Tetracyanoquinodimethane complexes of copper and a 17-membered N,O-donor macrocycle

An axially elongated copper(II) complex, CuL¹Cl₂, has been obtained by reaction of copper(II) chloride with a 17-membered N,O-donor macrocyclic ligand (L¹). In an attempt to prepare the complex from copper(II) perchlorate, crystals of L¹ suitable for X-ray were obtained as its diperchlorate salt, [H₂L¹][ClO₄]₂. Further reaction of CuL¹Cl₂ with LiTCNQ and Et₃NH(TCNQ)₂ furnished the charge transfer copper(I) complexes CuL¹(TCNQ)₂·3H₂O and CuL¹(TCNQ)₃, with TCNQ carrying partially reduced charge. The presence of a diamagnetic metallic centre was confirmed by EPR and magnetic measurements.     

Structure of the Cu(II) chloride complex with 4-amino-l,2,4-triazole Cu(C2H4N4)Cl2

The coordination compounds of copper(II) chloride and bromide with 1,2,4-triazole (L¹) and 4-amino1,2,4-triazole (L²), CuL¹Hal₂ and CuL²Hal₂, possess interesting magnetic properties [1, 2]. For example, at very low temperatures CuL¹Cl₂ and CuL¹Br₂ are ferromagnets [2](T _c ≈ 3.3 and 6.5 K, respectively). To explain the magnetic behavior of copper(II) halide complexes with the above nitrogen heterocycles it is generally assumed that the complexes are polynuclear chain compounds in which the copper atoms are bridged by two halogen ions and bridging bidentate heterocycle molecules (coordination of N1 and N2 atoms). This hypothesis is made on the basis of the X-ray diffraction analysis of CuL¹Cl₂ [3]. It is interesting to perform an X-ray diffraction study of CuL²Cl₂ and CuL2Br2; this is important for obtaining reliable magnetostructural correlations for this group of compounds. In this study, we investigated single crystals of the complexes; this demanded choosing special conditions of synthesis, which differ from the conditions suggested for the synthesis of polycrystals in [1]. In this communication we report on the results of synthesis and X-ray diffraction analysis of the single crystals of the coordination compound CuL²Cl₂. Translated fromZhurnal Strukturnoi Khimii, Vol. 38, No. 1, pp. 207–212, January–February, 1997.     

Gas chromatographic study of the thermal and analytical properties of a nematic luquid crystal and its cupric complex

The nematic compound N-4-(2′-(4″-dodecyloxybenzoyloxy)-4′-do-decyloxy)azobenzenyl-4-dodecyloxysalicylideneimine, known as LH, and its cupric complex, bis[N-4-(2′-(4″-dodecyloxybenzoyloxy)-4′-dodecyloxy)azobenzenyl-4-dodecyloxysalicylidene]iminato of copper (II), known as CuL₂ have been used as stationary phases for gas chromatography. The thermal properties of LH and CuL₂ have been determined with conventional metal columns, using n-alkanes as solute probes. Plots of In V⁰_g against 1/T clearly show the temperature transitions of LH and CuL₂. The analytical capabilities of the two stationary phases were established by use of 25 m glass capillary columns. Satisfactory separations were obtained for positional hydrocarbon and halocarbon isomers, aromatic and polyaromatic compounds, and volatile essential oil constitutents.     

Copper <Emphasis Type="Italic">N</Emphasis>-(4′-benzo-15-crown-5)-2-(amino-<Emphasis Type="Italic">N</Emphasis>-tosyl)phenylaldiminate: Complexing and ion-selective properties

Copper(II) chelate with N-(4′-benzo-15-crown-5)-2-(amino-N-tosyl)phenylaldiminate CuL₂ and its coordination compounds with Li, Na, and K salts have been synthesized. Their IR spectra have been studied and assignment of the key vibration frequencies of CuL₂ and complexes based on it. On the basis of spectral, thermogravimetric, and elemental analysis datasassumptions concerning the compound structure are made. The ion-selective properties of CuL₂ are studied by potentiometry.     

