Synthesis and structural studies of phosphorus carbonyl manganacycles containing the tetraphenyldiselenoimidodiphosphinato ligand

The [Mn(CO)_4−x(L){Ph₂P(Se)NP(Se)Ph₂-κ²Se}] complexes, where x = 1 for L = PPh₃ and PMePh₂, and x = 2 for L = Ph₂PCH₂CH₂PPh₂ (diphos), were synthesized by two routes. The complexes were characterized by IR, mass spectrometry (FAB+), NMR (¹H, ¹³C, ³¹P, ⁷⁷Se) spectroscopy and/or single crystal X-ray diffraction. The X-ray diffraction analysis for [Mn(CO)₃PMePh₂{Ph₂P(Se)NP(Se)Ph₂-κ²Se}] showed that the unit cell contains two independent mononuclear molecules with different MnSePNPSe rings’ conformations.     

Silver(I) and copper(I) complexes with ferrocenyl ligands bearing imidazole or pyridyl substituents

The reactions between five ferrocenyl derivatives containing both a CO and at least an imidazole or pyridine nitrogen atom and AgPF₆, AgOTf, or [Cu(NCCH₃)₄]PF₆ precursors were studied. The ligand {[bis(2-pyridyl)amino]carbonyl}ferrocene (L3), derived from (2-pyridyl)amine, favored tetrahedral coordination of Ag⁺ (with two ligands) and of Cu⁺ (with two acetonitrile ligands left from the precursor). In all the other ligands, both metal centers coordinated linearly to two ligands, preferring the imidazole or pyridinic nitrogen to other nitrogen atoms (amine) or oxygen donors.When the counter anions were triflate, the crystal structure showed a dimerization of the complex, with the ferrocenyl moieties occupying cis positions, by means of a weak Ag?Ag interaction. This was shown experimentally in the crystal structure of complex [Ag(L1)₂]OTf (L1 = ferrocenyl imidazole) and in the presence of peaks corresponding to {Ag₂(L2)₃(OTf)}⁺ and {Ag₂(L2)₄(OTf)}⁺ in the mass spectra of [Ag(L2)₂]OTf (L2 = ferrocenyl benzimidazole). In all complexes containing PF₆, there was no evidence for dimerization. Indeed, in the crystal structure of [Ag(L2)₂]PF₆, the ferrocenyl moieties occupy trans positions and the metal centers are far from each other. DFT calculations showed that the energy of the cis and trans conformers is practically the same and the balance of crystal packing forces leads to dimerization when triflate is present.     

Six-membered tetracarbonylmanganese(I) and -rhenium(I) metalacycles containing the [Ph2P(Se)NP(Se)Ph2] ligand: solution and solid state characterization

The halocarbonyls BrM(CO)₅, M = Mn and Re, were reacted with the KN(SePPh₂)₂ salt in equimolar amounts; the reactions were thermally carried out and resulted in the generation of the hexacoordinated isostructural complexes [M(CO)₄{Ph₂P(Se)NP(Se)Ph₂-Se,Se′}] with a twist MSePNPSe ring conformation. Complexes’ characterizations were achieved by IR, mass, NMR (¹H, ¹³C, ³¹P, ⁷⁷Se) spectroscopies, and by single-crystal X-ray diffraction.     

Synthetic studies for the preparation of phosphorus carbonyl rhenacycles with the selenoimidodiphosphinate ligand [N(SePPh2)2]

The synthesis of the rhenacycles [Re(CO)₃(PR₃){Ph₂P(Se)NP(Se)Ph₂-κ²Se}], PR₃ = PPh₃ (1), PMePh₂ (2), and PMe₂Ph (3) by a straightforward high yield procedure is described. Attempts at the preparation of the spiro [Re(CO)₂(Ph₂PCH₂CH₂PPh₂-κ²P){Ph₂P(Se)NP(Se)Ph₂-κ²Se}] resulted in the formation of complexes [Re₂(CO)₆{Ph₂P(Se)NP(Se)Ph₂-κ²Se}₂(μ-Ph₂PCH₂CH₂PPh₂)] (4) and [Re(CO)₃(Ph₂PCH₂CH₂PPh₂-κ²P){Ph₂P(Se)NP(Se)Ph₂-κSe}] (5). All new inorganic rhenacycles 1-5 were characterized in solution and in solid state. The X-ray diffraction analysis of [Re(CO)₃PPh₃{Ph₂P(Se)NP(Se)Ph₂-κ²Se}] showed that its MnSePNPSe ring conformation is sensitive to temperature.     

