Transition metal complexes are indispensable tools for any synthetic chemist. Ideally, metal-mediated process should be fast, clean, efficient, and selective take place in a catalytic manner. These criteria especially important considering that many of the transition metals employed catalysis rare expensive. One ways modifying controlling properties is use appropriate ligand systems, such as pincer ligands. Usually consisting central aromatic backbone tethered to two two-electron donor...

This study represents the first example an environmentally benign, sustainable, and practical synthesis of substituted quinolines pyrimidines using combinations 2-aminobenzyl alcohols as well benzamidine two different alcohols, respectively. These reactions proceed with high atom efficiency via a sequence dehydrogenation condensation steps that give rise to selective C-C C-N bond formations, thereby releasing 2 equiv hydrogen water. A hydride Mn(I) PNP pincer complex recently developed in...

ConspectusSustainable processes that utilize nontoxic, readily available, and inexpensive starting materials for organic synthesis constitute a major objective in modern chemical research. In this context, it is highly important to perform reactions under catalytic conditions replace precious metal catalysts by earth-abundant nonprecious catalysts. particular, iron manganese are promising candidates, as these among the most abundant metals earth's crust, inexpensive, exhibit low...

Abstract Herein, we describe an efficient coupling of alcohols and amines catalyzed by well‐defined isoelectronic hydride Mn I Fe II complexes, which are stabilized a PNP ligand based on the 2,6‐diaminopyridine scaffold. This reaction is environmentally benign process implementing inexpensive, earth‐abundant non‐precious metal catalysts, acceptorless alcohol dehydrogenation concept. A range including both aromatic aliphatic substrates were efficiently converted in good to excellent isolated...

This study represents the first example of a manganese-catalyzed environmentally benign, practical three-component aminomethylation activated aromatic compounds including naphtols, phenols, pyridines, indoles, carbazoles, and thiophenes in combination with amines MeOH as C1 source. These reactions proceed high atom efficiency via sequence dehydrogenation condensation steps which give rise to selective C–C C–N bond formations, thereby releasing hydrogen water. A well-defined hydride Mn(I) PNP...

Mn(<sc>i</sc>) PNP pincer hydride complexes were shown for the first time to catalyse hydrogenation of CO₂ formate reaching quantitative yields and high TONs.

The synthesis, characterization, and catalytic activity of nonclassical iron(II) polyhydride complexes containing tridentate PNP pincer-type ligands is described. These compounds the general formula [Fe(PNP)(H)2(η2-H2)] exhibit remarkable reactivity toward terminal alkynes. They efficiently promote dimerization aryl acetylenes giving corresponding conjugated 1,3-enynes in excellent yields with low catalyst loadings. When reaction carried out presence pinacolborane, vinyl boronates are...

Efficient alkylations of amines by alcohols catalyzed well-defined Co(II) complexes are described that stabilized a PCP ligand (N,N′-bis(diisopropylphosphino)-N,N′-dimethyl-1,3-diaminobenzene) based on the 1,3-diaminobenzene scaffold. This reaction is an environmentally benign process implementing inexpensive, earth-abundant nonprecious metal catalysts and acceptorless alcohol dehydrogenation concept. A range primary aromatic were efficiently converted into mono-N-alkylated in good to...

The synthesis and characterization of a series molybdenum, iron, ruthenium, nickel, palladium, platinum complexes containing new achiral chiral PNP pincer-type ligands based on the N-heterocyclic diamines 2,6-diaminopyridine, N,N'-di-10-undecenyl-2,6-diaminopyridine, N,N'-dihexyl-2,6-diaminopyridine, 2,6-diamino-4-phenyl-1,3,5-triazine are reported. prepared conveniently in high yield by treatment respective with 2 equiv variety R2PCl compounds presence base. Molybdenum type...

Fe(II) hydrido carbonyl complexes supported by PNP pincer ligands based on the 2,6-diaminopyridine scaffold were found to promote catalytic hydrogenation of CO2 and NaHCO3 formate in protic solvents presence bases, reaching quantitative yields high TONs under mild reaction conditions, with pressures as low 8.5 bar temperatures 25 °C. NMR DFT studies highlighted role dihydrido catalysis.

This perspective article provides an overview of the advancements in field non-precious metal PCsp²P and PCsp³P pincer complexes.

Several hydride Mn(I) and Re(I) PNP pincer complexes were applied as catalysts for the homogeneous chemoselective hydrogenation of aldehydes. Among these, [Mn(PNP-iPr)(CO)2(H)] was found to be one most efficient base metal this process represents a rare example which permits selective aldehydes in presence ketones other reducible functionalities, such C═C double bonds, esters, or nitriles. The reaction proceeds at room temperature under base-free conditions with catalyst loadings between 0.1...

The synthesis and application of [Fe(PNPMe-iPr)(CO)(H)(Br)] [Fe(PNPMe-iPr)(H)2(CO)] as catalysts for the homogeneous hydrogenation aldehydes is described. These systems were found to be among most efficient this process reported date constitute rare examples a catalytic which allows selective reduction in presence ketones other reducible functionalities. In some cases, TONs TOFs up 80000 20000 h–1, respectively, reached. On basis stoichiometric experiments computational studies, mechanism...

Abstract Manganese complexes of the types [Mn(PNP′)(Br)(CO) 2 ] and [Mn(PNP′)(H)(CO) containing a tridentate ligand with planar chiral ferrocene centro aliphatic unit were synthesized, characterized, tested in enantioselective transfer hydrogenations 13 ketones. The catalytic reactions proceeded conversions up to 96 % ee values 86 %. absolute configuration all products was determined be ( S ). Notably, presence dihydrogen (up 20 bar) did not affect reduction. On basis DFT calculations,...

