Reactions of 1,1′‐Diphosphaferrocene with CuCl and CuBr Resulting in Cu4P4X4Fe2 (X = Cl,Br) Complexes with Adamantane‐like Topologies

Cu₄P₄X₄Fe₂ (X = Cl, Br) cages are formed upon reactions of octaethyl‐1,1′‐diphosphaferrocene (odpf) with the respective Cu^I halide in CH₂Cl₂/CH₃CN solvent mixtures. These cages have adamantoid Cu₄X₄P₂ cores with two planar anelated CuP₂Fe rings as the flaps. Both complexes 1 and 2 feature tri‐ and tetracoordinate Cu^I ions and an additional acetonitrile solvent molecule in the crystal. In 1 , the solvent molecule is coordinated to one copper ion whereas it remains uncoordinated in 2 . The tricoordinate Cu^I ions show a slight pyramidalization at the metal atom and somewhat short contacts to the other tricoordinate Cu^I ion in 2 or the Cu₃‐triangle in 1 . NMR spectroscopy revealed easy decoordination of the acetonitrile ligand from 1 and a dynamic “windshield‐wiper”‐type process that interconverts the differently coordinated phospholide rings of each odpf ligand and the tri‐ and tetracoordinate Cu^I ions.     

Hexa‐μ‐chloro‐μ4‐oxo‐tetrakis{[5‐(2,4,6‐trimethylphenyl)pyrazole‐κN2]copper(II)}

The title compound, [Cu₄Cl₆O(C₁₂H₁₄N₂)₄], is a new example of the well known [Cu₄(μ₄‐O)(μ‐X)₆L₄] class of complex (X⁻ is Cl⁻, Br⁻ or I⁻, and L is a monodentate ligand). The molecule has crystallographic C₂ symmetry, with two Cl⁻ ions on each edge of a Cu₄ tetrahedron. Two of these, on opposite edges of the tetrahedron, accept intramolecular hydrogen bonds from two of the pyrazole N—H donors.     

Bis[μ‐4‐(ethylammoniomethyl)‐3,5‐dimethylpyrazolato‐κ2N1:N2]bis[(η4‐1,5‐cyclooctadiene)rhodium(I)] dichloride dichloromethane methanol solvate

In the title compound, [Rh₂(C₈H₁₅N₃)₂(C₈H₁₂)₂]Cl₂·CH₂Cl₂·CH₃OH, the dinuclear Rh^I complex has C₂ symmetry and the two pyrazolato ligands act as μ‐bridges. The coordination of each Rh^I cation is completed by one cyclo­octa­diene (COD) ligand. It is shown that the average Rh—C(COD) distance is linearly dependent on the Rh—N(pyrazole) distance in this type of compound, and this is ascribed to the steric hindrance produced by the packing.     

Visible‐Light‐Accelerated Copper(II)‐Catalyzed Regio‐ and Chemoselective Oxo‐Azidation of Vinyl Arenes

The visible‐light‐accelerated oxo‐azidation of vinyl arenes with trimethylsilylazide and molecular oxygen as stoichiometric oxidant was achieved. In contrast to photocatalysts based on iridium, ruthenium, or organic dyes, [Cu(dap)₂]Cl or [Cu(dap)Cl₂] were found to be unique for this transformation, which is attributed to their ability to interact with the substrates through ligand exchange and rebound mechanisms. Cu^II is proposed as the catalytically active species, which upon coordinating azide will undergo light‐accelerated homolysis to form Cu^I and azide radicals. This activation principle (Cu^II‐X→Cu^I+X^.) opens up new avenues for copper‐based photocatalysis.     

Bis[N,N′‐(2‐chlorobenzylidene)ethylenediamine‐κ2N,N′]copper(I) dichloridocuprate(I) acetonitrile solvate

The 1:1 adduct of N,N′‐bis(2‐chlorobenzylidene)ethylenediamine (cb₂en) with copper(I) chloride proves to be an ionic compound with Cu^I‐centred cations and anions, [Cu(C₁₆H₁₄Cl₂N₂)₂][CuCl₂]·CH₃CN. In the cation, the Cu^I atom has a flattened tetrahedral coordination geometry, with a small bite angle for the chelating ligands, which form a double‐helical arrangement around the metal centre. The anion is almost linear, as expected. The packing of the cations involves intermolecular π–π interactions, which lead to columns of translationally related cations along the shortest unit‐cell axis, with anions and solvent molecules in channels between them.     

