Bidentate Nitrogen Donor Ligands Research Articles

Synthesis and structural studies of phenyl(iodo)- and methyl(phenyl)palladium(II) complexes of bidentate nitrogen donor ligands

Phenylpalladium(II) complexes of the type PdIPh(NN), with NN = N,N,N′,N′-tetramethylethylenediamine (tmeda) or 2,2′-bipyridyl (bpy), can be conveniently prepared in 70–95% yield by oxidative addition of iodobenzene to bis(dibenzylideneacetone)palladium(O) in the presence of the appropriate nitrogen donor ligand. The bromo analogues were obtained in only 5–12% yield in this way. The complex PdIPh(tmeda) ( 1a) reacts readily with MeLi to give PdMePh(tmeda) ( 3) in 88% yield, whereas PdIPh(bpy) ( 2a) gives PdMePh(bpy) ( 4) and PdMe 2(bpy) in varying ratios. The formation of PdMe 2(bpy) was found to result from the synergistic action of lithium iodide and methyllithium. Pure PdMePh(bpy) ( 4) was obtained in 82% yield via ligand-exchange from PdMePh (tmeda) ( 3). The crystal structures of PdIPh(NN) ( 1a, 2a) and PdMePh(NN) ( 3, 4) complexes were determined by X-ray diffraction studies. The results show that the phenyl group is alw ays oriented perpendicular to the coordi 3 (14.3(2)°). The PdN bond distances in the tmeda complexes (2.127(6)–2.210(3) Å) are larger than those in the bpy-coordinated complexes (2.070(8)–2.144(8) Å). Similarly, the PdC(Me) bond distances (2.5703(8) and 2.575(1) Å) are larger than the PdC(Pb) bond distances (1.985(3)–1.996(10)Å).

Coordination properties of new indazole derivatives

The bidentate nitrogen donor ligands 2-(1-indazolyl) pyridine and 2-(1-indazolyl) pyrimidine have been synthesised. Their complexes with MnII, CoII, NiII, CuII and ZnII have been prepared and characterised by elemental analysis, i.r., u.v. spectra and magnetic susceptibility measurements. The complexes are nonelectrolytes and have magnetic moments consistent with an octahedral environment.

Synthesis and characterization of technetium(V) and (VII) complexes with bidentate nitrogen donor ligands. X-ray molecular structures of tetrabutylammonium bis(1,2-diimidobenzene)oxotechnetium(V) and tris(1,2-diimidobenzene)technetium(VII) pertechnetate

The reaction of pertechnetate with 1,2-diaminobenzene (H 2pda) in the presence of the reducing agent sodium dithionite in alkaline aqueous solution led to the formation and isolation of (n-Bu 4N)[TcO(pda) 2] ( 1). If the reaction is performed without reducing agent in methanol, the green compound [Tc(pda) 3](TcO 4) ( 2) is formed. Both complexes are diamagnetic, and a single NH stretching frequency in both indicates that each pda ligand contains one hydrogen per nitrogen, and is dianionic. X-ray crystal structures of both compounds are also reported. Crystal data for complex 1, C 28H 48N 5OTc: orthorhombic, space group P2 12 12 1, a=11.644(3), b=15.303(4), c=16.950(5) Å and U=3020.3(1.5) Å 3 to give Z=4 for D calc=1.25 g cm −3. Crystal data for 2, C 18H 18N 6O 4Tc 2: orthorhombic, Pna2 1, a=13.869(4), b=12.799(5), c=10.851(3) Å and U=1926.2(1.1) Å 3 to give Z=4 for D calc=1.99 g cm −3. The structures have been solved by Patterson and Fourier methods and refined by least-squares methods to R=0.058 for 1 and 0.090 for 2. Complex 2 represents the first tris-bidentate cationic complex of technetium to be structurally characterized. Complex 1, with an unexpectedly low ν(TcO) of 891 cm −1, has a TcO bond distance of 1.668(7) Å, that is typical for monooxotechnetium(V) square-pyramidal complexes.

