Metallionen und H2O2. V. Über Struktur und Aktivität der den H2O2-Zerfall katalysierenden Cu2+-Komplexe III. Versuche zur Lösung von Strukturproblemen mit Hilfe der Katalyseeigenschaften

The catalytic properties of Cu²⁺-chelates of the following ligands in H₂O₂ decomposition have been investigated: N, N′-diglycyldiaminoethane (I), N, N′-diglycyl-1,5-diaminopentane (II), N, N′-diglycyl-1,3-diaminopropane (III) [6], glycinamide (IV), glycylglycinamide (V) and polymyxin B (VI). It is confirmed that the catalysis of H₂O₂ decomposition by Cu²⁺-chelates and the formation of ternary peroxo complexes (absorbing at 360 nm) depend on the number of free coordination positions. It is now shown that in reversal the number of free coordination positions on the Cu²⁺ in its complexes can be determined by measuring their catalytic activity on the H₂O₂ decomposition, and their absorption at 360 nm.     

Über Struktur und Aktivität der den H2O2-Zerfall katalysierenden Cu2+-Komplexe. V. Vergleich der katalytischen Aktivität der Cu2+-Komplexe isomerer β-Hydroxythiophen-Derivate. Mettallionen und H2O2, 9. Mitteilung

The catalytic properties in H₂O₂ decomposition of the Cu²⁺-chelates of 2- Acetyl-3-hydroxy-thiophene (I) and 3-Acetyl-4-hydroxy-thiophene (II) have been investigated. Evidence is given that the catalytic activity of the chelates is a function of the respective bond orders of the α, β (I) and β, β′ (II) thiophene bonds of the chelate ring.     

Metallionen und H2O2. VI. Über Struktur und Aktivität der den H2O2-Zerfall katalysierenden Ni2+-Komplexe

The catalytic properties in H₂O₂ decomposition of Ni²⁺-chelates of the following ligands have been investigated: ethylenediamine, diethylenetriamine, triethylenetetramine, 2,2′-bipyridine, pyrophosphate and ethylenediamine-N, N, N′, N′-tetra-acetic acid, and of the following peptides and peptide-like ligands: glycylglycine, N,N′-diglycyl-ethylenediamine, N, N′-diglycyl-1, 5-diaminopentane and polymyxin B.     

Zur Kinetik des durch Cu2+-Äthylendiamin katalysierten H2O2-Zerfalls: Metallionen und H2O2, 14. Mitteilung

Kinetic studies of the Cu²⁺-ethylenediamine catalysed decomposition of H₂O₂ show the initial rate v₀ of H₂O₂ decomposition to be proportional to [H+]^?1, [H₂O₂], and [Cu²⁺-en]². Maximal velocity is found at a ratio of [Cu²⁺]_tot:[en]_tot = 1:1,5. It is suggested that the active complex has a binuclear structure. This structure and probable mechanisms of the reaction are discussed. The kinetic measurements of the Cu²⁺-diethylenetriamine-H₂O₂ system are difficult to interprete because of degradation of the ligand by H₂O₂.     

A twofold interwoven two‐dimensional→two‐dimensional (2‐D→2‐D) cluster–organic network based on the [Cu2I2] cluster and the 4,4′‐(diazenediyl)dipyridine ligand: poly[[μ2‐4,4′‐(diazenediyl)dipyridine]‐μ2‐iodido‐copper(I)]

In the polymeric title compound, [CuI(C₁₀H₈N₄)]_n, the Cu^I atom is in a four‐coordinated tetrahedral geometry, formed by two I atoms and two pyridine N atoms from two different 4,4′‐(diazenediyl)dipyridine (4,4′‐azpy) ligands. Two μ₂‐I atoms link two Cu^I atoms to form a planar rhomboid [Cu₂I₂] cluster located on an inversion centre, where the distance between two Cu^I atoms is 2.7781 (15) Å and the Cu—I bond lengths are 2.6290 (13) and 2.7495 (15) Å. The bridging 4,4′‐azpy ligands connect the [Cu₂I₂] clusters into a two‐dimensional (2‐D) double‐layered grid‐like network [parallel to the (10) plane], with a (4,4)‐connected topology. Two 2‐D grid‐like networks interweave each other by long 4,4′‐azpy bridging ligands to form a dense 2‐D double‐layered network. To the best of our knowledge, this interwoven 2‐D→2‐D network is observed for the first time in [Cu₂I₂]–organic compounds.     

