Dimeric copper(II) 3,3‐dimethyl­butyrate adducts with ethanol, 2‐methylpyridine, 3‐methylpyridine, 4‐methylpyridine and 3,3‐dimethylbutyric acid

In the crystals of the five title compounds, tetrakis‐(μ‐3,3‐dimethylbutyrato‐O:O′)bis(ethanol‐O)dicopper(II)–ethanol (1/2), [Cu₂(C₆H₁₁O₂)₄(C₂H₆O)₂]·2C₂H₆O, (I), tetrakis(μ‐3,3‐dimethylbutyrato‐O:O′)bis(2‐methylpyridine‐N)di­copper(II), [Cu₂(C₆H₁₁O₂)₄(C₆H₇N)₂], (II), tetrakis‐(μ‐3,3‐dimethylbutyrato‐O:O′)bis(3‐methylpyridine‐N)di‐copper(II), [Cu₂(C₆H₁₁O₂)₄(C₆H₇N)₂], (III), tetrakis‐(μ‐3,3‐dimethylbutyrato‐O:O′)bis(4‐methylpyridine‐N)di‐copper(II), [Cu₂(C₆H₁₁O₂)₄(C₆H₇N)₂], (IV), and tetrakis‐(μ‐3,3‐dimethylbutyrato‐O:O′)bis(3,3‐dimethylbutyric acid‐O)dicopper(II), [Cu₂(C₆H₁₁O₂)₄(C₆H₁₂O₂)₂], (V), the di­nuclear Cu^II complexes all have centrosymmetric cage structures and (IV) has two independent molecules. The Cu?Cu separations are: (I) 2.602 (3) Å, (II) 2.666 (3) Å, (III) 2.640 (2) Å, (IV) 2.638 (4) Å and (V) 2.599 (1) Å.     

Bis{μ‐6,6′‐dimethoxy‐2,2′‐[propane‐1,2‐diylbis(iminomethylene)]diphenolato}bis[aquacopper(II)] dihydrate

In the title compound, [Cu₂(C₁₉H₂₄N₂O₄)₂(H₂O)₂]·2H₂O, the asymmetric unit consists of one half of the bis{μ‐6,6′‐dimethoxy‐2,2′‐[propane‐1,2‐diylbis(iminomethylene)]diphenolato}bis[aquacopper(II)] complex and two water molecules. Two Cu^II centres are bridged through a pair of phenolate groups, resulting in a complex with a centrosymmetric structure, with the centre of inversion at the middle of the Cu₂O₂ plane. The Cu atoms are in a slightly distorted square‐pyramidal coordination environment (τ = 0.07). The average equatorial Cu—O bond length and the axial Cu—O bond length are 1.928 (3) and 2.486 (3) Å, respectively. The Cu—O(water) bond length is 2.865 (4) Å, so the compound could be described as having a weakly coordinating water molecule at each Cu^II ion and two solvent water molecules per dimetallic unit. The Cu...Cu distance and Cu—O—Cu angle are 3.0901 (10) Å and 87.56 (10)°, respectively. The molecules are linked into a sheet by O—H...O and C—H...O hydrogen bonds parallel to the [001] plane.     

Four‐ and five‐coordinate copper(II) complexes with N‐(4,4‐diphenyl‐5‐oxo‐4,5‐dihydro‐1H‐imidazol‐2‐yl)glycine

The two title mononuclear compounds are four‐coordinate bis[N‐(5‐oxo‐4,4‐diphenyl‐4,5‐dihydro‐1H‐imidazolidin‐2‐ylidene)glycinato]copper(II) dimethylformamide disolvate, [Cu(C₁₇H₁₄N₃O₃)₂]·2C₃H₇NO, (I), and five‐coordinate aquabis[N‐(5‐oxo‐4,4‐diphenyl‐4,5‐dihydro‐1H‐imidazolidin‐2‐ylidene)glycinato]copper(II) dimethylformamide disolvate, [Cu(C₁₇H₁₄N₃O₃)₂(H₂O)]·2C₃H₇NO, (II). In (I), the Cu^II ion lies on an inversion centre with one‐half of the complex molecule in the asymmetric unit, while in (II) there are two independent ligand molecules in the asymmetric unit, with the Cu^II ion and coordinated water molecule located on a general position. In both crystal structures, the complex molecules assemble in ribbons via N—H...O hydrogen‐bond networks.     

