A Novel Phase‐Transfer Catalyst: Monomeric Copper(II) Coordination Compound

The Copper(II) complex benzylcinchonidinium trichlorocuprate(II) ( 1 ) was obtained by the thermal treatments of CuCl₂ with benzylcinchonidinium chloride ( L1 ) in Pyrex tubes. The enantioselective efficiency of 1 studied by alkylation reaction of N‐(diphenylmethylene)glycine tert‐butyl ester ( L2 ) is similar to that of normal benzylcinchonidinium chloride ( L1 ).     

1‐(2‐Hydroxyethyl)‐3‐nitro‐1, 2, 4‐triazole and its Complexes with Copper(II) Chloride and Copper(II) Perchlorate

1‐(2‐Hydroxyethyl)‐3‐nitro‐1, 2, 4‐triazole (hnt), prepared by alkylation of 3‐nitro‐1, 2, 4‐triazole with 2‐chloroethanol, was found to react with copper(II) chloride and copper(II) perchlorate in acetonitrile/ethanol solutions giving complexes [Cu₂(hnt)₂Cl₄(H₂O)₂] and[Cu(hnt)₂(H₂O)₃](ClO₄)₂, respectively. They are the first examples of coordination compounds with a neutral N‐substituted 3‐nitro‐1, 2, 4‐triazole ligand. 1‐(2‐Hydroxyethyl)‐3‐nitro‐1, 2, 4‐triazole and the obtained complexes were characterized by NMR and IR spectroscopy, X‐ray, and thermal analyses. [Cu₂(hnt)₂Cl₄(H₂O)₂] presents a dinuclear chlorido‐bridged complex in which hnt acts as a chelating bidentate ligand, coordinated to the metal by a nitrogen atom of the triazole ring and an oxygen atom of the nitro group, and the copper atoms are inconsiderably distorted octahedral coordination. [Cu(hnt)₂(H₂O)₃](ClO₄)₂comprises a mononuclear complex cation, in which two nitrogen atoms of two hnt ligands in trans configuration and three water oxygen atoms form a square pyramidal environment around the copper atom, which is completed to an distorted octahedron with a bifurcated vertex due to two additional elongated Cu–O bonds with two nitro groups. In both complexes, Cu–O bonds with the nitro groups may be considered as semi‐coordinated.     

Synthesis and Characterization of Bis(triaminoguanidinium) 5,5′‐Dinitrimino‐3,3′‐azo‐1H‐1,2,4‐triazolate – A Novel Insensitive Energetic Material

The synthesis of 5,5′‐diamino‐3,3′‐azo‐1H‐1,2,4‐triazole ( 3 ) by reaction of 5‐acetylamino‐3‐amino‐1H‐1,2,4‐triazole ( 2 ) with potassium permanganate is described. The application of the very straightforward and efficient acetyl protection of 3,5‐diamino‐1H‐1,2,4‐triazole allows selective reactions of the remaining free amino group to form the azo‐functionality. Compound 3 is used as starting material for the synthesis of 5,5′‐dinitrimino‐3,3′‐azo‐1H‐1,2,4‐triazole ( 4 ), which subsequently reacted with organic bases (ammonia, hydrazine, guanidine, aminoguanidine, triaminoguanidine) to form the corresponding nitrogen‐rich triazolate salts ( 5 – 9 ). All substances were fully characterized by IR and Raman as well as multinuclear NMR spectroscopy, mass spectrometry, and differential scanning calorimetry. Selected compounds were additionally characterized by low temperature single‐crystal X‐ray diffraction measurements. The heats of formation of 4 – 9 were calculated by the CBS‐4M method to be 647.7 ( 4 ), 401.2 ( 5 ), 700.4 ( 6 ), 398.4 ( 7 ), 676.5 ( 8 ), and 1089.2 ( 9 ) kJ · mol^–1. With these values as well as the experimentally determined densities several detonation parameters were calculated using both computer codes EXPLO5.03 and EXPLO5.04. In addition, the sensitivities of 5 – 9 were determined by the BAM drophammer and friction tester as well as a small scale electrical discharge device.     