Synthesis and Crystal Structure of [Cu2(H2O)2(phen)2(OH)2][Cu2(phen)2(OH)2(CO3)2] · 10 H2O with phen = 1,10‐phenanthroline

The blue copper complex [Cu₂(H₂O)₂(phen)₂(OH)₂][Cu₂(phen)₂(OH)₂(CO₃)₂] · 10 H₂O, which was prepared by reaction of 1,10‐phenanthroline monohydrate, CuCl₂ · 2 H₂O and Na₂CO₃ in the presence of succinic acid in CH3OH/H₂O at pH = 13.0, crystallized in the triclinic space group P1 (no. 2) with cell dimensions: a = 9.515(1) Å, b = 12.039(1) Å, c = 12.412(2) Å, α = 70.16(1)°, β = 85.45(1)°, γ = 81.85(1)°, V = 1323.2(2) ų, Z = 1. The crystal structure consists of dinuclear [Cu₂(H₂O)₂(phen)₂(OH)₂]²⁺ complex cations, dinuclear [Cu₂(phen)₂(OH)₂(CO₃)₂]^2– complex anions and hydrogen bonded H₂O molecules. In both the centrosymmetric dinuclear cation and anion, the Cu atoms are coordinated by two N atoms of one phen ligand, three O atoms of two μ‐OH groups and respectively one H₂O molecule or one CO₃^2– anion to complete distorted [CuN₂O₃] square‐pyramids with the H₂O molecule or the CO₃^2– anion at the apical position (equatorial d(Cu–O) = 1.939–1.961 Å, d(Cu–N) = 2.026–2.051 Å and axial d(Cu–O) = 2.194, 2.252 Å). Two adjacent [CuN₂O₃] square pyramids are condensed via two μ‐OH groups. Through the interionic hydrogen bonds, the dinuclear cations and anions are linked into 1D chains with parallel phen ligands on both sides. Interdigitation of phen ligands of neighboring 1D chains generated 2D layers, between which the hydrogen bonded water molecules are sandwiched.     

A Novel 3D Framework Coordination Polymer based on Succinato bridged Helical Chains Connected by 4, 4' ‐ Bipyridine: [Cu(bpy)(H2O)2(C4H4O4)]?2H2O

Blue needle—shaped crystals of [Cu(bpy)(H₂O)₂(C₄H₄O₄)]· 2H₂O were obtained by slow evaporation of a methanolic aqueous solution containing a fresh Cu(C₄H₄O₄)· 2H₂O precipitate, 4, 4′—bipyridine, and ammonia. Within the complex, the six—coordinated Cu atoms are linked by bis—monodentate gauche succinate anions into chains propagating helically around the [001] axis. The chains are interconnected by 4, 4′—bipyridine ligands into a 3D framework with the crystal H₂O molecules located in the channels along the [100], [010] and [110] directions. The Cu²⁺ ions are in distorted octahedral coordination of two nitrogen and four oxygen atoms (equatorial bonds: Cu—N 1.986(5), 2.015(5)Å; Cu—O 1.950(6), 1.954(6)Å; axial bonds Cu—O: 2.524(9), 2.539(8)Å). Furthermore, the thermal and magnetic behavior of the compound will be discussed. Crystal data: hexagonal, P6₁ (no. 169), a = 11.066(2)Å, c = 24.965(5)Å, V = 2647.5(8)ų, Z = 6, R = 0.0528 and wR₂ = 0.1103 for 1426 observed reflections (F_o² > 2σ(F_o²)) out of 2170 unique reflections.     

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)].     

