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The reactivity of a series of N,N-dimethyl-2-iodoanilines bearing different chelating "arms" at the 3-position with Pd(2)(dba)(3) has been explored. 3-[(Diphenylphosphino)methyl]-2-iodo-N,N-dimethylaniline reacted with Pd(2)(dba)(3) and PPh(3) under aerobic conditions to give the OCP-pincer complex , which was formed by sequential C(sp(3))-H activation/oxidation at the alpha-position of the aniline N atom. On the other hand, under similar reaction conditions, 3-[2-(dimethylamino)ethyl]-2-iodo-N,N-dimethylaniline afforded the CCN-pincer complex , after a second C-H activation process at the formyl group of the initially formed OCN-pincer complex. In contrast, 2-iodo-3-(1H-1,2,4-triazol-1-ylmethyl)-N,N-dimethylaniline and 2-iodo-3-(pyrazol-1-ylmethyl)-N,N-dimethylaniline reacted with Pd(2)(dba)(3) and PPh(3), respectively, to give the 6-membered azapalladacycles and , in which the aniline nitrogen is merely a spectator substituent. Finally, treatment of iodide complex with Tl(TfO) afforded the CN-bidentate cationic complex. Solid-state structures of palladium complexes, and CH(2)Cl(2).3CH(3)OH.5H(2)O were determined by X-ray analysis.

We report that the action of Lewis bases, such as triphenylphosphine, pyridine, or trimethylamine, on imine metallacycles derived from amino acids leads to the formation of the first organometallic compound of an NH aldimine, a highly reactive organic species, and the corresponding alpha-ketoester, in a deamination reaction that mimics the metabolism of alpha-amino acids. The synthesis of different cyclopalladated compounds by a reaction between palladium acetate and the Schiff bases 2,4,6-Me(3)C(6)H(2)CH=NCH(R(1))COOR(2) (R(1) = CH(2)Ph, R(2) = Et and R(1) = Ph, R(2) = Me) is also reported.

In the reaction of (3,5-dimethyl-1H-pyrazol-1-yl)methyldiphenylphosphinite (dmpmp) with [PdCl2(CH3CN)2], we have obtained hydrolysis and phosphorus oxidation products and the unexpected complex cis-[PdCl2(dmbpm)] (dmbpm = bis(3,5-dimethyl-1H-pyrazol-1-yl)methane). Modifications in the synthesis of dmpmp (high temperature, strong base, and the presence of Ph2P(O)Cl) show that dmbpm is a by-product from the synthetic route to dmpmp. The complex cis-[PdCl2(dmbpm)] is isolated and fully characterized by mass spectrometry, analytical, and spectroscopy techniques and the crystal structure is obtained by X-ray diffraction methods. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis and characterization of pyrazole derivatives of general formula [C6H4-4-R-1-{(3,5-Me2–C3N2)–CH2–(η5-C5H4)Fe(η5-C5H5)}] [R=OMe (1a) or H (1b)] with a ferrocenylmethyl substituent are described.The study of the reactivity of compounds 1 with palladium(II) acetate has allowed the isolation of complexes (μ-AcO)2[Pd{κ2-C,N-C6H3-4-R-1-[(3,5-Me2–C3N2)–CH2–(η5-C5H4)Fe(η5-C5H5)]}]2 (2) [R=OMe (2a) or H (2b)] that contain a bidentate [C(sp2,phenyl),N]− ligand and a central “Pd(μ-AcO)2Pd” unit.Furthermore, treatment of 2 with LiCl produced complexes (μ-Cl)2[Pd{κ2-C,N-C6H3-4-R-1-[(3,5-Me2–C3N2)–CH2–(η5-C5H4)Fe(η5-C5H5)]}]2 (3) [R=OMe (3a) or H (3b)] that arise from the replacement of the acetato ligands by the Cl−.Compounds 2 and 3 also react with PPh3 giving the monomeric complexes [Pd{κ2-C,N-C6H3-4-R-1-[(3,5-Me2–C3N2)–CH2–(η5-C5H4)Fe(η5-C5H5)]}X(PPh3)] {X− =AcO− and R=OMe (5a) or H (5b) or X− =Cl− and R=OMe(6a) or H (6b)}, where the phosphine is in a cis-arrangement to the metallated carbon atom. Treatment of 3 with thallium(I) acetylacetonate produced [Pd{κ2-C,N-C6H3-4-R-1-[(3,5-Me2–C3N2)–CH2–(η5-C5H4)Fe(η5-C5H5)]}(acac)] (7) [R=OMe (7a) or H (7b)]. Electrochemical studies of the free ligands and the cyclopalladated complexes are also reported. The dimeric complexes 3 also react with MeO2C–CCO2Me (in a 1:4 molar ratio) giving [Pd{(MeO2C–CCO2Me)2C6H3-4-R-1-[(3,5-Me2–C3N2)–CH2–(η5-C5H4)Fe(η5-C5H5)]}Cl] (8) [R=OMe (8a) or H (8b)], which arise from the bis(insertion) of the alkyne into the σ{Pd–C(sp2,phenyl)} bond of 3. [Copyright &y& Elsevier]

