Copper(II) complexes of entwined 2,9-di(o-substituted phenyl)-1,10-phenanthroline type ligands and intramolecular quenching in copper(I) complexes

Cu¹¹ complexes of 1,10-phenanthroline, disubstituted at the 2 and 9 positions or monosubstituted at the 2 position by phenyl moieties possessingortho substituents, were prepared and investigated by spectroscopic and electrochemical methods. The electronic spectral d-d band position varies from 14 500 to 13 200 cm⁻¹. E.s.r. g_‖ values are between 2.256 to 2.283 and A_‖ between 164 to 117×10⁻⁴ cm⁻¹. Thebis[2,9-di(o-substituted phenyl)-1,10-phenanthroline]Cu¹¹ complexes undergo reversible one-electron electrochemical reduction (Cu¹¹/Cu¹) in the +0.536 to +0.825 V potential range versus s.c.e., whereas thebis[2-mono(o-substituted phenyl)-1,10-phenanthroline]Cu¹¹ complexes undergo reduction in the +0.360 to +0.405 V range; the redox couple is found to be quasireversible. Emission studies on copper(I) complexes show that onlybis[2,9-di(o-tolyl)-1,10-phen]Copper(I) complex exhibits emission properties. Emission behaviour of other structurally similar compounds is explored. TMC 2555     

Novel Copper(I) Clusters with 2‐(Diphenylphosphanyl)anilide Ligands. Synthesis and Crystal Structures of [Cu6X2(NHR)4] (X = Cl,Br, I; R = C6H4‐2‐PPh2)

Treatment of copper(I) halides CuX (X = Cl, Br, I) with lithium 2‐(diphenylphosphanyl)anilide [Li(HL)] in THF led to the formation of hexanuclear copper(I) complexes [Cu₆X₂(HL)₄] [X = Cl ( 1 ), Br ( 2 ), I ( 3 )]. In compounds 1 – 3 , the copper atoms are in a distorted octahedral arrangement and the amide ligands adopt a μ₃‐κP,κ²N bridging mode. Additionally there are two μ₂‐bridging halide ligands. Each of the [Cu₆X₂(HL)₄] clusters comprises two copper atoms, which are surrounded by two amide nitrogen atoms in an almost linear coordination [Cu–N: 186.2(3)–188.0(3) pm] and four copper atoms, which are connected to an amide N atom, a P atom, and a halogen atom in a distorted trigonal planar fashion [Cu–N: 199.6(3)–202.3(3) pm)].     

Synthesis of unsymmetrical compartmental oxime nickel(II) and copper(II) complexes: spectral, electrochemical and magnetic studies

A new series of binuclear unsymmetrical compartmental oxime complexes (1–5) [M₂L] [M=Cu(II), Ni(II)] have been synthesized using mononuclear complex [ML] (L=1,4-bis[2-hydroxy-3-(formyl)-5-methylbenzyl]piperazine), hydroxylamine hydrochloride and triethylamine. In this system there are two different compartments, one has piperazinyl nitrogens and phenolic oxygens and the other compartment has two oxime nitrogens and phenolic oxygens as coordinating sites. The complexes were characterized by elemental and spectral analysis. Electrochemical studies of the complexes show two step single electron quasi-reversible redox processes at cathodic potential region. For copper complexes E¹ _pc=−0.18 to −0.62 and E² _pc=−1.18 to −1.25 V, for nickel complexes E¹ _pc=−0.40 to −0.63 and E² _pc=−1.08 to −1.10 V and reduction potentials are sensitive towards the chemical environment around the copper and nickel atoms. The nickel(II) complexes undergo two electrons oxidation. The first one electron oxidation is observed around +0.75 V and the second around +1.13 V. ESR Spectra of the binuclear copper(II) complexes [Cu₂L](ClO₄), [Cu₂L(Cl)], [Cu₂L(NO₃)] shows a broad signal at g=2.1 indicating the presence of coupling between the two copper centers. Copper(II) complexes show a magnetic moment value of μ_eff around 1.59 B.M at 298 K and variable temperature magnetic measurements show a −2J value of 172 cm⁻¹ indicating presence of antiferromagnetic exchange interaction between copper(II) centres.     