Two Novel CuII Phenanthroline Adipato Complexes with π‐π Stacking Interactions: [Cu(phen)2(C6H8O4)] · 4.5 H2O and [(Cu2(phen)2Cl2)(C6H8O4)] · 4 H2O

The blue copper complex compounds [Cu(phen)₂(C₆H₈O₄)] · 4.5 H₂O ( 1 ) and [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)] · 4 H₂O ( 2 ) were synthesized from CuCl₂, 1,10‐phenanthroline (phen) and adipic acid in CH₃OH/H₂O solutions. [Cu(phen)₂‐ (C₆H₈O₄)] complexes and hydrogen bonded H₂O molecules form the crystal structure of ( 1 ) (P1 (no. 2), a = 10.086(2) Å, b = 11.470(2) Å, c = 16.523(3) Å, α = 99.80(1)°, β = 115.13(1)°, γ = 115.13(1)°, V = 1617.5(5) ų, Z = 2). The Cu atoms are square‐pyramidally coordinated by four N atoms of the phen ligands and one O atom of the adipate anion (d(Cu–O) = 1.989 Å, d(Cu–N) = 2.032–2.040 Å, axial d(Cu–N) = 2.235 Å). π‐π stacking interactions between phen ligands are responsible for the formation of supramolecular assemblies of [Cu(phen)₂(C₆H₈O₄)] complex molecules into 1 D chains along [111]. The crystal structure of ( 2 ) shows polymeric [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)_2/2] chains (P1 (no. 2), a = 7.013(1) Å, b = 10.376(1) Å, c = 11.372(3) Å, α = 73.64(1)°, β = 78.15(2)°, γ = 81.44(1)°, V = 773.5(2) ų, Z = 1). The Cu atoms are fivefold coordinated by two Cl atoms, two N atoms of phen ligands and one O atom of the adipate anion, forming [CuCl₂N₂O] square pyramids with an axial Cl atom (d(Cu–O) = 1.958 Å, d(Cu–N) = 2.017–2.033 Å, d(Cu–Cl) = 2.281 Å; axial d(Cu–Cl) = 2.724 Å). Two square pyramids are condensed via the common Cl–Cl edge to centrosymmetric [Cu₂Cl₂N₄O₂] dimers, which are connected via the adipate anions to form the [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)_2/2] chains. The supramolecular 3 D network results from π‐π stacking interactions between the chains. H₂O molecules are located in tunnels.     

Poly[tetraamminecopper(II) bis[tris(μ2‐cyanido‐κ2C,N)dicuprate(I)]]: a unique CuI–CuII mixed‐valence complex containing anionic cuprous cyanide layers and [Cu(NH3)4]2+ cations

The title compound, {[Cu(NH₃)₄][Cu(CN)₃]₂}_n, features a Cu^I–Cu^II mixed‐valence CuCN framework based on {[Cu₂(CN)₃]⁻}_n anionic layers and [Cu(NH₃)₄]²⁺ cations. The asymmetric unit contains two different Cu^I ions and one Cu^II ion which lies on a centre of inversion. Each Cu^I ion is coordinated to three cyanide ligands with a distorted trigonal–planar geometry, while the Cu^II ion is ligated by four ammine ligands, with a distorted square‐planar coordination geometry. The interlinkage between Cu^I ions and cyanide bridges produces a honeycomb‐like {[Cu₂(CN)₃]⁻}_n anionic layer containing 18‐membered planar [Cu(CN)]₆ metallocycles. A [Cu(NH₃)₄]²⁺ cation fills each metallocyclic cavity within pairs of exactly superimposed {[Cu₂(CN)₃]⁻}_n anionic layers, but there are no cations between the layers of adjacent pairs, which are offset. Pairs of N—H...N hydrogen‐bonding interactions link the N—H groups of the ammine ligands to the N atoms of cyanide ligands.     

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.     

über Struktur und Aktivität der den H2O2-Zerfall katalysierenden Cu2+-Komplexe VII

It has been stated in a preceding paper [3] that only parts of a ligand coordinated to a metal ion can be oxidized by H₂O₂ (= peroxidative activity). Considering the reversal of this statement to be true, it is shown by means of the peroxidative activity of the Cu²⁺-complexes of ATP, ITP, CTP, UTP, and TTP that in these complexes the heteroaromatic groups contribute to the coordination of Cu²⁺ ion. By analogy with the Cu²⁺-ATP-complex, where a macrocyclic phosphate-metal-adenine chelate is formed [4], and based on his experimental results, the author considers the existence of such a macrocyclic chelate in the copper complexes of ITP, GTP, CTP, UTP, and TTP as established. The coordination sites of the heteroaromatic groups in these complexes are discussed.     