Ruthenium(II), copper(I) and silver(I) complexes of large bite bisphosphinite, bis(2-diphenylphosphinoxynaphthalen-1-yl)methane: Application of Ru(II) complexes towards the hydrogenation of styrene and phenylacetylene

Ruthenium(II), copper(I) and silver(I) complexes of large bite bisphosphinite Ph₂P{(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)}PPh₂ (1) are described. Reactions of bisphosphinite 1 with [Ru(η⁶-p-cymene)(μ-Cl)Cl]₂ and RuCl₂(PPh₃)₃ afford mono- and bis-chelate complexes [RuCl(η⁶-p-cymene){η²-Ph₂P{(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)}PPh₂-κP,κP}]Cl (2) and trans-[RuCl₂{η²-Ph₂P{(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)}PPh₂-κP,κP}₂] (3), respectively. Treatment of 1 with CuX (X = Cl, Br and I) furnish 10-membered chelate complexes of the type [Cu(X){η²-Ph₂P(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)PPh₂-κP,κP}] (4, X = Cl; 5, X = Br; 6, X = I), whereas [Cu(MeCN)₄]PF₆ affords a bis-chelated cationic complex [Cu{η²-Ph₂P(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)PPh₂-κP,κP}₂][PF₆] (7). Reaction between 1 and AgOTf produce both mono- and bis-chelated complexes [Ag{η²-Ph₂P(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)PPh₂-κP,κP}(SO₃CF₃)] (8) and [Ag{η²-Ph₂P(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)PPh₂-κP,κP}₂][SO₃CF₃] (9), respectively; whereas the similar reaction of 1 with[Ag(OTf)PPh₃] affords chelate complex of the type [Ag{η²-Ph₂P(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)PPh₂-κP,κP}(PPh₃)(SO₃CF₃)] (10). All the complexes were characterized by ¹H NMR, ³¹P NMR, elemental analysis and mass spectrometry, including low-temperature NMR studies in the case of silver complexes. The molecular structures of 4 and 6 are determined by X-ray diffraction studies. Ruthenium complexes 2 and 3 promote catalytic hydrogenation of styrene and phenylacetylene with good turnover numbers.     

Copper(II) complexes of tridentate selenobisphenolate ligand in mixed ligand environments: Synthesis, crystal structure, EPR and electrochemical studies

A series of square-pyramidal copper(II) complexes, [Cu(L^Se)(N^∧N)] (H₂L^Se = seleno-bisphenolate; N^∧N = bipyridyl, phenanthroline or N,N-dimethylethylenediamine) have been synthesized and characterized by elemental analyses, magnetic measurements, IR, EPR, and electronic spectral studies. Single crystal X-ray structures of [Cu(L^Se)(bpy)]·H₂O (2), [Cu(L^Se)(phen)]·CH₂Cl₂ (3) and [Cu(L^Se)(N,N-Me₂en)] (4) showed that all the complexes have approximately square-pyramidal geometry. In complexes 2 and 3, the square plane is occupied by O(1), O(2), N(1) and N(2) and the apical position by Se atom of L^{Se 2−} ligand. The asymmetric unit of complex 4 contains two crystallographically independent discrete molecules A and B with CuN₂OSe chromophore comprising the square plane and the axial position being occupied by another phenolate oxygen atom. Complexes 2, 3 and 4 are found to be paramagnetic and EPR parameters extracted are: g_∥ = 2.232, g_⊥ = 2.069; 〈g_eff〉 = 1.95; and g_∥ = 2.232, g_⊥ = 2.083 for complexes 2, 3 and 4, respectively. Both the complexes 2 and 4 show three reduction processes: (a) a quasi-reversible reduction of Cu^II to Cu^I, (b) an irreversible reduction of Cu^I to Cu⁰ with the release of free ligand, and (c) a reduction process occurs at this coordinated ligand. They also show a well-defined quasi-reversible oxidation of Cu^II to Cu^III and an irreversible oxidation peak at ∼1.30 and 1.40 V vs. Ag/AgCl for 4 and 2, respectively, with no cathodic counterpart, and were attributed to the oxidation of the metal coordinated ligand.     

