Equivalents Of PPh3 Research Articles

Photolytic C-Diazeniumdiolate Disassembly in the β-Diketiminate Complexes [MeLM(O2N2CPh3)] (M = Fe, Co, Cu).

The reaction of [K(18-crown-6)][O2N2CPh3] with [MeLCo(μ-Br)2Li(OEt2)] (MeL = {(2,6-iPr2C6H3)NC(Me)}2CH) generates the trityl diazeniumdiolate complex, [MeLCo(O2N2CPh3)] (1), in moderate yield. Similar metathesis reactions result in the formation of the Fe and Cu analogues, [MeLM(O2N2CPh3)] (Fe, 2; Cu, 3), which can also be isolated in moderate yields. Complexes 1-3 were characterized by ultraviolet-visible (UV-vis) spectroscopy, and their solid-state structures were determined by X-ray crystallography. These complexes were further characterized via 1H NMR spectroscopy (in the case of 1 and 2) or EPR spectroscopy (in the case of 3). Irradiation of complexes 1 and 2 with 371 nm light generates the known dinitrosyl complexes, [MeLM(NO)2] (M = Co, 4; Fe, 5), along with Ph3CH and 9-phenylfluorene. We propose that 4 and 5 are formed via the putative hyponitrite intermediates, [MeLM(κ2-O,O-ONNO)], which are formed by photoinduced homolysis of the C-N bond of the [O2N2CPh3] ligand. In contrast, irradiation of complex 3 with 371 nm light, in the presence of 1 equiv of PPh3, led to the formation of the Cu(I) complexes, [MeLCu(PPh3)], [(ArNCMeC(NO)CMeNAr)Cu(PPh3)] (6), and [(ArNCMeC(NO)CMeNAr)Cu]2 (7), of which the latter two are products of γ-nitrosation of the β-diketiminiate ligand. Also formed in this transformation are Ph3CN(H)OCPh3, Ph3PO, and N2O, along with trace amounts of NO.

Reactivity of a Dinuclear PdI Complex [Pd2(μ-PPh2)(μ2-OAc)(PPh3)2] with PPh3: Implications for Cross-Coupling Catalysis Using the Ubiquitous Pd(OAc)2/nPPh3 Catalyst System.

[PdI2(μ-PPh2)(μ2-OAc)(PPh3)2] is the reduction product of PdII(OAc)2(PPh3)2, generated by reaction of ‘Pd(OAc)2’ with two equivalents of PPh3. Here, we report that the reaction of [PdI2(μ-PPh2)(μ2-OAc)(PPh3)2] with PPh3 results in a nuanced disproportionation reaction, forming [Pd0(PPh3)3] and a phosphinito-bridged PdI-dinuclear complex, namely [PdI2(μ-PPh2){κ2-P,O-μ-P(O)Ph2}(κ-PPh3)2]. The latter complex is proposed to form by abstraction of an oxygen atom from an acetate ligand at Pd. A mechanism for the formal reduction of a putative PdII disproportionation species to the observed PdI complex is postulated. Upon reaction of the mixture of [Pd0(PPh)3] and [PdI2(μ-PPh2){κ2-P,O-μ-P(O)Ph2}(κ-PPh3)2] with 2-bromopyridine, the former Pd0 complex undergoes a fast oxidative addition reaction, while the latter dinuclear PdI complex converts slowly to a tripalladium cluster, of the type [Pd3(μ-X)(μ-PPh2)2(PPh3)3]X, with an overall 4/3 oxidation state per Pd. Our findings reveal complexity associated with the precatalyst activation step for the ubiquitous ‘Pd(OAc)2’/nPPh3 catalyst system, with implications for cross-coupling catalysis.