Proton NMR detection of cationic organopalladium(IV) intermediates in oxidative-addition reactions and the structure of fac-PdBrMe2(CH2COPh)(bpy)

Phenacyl bromides react with dimethylpalladium(I1) complexes PdMe2(L2) (L2 = bpy, phen) to form the palladium(IV) complexes fac-PdBrMe2(CH2COAr)(L2) (Ar = Ph, p-C6H4Br), which have both methyl groups trans to the bidentate nitrogen donor ligand. 1H NMR studies of the oxidative addition of phenacyl bromides to PdMe2(bpy) in (CD3)2C0 at -5 C indicate the formation of two similar cationic intermediates, prior to formation of the neutral product. As the cations have only one of the methyl groups trans to bpy, configurational changes at palladium occur on cation formation and on conversion of the cations to the neutral product. It is proposed that one of the cations may be stabilized via an intramolecularly coordinated phenacyl group, [PdMe2(CH2COAr-C,0)(L2)]+. A single cation, exhibiting NMR spectra similar to those of the cations of the bpy complexes, is detected as an intermediate in the reaction of PdMe2(phen) with ArCOCH2Br. A cation has also been detected for the reaction of PdMe2(bpy) with CD3I in (CD3)2C0 at -50 C, prior to formation of PdIMe2(CD3)(bpy). Both the cation, most likely [PdMe2(CD3)(bpy)((CD3)2CO)]+, and the neutral product display scrambled Me and CD3 groups, in contrast to the trans oxidative addition reported for the analogous reaction of PtMe2(bpy) with CD3I. Crystals of PdBrMe2(CH2COAr)(bpy) are orthorhombic, space group Pbca, with a = 19.554(3) A, b = 15.007(9) A, c = 13.282(4) 1, and Z = 8.

Synthesis and characterization of novel trinuclear iron(II) and manganese(II) carboxylate complexes: structural trends in low valent iron and manganese carboxylates

Reaction of Fe(O 2 CCH 3 ) 2 or Mn(O 2 CCH 3 ) 2 .4H 2 O) with bidentate nitrogen donor ligands affords the trinuclear complexes [M 3 (O 2 CCH 3 ) 6 L 2 ] [M=Fe, L=BIPhMe (1) ; M=Mn, L=BiPhMe (2) or, 1,10-phenanthroline (3)] in high yields. As judged from X-ray diffraction studies, these complexes adopt a novel linear structure, with one monodentate and two bidentate bridging carboxylates spanning each pair of metal atoms.

Synthesis and Characterization of Six-Coordinate Cationic Technetium(V) And Rhenium(V) Complexes withN-(2-Oxidophenyl)Salicylideneiminate and Bidentate Aromatic Nitrogen-Donor Ligands

Abstract Six-coordinate cationic complexes of rhenium(V) and technetium(V) with the tridentate N-(2-oxidophenyl)-salicylideneiminate (OPhsal2-) and the bidentate aromatic nitrogen-donor ligands 2,2′-dipyridine, 1,10-phenanthroline, 2,2′-dipyridylamine and bis(2-pyridyl)ketone (NN) have been prepared. Complexes of general formula [MO(OPhsal)(NN)]X (M = Re, Tc; X = Cl, PF6) were isolated by the reaction of ReOCl(OPhsal)(PPh3) and TcOCl(O Phsal) with the bidentate nitrogen-donor ligands. The reaction of TcOCl(O Phsal) with bis(2-pyridyl)ketone (dpk) in ethanol produced the complex [TcO(OPhsal)-(dpk.EtOH)]Cl, in which alcoholation of ethanol across the ketone double bond of dpk has occurred. Spectroscopic and analytical results obtained for all the isolated complexes suggest terdentate coordination of OPhsal2- in the equatorial plane cis to the oxo oxygen, with the bidentate pyridyl nitrogen-donor ligands bridging the fourth equatorial site and the position trans to the oxo group.

