Uranyl(VI) complexes with a diaminobisphenol from eugenol and N-(2-aminoethyl)morpholine: Syntheses, structures and extraction studies

The syntheses and structural studies of an [O,N,O,N′]-type phenolic ligand [(N’,N’-bis(2-hydroxy-3-methoxy-5-(propen-2-yl)benzyl)-N-(2-aminoethyl)morpholine), (H₂L) and two new uranyl complexes of this ligand are described. The reaction between uranyl nitrate hexahydrate and H₂L in a 1:2 M ratio (M to H₂L) results in a uranyl complex of the formula [UO₂(HL)(NO₃)(H₂O)] (1). In the presence of a base (triethylamine), with the same molar ratio, the uranyl complex [UO₂(HL)₂]·2CH₃CN (2) is formed. The molecular structures H₂L, 1 and 2 were verified by X-ray crystallography. Both uranyl complexes are zwitterions with a neutral net charge. A comprehensive NMR-structural analyses of all compounds were performed in CDCl₃, DMSO-d₆ and pyridine-d₅. Complex 2 dissociates in all the studied NMR-solvents, forming a 1:1 complex and free ligand, but according to the spectra the formed complexes are not alike. The results of the ability of the ligand to extract the uranyl ion from water into dichloromethane are also presented.     

Uranyl ion complexes with long chain aminoalcoholbis(phenolate) [O,N,O,O′] donor ligands

The reaction between uranyl nitrate hexahydrate and phenolic ligand precursor [(N,N-bis(2-hydroxy-3,5-dimethylbenzyl)-4-amino-1-butanol) · HCl], H₃L1 · HCl, leads to a uranyl complex [UO₂(H₂L1)₂] (1a) and [UO₂(H₂L1)₂] · 2CH₃CN (1b). The ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methylbenzyl)-4-amino-1-butanol)H₃L2 · HCl], H₃L2 · HCl, yields a uranyl complex with a formula [UO₂(H₂L2)₂] · CH₃CN (2). The ligand [(N,N-bis(2-hydroxy-3,5-dimethylbenzyl)-5-amino-1-pentanol) · HCl], H₃L3 · HCl, produces a uranyl complex with a formula [UO₂(H₂L3)₂] · 2CH₃CN (3) and the ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methylbenzyl)-5-amino-1-pentanol) · HCl], H₃L4 · HCl, leads to a uranyl complex with a formula [UO₂(H₂L4)₂] · 2CH₃CN (4). The ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methylbenzyl)-6-amino-1-hexanol) · HCl], H₃L5 · HCl, leads to a uranyl complex with a formula [UO₂(H₂L5)₂] · 4toluene (5). The complexes 1–5 are obtained using a molar ratio of 1:2 (U to L) in the presence of a base (triethylamine). The molecular structures of 1a, 1b, 3, 4 and 5 were verified by X-ray crystallography. All complexes are neutral zwitterions and have similar centrosymmetric, mononuclear, distorted octahedral uranyl structures with the four coordinating phenoxo ligands in an equatorial plane. In uranyl ion extraction studies from water to dichloromethane with ligands H₃L1 · HCl–H₃L5 · HCl, ligands H₃L1 · HCl, H₃L4 · HCl and H₃L5 · HCl are the most effective ones.     

Aminoalkylbis(phenolate) [O,N,O] donor ligands for uranyl(VI) ion coordination: Syntheses,structures, and extraction studies