Synthesis, characterization and electrochemical properties of phosphine-disubstituted diiron bis(monoselenolate) carbonyls

The properties of diiron dithiolates/diselenolates have been exhaustively studied, the substituted bis(monoselenolate) carbonyls are rarely described. In order to enrich the chemistry of diiron diselenolate compounds and synthesize new hydrogen evolution catalysts, a series of monosubstituted diiron bis(monoselenolate) carbonyls [Fe2(µ-SeCH2Ph)2(CO)5L] (L = PPh3, 1a; PPh2Me, 1b; PPhMe2, 1c; PMe3, 1d), and two disubstituted diiron bis(monoselenolate) carbonyls [Fe2(µ-SeCH2Ph)2(CO)4L2] (L = PPh3, 2a; PPh2Me, 2b) have been prepared. That is, treatment of [Fe2(μ-SeCH2Ph)2(CO)6](1) with 1 equivalent of PR3 ligand in the presence of Me3NO·2H2O afforded the 1a-1d in 47–63% yields. Alternately, treatment of [Fe2(μ-SeCH2Ph)2(CO)6] (1) with 2 equivalents of PPh3 and PPh2Me under efficient one-pot UV-irradiation produced 2a and 2b in moderate yields. 1a-1d exist as two isomers, while only syn-isomer are found in 2a and 2b. All the new compounds were characterized by elemental analysis, IR, NMR spectroscopy and X-ray crystallography. In addition, the electrochemical and electrocatalytic properties of these models were studied by cyclic voltammetry (CV) in MeCN.

Cobalt-Catalyzed Divergent Aminofluorination and Diamination of Styrenes with N-Fluorosulfonamides

A cobalt-catalyzed aminofluorination reaction of styrenes with N-fluorosulfonamides serving as both the amination and fluorination agents has been developed. The switch of selectivity in this catalytic reaction from aminofluorination to diamination could be easily achieved by the addition of 1.0 equiv of PPh3. Both transformations tolerated a wide array of substrates under mild reaction conditions.

Trichloroisocyanuric Acid Mediated High-Yielding Synthesis of N-Acylbenzotriazoles under Mild Reaction Conditions

N-Acylbenzotriazoles are achieved in good yields from the corresponding carboxylic acids by using only 0.35 equivalent of trichloroisocyanuric acid and 1.2 equivalents of PPh3. The salient features of the developed reaction path include an economic, facile, base-free, and equally useful method in milligram to gram scale.

Recyclable and Reusable Heteroleptic Nickel Catalyst Immobilized on Metal–Organic Framework for Suzuki–Miyaura Coupling

Metal-organic frameworks (MOFs) provide highly versatile platforms to stabilize molecular catalysts that are not readily accessible under homogeneous conditions, thus enabling access to a new set of catalytic materials. Herein, we describe a recyclable and highly active nickel catalyst immobilized on MOF for Suzuki-Miyaura coupling reaction, which operates under mild conditions. This mixed ligand catalyst forms from the combination of 1 equiv of MOF-immobilized ligand, 1 equiv of nickel source, and 1 equiv of PPh3. The nature of the catalyst was verified through a series of analytical tests and catalysis experiments. The immobilized catalyst was reusable for at least up to 7 cycles without decrease in the yield of the coupled product. We also verified that this reaction does not work under homogeneous conditions and that the reaction is truly heterogeneous through "hot filtration" experiments. We identified that the reaction is first order in arylborane concentration and negative order in arylbromide concentration through the effect of substrate concentrations on the initial rate. This informed us to conduct the catalysis under slow addition of the arylbromide and reduce the catalyst loading to 1% from 3%, without detriment to the yield or rate of the reaction. The catalyst gave good to excellent isolated yields with a range of functionalities, including heterocycles on aryl bromide with widely varying electronic properties.