Trimethylpalladium(IV) chemistry. Conformational and fluxional effects in related palladium(IV) and platinum(IV) complexes of flexible bidentate nitrogen donor ligands

Iodomethane reacts with palladium(II) complexes PdMe 2(L 2), where L 2 is a flexible nitrogen donor ligand such as 1,1-bis(pyridin-2-yl)ethane [(py) 2CHMe], to form unstable trimethylpalladium(IV) complexes characterized as fac-PdIMe 3(L 2) by comparison of their variable temperature 1H NMR spectra with those of stable trimethylplatinum(IV) analogues. The complexes fac-MIMe 3{(py) 2CHMe} occur as mixtures of isomers, with the chelate ring having the CH group adjacent to iodine in one isomer and adjacent to the methyl group trans to iodine in the other isomer. Complexes containing pyrazol-1-yl (pz) or N-methylimidazol-1-yl (mim) donors, fac-MIMe 3(L 2) [L 2 = (pz) 2CH 2, (pz)(mim)CH 2, and (py)(pz)CH 2] undergo fluxional behaviour involving inversion of the six-membered chelate rings.

Neutral, cationic and dicationic seven-coordinate complexes of molybdenum(II) and tungsten(II) containing mono- and bidentate nitrogen donor ligands

The seven-coordinate complexes [MI2(CO)3(NCMe)2] (M=Mo or W) react with two equivalents of L(L=py, 4Me-py, 3Cl-py or 3Br-py) or one equivalent of NN {NN=2,2′-bipyridine(bipy), 1,10-phenanthroline(phen), 5,6-dimethyl-1, 10-phenanthroline (5,6-Me2-1, 10-phen), 5-Nitro-1, 10-phenanthroline (5-NO2-1, 10-phen) and C6H4(o-NH2)2 (o-diam) (for M=Mo only)} in CH2Cl2 at room temperature to give the substituted products [MI2(CO)3L2] or [MI2(CO)3(NN)] (1–17) in high yield. The compounds [MI2(CO)3(NCMe)2] react with two equivalents of NN (for M=W, NN=bipy; for M=Mo, NN=phen) to give the dicationic salts [M(CO)3(NN)2]2I(18–19). The compounds [MI2(CO)3(NCMe)2] (M=Mo or W) react with two equivalents of 5,6-Me2-1, 10-phen to yield the monocationic dicarbonyl compounds [MI(CO)2(5,6-Me2-phen)2]I (20 and21). The dicationic mixed ligand complexes [M(CO)3(bipy)(5,6-Me2-phen)]2I (22 and23) are prepared by reacting [MI2(CO)3(NCMe)2] with one equivalent of bipy, followed by anin situ reaction with 5,6-Me2-1, 10-phen to afford the products22 and23. The complexes (1–23) described in this paper have been characterised by elemental analysis (C, H and N), i.r. spectroscopy and, in selected cases,1Hn.m.r. spectroscopy. Magnetic susceptibility measurements show the compounds to be diamagnetic.

Synthetic routes to methylpalladium(II) and dimethylpalladium(II) chemistry and the synthesis of new nitrogen donor ligand systems

Convenient and widely applicable synthetic routes to methylhalogenopalladium(II), PdXMe(L2), and dimethylpalladium(II) complexes, PdMe2(L2), have been developed, including complexes of triphenylphosphine and a wide range of bidentate nitrogen donor ligands. These routes involve either the generation of PdMe, species at low temperature from methyllithium reagents and trans-PdCl2(SMe2)2 followed by addition of ligand, PdIMe(2,2'-bipyridyl) being synthesized through the oxidative-addition reactivity of Pd2(dba)3(CHCl3), or the facile synthesis of complexes with the reagents [PdIMe(SMe2)]2 and [PdMe2(pyridazine)], in organic solvents at ambient temperature. These reagents are particularly suitable for ligands sensitive to MeLi reagents, and [PdIMe(SMe2)]2 is also a suitable substrate for the synthesis of chloro and bromo complexes, PdXMe(L2), including PPh3 complexes. Several new nitrogen donor bidentate ligands are described, containing 1-methylimidazol-2-y1(mim) and pyridin-2-y1 (py) groups in (mim)2C=CH2 and (py)(mim)C=CH2 as relatives of planar ligands such as 2,2'-bipyridyl and mim, py, and pyrazol-1-yl (pz) groups in (py)(mim)CH2, (py)(mim)CHMe, (mim)2CH2, (mim)2CHMe, and (pz)(mim)CH2 as relatives of ligands such as (py)2CH2 and (pz)2CH2. Methylpalladium(II) complexes of unsymmetrical bidentate ligands exhibit isomerism; e.g., isomers of PdIMe[(py)(mim)C=O] occur in the ratio 9:1, where the dominant isomer has the pyridine ring trans to methyl. The ligands with methane bridges, e.g. (pz)(py)CH2, ethane bridges, e.g. (pz)2CHMe, and propane bridges, e.g. (py)CMe2, form complexes PdMe2(L2) and PdIMe(L2) that exhibit variable-temperature NMR spectra indicating boat-to-boat inversion of the chelate ring, but complexes of (mim)2CHMe and (py)(mim)CHMe appear to adopt only the conformation with the methyl group axial and adjacent to palladium.