The syntheses of five new aminoalkylbis(phenolate) ligands (as hydrochlorides) and their uranyl complexes are described. The reaction between uranyl nitrate hexahydrate and phenolic ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methylbenzyl)-1-aminopropane) · HCl], H₂L1 · HCl, forms a uranyl complex [UO₂(HL1)₂] · 2CH₃CN (1). The ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methylbenzyl)-1-aminobutane) · HCl], H₂L2 · HCl, forms a uranyl complex with a formula [UO₂(HL2)₂] · 2CH₃CN (2). The ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methyl benzyl)-1-aminohexane) · HCl], H₂L3 · HCl, yields a uranyl complex with a formula [UO₂(HL3)₂] · 2CH₃CN (3) and the ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methylbenzyl)-cyclohexylamine) · HCl], H₂L4 · HCl, yields a uranyl complex with a formula [UO₂(HL4)₂] (4). The ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methylbenzyl)-benzylamine) · HCl], H₂L5 · HCl, forms a uranyl complex with a formula [UO₂(HL5)₂] · 2MeOH (5). The molecular structures of 1, 2′ (2 without methanol), 3, 4 and 5 were verified by X-ray crystallography. The complexes 1–5 are neutral zwitterions which form in a molar ratio of 1:2 (U to L) in the presence of a base (triethylamine) and bear similar mononuclear, distorted octahedral uranyl structures with the four coordinating phenoxo ligands forming an equatorial plane and resulting in a centrosymmetric structure for the uranyl ion. In uranyl ion extraction studies from water to dichloromethane with ligands H₂L1 · HCl–H₂L5 · HCl, the ligands H₂L2 · HCl and H₂L4 · HCl are the most effective ones.     

Alkoxo, chlorido, and methyl derivatives of oxidomolybdenum(VI) complexes with tetradentate [O3N]-type ligands

Dioxomolybdenum(VI) complex [MoO₂(Heg)₂] (H₂eg = 1,2-ethanediol) reacts with phenolic ligand precursors tris(2-hydroxy-3,5-dimethylbenzyl)amine (H₃L^Me) and tris(2-hydroxy-3,5-di-tert-butylbenzyl)amine (H₃L^tBu) to form oxomolybdenum(VI) complexes of type [MoO(L^R) (Heg)]. The Heg ligand can be replaced by other alcohols (i.e. 2-aminoethanol, 2-amino-2-methylpropan-1-ol, 2-(dimethylamino)ethanol or allyl alcohol) in the reaction at refluxing toluene or at neat alcohol. Treatment of [MoO(L^R)(Heg)] with Me₃SiCl yields corresponding chlorido complexes [MoO(L^R)Cl]. These are also formed in the reaction of H₃L^R with [MoO₂Cl₂(dmf)₂]. The reaction of [MoO(L^R)Cl] with MeMgI yields air-stable monomethyl derivatives [MoO(L^R)(Me)]. X-ray analyses of [MoO(L^tBu)X] (X = Heg, 2-methyl-2-aminopropanolate anion or Cl) reveal that the ligand L^R has a tetradentate coordination through three oxygen donors and one nitrogen donor, which is located trans to the terminal oxo group. The sixth coordination site is occupied by an oxygen donor, a chlorido ligand or a methyl group.     

Syntheses, structures and catalytic activity of copper(II) complexes bearing N,O-chelate ligands

Copper complexes [Cu(Lⁿ)₂] 1-4 bearing N,O-chelating β-ketoamine ligands Lⁿ based on condensation products of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone with aniline (L¹), α-naphthylamine (L²), o-methylaniline (L³), and p-nitroaniline (L⁴), respectively, were synthesized and characterized by IR, ¹H NMR and X-ray crystallography (except 2). They were shown to catalyze the vinyl polymerization of norbornene when activated by methylaluminoxane (MAO). Both steric and electronic effects are important and influential factors contributing to the catalytic activity of the complexes with the order of 2 > 4 > 3 > 1.     

Spectroscopic and structural characterization of cationic N-(2-aminoethyl)aziridine-N,N′ chelate complexes of the d-metals Rh(III) and Ir(III)

The syntheses of the compounds [M(Cp^∗)(aeaz)(az)](OTf)₂ (4, 5) (M = Rh(III), Ir(III); aeaz = C₂H₄NC₂H₄NH₂, az = C₂H₄NH (3)) containing cationic N-(2-aminoethyl)aziridine-N,N′ chelate complexes are described. The bis-aziridine complexes [MCl(Cp^∗)(az)₂]Cl (M = Rh (1), M = Ir (2)) react with an excess of the aziridine (az) in the presence of AgO₃SCF₃ (=AgOTf) via AgCl precipitation and az addition followed by a metal-mediated coupling reaction, to give the compounds [M(Cp^∗)(aeaz)(az)](OTf)₂ (4, 5). The new aeaz ligand is formally the dimerisation product of az. Using the same reaction conditions with the analogous, but weaker Lewis acidic ruthenium(II) complex [RuCl(C₆Me₆)(az)₂]Cl (6) an anion exchange reaction yielding [RuCl(C₆Me₆)(az)₂]OTf (8) is observed. After purification, all compounds are fully characterized using IR, FAB-MS, ¹H and ¹³C NMR spectroscopy. The single crystal X-ray structure analysis reveals a distorted octahedral geometry for all complexes.     