(2‐Methyl­quinolin‐8‐olato)­iron(III) and ‐copper(II) complexes

The crystal structures of tris(2‐methyl­quinolin‐8‐olato‐N,O)­iron(III), [Fe­(C₁₀­H₈­NO)₃], (I), and aqua­bis(2‐methyl­quinolin‐8‐olato‐N,O)­copper(II), [Cu­(C₁₀­H₈NO)₂­(H₂O)], (II), have been determined. Compound (I) has a distorted octahedral configuration, in which the central Fe atom is coordinated by three N atoms and three O atoms from three 2‐methylquinolin‐8‐olate ligands. The three Fe—O bond distances are in the range 1.934 (2)–1.947 (2) Å, while the three Fe—N bond distances range from 2.204 (2) to 2.405 (2) Å. In compound (II), the central Cu^II atom and H₂O group lie on the crystallographic twofold axis and the coordination geometry of the Cu^II atom is close to trigonal bipyramidal, with the three O atoms in the basal plane and the two N atoms in apical positions. The Cu—N bond length is 2.018 (5) Å. The Cu—O bond length in the basal positions is 1.991 (4) Å, while the Cu—O bond length in the apical position is 2.273 (6) Å. There is an intermolecular OW—H?O hydrogen bond which links the mol­ecules into a linear chain along the b axis.     

Poly[[aqua­tetra­imidazole­di‐μ‐phthalato‐dicopper(II)] monohydrate]

The title complex, {[Cu₂(C₈H₄O₄)₂(C₃H₄N₂)₄(H₂O)]·H₂O}_n, is a three‐dimensional polymer formed through bridging by phthalate dianions of two different Cu^II cations and a network of O(N)—H⋯O hydrogen bonds. The Cu—O and Cu—N inter­action distances are in the ranges 2.0020 (16)–2.4835 (17) and 1.968 (2)–1.9855 (19) Å, respectively. The structure is composed of alternating polymer chains parallel to the c axis, with a shortest Cu⋯Cu distance of 6.3000 (5) Å.     

Bis(μ‐succinato‐O,O′:O′′,O′′′)bis[bis(2‐amino‐1,3‐benzothiazole‐N3)copper(II)]

In the title dimeric complex, [Cu₂(C₄H₄O₄)₂(C₇H₆N₂S)₄], which possesses a centre of symmetry, the Cu atoms are enclosed in a 14‐membered ring. They adopt a distorted square‐bipyramidal (4+2) coordination. The four closest donor atoms are two N atoms of 2‐amino­benzo­thiazole ligands and two O atoms of the succinate carboxylate groups. They form a square‐planar cis arrangement, with an average Cu—N distance of 2.003 (3) Å and Cu—O distances of 1.949 (3) and 1.965 (3) Å. Two longer Cu—O bonds of 2.709 (3) and 2.613 (3) Å involving the remaining O atoms of the carboxylate groups complete the sixfold coordination of the Cu atoms. The H atoms of each amino group of the 2‐amino­benzo­thiazole molecules form intra‐ and inter­molecular N—H?O hydrogen bonds. A nearly perpendicular inter­molecular C—H?Cg interaction (Cg is the centroid of the imidazole ring) is observed. The intramolecular Cu?Cu distance is 6.384 (2) Å.     

Acetato(N‐phenylpyridine‐2‐carboxamidato‐κ2N,N)(N‐phenylpyridine‐2‐carboxamide‐κ2N1,O)copper(II)

The title complex, [Cu(C₁₂H₉N₂O)(C₂H₃O₂)(C₁₂H₁₀N₂O)], is a neutral Cu^II complex with a primary N₃O₂ coordination sphere. The Cu centre coordinates to both a deprotonated and a neutral molecule of N‐phenylpyridine‐2‐carboxamide and also to an acetate anion. The coordination around the metal centre is asymmetric, the deprotonated ligand providing two N donor atoms [Cu—N = 1.995 (2) and 2.013 (2) Å] and the neutral ligand providing one N and one O donor atom to the coordination environment [Cu—N = 2.042 (2) Å and Cu—O = 2.2557 (19) Å], the fifth donor being an O atom of the acetate ion [Cu—O = 1.9534 (19) Å]. The remaining O atom from the acetate ion can be considered as a weak donor atom [Cu—O = 2.789 (2) Å], conferring to the Cu complex an asymmetric octahedral geometry. The crystal structure is stabilized by intermolecular N—H...O, C—H...O and C—H...π interactions.     