We have prepared and structurally characterized a new class of Fe(II) PNP pincer hydride complexes [Fe(PNP-iPr)(H)(CO)(L)]n (L = Br–, CH3CN, pyridine, PMe3, SCN–, CO, BH4–; n 0, +1) based on the 2,6-diaminopyridine scaffold where PiPr2 moieties ligand are connected to pyridine ring via NH and/or NMe spacers. Complexes with labile ligands BH4–) spacers efficient catalysts for hydrogenation both ketones aldehydes alcohols under mild conditions, while those containing inert CO) catalytically...

Fe(II) hydrido carbonyl complexes supported by PNP pincer ligands based on the 2,6-diaminopyridine scaffold were studied as homogeneous, non-precious-metal-based catalysts for selective formic acid dehydrogenation to hydrogen and carbon dioxide, reaching quantitative yields high TONs under mild reaction conditions.

Abstract A series of well‐defined iron(II) complexes the types [Fe(PNP)Br 2 ] and [Fe(PNP)(CO)Br with PNP pincer ligands based on triazine pyridine backbones were prepared fully characterized. These tested as catalysts for alkylation amines by alcohols. The high‐spin are catalytically inactive. low‐spin bearing a carbonyl co‐ligand efficiently selectively convert primary alcohols aromatic benzylic into mono‐ N ‐alkylated in good to excellent isolated yields. mechanistic proposal is given....

Efficient hydrogenations of nitriles and ketones with molecular hydrogen catalyzed by a well-defined bench-stable bisphosphine Mn(I) complex are described. These reactions environmentally benign atomically economic, implementing an inexpensive, earth-abundant nonprecious metal catalyst. A range aromatic aliphatic were efficiently converted into primary amines alcohols, respectively, in good to excellent yields. The hydrogenation proceeds at 100 °C catalyst loading 2 mol % 20 base ( t-BuOK),...

Well-defined Mn(I) hydrido carbonyl PNP pincer-type complexes were tested as efficient and selective nonprecious transition metal catalysts for the reduction of CO2 to MeOH in presence hydrosilanes. The choice reaction temperature type silanes proved be pivotal achieve fast reactions high selectivity methoxysilyl- vs silylformate derivatives DMSO. catalytic data are complemented by DFT calculations, highlighting a stepwise mechanism centered on Mn catalyst without metal-to-ligand cooperation.

An efficient additive-free manganese-catalyzed hydrogenation of alkenes to alkanes with molecular hydrogen is described. This reaction atom economic, implementing an inexpensive, earth-abundant nonprecious metal catalyst. The most precatalyst the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. catalytic process initiated by migratory insertion a CO ligand into Mn-alkyl bond yield acyl intermediate which undergoes rapid hydrogenolysis form active 16e hydride...

The catalytic reduction of carbon dioxide is a process growing interest for the use this simple and abundant molecule as renewable building block in C1-chemical synthesis hydrogen storage. well-defined, bench-stable alkylcarbonyl Mn(I) bis(phosphine) complex fac-[Mn(CH2CH2CH3)(dippe)(CO)3] [dippe = 1,2-bis(diisopropylphosphino)ethane] was tested an efficient selective non-precious-metal precatalyst hydrogenation CO2 to formate under mild conditions (75 bar total pressure, 80 °C), presence...

A complete catalytic cycle for the cyclotrimerization of acetylene with CpRuCl fragment has been proposed and discussed based on DFT/B3LYP calculations, which revealed a couple uncommon intermediates. The first is metallacyclopentatriene complex RuCp(Cl)(C(4)H(4)) (B), generated through oxidative coupling two alkyne ligands. It adds another in eta(2) fashion to give an (C). No less than three successive intermediates could be located subsequent arene formation. first, unusual five-...

The complexes RuTp(PPh3)2Cl (1) and RuTp(PPh3)(py)Cl (2) catalyze the dimerization of HC⋮CR, where R = Ph, SiMe3, n-Bu, t-Bu, to give 1,4- 2,4-disubstituted butenynes with both conversion selectivity strongly depending on alkyne substituent, catalytic precursor is neutral vinylidene complex RuTp(PPh3)(Cl)(=CCHR). hydride RuTp(PPh3)2H (3) exhibits same activity as 1 2.

The synthesis and catalytic reactivity of a variety new ruthenium complexes the tris(pyrazolyl)borate ligand (HB(pz)3) are reported in this paper. From parent complex Ru(HB(pz)3)(COD)X (X = Cl, Br) cationic derivatives [Ru(HB(pz)3)(COD)L]+ (L H2O, CH3CN, pyridine, dmso) have been obtained by treatment with 1 equiv AgCF3SO3 CH2Cl2 solutions L. Displacement COD from these latter has accomplished boiling dmf ligands L2 Ph2PCH2PPh2 (dppm), Ph2PCH2CH2NMe2 (pn), Me2NCH2CH2NMe2 (tmeda) as well L...

An opening for CO: iron PNP pincer complex self-assembles in the solid state through intermolecular FeCl⋅⋅⋅HN hydrogen bonds to form a 3D supramolecular network. This compound reacts readily with gaseous CO and solution stereospecifically give octahedral complexes cis- trans-[Fe(PNP-iPr)(CO)(Cl)2], respectively. In solid-state process connectivities between individual molecules are maintained without loss of crystallinity.