Charge-transfer salts of methylferrocenes with DCNQI derivatives (DCNQI = N,N′-dicyano-1,4-benzoquinonediimine): Crystal structures and magnetic properties

Organometallic charge-transfer salts composed of decamethyl-, octamethyl-, and dimethylferrocene with N,N′-dicyano-1,4-benzoquinonediimine (DCNQI) derivatives were prepared. [Fe(C₅Me₅)₂][(MeO)₂DCNQI] (1) and [Fe(C₅Me₄H)₂][Me₂DCNQI] (2) were 1:1 DA salts with mixed-stack structures, whereas [Fe(C₅Me₄H)₂][(MeO)₂DCNQI]₂ (3) and [Fe(C₅MeH₄)₂][DCNQI]₂ (4) were 1:2 DA salts. 3 exhibited a segregated-stack structure, in which charge separation was observed in the acceptor column. 1 became a metamagnet below T_N = 5.0 K, whereas the other salts were paramagnets. Valence states and charge-transfer (CT) transitions in these complexes are discussed based on the neutral-ionic (NI) phase diagram.     

From N,N-diphenyl-N-naphtho[2,1-b]thieno[2,3-b:3′,2′-d]dithiophene-5-yl-amine to propeller-shaped N,N,N-tri(naphtho[2,1-b]thieno[2,3-b:3′,2′-d]dithiophene-5-yl)-amine: syntheses and structures

Three unique propeller-shaped helicenyl amines compounds: N,N-diphenyl-N-naphtho[2,1-b]thieno[2,3-b:3′,2′-d]dithiophene-5-yl-amine (1), N-phenyl-N,N-di(naphtho[2,1-b]thieno[2,3-b:3′,2′-d]dithiophene-5-yl)amine (2), and N,N,N-tri(naphtho[2,1-b]thieno[2,3-b:3′,2′-d]dithiophene-5-yl)amine (3) were efficiently synthesized by Wittig reaction and oxidative photocyclization. The crystal structures of 1, 2 and molecular configuration optimization (DFT-B3LYP/6-31+G(d)) of 3 reveal that the steric hindrance from the moiety of trithia[5]helicene effectively forces the nitrogen atom and the three bonded carbon atoms to coplanar and the interplanar angles of the facing terminal thiophene ring and benzene ring becoming larger when the helical arm increased from 1 to 3. Electrochemical properties and UV–vis absorption behaviors of 1, 2, 3 were primarily determined by the moiety of trithia[5]helicene.     

Syntheses, crystal structures and properties of Co(II) complexes with N,N′-bis(3-pyridylmethyl)-1,4-benzenedimethyleneimine (bpb), and Cd(II), Hg(II) complexes with reduced bpb

Five novel coordination polymers, [Co(bpb)₂Cl₂] (1), [Co(bpb)₂(SCN)₂] (2), [Cd(H₄bpb)_0.5(dmf)(NO₃)₂] (3), [Cd₂(H₄bpb)Br₄] (4), and [Hg₂(H₄bpb)I₄] (5) [bpb=N,N′-bis(3-pyridylmethyl)-1,4-benzenedimethyleneimine, H₄bpb=N,N′-bis(3-pyridylmethyl)-1,4-benzenedimethylamine], were synthesized and their structures were determined by X-ray crystallography. In the solid state, complex 1 is a 1D hinged chain, while 2 has 2D network structure with the ligand bpb serving as a bridging ligand using its two pyridyl N atoms. The imine N atoms keep free of coordination and bpb acts as a bidentate ligand in both 1 and 2. Complexes 3, 4, and 5 with reduced bpb ligand, i.e. H₄bpb, show similar 2D network structure, in which ligand H₄bpb serves as a tetradentate ligand. Thermogravimetric analyses for complexes 1-5 were carried out and found that they have high thermal stability. The magnetic susceptibilities of compounds 1, 2 were measured over a temperature range of 75-300 K.     