Dimeric copper(II) trimethylsilyl­acetate adducts with pyridine, 2‐­methylpyridine, 3‐methylpyridine and quinoline,and a polymeric copper(II) trimethylsilylacetate

In the crystals of bis(pyridine‐N)tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₅H₅N)₂], (I), the dinuclear Cu^II complexes have cage structures with Cu?Cu distances of 2.632 (1) and 2.635 (1) Å. In the crystals of bis(2‐­methylpyridine‐N)tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₆H₇N)₂], (II), bis­(3‐methylpyridine‐N)tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₆H₇N)₂], (III), and bis(quinoline‐N)­tetrakis(μ‐­trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₉H₇N)₂], (IV), the centrosymmetric dinuclear Cu^II complexes have a cage structure with Cu?Cu distances of 2.664 (1), 2.638 (3) and 2.665 (1) Å, respectively. In the crystals of catena‐poly­[tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II)], [Cu₂(C₅H₁₁O₂Si)₄]_n, (V), the dinuclear Cu^II units of a cage structure are linked by the cyclic Cu—O bonds at the apical positions to form a linear chain by use of a glide translation.     

trans‐Bis(dimethyl sulfoxide‐κO)bis(3‐oxo‐3,4‐dihydroquinoxaline‐2‐carboxylato‐κ2N1,O2)copper(II)

The title compound, [Cu(C₉H₅N₂O₃)₂(C₂H₆OS)₂], consists of octahedrally coordinated Cu^II ions, with the 3‐oxo‐3,4‐dihydroquinoxaline‐2‐carboxylate ligands acting in a bidentate manner [Cu—O = 1.9116 (14) Å and Cu—N = 2.1191 (16) Å] and a dimethyl sulfoxide (DMSO) molecule coordinated axially via the O atom [Cu—O = 2.336 (5) and 2.418 (7) Å for the major and minor disorder components, respectively]. The whole DMSO molecule exhibits positional disorder [0.62 (1):0.38 (1)]. The octahedron around the Cu^II atom, which lies on an inversion centre, is elongated in the axial direction, exhibiting a Jahn–Teller effect. The ligand exhibits tautomerization by H‐atom transfer from the hydroxyl group at position 3 to the N atom at position 4 of the quinoxaline ring of the ligand. The complex molecules are linked through an intermolecular N—H...O hydrogen bond [N...O = 2.838 (2) Å] formed between the quinoxaline NH group and a carboxylate O atom, and by a weak intermolecular C—H...O hydrogen bond [3.392 (11) Å] formed between a carboxylate O atom and a methyl C atom of the DMSO ligand. There is a weak intramolecular C—H...O hydrogen bond [3.065 (3) Å] formed between a benzene CH group and a carboxylate O atom.     

The dinuclear copper(II) complexes di‐μ‐chlorido‐bis{[N,N′‐bis(4‐chlorobenzyl)propane‐1,2‐diamine]chloridocopper(II)} and di‐μ‐chlorido‐bis{[N,N′‐bis(3,4‐methylenedioxybenzyl)propane‐1,2‐diamine]chloridocopper(II)}