The coordination chemistry of the ligand bis[2-(3,5-dimethyl-1-pyrazolyl)ethyl]ether (L1) was tested in front of Pd(II) and Pt(II). Complexes cis-[MCl2(L1)] (M=Pd(II) and Pt(II)) were obtained, due to the chelate condition of the ligand and the formation of a stable 10-membered ring. The crystal structure of cis-[PtCl2(L1)] was resolved by X-ray diffraction. Treatment of [PdCl2(L1)] or [Pd(CH3CN)4](BF4)2 with AgBF4 in the presence of L1 gave the complex [Pd(L1)2](BF4)2. The initial cis-[PdCl2(L1)] was recovered by reacting [Pd(L1)2](BF4)2 with an excess of NEt4Cl. Reaction of [Pt(CH3CN)4](BF4)2 (generated in situ from [PtCl2(CH3CN)2] and AgBF4 in acetonitrile) with ligand L1 yields complex [Pt(L1)2](BF4)2. [Copyright &y& Elsevier]

The ligands 1-hydroxymethylpyrazole (hl1), 1-(2-hydroxyethyl)pyrazole (hl2) and 1-(3-hydroxypropyl)pyrazole (hl3) react with [PdCl2(CH3CN)2] to give trans-[PdCl2(hl)2] compounds. Due to a hindered rotation around the Pd-bond, these compounds present two different conformations in solution: anti and syn. The conformation presented depends on the relative disposition of the hydroxyalkylic chains of the two pyrazolic ligands. The present study was carried out on the basis of NMR experiments. The present paper reports the crystal structure of trans-[PdCl2(hl2)2]. The synthesis and characterisation of compounds [Pd(hl)4](BF4)2 (hl = hl1, hl2 and hl3) starting from [Pd(CH3CN)4](BF4)2 and the corresponding chlorocomplexes trans-[PdCl2(hl)2] are also described. [Copyright &y& Elsevier]

Treatment of the ligand N-(2-mercaptoethyl)-3,5-dimethylpyrazole with [Pd(CH3COO)2]3 and reaction of [PdCl(μ-med)]2 with pyridine (py) or triphenylphosphine (PPh3) in the presence of AgBF4 produced the following complexes: [Pd(CH3COO)(μ-med)]2, [Pd(μ-med)(py)]2(BF4)2 and [Pd(μ-med)(PPh3)]2(BF4)2. Similar reactions carried out with 2,2′-bipyridine (bpy) or 1,3-bis(diphenylphosphino)propane (dppp) produced [Pd(μ-med)(bpy)]x(BF4)x (x=1 or 2) and [Pd(μ-med)(dppp)]x(BF4)x (x=1 or 2). Treatment of [Pd(μ-med)(bpy)]x(BF4)x with [PdCl2(CH3CN)2] produced [Pd3Cl2(μ-med)2(bpy)2](BF4)2. Treatment of [Pd(μ-med)(dppp)]x(BF4)x with [PdCl2(CH3CN)2] produced a mixture of [Pd(μ-Cl)(dppp)]2(BF4)2 and [Pd(μ-med)2(dppp)]2+. X-ray crystal structures of [Pd(μ-med)(PPh3)]2(BF4)2 · 2CH3CN and [Pd(μ-med)(bpy)]2(BF4)2 · 0.5CH3OH are presented. [Copyright &y& Elsevier]