Lithium and sodium N,N′-di(2,6-dialkylphenyl)formamidinate complexes

A study has been undertaken of the lithium and sodium metallation of N,N′-di(aryl)formamidines with alkyl groups at the 2- and 6-aryl position. ¹H NMR and X-ray diffraction data indicate an increase in steric bulk from 2,6-dimethylphenyl to 2,6-diethylphenyl to 2,6-diisopropylphenyl incites incremental changes in amidinate binding and nuclearity. In selected instances, this invokes the first lithium and sodium amidinate/guanidinate complexes to exhibit metal-arene contacts.     

Ruthenium(III) complexes with N-(acetyl)-N′-(5-R-salicylidene)hydrazines: Syntheses,structures and properties

The reactions of 1 mol equiv. each of [Ru(PPh₃)₃Cl₂] and N-(acetyl)-N′-(5-R-salicylidene)hydrazines (H₂ahsR, R = H, OCH₃, Cl, Br and NO₂) in alcoholic media afford simultaneously two types of complexes having the general formulae [Ru(HahsR)(PPh₃)₂Cl₂] and [Ru(ahsR)(PPh₃)₂Cl]. The complexes have been characterized by elemental analysis, magnetic, spectroscopic and electrochemical measurements. Molecular structures of [Ru(HahsH)(PPh₃)₂Cl₂] and [Ru(ahsH)(PPh₃)₂Cl] have been confirmed by X-ray crystallography. In both species, the PPh₃ ligands are trans to each other. The bidentate HahsH⁻ coordinates to the metal ion via the O atom of the deprotonated amide and the imine–N atom in [Ru(HahsH)(PPh₃)₂Cl₂]. In HahsH⁻, the phenolic OH is involved in a strong intramolecular hydrogen bond with the uncoordinated amide N atom forming a seven-membered ring. In [Ru(ahsH)(PPh₃)₂Cl], the tridentate ahsH²⁻ binds to the metal ion via the deprotonated amide O, the imine N and the phenolate O atoms. In the electronic spectra, the green [Ru(HahsR)(PPh₃)₂Cl₂] and brown [Ru(ahsR)(PPh₃)₂Cl] complexes display several absorptions in the ranges 385–283 and 457–269 nm, respectively. Both complexes are low-spin and display rhombic EPR spectra in frozen solutions. Both types of complexes are redox active and display a quasi-reversible ruthenium(III) to ruthenium(II) reduction which is sensitive to the polar effect of the substituent on the chelating ligand. The reduction potentials are in the ranges −0.21 to −0.12 and −0.42 to −0.21 V (versus Ag/AgCl) for [Ru(HahsR)(PPh₃)₂Cl₂] and [Ru(ahsR)(PPh₃)₂Cl], respectively.     

Strong antiferromagnetic coupling in doubly N,O oximato-bridged dinuclear copper(II) complexes

The use of di-2-pyridyl ketone oxime, (py)pkoH, and phenyl 2-pyridyl ketone oxime, ppkoH, in copper(II) hexafluoroacetylacetonate chemistry is reported. The reaction of CuCl₂·2H₂O with one and two equivalents of ppkoH and Na(hfac), respectively, in CH₂Cl₂ affords the dinuclear complex [Cu₂(hfac)₂(ppko)₂] (1) in excellent yield. The replacement of ppkoH by (py)pkoH gives the isostructural compound [Cu₂(hfac)₂{(py)pko}₂] (2) in good yield. The Cu^II atoms in both 1 and 2 are doubly bridged by the oximate groups of two η¹:η¹:η¹:μ₂ ppko⁻ and (py)pko⁻ ligands, respectively. The bridging Cu–(R–NO)–Cu′ units are not planar, with the torsion angles being 23.2° (1) and 20.3° (2). A bidentate chelating hfac⁻ ligand completes five-coordination at each square pyramidal metal ion. The hfac⁻-free reaction system CuCl₂·2H₂O/(py)pkoH/NEt₃ (1:2:1) gives instead the mononuclear complex [CuCl{(py)pko}{(py)pkoH}] (3) in very good yield. The Cu^II atom is coordinated by two N,N′-bidentate (py)pko⁻/(py)pkoH chelates and a monodentate chloride anion resulting in a distorted square pyramidal geometry around the metal center. Variable-temperature, solid-state dc magnetic studies were carried out on the representative dinuclear complex 1 in the 2.0–300 K range. The data indicate a very strong antiferromagnetic exchange interaction and a resulting S = 0 ground state, which is well isolated from the S = 1 excited state. The J value of −720 cm⁻¹ was derived from the fitting of the experimental data using the Hamiltonian H = −J(S₁ · S₂).     