The two title dinuclear copper(II) complexes, [Cu₂Cl₄(C₁₇H₂₀Cl₂N₂)₂], (I), and [Cu₂Cl₄(C₁₉H₂₂N₂O₄)₂], (II), have similar coordination environments. In each complex, the asymmetric unit consists of one half‐molecule and the two copper centres are bridged by a pair of Cl atoms, resulting in complexes with centrosymmetric structures containing Cu(μ‐Cl)₂Cu parallelogram cores; the Cu...Cu separations and Cu—Cl—Cu angles are 3.4285 (8) Å and 83.36 (3)°, respectively, for (I), and 3.565 (2) Å and 84.39 (7)° for (II). Each Cu atom is five‐coordinated and the coordination geometry around the Cu atom is best described as a distorted square‐pyramid with a τ value of 0.155 (3) for (I) and 0.092 (7) for (II). The apical Cu—Cl bond length is 2.852 (1) Å for (I) and 2.971 (2) Å for (II). The basal Cu—Cl and Cu—N average bonds lengths are 2.2673 (9) and 2.030 (2) Å, respectively, for (I), and 2.280 (2) and 2.038 (6) Å for (II). The molecules of (I) are linked by one C—H...Cl hydrogen bond into a complex [10] sheet. The molecules of (II) are linked by one C—H...Cl and one N—H...O hydrogen bond into a complex [100] sheet.     

A novel three‐dimensional copper(II) network via hydrogen bonds: diaquabis[bis(pyrazol‐1‐yl‐κN2)methane]copper(II) diperchlorate

The crystal structure of the title complex, [Cu(C₇H₈N₄)₂(H₂O)₂](ClO₄)₂, consists of a discrete centrosymmetric [Cu(C₇H₈N₄)₂(H₂O)₂]²⁺ cation and two perchlorate anions. The Cu^II centre is six‐coordinated by four N donors from the two pyrazole rings [Cu—N 1.998 (2) and 2.032 (3) Å] and two O atoms from the water mol­ecules occupying the apical sites [Cu—O 2.459 (3) Å]. The coordination geometry of the complex can be described as octahedral. There is a unique three‐dimensional network in which the perchlorate units are linked by a combination of strong O—H?O and weak C—H?O hydrogen bonds.     

Bis­(acetone‐κO)­bis(N,N′‐di­methyl­ethyl­enedi­amine‐κ2N,N′)copper(II) diperchlorate

The title compound, [Cu(C₄H₁₂N₂)₂(C₃H₆O)₂](ClO₄)₂, is the first structurally characterized Cu^II complex having acetone as axial ligands. The complex adopts an elongated octahedral trans‐[CuN₄O₂] coordination geometry, with the Cu atom having 222 site symmetry. The axial Cu—O(acetone) and in‐plane Cu—N bond lengths are 2.507 (5) and 2.041 (3) Å, respectively.     

Completing the bis[hydroxybis(pyridin‐2‐yl)methanesulfonato‐κ3N,O,N′]MII series (M = Mn to Zn) with the copper(II) and cobalt(II) structures

The Cu^II complex bis[hydroxybis(pyridin‐2‐yl)methanesulfonato‐κ³N,O,N′]copper(II) hexahydrate, [Cu(C₁₁H₉N₂O₄S)₂]·6H₂O, (I), crystallizes in the space group P, compared with P2₁/c for the anhydrous Co^II analogue bis[hydroxybis(pyridin‐2‐yl)methanesulfonato‐κ³N,O,N′]cobalt(II), [Co(C₁₁H₉N₂O₄S)₂], (II). However, both molecules sit on a crystallographic inversion centre and are thus very similar in appearance. Jahn–Teller elongation of the Cu—O bonds [2.347 (3) Å in (I) and 2.064 (2) Å in (II)] influences the S—O bond lengths, which are all around 1.455 (3) Å in (I) and 1.436 (2)–1.473 (2) Å in (II).     

(Aqua‐2κO)bis(2,2′‐bipyridine‐1κ2N,N′){μ‐N‐[3‐(dimethylamino)propyl]‐N′‐(2‐oxidophenyl)oxamidato(3−)‐1:2κ2O,O′:κ4O′′,N,N′,N′′}copper(II)nickel(II) perchlorate

The title complex, [CuNi(C₁₃H₁₆N₃O₃)(C₁₀H₈N₂)₂(H₂O)]ClO₄, has a cis‐oxamide‐bridged heterobinuclear cation, with a Cu...Ni separation of 5.3297 (6) Å, counterbalanced by a disordered perchlorate anion. The Cu^II and Ni^II cations are located in square‐pyramidal and octahedral coordination environments, respectively. The complex molecules are assembled into a three‐dimensional supramolecular structure through hydrogen bonds and π–π stacking interactions. The influence of the two types of metal cation on the supramolecular structure is discussed.     