Kinetics and mechanisms of homogeneous catalytic reactions: Part 15. Regio-specific hydroformylation of limonene catalysed by rhodium complexes of phosphine ligands

Limonene hydroformylation was studied in the presence of Rh-based catalytic systems, which were prepared in situ by addition of three equivalents of PPh3, one of 1,2-bis(diphenylphosphino)ethane (dppe), or one of 1,1,1-tris(diphenylphosphino)ethane (triphos) to Rh(CO)2(acac) (1). These systems were efficient precatalysts for the target reaction, generating limonenal regio-specifically under mild reaction conditions (80 °C and 20 atm of syngas). The found activity order was: (1)/3 PPh3 > (1)/triphos > (1)/dppe. The active catalytic species are proposed to be square planar hydrido-carbonyl complexes containing two phosphorus atoms coordinated at the rhodium centre. A kinetic study of this reaction catalysed by (1)/3 PPh3, the most active catalytic system, allowed us to propose that the mechanism of hydroformylation of limonene is similar to those reported for other olefins using RhH(CO)(PPh3)3 or Rh systems containing either dppe or triphos as precatalysts.

Tuning the regioselectivity of (benzimidazolylmethyl)amine palladium(II) complexes in the methoxycarbonylation of hexenes and octenes

Reactions of N-(1H-benzoimidazol-2-ylmethyl-2-methoxy)aniline (L1) and N-(1H-benzoimidazol-2-ylmethyl-2-bromo)aniline (L2) with p-TsOH, Pd(AOc)2 and two equivalents of PPh3 or PCy3 produced the corresponding palladium complexes, [Pd(L1)(OTs)(PPh3)] (1), [Pd(L2)(OTs)(PPh3)] (2) and [Pd(L1)(OTs)(PCy3)] (3), respectively, in good yields. The new palladium complexes 1–3 and the previously reported complexes [Pd(L1)ClMe] (4) and [Pd(L2)ClMe] (5) gave active catalysts in the methoxycarbonylation of terminal and internal olefins to produce branched and linear esters. The effects of complex structure, nature of phosphine derivative, acid promoter and alkene substrate on the catalytic activities and selectivity have been studied and are herein reported.

Catalytic racemization of secondary alcohols with new (arene)Ru(II)-NHC and (arene)Ru(II)-NHC-tertiary phosphine complexes

Five new complexes of the type [RuCl2(NHC)(η6-arene)] (4, 5, and 6) and [RuCl(NHC)(η6-arene)(PR3)]Cl (7 and 8) (NHCN-heterocyclic carbene=bmim, emim; arene=benzene, p-cymene; PR3=PPh3 or pta=1,3,5-triaza-7-phosphaadamantane) were synthetized and applied as catalysts (together with the known [RuCl2(bmim)(η6-p-cymene)] (3) with and without added PPh3) in racemization of optically active secondary alcohols in toluene. The highest catalytic activity, TOF=9.3h−1 (ee as low as 1.3% in 4h at 95°C) was observed in racemization of (S)-1-phenylethanol with a catalyst (4mol%) prepared in situ from 3 and 1 equivalent of PPh3. It is of practical significance that formation of acetophenone byproduct was suppressed to 3.5% by 17% v/v isopropanol in toluene. DFT calculations revealed that the rate determining step in the suggested reaction mechanism was the agostic coordination of hydrogen on the chiral carbon atom of the alcohol substrate.

Syntheses of [Pt6(CO)8(SnCl2)(SnCl3)4]4– and [Pt6(CO)8(SnCl2)(SnCl3)2(PPh3)2]2– Platinum–Carbonyl Clusters Decorated by SnII Fragments

The reaction of [Pt6(CO)6(SnCl2)2(SnCl3)4]4– (1) with CO under atmospheric pressure resulted in the new [Pt6(CO)8(SnCl2)(SnCl3)4]4– (2) cluster by the addition of two CO ligands and the elimination of a stannylene SnCl2 group. In turn, 2 reacted with 2 equivalents of PPh3 under a CO atmosphere to afford [Pt6(CO)8(SnCl2)(SnCl3)2(PPh3)2]2– (3) by elimination of two stannyl [SnCl3]– ligands. Conversely, the reaction of 2 with 2 equivalents of PPh3 under a N2 atmosphere resulted in a species tentatively formulated as [Pt6(CO)5(SnCl2)2(SnCl3)2(PPh3)2]2– (4–5CO) on the basis of 13C NMR, 31P NMR spectroscopy and ESI‐MS studies. Compounds 2–4 were spectroscopically characterized by IR spectroscopy and multinuclear (13C and 31P) variable‐temperature NMR spectroscopy. The crystal structures of 2 and 3 were determined by means of single‐crystal X‐ray diffraction, and their bonding was computationally investigated by DFT calculations. The possible structure of 4–5CO was predicted by means of DFT methods.