Darstellung und Reaktivitätsuntersuchungen an einem intramolekular basenstabilisierten Germanium(II)‐azid

Synthesis and Reactivity Investigations of an Intramolecularly Base Stabilized Germanium(II) Azide By the reaction of the lithiumamide [tBuO(Me₂)Si]₂NLi ( 2 ) with the dioxane adduct of germanium(II) chloride, the asymmetrically substituted aminochlorogermandiyl [tBuO(Me₂)Si]₂NGeCl ( 3 ) is synthesised. Compound 3 , a yellow unstable liquid, forms on heating the chlorogermaniumalkoxide [ClGe(OtBu)]₂ ( 4 ), present as a dimer in the solid phase. With sodium azide 3 reacts to the germanium(II) azide [tBuO(Me₂)Si]₂NGeN₃ ( 5 ), forming a dimer in the solid, whereas in solution it exists also as a monomer, depending on the concentration of the solution. The azide 5 can be sublimed without decomposition. However, if the temperature is raised beyond 50 °C, 5 will decompose to several products the bis(amino)germandiyl {[tBuO(Me₂)Si]₂N}₂Ge ( 6 ) being easily detectable by NMR. In a selective synthesis, 6 is formed by the reaction of germanium(II) chloride dioxane adduct with two equivalents of the lithiumsalt 2 . Under elimination of dinitrogen, the azide compound 5 reacts with trimethylsilylazide to give the cyclodigermazane {[(tBuO(Me₂)Si)₂N](N₃)GeN–SiMe₃}₂ ( 7 ). Structural details of the molecules 5 , 6 , and 7 can be derived from single crystal X‐ray analyses.     

A Novel Three‐Dimensional Copper(II) 1,2‐Ethylenediphosphonate Framework with Channel‐like Voids

Turquoise monoclinic single crystals of the novel three‐dimensional Cu₂[μ₈‐O₃P(CH₂)₂PO₃] · 3.2H₂O coordination polymer were prepared using the silica gel method. Space group C2/m (no. 12) with a = 1483.6(2), b = 668.44(8), c = 436.30(6) pm, β = 93.28(2)°. The Cu²⁺ cation is coordinated by four oxygen atoms stemming from the 1,2‐ethylenediphosphonate dianions in a square planar manner and two water molecules in the axial positions. The connection between the Cu²⁺ cations and the [CPO₃] units from the 1,2‐ethylenediphosphonate dianions leads to layers parallel to (100), which are linked by the ethylene groups to a three‐dimensional framework with channel‐like voids. The channel‐like voids accommodate water molecules not bound to Cu²⁺ and extend parallel to [001] with an opening of about 550 pm × 260 pm. Magnetic measurements reveal an antiferromagnetic behavior due to a superexchange coupling between Cu²⁺ ions through an oxygen bridge. The UV/Vis spectrum reveals three d–d transition bands at 694, 774, and 918 nm. The compound can be fully dehydrated by thermal treatment and rehydrated by storage in ambient air.     

Synthesis of a One‐dimensional Coordination Polymer Based on Copper(II) Nitrate and 1,2‐Bis(5‐monomethylhydrazinyl‐1H‐tetrazolyl)ethane

A one‐dimensional coordination polymer based on copper(II) nitrate and 1,2‐bis(5‐monomethylhydrazinyl‐1H‐tetrazolyl)ethane as ligand was prepared. The thermal and physical stability was determined by differential scanning calorimetry and BAM methods. The polymer was investigated by vibrational spectroscopy and single X‐ray diffraction. Moreover, the ligand itself and the 1,2‐bis(1H‐tetrazolyl)ethane were characterized as energetic material by bomb calorimetric measurements along with calculations using the EXPLO5 software. Both compounds have moderate energetic properties along with a high thermal and physical stability. These findings render these compounds into promising environment friendly gas generating agents.     