Synthese und Strukturen neuer selenido‐ und selenolatoverbrückter Kupfercluster: [Cu38Se13(SePh)12(dppb)6] (1), [Cu(dppp)2][Cu25Se4(SePh)18(dppp)2] (2), [Cu36Se5(SePh)26(dppa)4] (3), [Cu58Se16(SePh)24(dppa)6] (4) und [Cu3(SeMes)3(dppm)] (5)

Syntheses and Crystal Structures of new Selenido‐ and Selenolato‐bridged Copper Clusters: [Cu₃₈Se₁₃(SePh)₁₂(dppb)₆] (1), [Cu(dppp)₂][Cu₂₅Se₄(SePh)₁₈(dppp)₂] (2), [Cu₃₆Se₅(SePh)₂₆(dppa)₄] (3), [Cu₅₈Se₁₆(SePh)₂₄(dppa)₆] (4), and [Cu₃(SeMes)₃(dppm)] (5) The reactions of copper(I) chloride or copper(I) acetate with monodentate phosphine ligands (PR₃; R = organic group) and Se(SiMe₃)₂ have already lead to the formation of CuSe clusters with up to 146 copper and 73 selenium atoms. If the starting materials and the bidentate phosphine ligands (Ph₂P–(CH₂)_n–PPh₂, n = 1: dppm, n = 3: dppp, n = 4: dppb; Ph₂P–C≡C–PPh₂: dppa) and silylated chalcogen derivates are changed (RSeSiMe₃; R = Ph, Mes) a series of new CuSe clusters can be synthesized. From single crystal X‐ray structure analysis one can characterise [Cu₃₈Se₁₃(SePh)₁₂(dppb)₆] ( 1 ), [Cu(dppp)₂] · [Cu₂₅Se₄(SePh)₁₈(dppp)₂] ( 2 ), [Cu₃₆Se₅(SePh)₂₆(dppa)₄] ( 3 ), [Cu₅₈Se₁₆(SePh)₂₄(dppa)₆] ( 4 ) and [Cu₃(SeMes)₃(dppm)] ( 5 ). In this new class of CuSe clusters, compounds 1 and 4 possess a spherical cluster skeleton, wheras 2 and 3 have a layered cluster core.     

Synthesis and characterization of organophosphine/phosphite stabilized silver(I) methanesulfonates: Crystal structures of [Ph3PAgO3SCH3] and [(Ph3P)2AgO3SCH3]

Six organophosphine/phosphite stabilized silver(I) methanesulfonates of type [L_nAgO₃SCH₃] (L = Ph₃P, n = 1, 2a; n = 2, 2b; n = 3, 2c; L = (EtO)₃P; n = 1, 2d; n = 2, 2e; n = 3, 2f) were synthesized by the reaction of silver methanesulfonates with triphenylphosphine or triethylphosphite in dichloromethane under nitrogen atmosphere. These complexes were obtained in high yields and characterized by elemental analysis, ¹H-, ¹³C{H} NMR, IR spectroscopy and thermogravimetric analysis (TGA), respectively. X-ray single crystal analysis reveals that complex 2a is a tetramer [Ph₃PAgO₃SCH₃]₄ and complex 2b is a monomer. The thermal stability of 2a has been studied by applying thermogravimetric analysis. It starts to decompose between 50 and 440 °C in a three-step process. The final residue (Ag) is about 20.50%.     

Synthesis,characterization and crystal structures of dinuclear macrocyclic Schiff base copper(I) complexes bearing different bridges

Utilizing a new 20-membered macrocyclic Schiff base ligand with two coordination sites formed from the [2+2] condensation of 1,3-diaminopropane and benzene-1,3-dicarboxaldehyde in the presence of CuX (X = Cl⁻, Br⁻, I⁻) salts, air-stable dicopper(I) complexes were synthesized in acetonitrile, intramolecularly linked via two halide groups, and characterized by different physico-chemical techniques. The single crystal X-ray diffraction technique indicates these complexes consist of two N₂X₂ donor sets that have distorted tetrahedral coordination environments around the copper(I) ions. In these halogen-bridged binuclear Cu₂LX₂ systems the Cu?Cu separation can be controlled, as this distance is reduced on increasing the halide size and hence the X?X repulsion, with the rigidity of the macrocycle playing a significant role.     