Synthesis and characterization of copper(I) compounds incorporating pyrazole-derived ligands: A study on carbon–carbon coupling reaction

A series of copper(I) compounds manifesting with the pyrazole mediated precursor, ArN[CH2(C3H3N2)]2 (Ar=2,6-diisopropylphenyl) (LN3), were synthesized conveniently and treatment of the derivatives with small organic molecules like pyrazine and triphenylphosphine were analyzed. Reacting one and two equivalents of LN3 with [Cu(CH3CN)4]PF6 in CH3CN at room temperature afforded [Cu(LN3)(CH3CN)2]PF6 (1) and [Cu(LN3)2]PF6 (2), respectively in high yield. Similarly, while reacting one equivalent of LN3 and CuI in acetonitrile for 12h, produced a white solid, [Cu(LN3)]I (3). Furthermore, by adding one or two equivalents of PPh3 into compound 1, using methylene chloride as solvent rendered [Cu(LN3)(PPh3)]PF6 (4) and [Cu(LN3)(PPh3)2]PF6 (5), respectively, in satisfactory yield. In addition, compound {[Cu(LN3)(C4H4N2)]2(PF6)2}n (6) was generated as one-dimensional polymer by treating compound 1 and pyrazine in THF at room temperature. All the Cu(I)-derivatives were characterized by 1H and 13C NMR spectroscopy and the molecular structures (1, 4, and 6) were determined by single crystal X-ray diffraction. Additionally, the catalytic reactions of Sonogashira type C–C coupling were discussed using compounds 2, 3, 5, and 6 as catalysts.

Palladium complexes of (benzoimidazol-2-ylmethyl)amine ligands as catalysts for methoxycarbonylation of olefins

Reactions of N-(1H-benzoimidazol-2-ylmethyl)-2-methoxy aniline (L1) and N-(1H-benzoimidazol-2-ylmethyl)-2-bromo aniline (L2) with either [PdCl2(COD)] or [PdClMe(COD)] afforded the neutral palladium complexes [PdCl2(L1)] (1), [PdClMe(L1)] (2) and [PdClMe(L2] (3), respectively. Treatment of 2 and 3 with one equivalent of PPh3 in the presence of NaBAr4 (Ar=3,5-(CF3)2C6H3) produced the corresponding cationic species, [PdMe(L1)]BAr4 (4) and [PdMe(L2)]BAr4 (5). All the palladium complexes formed active catalysts in the methoxycarbonylation of alkenes to produce linear and branched esters. The catalytic behaviour was dependent on the catalyst structure, presence of PPh3, acid promoter and alkene chain length.

Novel Hydrido-Rhodium (III) Complexes with Some Schiff Bases Derived from Substituted Pyridines and Aryl Amines

A Series of rhodium (III) cyclometallated complexes of the type (RhHCl(NC5H2C=N Ar (PPh3)2} (Ar=Substituted aryl), have been synthesized and characterized. Schiff bases derived from a substituted benzaldehyde and 2-amino pyridine substituents were allowed to react with [RhCl(PPh3)3] or [Rh(μ-Cl)(COD)]2 in the presence of 4 equivalents of PPh3 (or Ph2BzP) to give Rh(III) Cyclometallated complexes, in which the imine C-H bond was added oxidatively to the rhodium metal to give (H-M-C). The complexes were characterized using IR and NMR spectroscopy confirmed by elemental micro-analysis. The absorption of the hydride ligand was inferred as trans to N-donar ligand.