[1‐Allylpyridinium][Cu2Cl3]: Synthesis,X‐ray Structure and the Regularity of Crystal Architecture of 1‐Allyl/(amino)‐pyridinium Copper(I) Chloride π‐Complexes

By alternating‐current electrochemical technique crystals of copper(I) π‐complex with 1‐allylpyridinium chloride of [C₅H₅N(C₃H₅)][Cu₂Cl₃] ( 1 ) composition have been obtained and structurally investigated. Compound 1 crystallizes in monoclinic system, space group C2/c a = 24.035(1) Å, b = 11.4870(9) Å, c = 7.8170(5) Å, β = 95.010(5)°, V = 2150.0(2) ų (at 100 K), Z = 8, R = 0.028, for 4836 independent reflections. In the structure 1 trigonal‐pyramidal environment of π‐coordinated copper(I) atom is formed by a lengthened to 1.376(2) Å C=C bond of allyl group and by three chlorine atoms. Other two copper atoms are tetrahedrally surrounded by chlorine atoms only. The coordination polyhedra are combined into an original infinite (Cu₄Cl₆^2—)_n fragment. Structural comparison of 1 and the recently studied copper(I) chloride π‐complexes with 3‐amino‐, 2‐amino‐, 4‐amino‐1‐allylpyridinium chlorides of respective [LCu₂Cl₃] ( 2 ), [L₂Cu₂Cl₄] ( 3 ), and [LCuCl₂] ( 4 ) compositions allowed us to reveal the trend of the inorganic fragment complication which depends on pKa (base) value of the corresponding initial heterocycle.     

Synthesis and characterization of mononuclear copper(II) and dinuclear cadmium(II) complexes with di-(2-picolyl)sulfide

The reaction of CuCl₂ · 2H₂O and CdCl₂ with di-(2-picolyl)sulfide (dps) leads to the formation of mononuclear copper(II) and binuclear cadmium(II) complexes, [Cu(dps)Cl₂] · H₂O (1) and [(dps)(Cl)Cd^II(μ-Cl)₂Cd^II(Cl)(dps)] (2). The copper atom in (1) is coordinated to one sulfur and two nitrogen atoms from the dps ligand and two chlorides in a distorted square-pyramidal environment. Complex (2) has two distorted octahedra sharing the basal edge that contain the bridging chloro ligands, each of which resides at a center of inversion. Cyclic voltammetric data show that (1) undergoes two reversible one-electron waves corresponding to Cu^II/Cu^III and Cu^II/Cu^I processes. However, cyclic voltammetry of (2) gives two irreversible reduced waves.     

Unusual electrochemical reduction of copper(II) to copper(I) in polyoxotungstates

The electrochemical behaviour of the copper-substituted Keggin-type and sandwich-type polyoxotungstate anions of the compounds α-[(C₄H₉)₄N]₄H[PW₁₁Cu^IIO₃₉] and α-B-[(C₄H₉)₄N]₇H₃[Cu^II₄(H₂O)₂(PW₉O₃₄)₂] was studied by cyclic voltammetry in acetonitrile. In both cases two copper 1-electron reduction waves were detected in the cathodic scan. The first one was due to the reduction of one Cu^II to Cu^I in the polyoxoanion and the second one to the consecutive reduction of the preformed Cu^I to Cu⁰, with the consequent deposition/adsorption of the ejected metal atom at the glassy carbon electrode surface. In the anodic scan, Cu⁰ was re-oxidised with regeneration of the initial copper(II) complexes, via a Cu^I intermediate. The observed two-step reduction of copper(II) to copper(0) and the formation of intermediate species containing copper(I) is here reported for the first time for copper substituted polyoxotungstates. The co-ordination of the acetonitrile molecules to the copper ions must play a role in the formation of the copper(I) species, which are not detected in aqueous solution.     