Chelatbildung mit 1,3-Diamino-2-methylenpropanen

Chelate Formation with 1,3-Diamino-2-methylene Propane1 1,3-Diamino-2-methylene propane and its N, N′ alkylated derivatives form crystalline chelates with Co^II (1:3), Ni^II (1:1, 1:2 and 1:3), Pd^II (1:1, 1:2), Rh^III (1:1) and Cu^II (1:2). Experiments for preparation of olefin complexes were unsuccessful. By potentiometric measurements the base strengths of the ligands as well as the stability constants of the Co^II, Ni^II, Pd^II, Cu^II, Zn^II, Cd^II chelates were evaluated and the kinetics of the formation of the 1:1 Pd^II complex is investigated. The magnetic behaviour of the Co^II?, Pd^II? and Cu^II? chelates is normal, whereas[Ni(dia)₂(H₂O)₂] (ClO₄)₂ shows anormal behaviour due to configurational isomerism between square planar and octahedral ligand geometry in solid state in type of a LIFSCHITZ -isomerism. The ESR-spectra of the Cu^II?compounds are discussed and the bonding parameters of the Cu? N?bonds were calculated.     

Crystal Structures of [Mn2(H2O)4(phen)2(C4H4O4)2] · 2 H2O and [Mn(phen)2(H2O)2][Mn(phen)2(C4H4O4)](C4H4O4) · 7 H2O

Reactions of 1,10‐phenanthroline monohydrate, Na₂C₄H₄O₄ · 6 H₂O and MnSO₄ · H₂O in CH₃OH/H₂O yielded a mixture of [Mn₂(H₂O)₄(phen)₂(C₄H₄O₄)₂] · 2 H₂O ( 1 ) and [Mn(phen)₂(H₂O)₂][Mn(phen)₂(C₄H₄O₄)](C₄H₄O₄) · 7 H₂O ( 2 ). The crystal structure of 1 (P1 (no. 2), a = 8.257(1) Å, b = 8.395(1) Å, c = 12.879(2) Å, α = 95.33(1)°, β = 104.56(1)°, γ = 106.76(1)°, V = 814.1(2) ų, Z = 1) consists of the dinuclear [Mn₂(H₂O)₄(phen)₂(C₄H₄O₄)₂] molecules and hydrogen bonded H₂O molecules. The centrosymmetric dinuclear molecules, in which the Mn atoms are octahedrally coordinated by two N atoms of one phen ligand and four O atoms from two H₂O molecules and two bis‐monodentate succinato ligands, are assembled via π‐π stacking interactions into 2 D supramolecular layers parallel to (101) (d(Mn–O) = 2.123–2.265 Å, d(Mn–N) = 2.307 Å). The crystal structure of 2 (P1 (no. 2), a = 14.289(2) Å, b = 15.182(2) Å, c = 15.913(2) Å, α = 67.108(7)°, β = 87.27(1)°, γ = 68.216(8)°, V = 2934.2(7) ų, Z = 2) is composed of the [Mn(phen)₂(H₂O)₂]²⁺ cations, [Mn(phen)₂(C₄H₄O₄)] complex molecules, (C₄H₄O₄)^2– anions, and H₂O molecules. The (C₄H₄O₄)^2– anions and H₂O molecules form 3 D hydrogen bonded network and the cations and complex molecules in the tunnels along [001] and [011], respectively, are assembled via the π‐π stacking interactions into 1 D supramolecular chains. The Mn atoms are octahedrally coordinated by four N atoms of two bidentate chelating phen ligands and two water O atoms or two carboxyl O atoms (d(Mn–O) = 2.088–2.129 Å, d(Mn–N) = 2.277–2.355 Å). Interestingly, the succinato ligands in the complex molecules assume gauche conformation bidentately to chelate the Mn atoms into seven‐membered rings.     