Heterocyclic-2-thione derivatives of silver(I): Synthesis, spectroscopy and structures of mono- and di-nuclear silver(I) halide complexes

The scarcely known chemistry of silver(I) halides with a series of heterocyclic thiones in acetonitrile (or methanol–acetonitrile) is described. Silver(I) chloride with a series of imidazolidine-2-thiones [C3H5NS(N–R)] in the presence of one equivalent of PPh3 with respect to the thione ligand has yielded chloro-bridged dinuclear complexes, [Ag2(μ-Cl)2(κ1-S-C3H5NS(N–R))2(PPh3)2] (1, R = H; 2, R = Me; 3, R = Et), and in the presence of two equivalents of PPh3, it has yielded mononuclear complexes, [Ag(κ1-Cl)(κ1-S-C3H5NS(N–R))(PPh3)2] (4, R = Me; 5, R = Et). The n-propyl-imidazolidine-2-thione with silver(I) chloride formed only a mononuclear complex, [Ag(κ1-Cl)(κ1-S-C3H5NS(N–Prn))(PPh3)2] (6), in the presence of one or two equivalents of PPh3. In contrast, silver(I) bromide with C3H5NS(N–R) in the presence of one or two equivalents of PPh3 with respect to the thione ligand has yielded bromide-bridged dinuclear complexes, [Ag2(μ-Br)2(κ1-S-C3H5NS(N–R))2(PPh3)2] (7, R = Me; 8, R = Et; 9, R = Prn). The related thio-ligands, namely, 1-methyl-imidazoline-2-thione and thiazolidine-2-thione with silver(I) bromide in the presence of one or two equivalents of PPh3 have formed bromide bridged dimeric [Ag2(μ-Br)2(κ1-S-C3H3NS(N–Me))2(PPh3)2] (10) or mononuclear Ag(κ1-Br)(κ1-S-C3H5NS2)(PPh3)2] (11) complexes respectively. The 2,4-dithiouracil (C4H4N2S2) with silver(I) chloride/bromide and PPh3 has yielded hetero-bridged dinuclear complexes, [Ag2(μ-S,S-C4H3N2S2)(μ-X)(PPh3)4] (X = Cl, 12; Br, 13) involving rupture of Ag–X bonds directly with a thio-ligand, a rare case of such rupture in metal-heterocyclic thione chemistry.

An NMR study on the mechanism of ethene hydromethoxycarbonylation catalyzed by cationic Pd(II)–PPh3 complexes

The reactivity of cis-[Pd(H2O)2(PPh3)2](TsO)2.2(H2O) (I,H2O), trans-[Pd(COEt)(TsO)(PPh3)2] (II) and trans-[Pd(COOMe)(TsO)(PPh3)2] (III) has been studied by 1H and 31P{1H} NMR spectroscopy under conditions that mime the catalytic ethene hydromethoxycarbonylation (EHMC), i.e. in the presence of PPh3, H2O and TsOH. (I,H2O), in the presence of two equivalents of PPh3, reacts with MeOH and CO (0.3 MPa) at 193 K to give [Pd(COOMe)(TsO)(PPh3)3] (III′), which reacts with H2O in the presence of TsOH at 293 K to generate [PdH(PPh3)3](TsO) (IV) quantitatively. This hydride inserts ethene (0.3 MPa, 293 K) to give trans-[Pd(Et)(TsO)(PPh3)2] (V), which reacts with CO (0.3 MPa, 223 K) giving [Pd(COEt)(PPh3)3](TsO) (II)′ and initiates the catalytic EHMC at 293 K. II, in combination with PPh3 and TsOH, reacts at 293 K with MeOH with quantitative formation of methyl propanoate (MP) and IV and promotes the catalysis starting from this temperature, under 0.6 MPa of CO/ethene (1/1) when the ratio PPh3/TsOH/II is 2/6/1; upon increasing the PPh3/II ratio, the catalytic activity passes through a maximum when the ratio is 4/1, even though it initiates at a higher temperature. In the absence of added ligand, MP is formed in a stoichiometric amount, catalysis is not observed and decomposition to Pd metal occurs. Therefore, PPh3 is essential in order to stabilize hydride IV, though an excess of ligand is detrimental. III does not insert ethene even at 343 K, a temperature well above that at which catalysis is observed. All these experimental evidences support the Pd–H cycle.