Structure and spectroscopic properties of the dimeric copper(I) N‐heterocyclic carbene complex [Cu2(CNCt‐Bu)2](PF6)2

In recent years, the use of copper N‐heterocyclic carbene (NHC) complexes has expanded to fields besides catalysis, namely medicinal chemistry and luminescence applications. In the latter case, multinuclear copper NHC compounds have attracted interest, however, the number of these complexes in the literature is still quite limited. Bis[μ‐1,3‐bis(3‐tert‐butylimidazolin‐2‐yliden‐1‐yl)pyridine]‐1κ⁴C²,N:N,C^2′;2κ⁴C²,N:N,C^2′‐dicopper(I) bis(hexafluoridophosphate), [Cu₂(C₁₉H₂₅N₅)₂](PF₆)₂, is a dimeric copper(I) complex bridged by two CNC, i.e. bis(N‐heterocyclic carbene)pyridine, ligands. Each Cu^I atom is almost linearly coordinated by two NHC ligands and interactions are observed between the pyridine N atoms and the metal centres, while no cuprophilic interactions were observed. Very strong absorption bands are evident in the UV–Vis spectrum at 236 and 274 nm, and an emission band is observed at 450 nm. The reported complex is a new example of a multinuclear copper NHC complex and a member of a compound class which has only rarely been reported.     

Relationship between the Auger parameter and the ground state valence charge of the core-ionized atom: The case of Cu(I) and Cu (II) compounds

We develop a simple semiempirical model that correlates the Auger parameter to the ground state valence charge of the core-ionized atom with closed shell electron configuration. Until now, the Auger parameter was employed to separate initial and final state effects that influence the core electron binding energy. The model is applied to Cu(I) and Cu (II) compounds with the Auger parameter defined as α' = E_b^FL (2p_3/2) + E_k^FL (L₃M₄₅M₄₅;¹G). The Auger parameter shift for Cu(I) ion in CuI, CuBr, CuFeS₂, Cu₂S, and Cu₂O compounds—with respect to the copper free atom—increases with the electronic polarizability of the nearest-neighbour ligands suggesting a nonlocal screening mechanism. This relaxation process is interpreted as due to an electron transfer from the nearest-neighbour ligands toward the spatially extended 4sp valence orbitals of the core-ionized Cu(I) ion. In agreement with our model, a linear relationship is found between the Auger parameter shift and the ground state Bader valence charge obtained by density functional theory calculations. The Auger parameter shift for the Cu (II) ion in CuF₂, CuCl₂, CuBr₂, CuSO₄, Cu (NO₃)₂•3H₂O, Cu₃(PO₄)₂, Cu (OH)₂, and CuO compounds is very close to the Auger parameter of metallic copper, and therefore, it is not related to the calculated ground state Bader valence charge. The relaxation process in the final state is dominated by the local screening mechanism, which involves an electron transfer from the nearest-neighbour ligands toward the spatially contracted 3d orbitals of the core-ionized Cu (II) ion.     

Syntheses and crystal structures of two heterometallic iodoplumbates containing mixed‐valence copper(I/II)

Mixed‐valence copper(I/II) atoms have been introduced successfully into a Pb/I skeleton to obtain two heterometallic iodoplumbates, namely poly[bis(tetra‐n‐butylammonium) [bis(μ₃‐dimethyldithiocarbamato)dodeca‐μ₃‐iodido‐hexa‐μ₂‐iodido‐tetracopper(I)copper(II)hexalead(II)]], {(C₁₆H₃₆N)₂[Cu₄^ICu^IIPb₆(C₃H₆NS₂)₂I₁₈]}_n , (I), and poly[[μ₃‐iodido‐tri‐μ₂‐iodido‐iodido[bis(1,10‐phenanthroline)copper(I)]copper(I)copper(II)lead(II)] hemiiodine], {[Cu^ICu^IIPbI₅(C₁₂H₈N₂)₂]·0.5I₂}_n , (II), under solution and solvothermal conditions, respectively. Compound (I) contains two‐dimensional anionic layers, which are built upon the linkages of Cu^II(S₂CNMe₂)₂ units and one‐dimensional anionic Pb/I/Cu^I chains. Tetra‐n‐butylammonium cations are located between the anionic layers and connected to them via C—H…I hydrogen‐bonding interactions. Compound (II) exhibits a one‐dimensional neutral structure, which is composed of [PbI₅] square pyramids, [Cu^II₄] tetrahedra and [Cu^IIN₄I] trigonal bipyramids. Face‐to‐face aromatic π–π stacking interactions between adjacent 1,10‐phenanthroline ligands stabilize the structure and assemble compound (II) into a three‐dimensional supramolecular structure. I₂ molecules lie in the voids of the structure.     