Poly[diaquabis(μ‐4,4′‐bipyridine‐κ2N:N′)bis(ethane‐1,2‐diol)di‐μ‐sulfato‐dicopper(II)]

The title compound, [Cu₂(SO₄)₂(C₁₀H₈N₂)₂(C₂H₆O₂)₂(H₂O)₂]_n, contains two crystallographically unique Cu^II centres, each lying on a twofold axis and having a slightly distorted octahedral environment. One Cu^II centre is coordinated by two bridging 4,4′‐bipyridine (4,4′‐bipy) ligands, two sulfate anions and two aqua ligands. The second is surrounded by two 4,4′‐bipy N atoms and four O atoms, two from bridging sulfate anions and two from ethane‐1,2‐diol ligands. The sulfate anion bridges adjacent Cu^II centres, leading to the formation of linear ...Cu1–Cu2–Cu1–Cu2... chains. Adjacent chains are further bridged by 4,4′‐bipy ligands, which are also located on the twofold axis, resulting in a two‐dimensional layered polymer. In the crystal structure, extensive O—H...O hydrogen‐bonding interactions between water molecules, ethane‐1,2‐diol molecules and sulfate anions lead to the formation of a three‐dimensional supramolecular network structure.     

catena‐Poly­[bis­[(2,2‐bi­pyridine‐κ2N,N′)­copper(II)]‐μ4‐1,2,4,5‐benzene­tetra­carboxyl­ato‐κ4O1:O2:O3:O4]

In the title complex, [Cu₂(C₁₀H₂O₈)(C₁₀H₈N₂)₂]_n, the Cu^II cation has a four‐coordinated environment, completed by two carboxyl O atoms belonging to two 1,2,4,5‐benzene­tetra­carboxyl­ate anions (TCB⁴⁻) and two N atoms from one 2,2′‐bi­pyridine (2,2′‐bipy) ligand, forming a distorted square‐planar geometry. The [Cu(2,2′‐bipy)]²⁺ moieties are bridged by TCB⁴⁻ anions, which lie about inversion centres, forming an infinite one‐dimensional coordination polymer with a double‐chain structure along the a axis. A two‐dimensional network structure is formed via a face‐to‐face π–π interaction between the 2,2′‐bipy rings belonging to two adjacent double chains, at a distance of approximately 3.56 Å.     

Zu den Kristallstrukturen der Übergangsmetall(II)‐Dodekahydro‐closo‐Dodekaborat‐Hydrate Cu(H2O)5,5[B12H12]·2,5 H2O und Zn(H2O)6[B12H12]·6 H2O

On the Crystal Structures of the Transition‐Metal(II) Dodecahydro‐closo‐Dodecaborate Hydrates Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O and Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O By neutralization of an aqueous solution of the free acid (H₃O)₂[B₁₂H₁₂] with basic copper(II) carbonate or zinc carbonate, blue lath‐shaped single crystals of the octahydrate Cu[B₁₂H₁₂]·8 H₂O (≡ Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O) and colourless face‐rich single crystals of the dodecahydrate Zn[B₁₂H₁₂]·12 H₂O (≡ Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O) could be isolated after isothermic evaporation. Copper(II) dodecahydro‐closo‐dodecaborate octahydrate crystallizes at room temperature in the monoclinic system with the non‐centrosymmetric space group Pm (Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O: a = 768.23(5), b = 1434.48(9), c = 777.31(5) pm, β = 90.894(6)°; Z = 2), whereas zinc dodecahydro‐closo‐dodecaborate dodecahydrate crystallizes cubic in the likewise non‐centrosymmetric space group F23 (Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O: a = 1637.43(9) pm; Z = 8). The crystal structure of Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O can be described as a monoclinic distortion variant of the CsCl‐type arrangement. As characteristic feature the formation of isolated [Cu₂(H₂O)₁₁]⁴⁺ units as a condensate of two corner‐linked Jahn‐Teller distorted [Cu(H₂O)₆]²⁺ octahedra via an oxygen atom of crystal water can be considered. Since “zeolitic” water of hydratation is also present, obviously both classical H–O^δ?···^+δH–O and non‐classical B–H^δ?···^+δH–O hydrogen bonds play a significant role for the stabilization of the structure. A direct coordinative influence of the quasi‐icosahedral [B₁₂H₁₂]^2? anions on the Cu²⁺ cations has not been determined. The zinc compound Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O crystallizes in a NaTl‐type related structure. Two crystallographically different [Zn(H₂O)₆]²⁺ octahedra are present, which only differ in their relative orientation within the packing of the [B₁₂H₁₂]^2? anions. The stabilization of the crystal structure takes place mainly via H–O^δ?···^+δH–O hydrogen bonds, since again the hydrogen atoms of the [B₁₂H₁₂]^2? anions have no direct coordinative influence on the Zn²⁺ cations.     