Synthesis, characterization and luminescence properties of copper(I) complexes containing 2-phenyl-3-(benzylamino)-1,2-dihydroquinazolin-4(3H)-one and triphenylphosphine as ligands

Some copper(I) complexes of the formula [Cu(L)(PPh₃)₂]X (1-4) [where L = 2-phenyl-3-(benzylamino)-1,2-dihydroquinazolin-4(3H)-one; PPh₃ = triphenylphosphine; X = Cl⁻, NO₃⁻, ClO₄⁻ and BF₄⁻] have been prepared and characterized on the basis of elemental analysis, IR, UV-Vis and ¹H NMR spectral studies. The representative complex of the series 4 has been characterized by single crystal X-ray diffraction which reveal that in the complex the central copper(I) ion assumes the irregular distorted-tetrahedral geometry. Cyclic voltammetry of the complexes indicate a quasireversible redox behavior corresponding to Cu(II)/Cu(I) couple. All the complexes exhibit intraligand (π → π^∗) fluorescence with high quantum yield in dichloromethane solution.     

Formation of carbonylrhenium cryptates with alkali metal cations: Coordination chemistry studies of [Ph2P(E)NP(E)Ph2], E = O,S, Se towards ReBr(CO)5

Reaction of ReBr(CO)₅ with Li[Ph₂P(O)NP(O)Ph₂] afforded the cryptate Li[Re₂(CO)₆{μ-Ph₂P(O)NP(O)Ph₂-κ²O,O’}₃]; whereas K[Ph₂P(O)NP(O)Ph₂] reacted with ReBr(CO)₅ to give K[Re₂(CO)₆{μ-Ph₂P(O)NP(O)Ph₂-κ²O,O′}{Ph₂P(O)NP(O)Ph₂-κ²O,O′}₂]. Other chalcogen ligands’ salts M[Ph₂P(E)NP(E)Ph₂], E = Se and S, M = K and Li gave dirhenium carbonyls with bromido and Ph₂P(E)NP(E)Ph₂, E = Se or S bridges upon reaction with ReBr(CO)₅.     

Copper(II) complexes of tetradentate N2S2 donor sets: Synthesis,crystal structure characterization and reactivity

Two mononuclear and one dinuclear copper(II) complexes, containing neutral tetradentate NSSN type ligands, of formulation [Cu^II(L¹)Cl]ClO₄ (1), [Cu^II(L²)Cl]ClO₄ (2) and [Cu^II₂(L³)₂Cl₂](ClO₄)₂ (3) were synthesized and isolated in pure form [where L¹ = 1,2-bis(2-pyridylmethylthio)ethane, L² = 1,3-bis(2-pyridylmethylthio)propane and L³ = 1,4-bis(2-pyridylmethylthio)butane]. All these green colored copper(II) complexes were characterized by physicochemical and spectroscopic methods. The dinuclear copper(II) complex 3 changed to a colorless dinuclear copper(I) species of formula [Cu^I₂(L³)₂](ClO₄)₂,0.5H₂O (4) in dimethylformamide even in the presence of air at ambient temperature, while complexes 1 and 2 showed no change under similar conditions. The solid-state structures of complexes 1, 2 and 4 were established by X-ray crystallography. The geometry about the copper in complexes 1 and 2 is trigonal bipyramidal whereas the coordination environment about the copper(I) in dinuclear complex 4 is distorted tetrahedral.     