Stereospecific reactions of copper(II) complexes of serine and threonine with formaldehyde

Summary Condensations of Cu(L-ser)₂ and Cu(L-thr)₂ (where L-ser=L-serinato anion and L-thr=L-threoninato anion) with formaldehyde at pH 4.5 yield two new optically active products:bis[L-(oxazolidine-4-carboxylato)]-copper(II) monohydrate (1) andbis[L-(N-hydroxymethyl-5-methyloxazolidine-4-carboxylato)]copper(II) dihydrate (2), respectively. Cu(D-ser)₂ and Cu(D-thr)₂ also undergo similar reactions. The new products are different from the products obtained from Cu(DL-ser)₂ and Cu(DL-thr)₂, and a mechanism has been suggested to explain the stereospecificity of these conversions. Condensation of Cu(L-ser)₂ with formaldehyde and ammonia at pH 4.5 yields the new product, [3N,7N-(1,3,5,7-tetraazabicyclo-[3.3.1]nonyl)di(hydroxymethyl)-acetato]copper(II), (3). The compexes have been characterized by analytical and by i.r. electronic and c.d. spectral data. Complexes (1) and (2) undergo a reversible Cu^II/Cu^I redox process in aqueous media at –0.18 Vversus s.c.e.; complex (3) exhibits irreversible Cu^II/Cu^I reduction at –0.49 V confirming the presence of a rigid pentamethylenediaza-bridged ligand system.     

Reduction from copper(II) to copper(I) upon collisional activation of (pyridine)2CuCl+

Electrospray ionization of dilute aqueous solutions of copper(II) chloride‐containing traces of pyridine (py) as well as ammonia permits the generation of the gaseous ions (py)₂Cu⁺ and (py)₂CuCl⁺, of which the latter is a formal copper(II) compound, whereas the former contains copper(I). Collision‐induced dissociation of the mass‐selected ions in an ion‐trap mass spectrometer (IT‐MS) leads to a loss of pyridine from (py)₂Cu⁺, whereas an expulsion of atomic chlorine largely prevails for (py)₂CuCl⁺. Theoretical studies using density functional theory predict a bond dissociation energy (BDE) of BDE[(py)₂Cu⁺ ‐Cl] = 125 kJ mol^?1, whereas the pyridine ligand is bound significantly stronger, i.e. BDE[(py)CuCl⁺ ‐py] = 194 kJ mol^?1 and BDE[(py)Cu⁺ ‐py] = 242 kJ mol^?1. The results are discussed with regard to the influence of the solvation on the stability of the Cu^I/Cu^II redox couple. Copyright © 2010 John Wiley & Sons, Ltd.     

Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square‐Planar Copper(I) Complex

6,6′′‐Bis(2,4,6‐trimethylanilido)terpyridine (H₂Tpy^NMes) was prepared as a rigid, tridentate pincer ligand containing pendent anilines as hydrogen bond donor groups in the secondary coordination sphere. The coordination geometry of (H₂Tpy^NMes)copper(I)‐halide (Cl, Br and I) complexes is dictated by the strength of the NH–halide hydrogen bond. The Cu^ICl and Cu^IICl complexes are nearly isostructural, the former presenting a highly unusual square‐planar geometry about Cu^I. The geometric constraints provided by secondary interactions are reminiscent of blue copper proteins where a constrained geometry, or entatic state, allows for extremely rapid Cu^I/Cu^II electron‐transfer self‐exchange rates. Cu(H₂Tpy^NMes)Cl shows similar fast electron transfer (≈10⁵ m ^?1 s^?1) which is the same order of magnitude as biological systems.     