Synthesis and characterization of (N→B) phenyl[N-alkyl-N-(2-alkyl)aminodiacetate-O,O′,N]boranes and phenyl[N-alkyl-N-(2-alkyl) aminodiacetate-O,O′,N]boranes

The reaction of boron heterocycles 1 and 2 with n-butyl lithium and alkyl halides led to (N→B) phenyl[N-alky-N-(2-alkyl)aminodiacetate-O,O′,N]boranes 3–6(a–b), 7(b) and 9(b), where alkyl can be in exo and/or endo position, and phenyl[N-alkyl-N-(2-alkyl)aminodiacetate-O,O′,N]boranes 7(c) and 8(c) isomers, which do not display the intramolecular N→B coordination bond. The existence of steric interactions between N-benzyl and the alkyl group at 2 position was indicated by ¹H and ¹³C NMR, while, the δ(¹¹B) values confirm the tetrahedral and trigonal environment of the ¹¹B nucleus in these compounds. Moreover, the compounds were characterized by COSY, HETCOR and homonuclear proton decoupling experiment. The study of the intramolecular N→B coordination by dynamic NMR afforded a ΔG‡ value of 81.09 kJ/mol for compound 6(b).     

Structure and C-C cross-coupling reactivity of iron(III) complexes of halogenated amine-bis(phenolate) ligands

The preparation of tetradentate amine-bis(phenol) proligands with dichloro and difluoro substituted phenol groups and their reaction with FeX₃ (X = Cl or Br) is described. The compounds, 2-pyridylamino-N,N-bis(2-methylene-4,6-dichlorophenol), H₂[L₁]; 2-pyridylamino-N,N-bis(2-methylene-4,6-difluorophenol), H₂[L₂]; dimethylaminoethylamino-N,N-bis(2-methylene-4,6-dichlorophenol), H₂[L₃]; 2-tetrahydrofurfuryl-N,N-bis(2-methylene-4,6-dichlorophenol), H₂[L₄]; and methoxyethylamino-N,N-bis(2-methylene-4,6-dichlorophenol), H₂[L₅] were prepared in aqueous medium and obtained as white powders in good to excellent yield. Ten new iron(III) halide complexes supported by these tetradentate ligands are reported. Representative single crystal X-ray diffraction structures were obtained for H₂[L₁] and a water adduct of the iron(III) complex, aquachloro{2-pyridylamino-N,N-bis(2-methylene-4,6-dichlorophenolato)}iron(III), 2·H₂O. The structure of the proligand H₂[L₁] shows intramolecular hydrogen bonding. In the solid-state structure, the iron complex exhibits intermolecular hydrogen bonding between the water ligand and the phenolate oxygen of a neighbouring complex. The anhydrous complexes were studied for catalytic activity towards C-C cross-coupling of Grignard reagent nucleophiles with alkyl halide electrophiles.     

Syntheses,crystal structures,and catalytic properties of dioxomolybdenum(VI) complexes with hydrazone ligands

Two new dioxomolybdenum(VI) complexes, [MoO₂L¹(CH₃OH)] (1) and [MoO₂L²(H₂O)] (2), where L¹ and L² are dianionic form of N′-(2-hydroxy-3-methoxybenzylidene)-4methoxybenzohydrazide and N′-(2-hydroxy-3methoxybenzylidene)-2-hydroxybenzohydrazide, respectively, have been synthesized and structurally characterized by spectroscopic methods and single-crystal X-ray determination. The complexes are mononuclear molybdenum(VI) compounds. Mo in each complex is octahedral. The difference in the substituent groups in the benzohydrazides leads to coordination of different solvent molecules. Crystals of the complexes are stabilized by hydrogen bonds. The complexes are effective catalysts for sulfoxidation.     