ChemInform Abstract: Seven‐Coordinate Complexes. Reactions of the Complex (MoCl(SnCl3)(CO)3(NCMe)2) with Bidentate Nitrogen Donor Ligands.

The complex is prepared in situ by reacting the trisacetonitrile compound [Mo(CO) 3 -(NCMe) 3 ] with an equimolar quantity of SnCl 4 . We describe its reactions with bidentate nitrogen donor ligands

Seven-coordinate complexes. Reactions of the complex [MoCl(SnCl 3)(CO) 3(NCMe) 2] with bidentate nitrogen donor ligands

The complex is prepared in situ by reacting the trisacetonitrile compound [Mo(CO) 3 -(NCMe) 3 ] with an equimolar quantity of SnCl 4 . We describe its reactions with bidentate nitrogen donor ligands

Formamide as a precursor to cyanide in mixed-valence copper(I,II) cyanide complexes

Copper(I) acetate reacts with acetic anhydride–formamide (1 : 1) in acetonitrile solution to give [Cu2(O2CMe)(CN)] or [Cu2(CN)2(NCMe)]. Anhydrous copper(II) acetate reacts with the same reagent to give [Cu(NCMe)4][Cu2(CN)4] and [Cu(O2CMe)2(HCONH2)]. The influence of various polar solvents on the products of the reaction is evaluated. The complex [Cu(NCMe)4)][Cu2(CN)4] reacts with unidentate nitrogen-donor ligands, L, to form [CuL4][Cu2(CN)4](L = pyridine or 4-methylpyridine) or [CuL3][Cu2(CN)4](L = 2-methylpyridine or 2,6-dimethylpyridine). With bidentate nitrogen-donor ligands, L–L, substitution in [Cu(NCMe)4][Cu2(CN)4] gives [Cu(L–L)2(NCMe)][Cu2(CN)4](L–L = 1,2-diaminoethane or 2,2′-bipyridine). The insoluble complex products are obtained in good yield and characterized by microanalysis and spectroscopy (i.r. and visible reflectance). The role of copper ions in promoting the dehydration of formamide by acetic anhydride is assessed.

Cationic iridium(I) complexes with 1,5-cyclooctadiene and nitrogen ligands

The preparation and catalytic properties of cationic tetracoordinated iridium complexes with 1,5-cyclooctadiene and mono- or bidentate nitrogen donor ligands are described. The related [Ir(COD)(/gp-PhNPh 2)]BF 4 and [Ir(COD)(π-PhNHPh)]BF 4 complexes, containing the amine group coordinated to the metal via π-interaction of an arene ring, have been also prepared. On the other hand five-coordinated complexes of formula [Ir(OClO 3)(COD)(TFB)] and [Ir(COD)(TFB)(nitrile)] + are reported.

Thiocarbonyl rhodium complexes with tricyclohexylphosphine and other nitrogen and phosphorus donor ligands

The preparation of the covalent Rh(OCIO3)(CS)(PCy3)2 and Rh(OClO3)(CS)(PPh3)(PCy3) perchlorato complexes is described, These complexes react with mono- or bidentate nitrogen donor ligands to give new cationic complexes of the [Rh(CS)(PCY3)2L]ClO4 and [Rh(CS)(PPh,)(PCy3)L]ClO4 types,

Preparation and catalytic activity of cationic rhodium tetrafluorobenzobarrelene complexes with nitrogen and phosphorus donor ligands

The preparation and properties of twenty five new cationic rhodium(I) complexes with tetrafluorobenzobarrelene and mono- or bidentate nitrogen or phosphorus donor ligands are described. The complexes with tertiary phosphines show high selectivities in the hydrogenation of 1-hexyne and several diolefins towards monoolefins. The dependence of the reduction rate upon the basicity of the phosphine has been studied.