[μ‐4,5‐Bis(diphenylphosphino)‐9,9‐dimethylxanthene]bis[(trifluoroacetato)gold(I)] and its dichloromethane 0.58‐solvate

The dinuclear Au^I complex containing the 4,5‐bis(diphenylphosphino)‐9,9‐dimethylxanthene (xantphos) ligand and trifluoroacetate anions exists in a solvent‐free form, [μ‐4,5‐bis(diphenylphosphino)‐9,9‐dimethylxanthene]bis[(trifluoroacetato)gold(I)], [Au₂(C₂F₃O₂)₂(C₃₉H₃₂OP₂)], (I), and as a dichloromethane solvate, [Au₂(C₂F₃O₂)₂(C₃₉H₃₂OP₂)]·0.58CH₂Cl₂, (II). The trifluoroacetate anions are coordinated to the Au^I centres bridged by the xantphos ligand in both compounds. The Au^I atoms are in distorted linear coordination environments in both compounds. The phosphine substituents are in a syn arrangement in the xantphos ligand, which facilitates the formation of short aurophilic Au...Au interactions of 2.8966 (8) Å in (I) and 2.9439 (6) Å in (II).     

Powder study of poly[(μ2‐2,2‐dimethylpropane‐1,3‐diyl diisocyanide)‐μ2‐iodido‐silver(I)]

In order to explore the chemistry of the bidentate ligand 2,2‐dimethylpropane‐1,3‐diyl diisocyanide and to investigate the effect of counter‐ions on the polymeric structure of (2,2‐dimethylpropane‐1,3‐diyl diisocyanide)silver(I) complexes, the title polymeric compound, [AgI(C₇H₁₀N₂)]_n, was synthesized by treatment of 2,2‐dimethylpropane‐1,3‐diyl diisocyanide with AgI. X‐ray powder diffraction studies show, as expected, a polymeric structure, similar to the very recently reported Cl⁻ and NO₃⁻ analogues [AgX(C₇H₁₀N₂)]_n (X = Cl⁻ or NO₃⁻). In the title structure, the Ag^I centre is bridged to two adjacent Ag^I neighbours by bidentate 2,2‐dimethylpropane‐1,3‐diyl diisocyanide ligands via the NC groups to form [Ag{CNCH₂C(CH₃)₂CH₂NC}]_n chains. The iodide counter‐ions crosslink the Ag^I centres of the chains to form a two‐dimensional polymeric {[Ag{CNCH₂C(CH₃)₂CH₂NC}]I}_n network. This study also shows that this bidentate ligand forms similar polymeric structures on treatment with AgX, regardless of the nature of the counter‐ion X⁻, and also has a strong tendency to form polymeric complexes rather than dimeric or trimeric ones.     

Chloro­bis­(thio­urea‐κS)copper(I) bis(4,5‐di­aza­fluoren‐9‐one) mono­hydrate

The title compound, [CuCl(CH₄N₂S)₂]·2C₁₁H₆N₂O·H₂O, consists of mol­ecules of a Cu^I–thio­urea complex, free 4,5‐di­aza­fluoren‐9‐one (dafone) and crystalline water. The planar complex mol­ecule has trigonal coordination geometry around the Cu^I atom. The dafone and water mol­ecules, which are hydrogen bonded to the Cu^I complex, are approximately coplanar with this complex. The crystal displays a sheet structure and π–π stacking is observed between neighbouring sheets.     

The Coordination Chemistry of the Versatile Ligand Bis(2‐pyridylthio)methane

Bis(2‐pyridylthio)methane [bpytm, (pyS)₂CH₂] and complexes of this ligand with Zn^II, Hg^II, Cu^I, and Ag^I have been prepared and characterised by elemental analysis, by IR, Raman and ¹H and ¹³C NMR spectroscopy, and by X‐ray diffractometry. The ligand is N, N′‐didentate in the Zn^II complexes; N‐monodentate in one Hg^II complex and N, N′‐bis(monodentate) in the other; N‐mono‐N′, S‐didentate in the Cu^I complex; and N, S′‐bis(mono)‐N′, S‐didentate in the Ag^I complex. The structural parameters of the ligand in each coordination mode are compared with those of the free ligand and those of the triiodide salt of the protonated ligand.     