Polysulfonylamine. XL Darstellung von Silber(I)-disulfonylamid-Acetonitril-Komplexen. Röntgenstrukturanalytische und thermochemische Charakterisierung von Tetraacetonitrilsilber(I)-bis(dimesylamido)argentat(I) und von (1,1,3,3-Tetraoxo-1,3,2-benzodithiazolido)acetonitrilsilber(I)

Polysulfonyl Amines. XL. Preparation of Silver(I) Disulfonylamide Acetonitrile Complexes. Characterization of Tetraacetonitrilesilver(I) bis(dimesylamido)argentate(I) and (1,1,3,3-Tetraoxo-1,3,2-benzodithiazolido)acetonitrilesilver(I) by X-Ray Diffractometry and Thermal Analysis The following silver(I) disulfonylamides were prepared for the first time or by improved procedures: AgN(SO₂CH₃)₂ ( 2a ); AgN(SO₂C₆H₄-4-X)₂ with X = F ( 2b ), Cl ( 2c ), Br ( 2d ), CH₃ ( 2e ); silver(I) 1,2-benzenedisulfonimide AgN(SO₂)₂C₆H₄ ( 2f ). With acetonitrile, the salts 2a to 2e form (1/2) complexes AgN(SO₂R)· 2 CH₃CN ( 4a to 4e ), whereas 2f gives the (1/1) complex AgN(SO₂)₂C₆H · CH₃CN ( 4f ). The crystallographic data (at - 95°C) for the title compounds 4a and 4f are: 4a , space group C2/c, a = 1 967.6(4), b = 562.2(1), c = 2 353.0(5) pm, β = 102.21(2)°, V = 2.5440 nm³, Z = 4, D_x = 1.891 Mg m^?3; 4f , space group P2₁/m, a = 741.5(3), b = 980.4(4), c = 756.6(3) pm, β = 99.28(2)°, V = 0.5428 nm³, Z = 2, D_x = 2.246 Mg m^?3. 4a forms an ionic crystal [Ag(NCCH₃)₄]^⊕[Ag{N(SO₂CH₃)₂}₂]^? with a tetrahedrally coordinated silver atom (lying on a twofold axis) in the cation (225.3/225.7 pm for the two independent Ag? N distances, N? Ag? N 106.2—114.5°) and a linear-dicoordinated silver atom in the centrosymmetric anion (Ag? N 213.9 pm, two intraionic secondary Ag…O contacts 303.4 pm). 4f consists of uncharged molecules [C₆H₄(SO₂)₂N¹AgN²CCH₃] with crystallographic mirror symmetry (Ag? N¹ 218.8, Ag? N² 216.1 pm, N¹? Ag? N² 174.3°), associated into strands by intermolecular secondary silver-oxygen contacts (Ag…O 273.8 pm, O…Ag…O 175.6, N? Ag…O 91.9/88.2°). The thermochemical behaviour of 4f was investigated using thermogravimetry, differential scanning calorimetry (DSC), time- and temperature-resolved X-ray diffractometry (TXRD), and solution calorimetry. The desolvation process occurs in the temperature range from 60 to 200°C and appears to be complex, although no crystalline intermediate could be detected. The desolvation enthalpy at 298 K was found to be + 26.8(4) kJ mol^?1. 4a is desolvated in two steps at - 15 to 60°C and 60 to 95°C (DSC), suggesting the formation of AgN(SO₂CH₃) · CH₃CN as an intermediate.     

Silver(I) and Silver(II) Complexes with Some Tetraazamacrocyclic Ligands in Aqueous Solutions

The reactions of silver(I) with isocyclam, scorpiand,trans-Me₂[14]anN₄, cis-Me₆[14]anN₄,(N-Me)Me₂py[14]anN₄ and py[12]anN₄ were investigated.The stability constant of the Ag(I) complex with py[12]anN₄ was determined. The aqueous solutions of the silver(II) complexes with the 14-membered ligands were obtained, and characterized by means of UV-VIS and CVA measurements. The Ag²⁺ ion does not form a five-coordinate complex with scorpiand. The formal potentials of the Ag(II)/Ag(I) system in the presence of scorpiand, trans-Me₂[14]anN₄, cis-Me₆[14]anN₄ and(N-Me)Me₂py[14]anN₄ were determined. The mechanism is also proposedfor the electroreduction of the silver(II) complexes with these compounds on a platinum electrode in aqueous solution.     