Synthese von Kupfer- und Silberkomplexen mit fünfzähnigen N,S- und sechszähnigen N,O-Chelatliganden – Charakterisierung und Kristallstrukturen von {Cu2[C6H4(SO2)NC(O)]2(C5H5N)4}, {Cu2[C5H3N(CHNC6H4SCH3)2]2}(PF6)2 und {Ag[C5H3N(CHNC6H4SCH3)2]}PO2F2

Synthesis of Copper and Silver Complexes with Pentadentate N,S and Hexadentate N,O Chelate Ligands – Characterization and Crystal Structures of {Cu₂[C₆H₄(SO₂)NC(O)]₂(C₅H₅N)₄}, {Cu₂[C₅H₃N(CHNC₆H₄SCH₃)₂]₂}(PF₆)₂, and {Ag[C₅H₃N(CHNC₆H₄SCH₃)₂]}PO₂F₂ In the course of the reaction of copper(II)-acetate monohydrate with 2,2′-bisbenzo[d][1,3]thiazolidyl in methanol the organic component is transformed to N,N′-bis-(2-thiophenyl)ethanediimine and subsequently oxidized to the N,N′-bis-(2-benzenesulfonyl)ethanediaciddiamide H₄BBSED, which coordinates in its deprotonated form two Cu²⁺ ions. Crystallisation from pyridine/n-hexane yields [Cu₂(BBSED)(py)₄] · MeOH. It forms triclinic crystals with the space group P1 and a = 995.5(2) pm, b = 1076.1(3) pm, c = 1120.7(2) pm, α = 104.17(1)°, β = 105.28(1)°, γ = 113.10(1)° and Z = 1. In the centrosymmetrical dinuclear complex the copper ions are coordinated in a square-pyramidal arrangement by three nitrogen and two oxygen atoms. The Jahn-Teller effect causes an elongation of the axial bond by approximately 30 pm. The reactions of the pentadentate ligand 2,6-Bis-[(2- methylthiophenyl)-2-azaethenyl]pyridine BMTEP with salts of copper(I), copper(II) and silver(I) yield the complexes [CU₂(BMTEP)₂](PF₆)₂, [Cu(BMTEP)]X₂ (X = BF, C1O) and [Ag(BMTEP)]X (X = PO₂F, ClO). [Cu₂(BMTEP)₂](PF₆)₂ crystallizes from acetone/diisopropyl- ether in form of monoclinic crystals with the space group C2/c, and a = 1833.2(3) pm, b = 2267.30(14) pm, c = 1323.5(2) pm, β= 118.286(5)°, and 2 = 4. In the dinuclear complex cation with the symmetry C₂ the copper ions are tetrahedrally coordinated by two bridging BMTEP ligands. The Cu? Cu distance of 278.3pm can be interpreted with weak Cu? Cu interactions which also manifest itself in a temperature independent paramagnetism of 0.45 B.M. The monomeric silver complex [Ag(BMTEP)]PO₂F₂ crystallizes from acetone/thf in the triclinic space group P1 with a = 768.7(3) pm, b = 1074.0(5) pm, c = 1356.8(5) pm, α = 99.52(2)°, β = 96.83(2)°, γ = 99.83(2)° and Z = 2. The central silver ion is coordinated by one sulfur and three nitrogen atoms of the ligand in a planar, semicircular arrangement. The bond lengths Ag? N = 240.4–261.7 and Ag? S = 257.2 pm are significantly elongated in comparison with single bonds.     