A new stepped tetranuclear copper(II) complex: synthesis,crystal structure and photoluminescence properties

Binuclear and tetranuclear copper(II) complexes are of interest because of their structural, magnetic and photoluminescence properties. Of the several important configurations of tetranuclear copper(II) complexes, there are limited reports on the crystal structures and solid‐state photoluminescence properties of `stepped' tetranuclear copper(II) complexes. A new Cu^II complex, namely bis{μ₃‐3‐[(4‐methoxy‐2‐oxidobenzylidene)amino]propanolato}bis{μ₂‐3‐[(4‐methoxy‐2‐oxidobenzylidene)amino]propanolato}tetracopper(II), [Cu₄(C₁₁H₁₃NO₃)₄], has been synthesized and characterized using elemental analysis, FT–IR, solid‐state UV–Vis spectroscopy and single‐crystal X‐ray diffraction. The crystal structure determination shows that the complex is a stepped tetranuclear structure consisting of two dinuclear [Cu₂(L )₂] units {L is 3‐[(4‐methoxy‐2‐oxidobenzylidene)amino]propanolate}. The two terminal Cu^II atoms are four‐coordinated in square‐planar environments, while the two central Cu^II atoms are five‐coordinated in square‐pyramidal environments. The solid‐state photoluminescence properties of both the complex and 3‐[(2‐hydroxy‐4‐methoxybenzylidene)amino]propanol (H₂L ) have been investigated at room temperature in the visible region. When the complex and H₂L are excited under UV light at 349 nm, the complex displays a strong blue emission at 469 nm and H₂L displays a green emission at 515 nm.     

Synthesis,crystal structure and properties of a novel copper(II) complex with tripod ligand tris(1H-benzimidazol- 2-ylmethyl)amine

A five-coordinate copper complex with the tripod ligand tris(1H-benzimidazol-2-ylmethyl)amine (ntb), of composition [Cu(ntb)(H₂O)] (C1O₄)₂?·?C₅H₄N₂O₃?·?H₂O (C₅H₄N₂O₃?=?4-nitropyridine-N-oxide), was synthesized and characterized by means of elemental analyses, electrical conductivities, thermal analyses, IR, and U.V. The crystal structure of the copper complex has been determined by single-crystal X-ray diffraction, and shows that the Cu^II is bonded to a tris(1H-benzimidazol-2-ylmethyl)amine (ntb) ligand and a water molecule through four N atoms and one O atom, giving a distorted trigonal–bipyramidal coordination geometry with approximate C ₃ molecular symmetry. Cyclic voltammograms of the copper complex indicate a quasi-reversible Cu⁺²/Cu⁺ couple. Electron spin resonance data confirm a trigonal-bipyramidal structure and with g ₂?<?g _ζ and a very small value of A ₂ (20?×?10^?4?cm^?1).     

Highly Effective Hybrid Copper(I) Iodide Cluster Emitter with Negative Thermal Quenched Phosphorescence for X-Ray Imaging

The low efficiency triplet emission of hybrid copper(I) iodide clusters is a critical obstacle to their further practical optoelectronic application. Herein, we present an efficient hybrid copper(I) iodide cluster emitter (DBA)₄Cu₄I₄ , where the cooperation of excited state structure reorganization and the metallophilicity interaction enables ultra-bright triplet yellow-orange emission with a photoluminescence quantum yield over 94.9 %, and the phonon-assisted de-trapping process of exciton induces the negative thermal quenching effect at 80–300 K. We also investigate the potential of this emitter for X-ray imaging. The (DBA)₄Cu₄I₄ wafer demonstrates a light yield higher than 10⁴ photons MeV⁻¹ and a high spatial resolution of ≈5.0 lp mm⁻¹, showing great potential in practical X-ray imaging applications. Our new copper(I) iodide cluster emitter can serve as a model for investigating the thermodynamic mechanism of photoluminescence in hybrid copper(I) halide phosphorescence materials.     