Synthesis and structural characterisation of five copper(I) and silver(I) complexes with 2-aminopyridine (2-APy), [Cu(μ-Cl)(2-Apy)(PPh3)]2, [Ag(μ-X)(2-Apy)(PPh3)]2 (X = Cl,Br), [Ag(μ-ONO2)(2-Apy)(EPh3)]2 (E = P,As)

Five new copper(I)/silver(I) complexes containing 2-aminopyridine, [Cu(μ-Cl)(2-Apy)(PPh₃)]₂(1), [Ag(μ-Cl)(2-Apy)(PPh₃)]₂(2), [Ag(μ-Br)(2-Apy)PPh₃)]₂(3), [Ag(μ-ONO₂)(2-Apy)(PPh₃)]₂(4), [Ag(μ-ONO₂)(2-Apy)(AsPh₃)]₂(5) have been synthesised for the first time. Complexes 1–5 are obtained by the reactions of MX (MX = CuCl for 1; M = Ag for 2–5; X = Cl, Br for 2–3; X = NO₃ for 4–5) with the monodentate ligands EPh₃ (E = P for 1–4; E = As for 5) and 2-Apy in the molar ratio of 1:1:2 in the mixed solvent of CH₂Cl₂ and MeOH. Complexes 1–5 are characterised by IR and X-ray diffraction. In 1–5, chloride, bromide and nitrate ions bridge two metal atoms to form dinuclear complexes containing the parallelogram cores M₂X₂ (M = Cu, Ag).     

Reverse atom transfer radical polymerisation (RATRP) of methacrylates using copper(I)/pyridinimine catalysts in conjunction with AIBN

N-n-Propyl-2-pyridylmethanimine, 1, N-n-octyl-2-pyridylmethanimine, 2, N-n-lauryl-2-pyridylmethanimine, 3, and N-n-octadecyl-2-pyridylmethanimine, 4 have been used in conjunction with copper(II) bromide and azo initiators for the reverse atom transfer radical polymerisation of a range of methacrylates. AIBN to Cu^IIBr₂ ratios of 0.5:1, 0.75:1 and 1:1 give PMMA with M_n 11 500 g mol⁻¹ (PDi = 1.24) (at 22% conversion), 12 500 g mol⁻¹ (PDi = 1.06) (at 83% conversion) and 10 900 g mol⁻¹ (PDi = 1.11) (at 84% conversion), respectively. A Cu^IIBr₂ complex is demonstrated to be needed at the start of the reaction for good control over molecular weight and polydispersity as reactions using Cu(I)Br as catalyst yielded PMMA of M_n 31 000 g mol⁻¹ (PDi = 2.90), reactions with no copper yield PMMA of M_n 33 000 g mol⁻¹ (PDi = 2.95). The RATRP of styrene was carried out using Cu^IIBr₂ as catalyst. AIBN to Cu^IIBr₂ ratio of 0.5:1, 0.75:1 and 1:1 gave PS with M_n = 12 400 g mol⁻¹ (PDi = 1.27) at low conversion, M_n = 15 500 g mol⁻¹ (PDi = 1.11) and 12 400 g mol⁻¹ (PDi = 1.38), respectively at ∼85% conversion. A series of block copolymers of MMA with BMA, BzMA and DMEAMA (15 600 g mol⁻¹ (PDi = 1.18), 13 300 g mol⁻¹ (PDi = 1.14) 15 300 g mol⁻¹ (PDi) = 1.16), using a PMMA macroinitiator were prepared. Emulsion polymerisation of MMA using [initiator]:[Cu^(II)Br₂] ratio = 0.5:1 with Brij surfactant gave a linear increase of M_n with respect to conversion, final M_n = 112 800 g mol⁻¹ (PDi = 1.42). Further reactions were carried out with [initiator]:[Cu^(II)Br₂] ratio = 0.75:1 and 1:1. Both giving PMMA with M_n ∼ 32 000 g mol⁻¹ (PDi ∼ 2.4). These reactions exhibit no control, this is because the azo initiator is present in excess and all of the monomer is consumed by a free radical polymerisation as opposed to a controlled reaction. Particle size analysis (DLS) showed the particle size between 160 and170 nm in all cases.     