Thiolate-bridged dinuclear nickel(II), palladium(II) and platinum(II) complexes with N-(2-mercaptoethyl)-3,5-dimethylpyrazole (Hmed), [MCl(med)]2 (M=Ni (1), Pd (2), Pt (3)), have been synthesised and characterised by elemental analyses, conductivity, IR, electronic spectra and NMR spectroscopies. The crystal structure of 2 was determined by a single-crystal X-ray diffraction method. The structure consists of thiolate-bridged dinuclear units. Each Pd(II) atom is coordinated by a pyrazolic nitrogen, one chlorine and two bridging sulfur atoms. When the synthesis of complex 1 was carried out in acetonitrile and in the presence of oxygen, [NiCl3(Hdeds)] (4) was formed (deds=1,1′-(dithiodiethylene)bis(3,5-dimethylpyrazole)). The crystal structure of this complex was also determined by single-crystal X-ray diffraction method. The structure consists of nickel(II) ions coordinated by three chloride ions and one pyrazolic nitrogen atom. Ligand deds is the result of the oxidation of N-(2-mercaptoethyl)-3,5-dimethylpyrazole (Hmed). [Copyright &y& Elsevier]

The present report is on the synthesis of new 3,5-dimethylpyrazolic derived ligands that are N1-substituted by polyether chains: 1-(2-methoxyethoxymethyl)-3,5-dimethylpyrazole (L1), 1-[2-(2-methoxyethoxymethoxy)ethyl]-3,5-dimethylpyrazole (L2) and 1-[2-[2-(2-methoxyethoxy)ethoxy]ethyl]-3,5-dimethylpyrazole (L3). These ligands form complexes with the formula [PdCl2L2] when reacting with [PdCl2(CH3CN)2] in the ratio 1M:2L. Two crystalline structures have been resolved with ligands L1 and L3, where the Pd(II) presents a square planar geometry with the ligands co-ordinated in a trans disposition. NMR studies prove the existence of two conformational diastereoisomers for each complex in solution, as a consequence of the slow rotation around the Pd–N bond: syn and anti. The reaction of ligands L1, L2 and L3 with [PdCl2(CH3CN)2] in presence of AgBF4 yields the compounds [PdClL3]BF4, characterised by elemental analysis, conductivity measurements, 1H NMR, 13C{1H} NMR, infrared spectra, and FIA ES(+)/MS. [Copyright &y& Elsevier]

The study of the reactivity of R&z.sbnd;CH&z.dbnd6;N&z.sbnd;(C6H4-2-SMe) with R=C6H5 or 2,4,6-Me3-C6H2 with palladium(II) salts is reported. These studies have allowed us to prepare and characterize the coordination complexes: cis-[Pd{R&z.sbnd;CH&z.dbnd6;N&z.sbnd;(C6H4-2-SMe)}Cl2] {R=C6H5 or 2,4,6-Me3-C6H2} and the cyclopalladated compounds [Pd{C6H4&z.sbnd;CH&z.dbnd6;N&z.sbnd;(C6H4-2-SMe)}Cl] and [Pd{(2-CH2-4,6-Me2-C6H2)&z.sbnd;CH&z.dbnd6;N&z.sbnd;(C6H4-2-SMe)}Cl]. The X-ray crystal structures of the latter complexes reveal that the thioimines act as a [Csp2, phenyl,N,S]− and as a [Csp3, N,S]− terdentate group, respectively. The study of the reactions of the cyclopalladated compounds with PPh3 is also reported. [Copyright &y& Elsevier]