Copper(II) Complexes with N,N'‐Bis(picolinidene‐N‐oxide)‐2‐hydroxy‐1, 3‐diaminopropane: Designing Binuclear Entities and Helical Chains by Versatile Ligand

Three novel copper(II) complex [Cu₂(bpa)(μ‐PhCO₂)](ClO₄)₂ ( 1 ), [Cu₂(bpa) (μ‐pyz)](ClO₄)₂ ( 2 ), and [Cu(Hbpa)](ClO₄)₂·2CH₃CN ( 3 ) have been synthesized by the reaction of Hbpa with Cu(ClO₄)₂·6H₂O in the presence and absence of exogenous ligands (where Hbpa = N, N'‐bis(picolinidene‐N‐oxide)‐2‐hydroxy‐1, 3‐diamino‐propane). Molecular structures of these compounds have been elucidated by single crystal X‐ray diffraction. 1 and 2 are both binuclear complexes in which two copper atoms are linked by the endogenous alkoxide oxygen and the exogenous benzoate and pyrazolate ligands, respectively. 3 consists of a one‐dimensional polymeric structure, in which Hbpa functions as a bridging mode.     

A Structural Study of the Iminodiacetate Moiety Conformation in N‐(1‐adamantyl)‐iminodiacetate(2‐) Copper(II) Complexes

N,N‐bis(carboxymethyl)‐1‐adamantylamine acid (H₂BCAA) or N‐(1‐adamantyl)‐iminodiacetic acid forms zwitterions that are intra‐stabilized by a ‘bifurcated’ N⁺‐H···O(carboxyl)₂ interaction. In the crystal, both half‐protonated carboxyl groups of H₂BCAA^± are involved in linear O‐H···O inter‐molecular bridges of 2.46Å. In the studied BCAA‐Cu^II derivatives, the iminodiacetate‐moiety of the BCAA chelating ligand exhibits a mer‐NO₂ conformation in [Cu(BCAA)(H₂O)₂] ( 1 ) and [Cu(BCAA)(Him)]₂ ( 2 ), but a fac‐O₂+N(apical) conformation in [Cu(BCAA)(bpy)(H₂O)]·3.5H₂O ( 3 ) [Him = imidazole, bpy =2,2′‐bipyridine]. In clear contrast, dipyridylamine (dpya), as auxiliary ligand, seems to be unable to promote the fac‐O₂+N(apical) conformation in BCAA, as reveal the structures of two new salts with the trinuclear cation [(dpya)₂Cu‐μ₂‐Cu(BCAA)₂‐Cu(dpya)₂]²⁺ and the anions [Cu(BCAA)₂]^2? ( 4 ) or NO₃^? ( 5 ), respectively.     

Synthesis and Characterization of Bis(azido)bis(2‐chloropyridine)palladium(II), Bis(azido)bis(3‐chloropyridine)palladium(II), Bis(azido)bis(quinoline)palladium(II), and the Crystal Structure of Bis(azido)bis(quinoline)palladium(II)

Three new monomeric complexes of palladium(II) azide with 2‐chloropyridine ( 1 ), 3‐chloropyridine ( 2 ), and quinoline ( 3 ), have been synthesized by reaction of palladium nitrate and the respective Lewis‐base with sodium azide in a water/acetone mixture. All three compounds were characterized by IR, Raman, and multinuclear NMR spectroscopy. The composition of the complexes were confirmed by elemental analysis. The spectroscopic investigations confirm terminal azide ligands in trans position. Complex 3 was also characterized by crystallographic methods. Each palladium atom of 3 is surrounded in a distorted square planar fashion by 4 nitrogen atoms. The terminal azide ligands are in trans position.     

A Novel 2‐D Copper(II) Complex with Paddlewheel‐like Building Block

By reaction of CuCl₂ with H₄btc (H₄btc = 1,2,4,5‐benzenetetracarboxylic acid) in mixed N,N‐dimethylformamide (DMF) and methanol solution, a new two‐dimensional (2‐D) copper(II) complex [Cu(btc)_0.5(DMF)]_n ( 1 ) based on the paddlewheel‐like [Cu₂(‐CO₂)₄(DMF)₂] building blocks has been synthesized, which is different from those previous Cu‐btc(II) coordination polymers obtained in water medium. Four carboxylate groups of (btc)^4? anion in 1 consistently exhibit bidentate bridging coordination mode, affording an unusual coordination mode of (btc)^4?. Further analysis indicates C–H···π weak interactions are the primary driving forces to assemble the 2‐D layers of 1 into a 3‐D packing structure.     