Structural studies of two-coordinate complexes of tris(2-methoxylphenyl)phosphine and tris(4-methoxyphenyl)phosphine with gold(I) halides

A series of five gold(I) halide complexes with the two isomeric methoxy-substituted triarylphosphines, tris(2-methoxyphenyl)phosphine [P(oanis)₃], [AuP(oanis)₃X] [for X = Cl, (1); X = Br, (2) and X = I, (3)] and tris(4-methoxyphenyl)phosphine [P(panis)₃], [AuP(panis)₃X] [for X = Br (4) and X = I (5)] have been synthesized and characterized by single crystal X-ray diffraction and solution ³¹P{¹H} NMR spectroscopy. The structure determinations confirm the expected presence of linear two-coordination about the gold centres in all five complexes with bond distance and angle data typical of this type of compound [Au–P, 2.239(2)–2.259(3) Å; Au–Cl, 2.294(2) Å; Au–Br, 2.385(2)–2.402(2) Å; Au–I, 2.546(1)–2.554(1) Å; P–Au–X; 175.3(1)–180°]. All analogues except the iodo complex 5 crystallize with one complex molecule in the crystallographic asymmetric unit. The bromo and iodo complexes 2 and 3 constitute a trigonal isomorphous set while the bromo complex 4 is also isomorphous with the previously determined chloro complex [AuP(panis)₃Cl]. The 2-methoxy analogues are stabilized by significant methoxy-O?Au interactions.     

Synthesis of a new N,N-ethane-1,2-bis(4-methoxyphenyl)carbothioamide ligand and its Cu(I) and Ag(I) complexes

[Cu(H₂L)(PPh₃)₂]NO₃ · 0.5H₂O (2) and [Ag(H₂L)(PPh₃)₂]NO₃ · 0.5H₂O (3) complexes of a new flexible thioamide ligand; N,N′-ethane-1,2-bis(4-methoxyphenyl)carbothioamide H₂L (1) have been synthesized using PPh₃ as a coligand. The synthesized compounds have been characterized with the help of elemental analyses, IR, ¹H, ¹³C and ³¹P NMR spectroscopy. The ligand and its Cu(I) complex have been studied by single crystal X-ray crystallography. The ligand acts as a neutral S-donor and forms a nine-membered chelate ring in [Cu(H₂L)(PPh₃)₂]NO₃ · 0.5H₂O. The molecular packing is stabilized by an anionic cavity formed by intermolecular hydrogen bonding between the basal plane of the complex molecule and the nitrate ions. The square shaped columnar channel has dimensions of 5.489(25) [N(11)–H(11A)?O(13)?H(21A)N(21)] × 3.693(7) [N(11)–C(11)–C(21)–N(21)] Å.     

Preparation,spectroscopic characterization and X-ray crystal and molecular structures of nickel(II), copper(II) and zinc(II) complexes of the Schiff base formed from isatin and S-methyldithiocarbazate (Hisa-sme)

Complexes of general formula, [M(isa-sme)₂] · n(solvate) [M = Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺; isa-sme = monoanionic form of the Schiff base formed by condensation of isatin with S-methyldithiocarbazate; n = 1 or 1.5; solvate = MeCN, DMSO, MeOH or H₂O] have been synthesized and characterized by a variety of physicochemical techniques. An X-ray crystallographic structure determination of the [Ni(isa-sme)₂] · MeCN complex reveals a six-coordinate, distorted octahedral geometry. The two uninegatively charged, tridentate, Schiff base ligands are coordinated to the nickel(II) ion meridionally via the amide O-atoms, the azomethine N-atoms and the thiolate S-atoms. By contrast, the crystal structure of [Zn(isa-sme)₂] · MeOH shows a four-coordinate distorted tetrahedral geometry. The two dithiocarbazate ligands are coordinated as N, S bidentate chelates with the amide O-atom not coordinated. The structure of the copper(II) complex [Cu(isa-sme)₂] · DMSO is complicated and comprises two different complexes in the asymmetric unit, one four- and the other five-coordinate. The four-coordinate copper(II) has a distorted (flattened) tetrahedral geometry as seen in the Zn(II) analogue whereas the five-coordinate copper(II) has a distorted square-pyramidal geometry with one ligand coordinated to the copper(II) ion as a tridentate (N, S, O) ligand and the other coordinated as a bidentate N, S chelate. EPR spectroscopy indicates that in solution only one form is present, that being a distorted tetrahedral complex.