Abstract: Complex [PdCl(bdtp)](BF4), in presence of AgBF4 or NaBF4, reacts with pyridine (py), triphenylphosphine (PPh3), cyanide (CN−), thiocyanate (SCN−) or azide (N3 −) ligands, leading to the formation of the following complexes: [Pd(bdtp)(py)](BF4)2 [1](BF4)2, [Pd(bdtp)(PPh3)](BF4)2 [2](BF4)2, [Pd(CN)(bdtp)](BF4) [3](BF4), [Pd(SCN)(bdtp)](BF4) [4](BF4) and [Pd(N3)(bdtp)](BF4) [5](BF4). These complexes were characterised by elemental analyses, mass spectrometry, conductivity measurements, infrared and NMR spectroscopies. The crystal structure of [2](BF4)2 was determined by single-crystal X-ray diffraction methods. The metal atom is coordinated by two azine nitrogen atoms, and one sulfur atom of the thioether–pyrazole ligand and one triphenylphosphine in a distorted square–planar geometry. [Copyright &y& Elsevier]

Abstract: Mononuclear palladium(II) complexes containing a pyrazole-thioether ligand, with general formula trans-[Pd(X)2(bddo)] (X=CN− (1), SCN− (2) or N3 − (3); bddo=1,8-bis(3,5-dimethyl-1-pyrazolyl)-3,6-dithiaoctane), have been prepared. Similar reactivity carried out with pyridine or triphenylphosphine has been assayed. When pyridine is used, a mixture of [Pd(bddo)(py)2](BF4)2 ([4](BF4)2) and [Pd(bddo)](BF4)2 is obtained. When triphenylphosphine is used, only [Pd(bddo)](BF4)2 is obtained. The complexes have been characterised by elemental analyses, conductivity measurements, IR and NMR spectroscopies. X-ray crystal structure of trans-[Pd(SCN)2(bddo)] (2) is presented. In this complex the metal atom is coordinated by the two azine nitrogen atoms of the pyrazole rings and two SCN− anions in trans disposition. [Copyright &y& Elsevier]

Abstract: The reaction of the complex [PdCl(μ-med)]2 (Hmed= N-(2-mercaptoethyl)-3,5-dimethylpyrazole) with NaCN, NaSCN or NaN3 in presence of AgBF4, yielded complexes with formula [Pd(X)(μ-med)]2 (X=CN− (1), SCN− (2) or (3)). These complexes have been characterised by elemental analyses, conductivity measurements, IR and NMR spectroscopies. X-ray crystal structures of [Pd(SCN)(μ-med)]2 ·0.5CH3CN and [Pd(N3)(μ-med)]2, are presented. These complexes consist of thiolate-bridged dinuclear units. Each Pd(II) is coordinated by a pyrazole nitrogen, two bridging sulfur atoms and one SCN− (2) or (3) anion. [Copyright &y& Elsevier]