Bis­[tris(3‐cyclo­hexyl­pyrazol‐1‐yl)­hydridoborato]copper(II) di­chloro­methane disolvate

The title compound, [Cu(C₂₇H₄₀BN₆)₂]·2CH₂Cl₂, contains a four‐coordinate Cu^II ion lying on a crystallographic inversion centre, giving rise to a near‐regular square‐planar stereochemistry. There is an axial contact of 2.71 Å between the Cu ion and ligand B—H group, although this is unlikely to correspond to a significant `agostic' interaction.     

Aqua(2,2′‐bi‐1H‐imidazole)chloro­copper(II) chloro­(imino­diacetato)copper(II) monohydrate

In the title compound, [CuCl(C₆H₆N₄)(H₂O)][Cu(C₄H₅NO₄)Cl]·H₂O, the Cu^II atom in the cation is coordinated by one Cl⁻ ion, two N atoms of the 2,2′‐biimidazole ligand and one aqua ligand. Within the anion, the Cu^II atom is bonded to one Cl⁻ ion, and one N and two O atoms of the imino­diacetate ligand. Neighbouring cations and anions are connected to each other by Cu·Cl semi‐coordination bonds of 2.830 (12) and 3.071 (12) Å, forming a Cu₂Cl₂ rectangular unit. The dinuclear units further link into a polymeric chain along the a axis through Cu·O_aqua interactions of 2.725 (3) Å. Including the long coordination bonds, the geometries around the Cu atoms in the cation and anion are square‐pyramidal and distorted octahedral, respectively.     

Reactivity of 2,2′‐Bis(2N‐(1,1′,3,3′‐tetramethyl‐guanidino))diphenylene‐amine with CuI and [Cu(MeCN)4][PF6]: Benzimidazole Formation vs. Cu Oxidation

The reaction of 2,2′‐Bis(2N‐(1,1′,3,3′‐tetramethyl‐guanidino))diphenylene‐amine (TMG₂PA) ( 1 ) with CuI in MeCN results in the formation of [Cu^II(TMG₂PA^amid)I] ( 2 ) indicatingthat Cu^I is the target of an oxidative attack of the N‐H proton of the ligand which itself is converted to molecular hydrogen. In contrast, if [Cu(MeCN)₄][PF₆] is used as the Cu^I source, [Cu^I₂(TMGbenz)₂][PF₆]₂ ( 3 ) is obtained instead. The use of the non‐coordinating counterion [PF₆]^– apparently prevents Cu^I from oxidation but induces itself a cyclisation reaction within the ligand which results in the formation of a benzimidazole‐guanidine ligand.     

Structural and Spectroscopic Studies of Halocuprate(I) and Haloargentate(I) Complexes [M2XnX′4−n]2−

The complexes [Cu₂Br₄]^2?, [Cu₂I₄]^2?, [Cu₂I₂Br₂]^2?, [Cu₂I₃Cl]^2?, [Ag₂Cl₄]^2? have been characterized as their isomorphous bis(triphenylphosphoranylidene)ammonium ([Ph₃PNPPh₃]⁺ = PNP⁺) salts by single crystal structural determinations. All anions show the centrosymmetric doubly halogen‐bridged forms [XM(μ‐X)₂MX]^2? with three‐coordinate metal atoms that have been observed in [M₂X₄]^2? complexes with other large organic cations. In [Cu₂I₂Br₂]^2? the iodide ligands occupy the bridging positions and the bromide the terminal positions, while in [Cu₂I₃Cl]^2?, obtained in an attempt to prepare [Cu₂I₂Cl₂]^2?, two of the iodide ligands occupy the bridging positions with the third iodide and the chloride ligand occupying two statistically disordered terminal positions. In [Ag₂Cl₄]^2? the distortion from ideal trigonal coordination of the metal atom is greater than in the copper complexes, but less than in other previously reported [Ag₂Cl₄]^2? complexes with organic cations. The ν(MX) bands have been assigned in the far‐IR spectra, and confirm previous observations regarding the unexpectedly simple IR spectra of [Cu₂X₄]^2? complexes.     