(1,3‐Dimethylimidazolidine‐2‐selone‐κSe)bis(1,10‐phenanthroline‐κ2N,N′)copper(II) bis(perchlorate) and bis(2,2′‐bipyridyl‐κ2N,N′)(imidazolidine‐2‐thione‐κS)copper(II) bis(perchlorate)

In the first title salt, [Cu(C₁₂H₈N₂)₂(C₅H₁₀N₂Se)](ClO₄)₂, the Cu^II centre occupies a distorted trigonal–bipyramidal environment defined by four N donors from two 1,10‐phenanthroline (phen) ligands and by the Se donor of a 1,3‐dimethylimidazolidine‐2‐selone ligand, with the equatorial plane defined by the Se and by two N donors from different phen ligands and the axial sites occupied by the two remaining N donors, one from each phen ligand. The Cu—N distances span the range 1.980 (10)–2.114 (11) Å and the Cu—Se distance is 2.491 (3) Å. Intermolecular π–π contacts between imidazolidine rings and the central rings of phen ligands generate chains of cations. In the second salt, [Cu(C₁₀H₈N₂)₂(C₃H₆N₂S)](ClO₄)₂, the Cu^II centre occupies a similar distorted trigonal–bipyramidal environment comprising four N donors from two 2,2′‐bipyridyl (bipy) ligands and an S donor from an imidazolidine‐2‐thione ligand. The equatorial plane is defined by the S donor and two N donors from different bipy ligands. The Cu—N distances span the range 1.984 (6)–2.069 (7) Å and the Cu—S distance is 2.366 (3) Å. Intermolecular π–π contacts between imidazolidine and pyridyl rings form chains of cations. A major difference between the two structures is due to the presence in the second complex of two N—H...O hydrogen bonds linking the imidazolidine N—H hydrogen‐bond donors to perchlorate O‐atom acceptors.     

Enantiomeric bis(μ‐N,N′‐hexamethylenedisalicylaldiminato)dicopper(II) complexes

The title dimeric complex, bis{μ‐2,2′‐[hexane‐1,6‐diyl­bis(nitrilo­methyl­idyne)]­diphenolato‐1:2κ⁴O,N:N′,O′}dicopper(II),[Cu₂(C₂₀H₂₂N₂O₂)₂], has been investigated by single‐crystal X‐ray diffraction, by thermogravimetric analysis and differential scanning calorimetry, and also by FT–IR spectroscopy. Different synthetic and crystallization procedures gave crystals which were quite different in appearance, and it was initially thought that these were different polymorphic forms. Subsequent structure determination showed, in fact, serendipitous preparation of crystals in the P4₁ space group by one method and in space group P4₃ by the other. In these enantiomorphic structures, the Cu atoms have a distorted flattened tetrahedral coordination, with Cu—N and Cu—O distances in the ranges 1.954 (4)–1.983 (4) and 1.887 (4)–1.903 (4) Å, respectively.     

Crystal Structures,Magnetic Properties and Catecholase‐Like Activities of μ‐Alkoxo‐μ‐Carboxylato Double Bridged Dinuclear and Tetranuclear Copper(II) Complexes