Synthesis and Properties of [Ba(CHZ)(BT)(H2O)2]n as a New Energetic Coordination Compound

In order to enhance the thermal stability of the barium salt of 5,5′‐bistetrazole (H₂BT), carbohydrazide (CHZ) was used to build [Ba(CHZ)(BT)(H₂O)₂]_n as a new energetic coordination compound by using a simple aqueous solution method. It was characterized by FT‐IR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction. The crystal belongs to the monoclinic P2₁/c space group [a = 8.6827(18) Å, b = 17.945(4) Å, c = 7.2525 Å, β = 94.395(2)°, V = 1126.7(4) ų, and ρ = 2.356 g · cm^–3]. The Ba^II cation is ten‐coordinated with one BT^2–, two shared carbohydrazides, and four shared water molecules. The thermal stabilities were investigated by differential scanning calorimetry (DSC) and thermal gravity analysis (TGA). The dehyration temperature (T_dehydro) is at 187 °C, whereas the decomposition temperature (T_d) is 432 °C. Non‐isothermal reaction kinetics parameters were calculated by Kissinger's method and Ozawa's method to work out E_K = 155.2 kJ · mol^–1, lgA_K = 9.25, and E_O = 158.8 kJ · mol^–1. The values of thermodynamic parameters, the peak temperature (while β → 0) (T_p0 = 674.85 K), the critical temperature of thermal explosion (T_b = 700.5 K), the free energy of activation (ΔG^≠ = 194.6 kJ · mol^–1), the entropy of activation (ΔS^≠ = –66.7 J · mol^–1), and the enthalpy of activation (ΔH^≠ = 149.6 kJ · mol^–1) were obtained. Additionally, the enthalpy of formation was calculated with density functional theory (DFT), obtaining Δ_fH°₂₉₈ ≈ 1962.6 kJ · mol^–1. Finally, the sensitivities toward impact and friction were assessed according to relevant methods. The result indicates the compound as an insensitive energetic material.     

Crystal Structure and Magnetic Exchange in the Single Chloride‐Bridged Copper(II) Chain Compound [CuCl2(TzHy)] [TzHy = (4,5‐dihydro‐1,3‐thiazol‐2‐yl)hydrazine]

The copper complex [CuCl₂(TzHy)] has been synthesized and its crystal structure determined. The coordination complex contains polymeric [CuCl₂(TzHy)]_n chains in which the units are linked by μ‐chloro bridges. The chains run along the crystallographic c axis. The geometry around the copper(II) is best described as distorted square pyramidal. The equatorial positions are occupied by Cl(1) and Cl(2) ligands and one thiazolinic nitrogen atom and another hydrazinic nitrogen atom, from TzHy ligand. The axial position is occupied by the Cl(2b) ligand. The magnetic susceptibility measurements in the temperature range 4 – 290 K show a weak antiferromagnetic intrachain interactions (J = ?8.6 cm^?1).     

Refinement of Copper(II) Azide with 1‐Alkyl‐5H‐tetrazoles: Adaptable Energetic Complexes

A concept for stabilizing highly sensitive and explosive copper(II) azide with 1‐N‐substituted tetrazoles is described. It was possible to stabilize the system by the use of highly endothermic, nitrogen‐rich ligands. The sensitivities of the resulting energetic copper coordination compounds can be tuned further by variation of the alkyl chain of the ligands and by phlegmatization of the complexes with classical additives during the synthesis. It is demonstrated, using the compound based on 1‐methyl‐5H‐tetrazole ([Cu(N₃)₂(MTZ)], 1 ) that this class of complexes can be applied as a potential replacement for both lead azide (LA) and lead styphnate (LS). The complex was extensively investigated according to its chemical (elemental analysis, single‐crystal and powder X‐ray diffraction, IR spectroscopy, scanning electron microscopy) and physico‐chemical properties (differential thermal analysis, sensitivities towards impact, friction, and electrostatic discharge) compared to pure copper(II) azide.     