Reductive Elimination from Platinum(IV) Aminotroponiminate Dimethyl Complexes Promoted by Sterically Hindered Lewis Bases

A series of PtII and PtIV aminotroponimate (ATI = N-tolyl-aminotroponiminate) complexes has been prepared. The PtII complex (ATI)Pt(CH3)(SMe2) (1a) is synthesized from the reaction of [Li][ATI] with (Me)(Cl)Pt(SMe2)2. Addition of either ethylene or carbon monoxide to 1a results in the formation of (ATI)Pt(CH3)(η2-C2H4) (1b) or (ATI)Pt(CH3)(CO) (1c), respectively. Oxidative addition of MeOTf or MeI to 1a results in formation of the PtIV complex [(ATI)Pt(CH3)2(X)(SMe2)] (X = OTf (3), I (2)). Complex 3 reacts with isocyanides, which replace the triflate ligand to form [(ATI)Pt(CH3)2(CNR)(SMe2)][OTf] (4). Complex 3 also undergoes ligand substitution reactions with azide or cyanide to form (ATI)Pt(CH3)2(N3)(SMe2) (5a) or (ATI)Pt(CH3)2(CN)(SMe2) (5b). Addition of PR3 results in the substitution product [(ATI)Pt(CH3)2(PR3)(SMe2)][OTf] for phosphines with cone angles ≤136° (P(OMe)3, PMe3, PMe2Ph). The PtIV complex [(ATI)Pt(CH3)2(PPh2Me)(SMe2)][OTf] (6c) reductively eliminates [PMe2Ph2][OTf] or [SMe3][OTf] to form the PtII complex (ATI)Pt(CH3)(PPh2Me) (7a) in solution at room temperature. Addition of 1 equiv of PPh3, which has a cone angle of 145°, results in the formation of 50% of PtII(ATI)Pt(CH3)(PR3) and [MePPh3][OTf]. Reaction of 3 with PCy3, which has a cone angle of 170°, yields complete and immediate conversion to (ATI)Pt(CH3)(SMe2) and [MePCy3][OTf].

Selective hydrosilylation of allyl esters with octahydridosilsesquioxane

Hydrosilylation of allyl esters with octahydridosilsesquioxane (T8H8) in the presence of platinum-based catalysts was studied. The effects of the catalysts and the reaction conditions on the conversion and the selectivity of the products were investigated. Karstedt's catalyst with two equivalents of PPh3 was found to be a superior hydrosilylation catalyst in terms of conversion and selectivity, compared with other Pt catalysts examined. An octasilsesquioxane functionalized with epoxy substituents was synthesized using the optimized reaction system, which was converted to a thermosetting polymer and its properties were investigated.

Synthesis, Characterization, and Electrochemical Properties of Benzyloxy-Functionalized Diiron 1,3-Propanedithiolate Complexes Relevant to the Active Site of [FeFe]-Hydrogenases