Liquid–liquid extraction of copper(II) with substituted salicylideneanilines from sulfate media

The liquid–liquid extraction of copper(II) with Schiff bases in chloroform from sulfate media is studied for pH and concentration of the extractant. Stoichiometry coefficients of the extracted species are determined by the slope analysis method. With salicylideneaniline, the copper(II) is extracted as a mixed chelate complex, CuL₂HL. In the presence of substituent, the copper is extracted as simple chelates, CuL₂. The trends in the values of extraction constants were explained in terms of the nature of the substituents.     

Synthesis,structure, and magnetic properties of nickel(II), copper(II), cobalt(II), and zinc(II) 2,2,5,5-tetramethyl-3-imidazolin-1-oxyl-4-(1′-butylidene-2′-oxylates)

Syntheses are reported for the coordination compounds of nickel(II), copper(II), cobalt(II), and zinc(II) with 4-(2 -oxobutylidene)-2,2,5,5-tetramethyl-3-imidazolin-1-oxyl (LH) with the formula NL₂. The central atom in solid NiL₂ has square coordination, while in solution, this atom has distorted tetrahedral coordination. The coordination of the central atom in the other ML₂ is distorted tetrahedral both in the solution and in the solid phase. CuL₂ and CoL₂ in the solid phase feature exchange clusters with ferromagnetic exchange interaction between the unpaired electrons of the paramagnetic sites.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 669–675, March, 1990.The authors thank L. B. Volodarskii for providing a sample of 1-hydroxy-2,2,5,5-tetramethyl-3-imidazoline and a consultation in planning the synthesis of LH, A. M. Atskanov for taking the PMR spectra, E. G. Boguslavskii for taking the EPR spectra, and K. M. Indrichan for taking the mass spectra.     

Solid,Solution, and Theoretical Approach of [Cu(CN‐acac)(dmeen)]+

The reaction of bis(3‐cyano‐2,4‐pentanedionato)copper(II), [Cu(NC‐acac)₂] with the nitrogenous base N,N‐dimethyl, N′‐ethyl‐1,2‐ethylenediamine (dmeen) in the presence of Cu(ClO₄)₂ · 6H₂O, afforded a new cationic mixed‐ligand chelate [Cu(CN‐acac)(dmeen)]⁺. Its structure was characterized spectroscopically (IR, UV/Vis, EPR) and verified by X‐ray diffraction studies as [Cu(CN‐acac)(dmeen)(H₂O)]ClO₄. The coordination of CN‐acac^– as bridging ligand leads to a polymeric helical chain, which extends in the crystallographic c axis. Density functional theory (DFT) calculations suggest that in the solid state the anion CN‐acac^– binding is envisaged through the nitrogen atom of the cyanido group, establishing an octahedral arrangement around copper, whereas in solution, the square‐planar arrangement is prevailed, in accordance with the EPR findings.     

Crystal and molecular structures of the copper dichloride complex with 1-isopropenylimidazole

Crystal and molecular structures of the [CuL₂Cl₂] complex (L is 1-isopropenylimidazole) (I) are determined (R = 0.038, (wR ₂ = 0.092 for 2026 reflections with F _o ≥ 4σ(F _o); R ₁ = 0.123, wR ₂ = 0.117 for all reflections)) and compared with the structure of the known cobalt complex of analogous composition [CoL₂Cl₂] (II). Unlike complex II with the usual tetrahedral environment of the cobalt atom, the structure of the coordination polyhedron of the copper atom in compound I is intermediate between tetrahedron and square (the average dihedral angle between the ClCuN planes is 35.9°, and the ClCuCl (147.5°) and NCuN (163.1°) angles are much larger than the ClCuN angle of 90.1°–93.1°). The Cu-N (1.975(3), 1.959(3) Å) and Cu-Cl bonds (2.291(1), 2.278(1) Å) in complex I are typical of the copper(II) compounds. Different spatial structures of the 1-alkenylimidazole cycles in complexes I and II are found. Different short intermolecular contacts in crystals of compounds I (Cu…Cl, Cu…H) and II (Cl…C) result in the formation of chains with different mutual arrangements of molecules of the complexes.     