Pyridinderivate als Komplexbildner. XI. Die Thermodynamik der Metallkomplexbildung mit Bis-, Tris- und Tetrakis[(2-pyridyl)methyl]-aminen

Pyridine Derivatives as Complexing Agents XI. Thermodynamics of Metal Complex Formation with Bis-, Tris- and Tetrakis[(2-pyridyl)methyl]-amines. The equilibria between H⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Cd²⁺, Pb²⁺, Hg²⁺ and Ag⁺, and the ligands bis(2-pyridylmethyl)-amine (=DPA), tris(2-pyridylmethyl)-amine (=TPA), tris(6-methyl-2-pyridylmethyl)-amine (=TLA) and N,N,N′,N′-tetrakis(2-pyridylmethyl)-ethylenediamine (=TPEN) have been studied. Only the stability constants of DPA and TLA with almost all these cations were obtained using the pH method. For the other ligands, the complexes are already formed in acid solutions and only the use of different ligand-ligand or metal-metal exchanges as well as of pM methods were successful. The protonation constants indicate that for DPA the protonation occurs firstly at the aliphatic nitrogen atom whereas in all other cases only the pyridine groups can be protonated. The thermodynamic functions of protonation are in agreement with this interpretation. The stability constants of the complexes are often similar in magnitude to those of the analogous aliphatic amines, in spite of the much lower basicities of the pyridine derivatives. The Fe(II)N₆ species of DPA and TPEN are appreciably more stable than those of the corresponding aliphatic ligands. This is due to the formation of low-spin complexes with an unexpected ΔH value. Comparison of the thermodynamic data of formation of the complexes with TPA and TLA shows the effect of the three bulky methyl groups of the second ligand. As a consequence of steric hindrance and of the major dehydration, ΔH and less ΔS are more positive for M(TLA)²⁺ than for M(TPA)²⁺. Therefore M(TLA)²⁺ is normally much less stable than M(TPA)²⁺. The data for MnTPA²⁺ and ZnTPA²⁺ appear to indicate that in these complexes the coordination number of the metal ion is seven and four respectively. In addition to the complexes ML²⁺, with these two ligands hydroxo complexes ML(OH)⁺ are formed at remarkably low pH. Further TPEN seems to be sexidentate in the 1:1 complexes with Mn²⁺, Co²⁺ and Ni²⁺ but quinquedentate in those with Cu²⁺ and Zn²⁺, also in agreement with the spectra in solution and of the solid complex salts. The reaction: M(DPA)₂²⁺ + TPEN → M(TPEN)²⁺ + 2DPA is for all metal ions favoured by ΔH and ΔS, whereas in the case of the corresponding aliphatic ligands only by the second term. This result is explained in terms of a different magnitude of hydration of the two sexidentate ligands as a consequence of the presence of the hydrophobic aromatic rings in TPEN.     

Synthesis and Crystal Structure of [La(phen)2(H2O)2(NO3)2]NO3 · 2(phen)(H2O) with phen = 1,10‐phenanthroline

The title compound [La(phen)₂(H₂O)₂(NO₃)₂](NO₃) · 2(phen)(H₂O) with phen = 1,10‐phenanthroline was prepared by the stoichiometric reaction of La(NO₃)₃ · 6 H₂O and 1,10‐phenanthroline monohydrate in a CH₃OH–H₂O solution. The crystal structure (triclinic, P 1 (no. 2), a = 11.052(2), b = 13.420(2), c = 16.300(2) Å, α = 78.12(1)°, β = 88.77(1)°, γ = 83.03(1)°, Z = 2, R = 0.0488, wR² = 0.1028) consists of [La(phen)₂(H₂O)₂(NO₃)₂]²⁺ complex cations, NO₃^– anions, phen and H₂O molecules. The La atom is 10‐fold coordinated by four N atoms of two bidentate chelating phen ligands and six O atoms of two H₂O molecules and two bidentate chelating NO₃^2– ligands with d(La–O) = 2.522–2.640 Å and d(La–N) = 2.689–2.738 Å. The intermolecular π‐π stacking interactions play an essential role in the formation of two different 2 D layers parallel to (001), which are formed by complex cations and uncoordinating phen molecules, respectively. The uncoordinated NO₃^– anions and H₂O molecules are sandwiched between the cationic and phen layers.