A series of new benzyloxy-functionalized 1,3-propanedithiolate (PDT)-type model complexes (A and 1–7) have been synthesized and structurally characterized. The benzyloxy-functionalized all-carbonyl complex [(μ-SCH2)2CH(OCH2Ph)]Fe2(CO)6 (A) can be prepared by condensation reaction of 2-benzyloxy-1,3-dibromopropane with the in situ generated (μ-LiS)2Fe2(CO)6, whereas it reacts with the in situ formed N-heterocyclic carbene 1-mesityl-3-methylimidazol-2-ylidene (IMes/Me) to give the corresponding carbene monosubstituted complex [(μ-SCH2)2CH(OCH2Ph)]Fe2(CO)5(IMes/Me) (1). The PMe3-monosubstituted complex [(μ-SCH2)2CH(OCH2Ph)]Fe2(CO)5(PMe3) (2) can be prepared by substitution of the CO ligand in parent complex A with 1 equiv of PMe3 in the presence of Me3NO·2H2O, whereas PPh3-monosubstituted and PPh3-disubstituted complexes [(μ-SCH2)2CH(OCH2Ph)]Fe2(CO)5(PPh3) (3) and [(μ-SCH2)2CH(OCH2Ph)]Fe2(CO)4(PPh3)2 (4) are prepared by reaction of A with 2 equiv of PPh3 under similar conditions. While the PPh3-disubstituted...

Naphthyridines. Part 3: First example of the polyfunctionally substituted 1,2,4-triazolo[1,5- g][1,6]naphthyridines ring system

Treatment of 1,2,4-triazoles ( 1) with diethylmalonate in bromobenzene gave 1,2,4-triazolo-[1,5- a]pyridines 2. Chlorination of 2 using POCl 3/DMF (Vilsmeier reagent) led to the isolation of 7-chloro-6-formyl-1,2,4-triazolo[1,5- a]pyridine derivative 4, which reacted with the stabilized ylid 5 to afford 6-ethoxycarbonylvinyl-1,2,4-triazolo[1,5- a]-pyridines 6. Azidation of 6 yielded the corresponding azido compound 7, (Scheme 2). Reduction of 7 with Na 2S 2O 4 gave the corresponding 7-amino compound 8, which cyclized in boiling DMF to give the novel 1,2,4-triazolo[1,5- g][1,6]naphthyridines 9. On the other hand, reacting 7 with one equivalent of PPh 3 (aza-Wittig reaction) in CH 2Cl 2 gave 7-imino-phosphorane derivative 10, and subsequent cyclization in boiling DMF afforded the new 1,2,4-triazolo[1,5- g][1,6]naphthyridine derivative 11 (Scheme 3). However, treatment of 10 with phenyl isothiocyanate in 1,2-dichlorobenzene at reflux temperature gave the new 1,2,4-triazolo[1,5- g][1,6]naphthyridine derivative 14 (Scheme 4). Refluxing 6 with excess of a primary amines 15a, b in absolute. EtOH yielded the corresponding 7-alkyl-amino-1,2,4-triazolo[1,5- a]pyridines 16a, b. These obtained amines 16a, b underwent intramolecular heterocyclization in boiling DMF to give the novel 9-alkyl-1,2,4-triazolo[1,5- g][1,6]-naphthyridines 17a, b, in excellent yields (Scheme 5).

Mo(CO) 3(NCMe)(PPh 3) 2: Synthesis, X-ray structure and evaluation of its catalytic activity for the homogeneous hydrogenation of olefins and their mixtures

The complex Mo(CO) 3(NCMe)(PPh 3) 2, was synthesized by the reaction of Mo(NCMe) 3(CO) 3 with two equivalents of PPh 3 and characterized by UV–Vis, IR, NMR and X-ray diffraction. This complex was used as a catalyst precursor for the hydrogenation of 1-hexene, styrene, cyclohexene and 2,3-dimethyl-1-butene and their mixtures under moderate conditions in homogeneous media. Under mild reaction conditions ( T = 373 K, P = 60 atm), the substrates showed the following reactivity order: styrene > 1-hexene > cyclohexene > 2,3-dimethyl-1-butene. A quaternary equimolar mixture showed a different hydrogenation order: 1-hexene > cyclohexene > styrene > 2,3-dimethyl-1-butene; the presence of dibenzothiophene or mercury does not interfere with the activity of the catalyst.