2-Amino-5-picoline N-oxide complexes formed from various copper(II) salts

Copper(II) complexes with 2-amino-5-picoline N-oxide (2am5PicO = L), CuL₄X₂(X = ClO₄, BF₄, and NO₃), CuL₂X₂ (X = Cl, Br) and CuLX₂ (X = Cl) have been isolated and characterized using spectral methods (i.e. IR, UV-vis and ESR). Coordination occurs via the N-oxide oxygen exclusively with the amine functional group showing only slight tendency to involve itself in hydrogen bonding to the anions. The halide complexes involve the halide ions in the coordination spheres while the polyatomic anions are not bound directly to copper. The latter compounds have monomeric, 4-coordinate CuO₄ chromophores while the former solids are apparently polymeric. Evidence for N-oxide bridging ligands in the CuL₂X₂ solids and halogen bridging in the CuLX₂ solid is presented.     

Structural,spectroscopic, luminescence sensing and TD–DFT theoretical studies of a CuP2N-type complex

Luminescent cuprous complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title heteroleptic cuprous complex, [2,2′-bis(diphenylphosphanyl)-1,1′-binaphthyl-κ²P,P′](2-phenylpyridine-κN)copper(I) hexafluoridophosphate, rac-[Cu(C₄₄H₃₂P₂)(C₁₁H₉N)]PF₆, conventionally abbreviated rac-[Cu(BINAP)(2-PhPy)]PF₆ ( I ), where BINAP and 2-PhPy represent 2,2′-bis(diphenylphosphanyl)-1,1′-binaphthyl and 2-phenylpyridine, respectively, is described. In this complex, the asymmetric unit consists of a hexafluoridophosphate anion and a heteroleptic cuprous complex cation, in which the cuprous centre in a CuP₂N coordination triangle is coordinated by two P atoms from the BINAP ligand and by one N atom from the 2-PhPy ligand. Time-dependent density functional theory (TD–DFT) calculations show that the UV–Vis absorption of I should be attributed to ligand-to-ligand charge transfer (LLCT) characteristic excited states. It was also found that the paper-based film of this complex exhibited obvious luminescence light-up sensing for pyridine.     

Hydrogen reduction of the Cu(acac)2 complex sorbed by cucurbit[8]uril

The hydrogen reduction of bis(2,4-pentanedionato)copper(II) sorbed by the cavitand cucurbit[8]uril has been studied. After sorption of the complex at 180°C, the crystal structure of the resulting phase differs from the structure of the individual compounds. EPR shows that the reduction of the complex with hydrogen at 250°C for 15 min leads to the loss of one of the ligands and formation of the coordination bond between the Cu²⁺ ion and a nitrogen atom of cucurbit[8]uril and the oxygen atom of the water molecule or OH^? group located in the cavitand cavity. The molecular structure of the resulting supramolecular compound has been optimized by density functional theory quantum-chemical calculations with the exchange-correlation functional with the use of the PRIRODA program package. EPR, EXAFS, and XANES show that an increase in the reduction time or temperature (to 280°C) leads to the formation of copper clusters.     

Structure and vibrational spectra of copper(II) 2-pyridylmethanolate tetrahydrate

In the memory of Prof. Ing. Ladislav Valko, DrSc. (1930–2013) A room-temperature synthesis of copper(II) 2-pyridylmethanolate tetrahydrate, [CuL₂] · 4H₂O, with nearly quantitative yields with its structure redetermined at 213 K is presented. In agreement with the X-ray structure data, the DFT quantum-chemical calculations confirmed the planar structure of CuL₂ (C _2h symmetry). The measured IR and Raman spectra were interpreted using the DFT calculations and some erroneous assignments in the previous studies have been corrected.     