Abstract: The reactivity of the dimeric cyclopalladated compounds derived from biphenyl-2-ylamine (μ-X)2[κ2- N2 ′, C1 -1-Pd-2-{(2′-NH2C6H4)C6H4}]2 [X=OAc (1), X=Cl (2)] towards unsaturated organic molecules is reported. Compound 1 reacted with carbon monoxide and t butyl isocyanide producing phenanthridin-6(5H)-one and N-tert-butylphenanthridin-6-amine in 63% and 88% yield, respectively. Compound 2 reacted separately with diphenylacetylene and 3-hexyne, affording the mononuclear organopalladium compounds [κ2- N2 ″, C1 -η2- C2 , C3 - 1-Pd{(R–CR)2-2′-(2″-NH2C6H4)C6H4}Cl] [R=Ph (5), R=Et (6)] in 50–60% yield, which derived from the insertion of two alkyne molecules into the C–Pd σ bonds of 2. The crystal structure of compounds 5 and 6 has been determined. Compound 5 crystallized in the monoclinic space group P21/n with a =13.3290(10)Å, b =10.6610(10)Å and c =22.3930(10)Å and β =100.2690(10)°. Compound 6 crystallized in the triclinic space group with a =7.271(7)Å, b =10.038(3)Å and c =16.012(5)Å, and α =106.79(3)°, β =96.25(4)° and γ =99.62(4)°. The crystal structures of 5 and 6 have short intermolecular Pd–Cl⋯H–N–Pd non-conventional hydrogen bonds, which associated the molecules in chains in the first case and in dimers in the second. [Copyright &y& Elsevier]

The reaction of [Pt(μ-Cl)(κ,η2-COE-MeO)]2 (2) (COE-MeO = 2-methoxy-5-cycloocten-1-yl) with trispyrrolylphosphine yields [PtCl{P(pyrl)3}(κ,η2-COE-MeO)] (3), in contrast to the crown-cycle complex [Pd(μ-Cl) {P(pyrl)3}]8 (1) obtained with the analogous palladium complex. The different reactivity has been explained in terms of the higher lability of the carbon–carbon double bond in the starting palladium compound, as compared with the related platinum derivative. The reaction of 1 with the ligand 2-[(pyridin-2-ylmethylene)aminophenol], (HNN′O), in the presence of thalium salt and NEt3, yields the complex [Pd(κ3N,N′,O-py-CH＝N-C6H4O)(P(O)(pyrl)2)] (5), which contains, for the first time, a di(N-pyrrolyl)phosphonato-P ligand. Treatment of [PdCl(κ3N,N′,O-py-CH＝N-C6H4O)] with P(pyrl)3 gives the amido derivative [PdCl{κ3P,N,N-(P(pyrl)2-O-C6H4-N-CH(CH2-CO-CH3)-py)}] (7), which displays a N–Pd–P–O–C2 six-membered metallacycle. In addition, the latter compound has been able to insert an acetone molecule into its framework. The crystal structures of 5 and 7 were solved by X-ray diffraction analysis. [Copyright &y& Elsevier]

Abstract: (R)-1-Phenylethyl-benzylidene-amine (1) reacted with Pd(OAc)2 in acetic acid at 60°C under nitrogen affording the acetato-bridged dinuclear endo five-membered ortho-cyclopalladated compound (μ-OAc)2[Pd(κ2-C,N-(R)-C6H4-CH)]2 (2) in 65% yield. Compound 2 was converted by a metathesis reaction with LiCl into the corresponding chloro-bridged dinuclear cyclopalladated compound (μ-Cl)2[Pd(κ2-C,N-(R)-C6H4-CH)]2 (3). 1H NMR of CDCl3 solutions of compounds 2 and 3 treated separately with py-d 5, (R)-1-phenylethylamine and racemic 1-phenylethylamine were consistent with the endo cyclopalladated structure and the R absolute configuration of the chiral carbon atoms of compounds 2 and 3. Compounds 2 and 3 reacted with carbon monoxide in methanol affording, as major compounds, methyl 2-formylbenzoate (91% chemical yield) and the epimers of 3-methoxy-2-[(R)-1-phenylethyl]isoindolin-1-one (64% chemical yield) in ca. 20% diastereomeric excess, respectively. The trans isomer of compound 3 crystallized in the P21 monoclinic space group with a =10.430(4)Å, b =12.082(8)Å, c =11.168(4)Å and β =95.20(3)° and presented C–H⋯Cl intramolecular and C–H⋯Pd intermolecular non-conventional hydrogen bonds. [Copyright &y& Elsevier]