Crystal Structures of Uranyl Ion Complexes of Tetrahydroxy[3.1.3.1]metacyclophane (Homocalix[4]arene)

The first crystal structures of complexes of tetrahydroxy-[3.1.3.1]metacyclophanes, also termed homocalix[4]arenes, are reported. In the two uranyl ion complexes obtained, with different para-substituents, the complex core is analogous to that in tetrahomodioxacalix[4]arene complexes, with the cation in a tetra-phenoxide, distorted square-planar environment. The packing in one of these complexes comprises two different arrangements, one of them being a columnar stacking of complex molecules with sandwiched triethylammonium counter-ions hydrogen bonded to one complex and held by cation–π and CH–π interactions within the cavity of the other neighbouring one.     

Syntheses,structures and hydrolytic properties of copper(II) complexes of asymmetrically N-functionalised 1,4,7-triazacyclononane ligands

A series of new asymmetrically N-substituted derivatives of the 1,4,7-triazacyclononane (tacn) macrocycle have been prepared from the common precursor 1,4,7-triazatricyclo[5.2.1.0^4,10]decane: 1-ethyl-4-isopropyl-1,4,7-triazacyclononane (L1), 1-isopropyl-4-propyl-1,4,7-triazacyclononane (L2), 1-(3-aminopropyl)-4-benzyl-7-isopropyl-1,4,7-triazacyclononane (L3), 1-benzyl-4-isopropyl-1,4,7-triazacyclononane (L4) and 1,4-bis(3-aminopropyl)-7-isopropyl-1,4,7-triazacyclononane (L5). The corresponding monomeric copper(II) complexes were synthesised and were found to be of composition: [Cu(L1)Cl₂] · 1/2 H₂O (C1), [Cu(L4)Cl₂] · 4H₂O (C2), [Cu(L3)(MeCN)](ClO₄)₂ (C3), [Cu(L5)](ClO₄)₂ · MeCN · NaClO₄ (C4) and [Cu(L2)Cl₂] · 1/2 H₂O (C5). The X-ray crystal structures of each complex revealed a distorted square-pyramidal copper(II) geometry, with the nitrogen donors on the ligands occupying 3 (C1 and C2), 4 (C3) or 5 (C4) coordination sites on the Cu(II) centre. The metal complexes were tested for the ability to hydrolytically cleave phosphate esters at near physiological conditions, using the model phosphodiester, bis(p-nitrophenyl)phosphate (BNPP). The observed rate constants for BNPP cleavage followed the order k_C1 ≈ k_C2 > k_C5 ? k_C3 > k_C4, confirming that tacn-type Cu(II) complexes efficiently accelerate phosphate ester hydrolysis by being able to bind phosphate esters and also form the nucleophile necessary to carry out intramolecular cleavage. Complexes C1 and C2, featuring asymmetrically disubstituted ligands, exhibited rate constants of the same order of magnitude as those reported for the Cu(II) complexes of symmetrically tri-N-alkylated tacn ligands (k ∼ 1.5 × 10⁻⁵ s⁻¹).     

Syntheses and structural studies of mononuclear arene ruthenium complexes with nitrogen-based chelating ligands

Dinuclear arene ruthenium complexes [(η⁶-arene)Ru(μ-Cl)Cl]₂ (arene?=?C₆H₆; p ⁱPrC₆H₄Me; C₆Me₆) and monomeric cyclopentadienyl complexes [(η⁵-Cp)Ru(PPh₃)₂Cl] (Cp?=?cyclopentadienyl) react with polypyridyl nitrogen ligands L¹ (3-(pyridin-2-yl)-1H-1,2,4-triazole) and L² (1,3-bis(di-2-pyridylaminomethyl)benzene) in methanol to afford cationic mononuclear compounds [(η⁶-arene)Ru(L¹)Cl]⁺ (arene?=?C₆H₆, 1; p ⁱPrC₆H₄Me, 2; C₆Me₆, 3), [(η⁶arene)Ru(L²)Cl]⁺ (arene?=?C₆H₆, 4; p ⁱPrC₆H₄Me, 5; C₆Me₆, 6), [(η⁵-Cp)Ru(L¹)(PPh₃)]⁺ (7), and [(η⁵Cp)Ru(L²)(PPh₃)]⁺ (8). All cationic mononuclear compounds were isolated as their hexafluorophosphate salts and characterized by elemental analyses, NMR, and IR spectroscopic methods and some representative complexes by UV-Vis spectroscopy. The solid state structures of two derivatives, [6]PF₆ and [7]PF₆, have been determined by the X-ray structure analysis.     