Copper(II) and Sodium(I) Complexes based on 3,7‐Diacetyl‐1,3,7‐triaza‐5‐phosphabicyclo[3.3.1]nonane‐5‐oxide: Synthesis,Characterization, and Catalytic Activity

The reaction of 3,7‐diacetyl‐1,3,7‐triaza‐5‐phosphabicyclo[3.3.1]nonane (DAPTA) with metal salts of Cu^II or Na^I/Ni^II under mild conditions led to the oxidized phosphane derivative 3,7‐diacetyl‐1,3,7‐triaza‐5‐phosphabicyclo[3.3.1]nonane‐5‐oxide (DAPTA=O) and to the first examples of metal complexes based on the DAPTA=O ligand, that is, [Cu^II(μ‐CH₃COO)₂(κO‐DAPTA=O)]₂ ( 1 ) and [Na(1κOO′;2κO‐DAPTA=O)(MeOH)]₂(BPh₄)₂ ( 2 ). The catalytic activity of 1 was tested in the Henry reaction and for the aerobic 2,2,6,6‐tetramethylpiperidin‐1‐oxyl (TEMPO)‐mediated oxidation of benzyl alcohol. Compound 1 was also evaluated as a model system for the catechol oxidase enzyme by using 3,5‐di‐tert‐butylcatechol as the substrate. The kinetic data fitted the Michaelis–Menten equation and enabled the obtainment of a rate constant for the catalytic reaction; this rate constant is among the highest obtained for this substrate with the use of dinuclear Cu^II complexes. DFT calculations discarded a bridging mode binding type of the substrate and suggested a mixed‐valence Cu^II/Cu^I complex intermediate, in which the spin electron density is mostly concentrated at one of the Cu atoms and at the organic ligand.     

Structural studies of (prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine hetero‐scorpionate copper complexes

The structures of five compounds consisting of (prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine complexed with copper in both the Cu^I and Cu^II oxidation states are presented, namely chlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ³N,N′,N′′}copper(I) 0.18‐hydrate, [CuCl(C₁₅H₁₇N₃)]·0.18H₂O, (1), catena‐poly[[copper(I)‐μ₂‐(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ⁵N,N′,N′′:C²,C³] perchlorate acetonitrile monosolvate], {[Cu(C₁₅H₁₇N₃)]ClO₄·CH₃CN}_n, (2), dichlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ³N,N′,N′′}copper(II) dichloromethane monosolvate, [CuCl₂(C₁₅H₁₇N₃)]·CH₂Cl₂, (3), chlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ³N,N′,N′′}copper(II) perchlorate, [CuCl(C₁₅H₁₇N₃)]ClO₄, (4), and di‐μ‐chlorido‐bis({(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ³N,N′,N′′}copper(II)) bis(tetraphenylborate), [Cu₂Cl₂(C₁₅H₁₇N₃)₂][(C₆H₅)₄B]₂, (5). Systematic variation of the anion from a coordinating chloride to a noncoordinating perchlorate for two Cu^I complexes results in either a discrete molecular species, as in (1), or a one‐dimensional chain structure, as in (2). In complex (1), there are two crystallographically independent molecules in the asymmetric unit. Complex (2) consists of the Cu^I atom coordinated by the amine and pyridyl N atoms of one ligand and by the vinyl moiety of another unit related by the crystallographic screw axis, yielding a one‐dimensional chain parallel to the crystallographic b axis. Three complexes with Cu^II show that varying the anion composition from two chlorides, to a chloride and a perchlorate to a chloride and a tetraphenylborate results in discrete molecular species, as in (3) and (4), or a bridged bis‐μ‐chlorido complex, as in (5). Complex (3) shows two strongly bound Cl atoms, while complex (4) has one strongly bound Cl atom and a weaker coordination by one perchlorate O atom. The large noncoordinating tetraphenylborate anion in complex (5) results in the core‐bridged Cu₂Cl₂ moiety.     

Di‐μ‐chlorido‐bis({2‐[1‐(2‐pyridylethylimino)ethyl]pyrrolato‐κ3N,N′,N′′}copper(II))

The title compound, [Cu₂(C₁₃H₁₄N₃)₂Cl₂], is a neutral dimeric copper(II) complex. The two Cu^II atoms are asymmetrically bridged by two chloride ions. Each Cu^II atom is also bound to the three N atoms of a deprotonated tridentate Schiff base ligand, giving a distorted square‐pyramidal N₃Cl₂ coordination environment overall. The dinuclear complex lies across an inversion centre in the space group P. This work demonstrates the effect of ligand flexibility and steric constraints on the structures of copper(II) complexes.     