Novel square-planar compounds [M(NC5H4C≡CH)2(dppp)](OTf)2 (M = Pd (1), Pt (2)), [Pt(C≡CC6H4CN)2(dppp)] (3) and [Pt(C6H4C≡CC5H4N)2(dppp)] (4) (dppp = 1,3-bis(diphenylphosphino)propane) were prepared and characterised. Their potential as building blocks in the generation of heterobimetallic squares was studied. The reaction of 4 and the ditopic acceptor species [Pd(H2O)2(dppf)](OTf)2 enabled a tetrametallic metallocycle containing two platinum and two palladium atoms to be obtained. The crystal X-ray structure of 4 shows that the Pt⋯N vectors are nearly perpendicular, and confirm the suitability of the compound to act as a corner unit for the construction of molecular squares. [Copyright &y& Elsevier]

The synthesis, characterisation and the study of the reactivity of the novel and bifunctional ferrocenyl Schiff bases [Fe{(η5-C5H4)–C(Me)&z.dbnd6;N–N&z.dbnd6;C(H)(C6H3–2,6-R2)}2] (with R=Cl or H) with palladium(II) salts under different experimental conditions are reported. The treatment of Na2[PdCl4], Na(CH3COO)·3H2O and the corresponding ligand [Fe{(η5-C5H4)–C(Me)&z.dbnd6;N–N&z.dbnd6;C(H)(C6H3–2,6-R2)}2] (with R=Cl or H) (in a 2:2:1 molar ratio) in methanol for 6 days followed by the addition of triphenylphosphine (PPh3), and a SiO2 column chromatography, allowed the isolation of the two isomers (meso- and d,l- forms) of the heterotrimetallic complexes of general formula [Pd2{Fe[(η5-C5H3)–C(Me)&z.dbnd6;N–N&z.dbnd6;C(H)(C6H5–2,6-R2)]2}Cl2(PPh3)2], (with R=Cl or H). [Copyright &y& Elsevier]

The action of palladium acetate on the Schiff bases 4-ClC6H4CH&z.dbnd6;N-CH(R2)COOR1 (R1=Me, Et; R2=Ph, CH2Ph), in acetic acid for 3 h at 70 °C and subsequent treatment of the reaction residues with LiCl in acetone, affords the corresponding chloro-bridged five-membered endo-metallacycles [PdCl(C&z.sbnd;N)]2, 1a, 2a. The action of palladium acetate on the Schiff bases 2,6-Cl2C6H3CH&z.dbnd6;N&z.sbnd;CH(R2)COOR1 (R1=Me, Et; R2=Ph, CH2Ph), in chloroform at room temperature and subsequent treatment of the reaction residues with LiCl in acetone, affords the corresponding chloro-bridged five- or six-membered exo-metallacycles, by metallation of the amino acid moiety [PdCl(C&z.sbnd;N)]2, 3a-exo, 4a-exo. A small amount of the endo-metallacycles was also obtained, probably by oxidative addition of the ortho C&z.sbnd;Cl bond of these imines to Pd(0) formed in situ. Reaction of dimers 1a–4a with PPh3 affords the mononuclear complexes [PdCl(C&z.sbnd;N)(PPh3)] 1b–4b. [Copyright &y& Elsevier]

The reaction of (SC)-[(η5-C5H5)Fe{(η5-C5H4)&z.sbnd;CH&z.dbnd6;N&z.sbnd;CH(CO2Me)CH2&z.sbnd;CH2SMe}] (1) with Na2[PdCl4] in the presence of NaAcO is studied. This process leads to the formation of the tetrametallic complex: [Pd2{[C{(CO2Me)&z.sbnd;CH2&z.sbnd;CH2&z.sbnd;SMe}N&z.dbnd6;CH&z.sbnd;(η5-C5H4)]Fe(η5-C5H5)}2Cl2]·CH2Cl2. The X-ray crystal structure of this complex revealed that the ligand exhibits an unusual mode of binding, and that each palladium is bound to a stereogenic Csp3* carbon atom. [Copyright &y& Elsevier]