Structural Study of Nickel(II), Copper(II), and Palladium(II) Complexes of 2‐Pyridineformamide 3‐Hexamethyleneiminylthiosemicarbazone

Reduction of 2‐cyanopyridine by sodium in the presence of 3‐hexamethyleneiminylthiosemicarbazide produces 2‐pyridineformamide 3‐hexamethyleneiminylthiosemicarbazone, HAmhexim. Complexes with nickel(II), copper(II) and palladium(II) have been prepared and the following complexes structurally characterized: [Ni(Amhexim)OAc], [{Cu(Amhexim)}₂C₄H₄O₄]·2DMSO·H₂O, [Cu(HAmhexim)Cl₂] and [Pd(Amhexim)Cl]. Coordination is via the pyridyl nitrogen, imine nitrogen and thiolato or thione sulfur atom when coordinating as the anionic or neutral ligand, respectively. [{Cu(Amhexim)}₂C₄H₄O₄] is a binuclear complex with the two copper(II) ions bridged by the succinato group in [Cu‐(HAmhexim)Cl₂] the Cu atom is 5‐coordinate and close to a square pyramid structure and in [Ni(Amhexim)OAc] and [Pd(Amhexim)Cl] the metal atoms are planar, 4‐coordinate.     

Synthesis and Characterization of 3,3′‐Bis(Dinitromethyl)‐5,5′‐Azo‐1H‐1,2,4‐Triazole

The synthesis of 3,3′‐bis(dinitromethyl)‐5,5′‐azo‐1H‐1,2,4‐triazole ( 5 ) using the readily available starting material 2‐(5‐amino‐1H‐1,2,4‐triazol‐3‐yl)acetic acid ( 1 ) is described. All compounds were characterized by means of NMR, IR, and Raman spectroscopy. The energetic compound 5 was additionally characterized by single‐crystal X‐ray diffraction and DSC measurements. The sensitivities towards impact, friction and electrical discharge were determined. In addition, detonation parameters (e.g. heat of explosion, detonation velocity) of the target compound were computed using the EXPLO5 code based on the calculated (CBS‐4M) heat of formation and X‐ray density.     

3‐(Arylhydrazono)pentane‐2, 4‐diones and their Complexes with Copper(II) and Nickel(II) — Synthesis and Crystal Structures

A series of new 3‐(arylhydrazono)pentane‐2, 4‐diones ( 1 ‐ 6 ) synthesized from pentane‐2, 4‐dione and diazonium salts of respective anilines using the procedure of Japp‐Klingemann are described. Complexes with Cu^II and Ni^II salts are prepared ( 7 ‐ 10 , respectively). Spectroscopic properties of these compounds have been studied and X‐ray crystal structures of selected hydrazones ( 3 , 4 , 6 ) and of the hydrazone complexes ( 7 ‐ 10 ) are reported. The structures of the uncomplexed hydrazones feature an intramolecular N‐H···O interaction to yield a six‐membered H‐bond ring reflecting preference of the hydrazone tautomeric structure. All the complexes are mononuclear 2:1 (L:M) structures of six‐membered chelate type involving N₂O₂ binding sites that are quadratic arranged but differ in the entire coordination environment dependent on the metal and the ligand substitution including distorted octahedral and quadratic pyramidal coordination geometries in the Cu^II complexes 7 and 8 or nearly regular square planar coordination geometry in the Ni^II complexes 9 and 10 , respectively. In the crystal packings, strong and weak H‐bond interactions cause supramolecular network structures.     