Synthesis,Structures and Spectroscopic Properties of Platinum(II), Palladium(II) and Copper(I) Halide Complexes with Pyrimidine‐phosphine Ligand

The reactions of pyrimidine‐phosphine ligand N‐[(diphenylphosphino)methyl]‐2‐pyrimidinamine ( L ) with various metal salts of Pt^II, Pd^II and Cu^I provide three new halide metal complexes, Pt₂Cl₄(μ‐L)₂·2CH₂Cl₂ ( 1 ), Pd₂Cl₄(μ‐L)₂ ( 2 ), and [Cu₂(μ‐I)₂L₂]_n ( 3 ). Single crystal X‐ray diffraction studies show that complexes 1 and 2 display a similar bimetallic twelve‐membered ring structure, while complex 3 consists of one‐dimensional polymeric chains, which are further connected into a 2‐D supramolecular framework through hydrogen bonds. In the binuclear complexes 1 and 2 , the ligand L serves as a bridge with the N and P as coordination atoms, but in the polymeric complex 3 , both bridging and chelating modes are adopted by the ligand. The spectroscopic properties of complexes 1 ‐ 3 as well as L have been investigated, in which complex 3 exhibits intense photoluminescence originating from intraligand charge transfer (ILCT) π→π* and metal‐to‐ligand charge‐transfer (MLCT) excited states both in acetonitrile solution and solid state, respectively.     

catena‐Poly[[bis(nicotinamide‐κN1)copper(I)]‐μ‐thiocyanato‐κ2N:S]

The Cu^I cations in the title compound, [Cu(NCS)(C₆H₆N₂O)₂]_n, are coordinated by N atoms from each of two mirror‐related nicotin­amide ligands, as well as by one N atom of one thio­cyanate ligand and one S atom of a symmetry‐related thio­cyanate ligand, within a slightly distorted tetrahedron. The Cu^I cations and the thio­cyanate anions are located on a crystallographic mirror plane and the nicotin­amide ligands occupy general positions. The Cu^I cations are connected by the thio­cyanate anions to form chains in the direction of the crystallographic a axis. These chains are connected by hydrogen bonds between the amide H atoms and the O atoms of adjacent nicotin­amide ligands, to give a three‐dimensional structure.     

Di‐μ‐chloro‐bis({2‐[N,N‐bis(2‐aminoethyl)amino‐κ3N]ethylaminium}copper(II)) bis(naphthalene‐1,5‐disulfonate) pentahydrate

The title compound, [Cu₂(C₆H₁₉N₄)₂Cl₂](C₁₀H₆O₆S₂)₂·5H₂O, is comprised of discrete [Cu₂(tren)₂Cl₂]²⁺ dimers {tren is 2‐[N,N‐bis(2‐amino­ethyl)­amino]­ethyl­aminium} and naphthalene‐1,5‐di­sulfonate anions. Two Cl^? anions bridge two Cu^II ions, each of which is also coordinated by two of the primary and the tertiary amino N atoms of the tren ligand, giving each metal atom a distorted square‐pyramidal coordination geometry. The cation lies about an inversion centre and the asymmetric unit also has two independent anions lying about inversion centres.     

A novel three‐dimensional heterometallic coordination polymer: poly[[diaquadi‐μ3‐chlorido‐μ2‐chlorido‐tri‐μ3‐nicotinato‐tricopper(I)gadolinium(III)] hemihydrate]

In the title polymeric heterometallic compound, {[Cu₃Gd(C₆H₄NO₂)₃Cl₃(H₂O)₂]·0.5H₂O}_n, comprising copper(I) and gadolinium(III) cations bridged by nicotinate (nic) ligands and chloride anions, the Gd^III centers display a bicapped trigonal prismatic geometry, defined by six carboxylate O atoms and two water molecules. For copper(I), one Cu center is three‐coordinated by three chloride ions and displays a trigonal–planar geometry; the other two Cu centers are four‐coordinated and display a very distorted tetrahedral geometry. The chloride anions act in μ₂‐ and μ₃‐bridging modes, linking the Cu^I ions into an infinite chain. The nic ligand exhibits a tridentate coordination mode, with the carboxylate O atoms linking to two Gd^III ions and the N atom linking to one Cu^I ion. Thus, a novel three‐dimensional heterometallic coordination polymer is constructed from Gd–carboxylate subunits and Cu—Cl chains. In addition, intra‐ and intermolecular O—H...O and O—H...Cl hydrogen bonds are also observed within the three‐dimensional structure. Topologically, the framework represents an unusual 3,6‐connected (4.8²)₃(4¹⁰.6⁵) net.