Oligo-m-phenyleneoxalamide copper(II) mesocates as electro-switchable ferromagnetic metal-organic wires

Double‐stranded copper(II) string complexes of varying nuclearity, from di‐ to tetranuclear species, have been prepared by the Cu^II‐mediated self‐assembly of a novel family of linear homo‐ and heteropolytopic ligands that contain two outer oxamato and either zero ( 1 b ), one ( 2 b ), or two ( 3 b ) inner oxamidato donor groups separated by rigid 2‐methyl‐1,3‐phenylene spacers. The X‐ray crystal structures of these Cu^II_n complexes (n=2 ( 1 d ), 3 ( 2 d ), and 4 ( 3 d )) show a linear array of metal atoms with an overall twisted coordination geometry for both the outer CuN₂O₂ and inner CuN₄ chromophores. Two such nonplanar all‐syn bridging ligands 1 b – 3 b in an anti arrangement clamp around the metal centers with alternating M and P helical chiralities to afford an overall double meso‐helicate‐type architecture for 1 d – 3 d . Variable‐temperature (2.0–300 K) magnetic susceptibility and variable‐field (0–5.0 T) magnetization measurements for 1 d – 3 d show the occurrence of S=nS_Cu (n=2–4) high‐spin ground states that arise from the moderate ferromagnetic coupling between the unpaired electrons of the linearly disposed Cu^II ions (S_Cu=1/2) through the two anti m‐phenylenediamidate‐type bridges (J values in the range of +15.0 to 16.8 cm^?1). Density functional theory (DFT) calculations for 1 d – 3 d evidence a sign alternation of the spin density in the meta‐substituted phenylene spacers in agreement with a spin polarization exchange mechanism along the linear metal array with overall intermetallic distances between terminal metal centers in the range of 0.7–2.2 nm. Cyclic voltammetry (CV) and rotating‐disk electrode (RDE) electrochemical measurements for 1 d – 3 d show several reversible or quasireversible one‐ or two‐electron steps that involve the consecutive metal‐centered oxidation of the inner and outer Cu^II ions (S_Cu=1/2) to diamagnetic Cu^III ones (S_Cu=0) at relatively low formal potentials (E values in the range of +0.14 to 0.25 V and of +0.43 to 0.67 V vs. SCE, respectively). Further developments may be envisaged for this family of oligo‐m‐phenyleneoxalamide copper(II) double mesocates as electroswitchable ferromagnetic ‘metal–organic wires’ (MOWs) on the basis of their unique ferromagnetic and multicenter redox behaviors.     

Cu3(CN)4(NH3)2Hg(CN)2: a novel inter­penetrating framework formed from CuI,CuII, HgII and cyanide bridges

The title compound, poly[diammine­hexa‐μ‐cyano‐di­copper(I)­copper(II)­mercury(II)], [Cu₃Hg(CN)₆(NH₃)₂]_n, has a novel threefold‐inter­penetrating structure of three‐dimensional frameworks. This three‐dimensional framework consists of two‐dimensional network Cu₃(CN)₄(NH₃)₂ complexes and rod‐like Hg(CN)₂ complexes. The two‐dimensional network complex contains trigonal–planar Cu^I (site symmetry m) and octa­hedral Cu^II (site symmetry 2/m) in a 2:1 ratio. Two types of cyanide group form bridges between three coordination sites of Cu^I and two equatorial sites of Cu^II to form a two‐dimensional structure with large hexa­gonal windows. One type of CN⁻ group is disordered across a center of inversion, while the other resides on the mirror plane. Two NH₃ mol­ecules (site symmetry 2) are located in the hexa­gonal windows and coordinate to the remaining equatorial sites of Cu^II. Both N atoms of the rod‐like Hg(CN)₂ group (Hg site symmetry 2/m and CN⁻ site symmetry m) coordinate to the axial sites of Cu^II. This linkage completes the three‐dimensional framework and penetrates two hexa­gonal windows of two two‐dimensional network complexes to form the threefold‐inter­penetrating structure.     