Copper(II) complexes based on 2-thenoyltrifluoroacetone aroyl hydrazones: Synthesis,spectroscopy, and X-ray diffraction analysis

Copper(II) complexes CuL ? NH₃ are synthesized by the interaction of ethanol solutions of parasubstituted 2-thenoyltrifluoroacetylmethane aroyl hydrazones (H₂L¹–H₂L⁴) and an aqueous-ammonia solution of copper(II) acetate in an equimolar ratio. The copper(II) complexes are studied by elemental analysis, IR spectroscopy, and EPR spectroscopy. Single crystals of CuL³ ? NH₃ are grown from 1-(2-thenoyl)- 3,3,3-trifluoroacetone para-methylbenzoyl hydrazone and studied using X-ray diffraction analysis (CIF file CCDC 1045841).     

Dinukleare Kupfer(II)‐Komplexe mit chiralen makrocyclischen Liganden vom Schiff‐Basen‐Typ: Synthesen und Strukturen

Complexes with Macrocyclic Ligands. V Dinuclear Copper(II) Complexes with Chiral Macrocyclic Ligands of Schiff‐Base Type: Syntheses and Structures The synthesis and properties of four chiral, dinuclear, macrocyclic, cationic copper(II) complexes, [Cu₂(L^m,n)]²⁺ ( 1 – 4 ), are described. The two symmetrical compounds [Cu₂(L^2,2)][ClO₄]₂ ( 1 and 2 ) were synthesized in a one‐step reaction from 2,6‐diformyl‐4‐tert.‐butylphenol, copper(II)‐perchlorate and the chiral diamine (1S,2S)‐1,2‐diphenylethylenediamine (synthesis of 1 ) and (1R,2R)‐1,2‐diaminocyclohexane (synthesis of 2 ), respectively. For the synthesis of the two unsymmetrical compounds [Cu₂(L^Ph,n)][ClO₄]₂ ( 3 and 4 ) the mononuclear, neutral copper(II) complex [CuL^Ph] ( 5 ) [synthesized from 2,6‐diformyl‐4‐tert.‐butylphenol, copper(II)‐acetate and 1,2‐phenylenediamine] was reacted with (1R,2R)‐1,2‐diaminocyclohexane (synthesis of 3 ) and (S)‐1,1′‐binaphthyl‐2,2′‐diamine (synthesis of 4 ), respectively. The structures of the two unsymmetrical copper(II) compounds ( 3 and 4 ) were determined by X‐ray diffraction.     

Copper(II) and nickel(II) complexes of a neutral pentadentate Schiff base

A new pentadentate Schiff base 2,6,10-triaza-1,11-bis(2′-aminophenyl)-undeca-1,10-diene, abaDPT, and its complexes of general formula M(abaDPT)X₂ where M = Cu(II), Ni(II), X = Cl, Br, I, NO₃ and ClO₄, have been prepared. The complexes have been characterized by electronic and IR spectra, EPR, magnetic moments, molar conductances, and elemental analysis. IR data show an interaction between halide anion of the outer coordination sphere and the complexed amino group. EPR and spectrophotometric data of most of the copper compounds are consistent with a distorted square pyramidal geometry. Single crystal EPR studies of Cu(abaDPT)(NO₃)₂ and Cu(abaDPT)Br₂ revealed that copper atoms in the former compound occupy two magnetically inequivalent places in the lattice while copper atoms in the latter compound take identical sites. Principal g tensor axes of the two compounds have been determined.     

Structure and Dynamical Behaviour of Bis(N-Diisopropoxy-Phosphorylthiobenzamido) Copper(II)

Abstract

Among the new compounds of N-(thio)phosphorylthiómides. the copper(II) complex with N-diisopropoxyphosphorylthiohenzamide (Cul. 2) exhibits series of unusual properties which have been extcnsively investigated in the present work. The X-ray structure of CuL₂ has been determined Crystals of CuL₂ are monoclinic. P2₁/c, a = 15.610, b = 11.880, and c = 18.320 Å, β = 106.74°. Z = 4. The CuL₂ complex has the cis-structure with Cu-S distances ranging from 2.238 to 2.253 Å and Cu-O distances being from 1.919 to 1.937 Å (Figure).     