Synthesis, characterization and crystal structures of cyclometallated palladium (II) compounds containing difunctional ligands with [P,P], [As,As], [N,N], [P,As], [P,N] and [P,O] donor atoms

Treatment of the chloro-bridged dinuclear complex [Pd{3,4-(MeO)₂C₆H₂C(H)N(Cy)-C6,N}(μ-Cl)]₂ (1) with homobidentate [P,P], [As,As], [N,N], and heterobidentate [P,As], [P,N] ligands in a 1:1 molar ratio gave the dinuclear complexes [{Pd[3,4-(MeO)₂C₆H₂C(H)N(Cy)-C6,N](Cl)}₂{μ-L}] (L = Ph₂PC₄H₆(NH)CH₂PPh₂ (2); Ph₂As(CH₂)₂AsPh₂ (3); 1,3-(NH₂CH₂)₂C₆H₄ (4); Ph₂P(CH₂)₂AsPh₂ (5); Ph₂P(CH₂)₂NH₂ (6)), with the bidentate ligands bridging the two cyclometallated fragments.The reaction with the homobidentate ligands in a 1:2 molar ratio in the presence of NaClO₄ afforded the mononuclear compounds [[Pd{3,4-(MeO)₂C₆H₂C(H)N(Cy)-C6,N}{L-P,P}][ClO₄] (L = Ph₂PC₄H₆(NH)CH₂PPh₂ (7); (o-Tol)₂P(CH₂)₂P(o-Tol)₂ (8)), [Pd{3,4-(MeO)₂C₆H₂C(H)N(Cy)-C6,N}{Ph₂As(CH₂)₂AsPh₂-As,As}][ClO₄] (9) and [Pd{3,4-(MeO)₂C₆H₂C(H)N(Cy)-C6,N}{L-N,N}][ClO₄] (L = NH₂(CH₂)₃NH₂ (10); NH₂(C₆H₈)CH₂(C₆H₈)NH₂ (11); 1,3-(NH₂CH₂)₂C₆H₄ (12); 1,3-(NH₂)₂C₅H₃N (13); NH₂(C₆H₄)O(C₆H₄)NH₂ (14); NMe₂(CH₂)₂NMe₂ (15)), in which the chloro ligands are absent and the bidentate ligands are chelated to the palladium atom.Reaction of 1 with Ph₂P(CH₂)₂AsPh₂ in 1:2 molar ratio in acetone in the presence of NH₄PF₆ afforded the analogous mononuclear compound [Pd{3,4-(MeO)₂C₆H₂C(H)N(Cy)-C6,N}{Ph₂P(CH₂)₂AsPh₂-P,As}][PF₆] (16); whereas reaction with Ph₂P(CH₂)₃NH₂ gave [Pd{3,4-(MeO)₂C₆H₂C(H)N(Cy)-C6,N}{Ph₂P(CH₂)₃N(CMe₂)-P,N}][PF₆] (17), derived from intermolecular condensation between the aminophosphine and acetone. Condensation of the NH₂ group was precluded by change of solvent, using dichloromethane.Iminophoshines also reacted with 1 in 1:2 molar ratio in acetone to give a new series of mononuclear cyclometallated complexes: [Pd{3,4-(MeO)₂C₆H₂C(H)N(Cy)-C6,N}{L-P,N}][ClO₄] (L = Ph₂PC₆H₄C(H)NCy (20); Ph₂PC₆H₄C(H)NC(CH₃)₃ (21); Ph₂PC₆H₄C(H)NNMe₂ (22); Ph₂PC₆H₄C(H)NNHMe (23); Ph₂PC₆H₄C(H)NNHPh (24)). Analogous complexes with a stable P,O-chelate were obtained using bidentate [P,O] donor ligands: [Pd{3,4-(MeO)₂C₆H₂C(H)N(Cy)-C6,N}{L-P,O}][Cl] (L = 2-(Ph₂P)C₆H₄CHO (25); Ph₂PN(Me)C(O)Me (26)).The crystal structures of compounds 1, 5, 15, 16, 18, 20 have been determined by X-ray crystallography.