Copper(I) d10···d10 Interactions and Diselenide(1–) Radical Anions in Mixed Valent Selenides Cu4–δBiSe4I

Melting reactions of copper, CuI, selenium, and Bi₂Se₃ yielded black, shiny needles of Cu₄BiSe₄I = Cu₄BiSe₂(Se₂)I. The compound decomposes peritectically above 635(5) K and crystallizes in the orthorhombic space group Pnma with a = 960.1(1) pm, b = 413.16(3) pm, and c = 2274.7(2) pm (T = 293(2) K). In the crystal structure, strands ${1}\atop{{\infty}}$ [BiSeSe_2/2(Se₂)_2/2]^3– run along [010]. Therein, the bismuth(III) cation is coordinated by five selenium atoms, which form a square pyramid. The copper(I) cations are coordinated tetrahedrally by selenide, diselenide and iodide ions. Edge‐sharing of these tetrahedra results in zigzag chains of copper cations with short distances of 262.7(4) pm. Enhanced dispersion of the 3d bands, the Crystal Orbital Hamilton Populations (COHP), and disynaptic ELI‐D basins indicate weakly attractive d¹⁰···d¹⁰ interactions between the copper cations. The semiconducting properties and the calculated electronic band structure suggest an electron‐precise compound. In copper‐deficient Cu_3.824(8)BiSe₄I, the Cu···Cu distances are 5 pm shorter, and Raman spectroscopy indicates the presence of diselenide(1–) radical anions besides the diselenide(2–) groups. As a result, in Cu_3.824(8)BiSe₄I, selenium coexists in the oxidations states –II, –I, and –0.5.     

Bis(homoleptische) vs. heteroleptische Kupfer(I)-Komplexe: Elektrosynthese,Spektroskopie und Kristallstruktur von {[Cu(BIK)2]+}2{[Cu4(SR)6]2−} · 3(CH3CN) · (RSH); BIK = Bis(N-methylimidazol-2-yl)keton,R = o-Tolyl

Bis(homoleptic) vs. Heteroleptic Copper(I) Complexes: Electrosynthesis, Spectroscopy, and Crystal Structure of {[Cu(BIK)₂]⁺}₂{[Cu₄(SR)₆]^2?} · 3(CH₃CN) · (RSH); BIK = Bis(2-methylimidazol-2-yl)ketone, R = o-Tolyl Anodic oxidation of copper in acetonitrile/2 mM tetrabutylammonium perchlorate and in the presence of bis(N-methylimidazol-2-yl)ketone (BIK) and excess o-thiocresol RSH yields the title compound as main product. Whereas the dianionic cluster [Cu₄(SR)₆]^2? is similar to previously reported such species with R = phenyl or methyl, the purple cations [Cu(BIK)₂]⁺ exhibit spectroscopic and structural effects of π back bonding between electron-rich Cu¹ and the π acceptor ligand BIK. In contrast to the formally related [Zn(BIK)₂]²⁺, the copper(I) complex cations exhibit distorted tetrahedral structures with almost coplanar BIK chelate arrangements which ensures maximum metal-ligand π interaction.     

Synthesis and Characterization of an Unexpected Asymmetric Binuclear Copper（Ⅰ） Complex Containing 4-Vinyl-pyridine

The asymmetric binuclear copper(I) complex [Cu₂(dppm)₂(C₇H₇N)(μ‐HCOO)](NO₃) (dppm=Ph₂PCH₂PPh₂, C₇H₇N=4‐vinyl‐pyridine) has been prepared and characterized by physicochemical and spectroscopic methods. The complex is photoluminescent at room temperature. It crystallizes in triclinic system, space group P‐1 with a= 1.2719(3) nm, b=1.8637(4) nm, c=1.1656(2) nm, a=97.16(3)°, β= 104.94(3)″, γ=89.39(3)°, V=2.648.1(9) nm³, D_c= 1.390 g.m^?3, Z=2, μ=0.974 mm^?1, R=0.0483 for 5716 independently observed reflections with I>2δ(I). The structure consists of [Cu₂(dppm)₂(C₇H₇N)(μ‐HCOO)]⁺cations and nitrate anions. The copper atoms show different coordination modes: Cu(1) displays a distorted trigonal and Cu(2) a tetrahedred geometry.