One μ‐alkoxo‐μ‐carboxylato bridged dinuclear copper(II) complex, [Cu₂(L¹)(μ‐C₆H₅CO₂)] ( 1 )(H₃L¹ = 1,3‐bis(salicylideneamino)‐2‐propanol)), and two μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear copper(II) complexes, [Cu₄(L¹)₂(μ‐C₈H₁₀O₄)(DMF)₂]·H₂O ( 2 ) and [Cu₄(L²)₂(μ‐C₅H₆O₄]·2H₂O·2CH₃CN ( 3 ) (H₃L² = 1,3‐bis(5‐bromo‐salicylideneamino)‐2‐propanol)) have been prepared and characterized. The single crystal X‐ray analysis shows that the structure of complex 1 is dimeric with two adjacent copper(II) atoms bridged by μ‐alkoxo‐μ‐carboxylato ligands where the Cu···Cu distances and Cu‐O(alkoxo)‐Cu angles are 3.5 11 Å and 132.8°, respectively. Complexes 2 and 3 consist of a μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear Cu(II) complex with mean Cu‐Cu distances and Cu‐O‐Cu angles of 3.092 Å and 104.2° for 2 and 3.486 Å and 129.9° for 3 , respectively. Magnetic measurements reveal that 1 is strong antiferromagnetically coupled with 2J =‐210 cm^?1 while 2 and 3 exhibit ferromagnetic coupling with 2J = 126 cm^?1 and 82 cm^?1 (averaged), respectively. The 2J values of 1–3 are correlated to dihedral angles and the Cu‐O‐Cu angles. Dependence of the pH at 25 °C on the reaction rate of oxidation of 3,5‐di‐tert‐butylcatechol (3,5‐DTBC) to the corresponding quinone (3,5‐DTBQ) catalyzed by 1–3 was studied. Complexes 1–3 exhibit catecholase‐like active at above pH 8 and 25 °C for oxidation of 3,5‐di‐tert‐butylcatechol.     

Bis[bis(methoxycarbimido)aminato]copper(II) 1‐methylpyrrolidin‐2‐one disolvate

The title compound, [Cu(C₄H₈N₃O₂)₂]·2C₅H₉NO, consists of a neutral copper complex, in which the Cu^II centre coordinates to two bis(methoxycarbimido)aminate ligands, solvated by two molecules of 1‐methylpyrrolidin‐2‐one. The complex is planar and centrosymmetric, with the Cu^II centre occupying a crystallographic inversion centre and adopting approximately square‐planar geometry. N—H...O hydrogen‐bonding interactions exist between the amine NH groups of the ligands and the O atoms of the 1‐methylpyrrolidin‐2‐one molecules. The associated units pack to form sheets.     

Di‐μ‐hydroxido‐bis{[bis(6‐methyl‐2‐pyridylmethyl)(2‐phenylethyl)amine‐κ3N′,N′′,N′′′]copper(II)} bis(perchlorate)

The title compund, [Cu₂(OH)₂(C₂₂H₂₅N₃)₂](ClO₄)₂, is a copper(II) dimer, with two [CuL]²⁺ units [L is bis(6‐methyl‐2‐pyridylmethyl)(2‐phenylethyl)amine] bridged by hydroxide groups to define the {[CuL](μ‐OH)₂[CuL]}²⁺ cation. Charge balance is provided by perchlorate counter‐anions. The cation has a crystallographic inversion centre halfway between the Cu^II ions, which are separated by 3.0161 (8) Å. The central core of the cation is an almost regular Cu₂O₂ parallelogram of sides 1.931 (2) and 1.935 (2) Å, with a Cu—O—Cu angle of 102.55 (11)°. The coordination geometry around each Cu^II centre can be best described as a square‐based pyramid, with three N atoms from L ligands and two hydroxide O atoms completing the coordination environment. Each cationic unit is hydrogen bonded to two perchlorate anions by means of hydroxide–perchlorate O—H...O interactions.     

Bis(μ‐di‐2‐pyridyl­aminato 1‐oxide)­bis­[(tri­fluoro­acetato)copper(II)] aceto­nitrile disolvate

The crystal structure of the title compound, [Cu₂(C₂F₃O₂)₂(C₁₀H₈N₃O)₂]·2CH₃CN, contains discrete [Cu₂(CF₃COO)₂(O‐dpa)₂] mol­ecules (O‐dpaH is di‐2‐pyridyl­amine 1‐oxide) which have imposed crystallographic twofold symmetry and an aceto­nitrile mol­ecule of solvation. The O‐dpa⁻ ligand is both bidentate and bridging, linking two Cu atoms with a separation of 3.4270 (11) Å. Each Cu atom is surrounded by four coordinated atoms that are almost coplanar, with dimensions Cu—N = 1.940 (2) and 1.984 (3) Å, and Cu—O = 1.912 (2) and 1.945 (2) Å.