An Aqua‐Bridged Helical‐Chain Copper(II)‐Saccharinato Polymer Linked into a Two‐Dimensional Supramolecular Framework

A new assembly [Cu₂(sac)₂(μ‐dmea)₂(μ‐H₂O)]_n (sac = saccharinate and Hdmea = 2‐dimethylaminoethanol) has been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X‐ray diffraction. The complex crystallizes in the monoclinic space group C2/c and consists of dinuclear modules of [Cu₂(sac)₂(dmea)₂]. The sac ligand is N‐coordinated, while the dmea ligand is in the deprotanated form by losing the ethanol hydrogen atom and acts as a bidentate donor through the alkoxo group and N atom. The alkoxo group also serves as a bridge between two copper(II) ions, leading to an intra‐dimer Cu···Cu separation of 3.0229(7) Å. The dimeric units are bridged by aqua ligands to generate a one‐dimensional water‐bridged helical chain, in which the copper(II) ions exhibit a distorted square‐pyramidal CuN₂O₃ coordination. The Cu–Cu distance in the chain separated by the bridging aqua ligands is 5.297Å. The polymeric chains are further linked by π(sac)···π(sac) and C–H···π(sac) interactions into a two‐dimensional supramolecular network.     

Copper(II), Cobalt(II), and Nickel(II) Complexes of two Novel Pyridine‐derived Macrocyclic Ligands bearing o‐ and pNitrobenzyl Pendant Groups

The pendant‐armed ligands L¹ and L² were synthesized by N‐alkylation of the four secondary amine groups of the macrocyclic precursor L using o‐nitrobenzylbromide (L¹) and p‐nitrobenzylbromide (L²). Nitrates and perchlorates of Cu^II, Ni^II and Co^II were used to synthesize the metal complexes of both ligands and the complexes were characterized by microanalysis, MS‐FAB, conductivity measurements, IR and UV‐Vis spectroscopy and magnetic studies. The crystal structures of L¹, [CuL¹](ClO₄)₂·CH₃CN·H₂O, [CuL²](ClO₄)₂·6CH₃CN, [CuL²][Cu(NO₃)₄]·5CH₃CN·0.5CH₃OH and [NiL²](ClO₄)₂·3CH₃CN·H₂O were determined by single crystal X‐ray crystallography. These structural analysis reveal the free ligand L¹, three mononuclear endomacrocyclic complexes {[CuL¹](ClO₄)₂·CH₃CN·H₂O, [CuL²](ClO₄)₂·6CH₃CN and [NiL²](ClO₄)₂·3CH₃CN·H₂O} and one binuclear complex {[CuL²][Cu(NO₃)₄]·5CH₃CN·0.5CH₃OH} in which one of the metals is in the macrocyclic framework and the other metal is outside the ligand cavity and coordinated to four nitrate ions.     

Synthesis and Crystal Structure of a Novel Dinuclear Copper(II) Complex, [Cu2(phen)2(H2O)2(OH)2](HCO3)2 · 6 H2O with phen = 1,10‐phenanthroline

Dark blue plate‐like crystals of [Cu₂(phen)₂ · (H₂O)₂(OH)₂](HCO₃)₂ · 6 H₂O were obtained from a CH₃OH–H₂O solution containing CuCl₂, 1,10‐phenanthroline (phen), sebacic acid and Na₂CO₃. The crystal structure (triclinic, P 1 (no. 2), a = 8.118(1), b = 9.624(1), c = 10.536(1) Å, α = 81.35(1)°, β = 88.51(1)°, γ = 75.77(1)°, Z = 1, R = 0.0332, wR² = 0.0981 for 4163 observed reflections (F ≥ 2σ(F ) out of 4595 unique reflections) consists of divalent [Cu₂(phen)₂(H₂O)₂(OH)₂]²⁺ complex cations, anionic (HCO₃)₂^2– dimers and H₂O molecules. The divalent complex cations (d(Cu…Cu) = 2.905(1) Å) are centered at inversion centers. The Cu atoms are fivefold square‐pyramidally coordinated by two nitrogen and three oxygen atoms from one bidentate chelating phen ligand, two bridging hydroxide groups and one axial water molecule (d(Cu–N)phen = 2.021(2), 2.024(2) Å; d(Cu–O)_OH = 1.941(1), 1.949(1) Å; d(Cu–O)_H2O = 2.254(2) Å). The divalent complex cations are stacked to form 2 D layers parallel (001) with 1 D π‐π stacking interactions along [100] via the terminal phen rings. The dimeric (HCO₃)₂^2– anions and the hydrogen bonded H₂O molecules are sandwiched between the 2 D layers.