Composition and stability of complexes of maleic and succinic acids with Cu2+ ions in water-ethanol solutions at 298 K

The composition and stability of coordination compounds of the anions of maleic (H₂L) and succinic (H₂Y) acids with copper(II) ions in water-ethanol solutions is studied by means of potentiometric titration at a sodium perchlorate ionic strength of 0.1 and a temperature of 298.15 K. The composition of the water-ethanol solvent was varied from 0 to 0.7 molar parts of ethanol for maleic acid and from 0 to 0.4 molar parts for succinic acid. The stability of monoligand complexes of copper ions with the anions of maleic and succinic acids grows with increase of ethanol concentration from 3.86 to 6.62 for logβ_CuL and from 2.98 to 6.01 for logβ_CuY. It is shown that a monotonic rise in stability upon an increase in the content of ethanol in solution is observed, while the values of logβ_CuL change more sharply. The succinic acid anion forms a stronger complex with copper ions than maleic acid anions do at an ethanol content of 0.4 molar parts. The possibility of the formation of a protonated CuHY⁺ particle is established.     

Anion binding to a tetracopper resorcinarene-based complex

UV–vis and electron paramagnetic resonance (EPR) spectroscopic studies have been carried out on the multinuclear copper(II) complex Cu₄BpaRes. The copper atoms are in a tetragonal distorted geometry with nitrogens from bispicolylamine (Bpa) coordinating in the equatorial plane and water molecules or anions completing four coordination sites. The interaction of anions with this polynuclear copper complex in aqueous solution supports the formation of different complex species, which depend on the type and the concentration of the anions. In the presence of excess anions, frozen solution EPR parameters show the formation of species in which the in-plane coordination is characterised by the presence of three nitrogen atoms coming from the ligand and a donor atom from the specific anion. For the bidentate anion ligands and especially for malonate, UV–vis titrations indicate the formation of a 1:4 (Cu₄BpaRes:anion) species. EPR experiments support the formation of such a species and indicate that the four copper centres are equivalent and reach penta-coordination via the coordination of both oxygens from the bidentate ligand.     

Copper(II), nickel(II), and zinc(II) complexes with <Emphasis Type="Italic">o</Emphasis>-tozylaminobenzaldehyde 4,6-dimethylpyrimidyl hydrazone

o-Tosylaminobenzaldehyde dimethylpyrimidyl hydrazone and its copper(II), nickel(II), and zinc(II) complexesare synthesized and studied. According to the X-ray diffraction data, the zinc(II) complex has the structure of a tetragonal pyramid with the N₃O donor ligand environment. According to EPR and magnetochemistry data, the copper(II) complex has a similar structure of the chelate core. In the nickel(II) complex, the solvent molecule completes the coordination core to an octahedron.     

The Crystal Structures of two Linearly Polymeric Copper(II) Complexes of 2, 2′‐Bipyridine with threefold Glycolato and Oxalato Bridges

The complex [Cu(HGLYO)₂(bipy)] ( I ) and two new copper(II) coordination polymers with the formulas {[Cu(GLYO)_1‐x(ox)_x(bipy)]·2.5H₂O}_n [GLYO = glycolato dianion, ox = oxalato dianion, bipy = 2, 2′‐bipyridine, x = 0.56 (in II ) or 0.71 (in III )] were synthesized using copper(II) glycolate as starting material and were characterized by IR, UV‐Vis and EPR spectrometry, by magnetic measurements ( II and III ), and by single‐crystal X‐ray diffractometry. Both II and III crystallized as one‐dimensional polymers composed of Cu₂O₂‐centred dimers with a Cu‐Cu distance of 3.282(1)Å (mean of II and III ) that are linked by Cu₂(OCO)₂ rings with a Cu‐Cu distance of 5.237(1)Å (mean of II and III ), both dianions acting as (μ‐1, 1, 2, 3) three‐way bridges connecting the two copper atoms of one dimer with one copper atom of a neighbouring dimer. Each copper atom is coordinated tetragonally in a CuN₂O₄ chromophore. In the mononuclear complex I the copper atom has a tetragonally distorted octahedral environment.