperatures. With equal catalyst loadings of Cp*RuCl(PR3)2 shows comparable activity and higher selectivity with regard to the most active catalysts known to...