Synthesis and vibrational spectra of tin(II) isothiocyanate adducts with some O- and N-donor ligands

Five new adducts of Sn(NCS)2 have been prepared and characterized: Sn(NCS)2•2L (L = 2,6-dimethyl-y-pyrone and N,N-dimethylacetamide), Sn(NCS)2•LL (LL = 1,10-phenanthroline and 2,2′-bipyridine), and Sn(NCS)(ox) (ox = 8-hydroxyquinolinate). By comparing their infrared and Raman spectra with those of SnX2•L (X = Cl, NCS; L = triphenylphosphine oxide), SnX2•2L (X = Cl, NCS; L = dimethylsulphoxide and pyridine-N-oxide), SnCl2•LL (LL = 1,10-phenanthroline and 2,2′-bipyridine), and SnCl(ox), assignments have been made for v(CN), v(CS), and δ(NCS) vibrations; these suggest the presence of N-bonded and —NCS— bridge-bonded thiocyanate groups. Molecular weight, conductivity, and X-ray powder diffraction data support the conclusion that the adducts with the oxygen donor ligands are molecular with only N-bonded thiocyanate groups. Adducts with the bidentate nitrogen donor ligands are polymeric and have —NCS— bridging and N-bonded thiocyanate.

Study of the reaction of cobalt(II) and nickel(II) benzeneseleninato complexes with bidentate nitrogen donor ligands

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStudy of the reaction of cobalt(II) and nickel(II) benzeneseleninato complexes with bidentate nitrogen donor ligandsCarlo. Preti and Giuseppe. TosiCite this: Inorg. Chem. 1977, 16, 11, 2805–2809Publication Date (Print):November 1, 1977Publication History Published online1 May 2002Published inissue 1 November 1977https://doi.org/10.1021/ic50177a026RIGHTS & PERMISSIONSArticle Views72Altmetric-Citations9LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (711 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Cationic rhodium(I) organic complexes with nitrogen donors and their carbonylation products

The preparation and properties of eleven new cationic rhodium(I) complexes with mono- and bi-dentate nitrogen donor ligands are described. Their carbonylation at normal pressure leads to the corresponding dicarbonyl compounds, in which one of the CO groups can be replaced by PPh 3.

Mössbauer and Related Studies of Complexes of R2 Sn(NCS)2 with Neutral Ligands Containing Oxygen Donor Atoms

Mössbauer, infrared, and electric dipole moment data are reported for several complexes of the type (i) R2Sn(NCS)2L2 and (ii) R2SnX2B (where R = C4H9, C2H3, C6H5; X = Cl, NCS; L = monodentate ligands with O, S donor atoms; B = bidentate ligands with O, P, As donor atoms). Quadrupole splittings indicate trans C—Sn—C bonds in octahedral complexes of divinyl-and diphenyltin diisothiocyanate with bidentate oxygen-donor ligands, in contrast to a cis configuration for complexes with bidentate nitrogen-donor ligands. Data indicate that the 1:2 complex of 2,2-bipyridyl-N,N′-dioxide with Bu2Sn(NCS)2 is polymeric, with octahedral monomer units having one bridging and one terminal NCS group, a bridging bipyO2 ligand and trans butyl groups. [Ph2Sn(NCS)2]2•bipyO2 appears to be a dimer with a bridging bipyO2 ligand and five-coordinate tin atoms. Mössbauer parameters for R2SnX2L2 and R2SnX2B complexes having oxygen donors are similar.

Dichloro-bis(pentafluorophenyl)(chelate) complexes of palladium(IV)

Four organometallic palladium(IV) complexes: Cl 2(C 6F 5) 2Pd(LL) (LL being a bidentate nitrogen-donor ligand) have been prepared by the oxidative addition of chlorine to the corresponding bis(pentafluorophenyl)palladium(II) complexes, (C 6F 5) 2Pd(LL). Some of their properties are described.