Copper Azide Research Articles

Synthesis, crystal structure, and third-order nonlinear optical properties of a copper(I) one-dimensional coordination polymer [Cu(μ-1,1,1,3-N3)] n

A novel copper(I) azide coordination polymer [Cu(μ-1,1,1,3-N3)]n has been synthesized by the low-temperature solution-state reaction. Crystal X-ray analyses reveal that compound [Cu(μ-1,1,1,3-N3)]n possesses a type of three-dimensional (3D) framework structure. The polymer was characterized by elemental analyses, IR spectra, and UV-Vis spectra. The third-order nonlinear optical (NLO) properties were also investigated, and they exhibit good linear absorption and self-defocusing performance with modulus of the hyperpolarizability (γ) 8.16 × 10−30 esu for [Cu(μ-1,1,1,3-N3)]n in a 1.96 × 10−4 mol dm−3 DMF solution.

Syntheses, crystal structures and characterizations of three new copper(II) azide coordination polymers with 1,2,4-triazole ligands

Three new copper(II) azide coordination polymers with derivatives of 1,2,4-triazole as bridging coligands, namely [Cu 2(admtrz) 2(N 3) 4] n ( 1) (admtrz = 4-amino-3,5-dimethyl-1,2,4-triazole), [Cu(4-abpt)(N 3) 2] n ·2 nH 2O ( 2) (4-abpt = 4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole) and [Cu 3(2-ptrz) 2(N 3) 6] n ( 3) (2-ptrz = 4-(2-pyridyl)-1,2,4-triazole), were prepared and characterized by elemental analyses, IR spectra and X-ray structural analyses. Compound 1 has a 1D chain structure in which Cu(II) ions are bridged by end-on (EO) azides and admtrz ligands. This compound contains three kinds of coordination modes for Cu(II) ions, including tetrahedral, square pyramidal and octahedral geometries. Compound 2 displays an interesting 3D framework structure, in which the azide ligands link Cu(II) ions in end-to-end (EE) mode affording a 2D square layer. This 2D layers are further bridged by bent 4-abpt ligands to form an interesting 3D framework. Furthermore, this structure also exhibits an alpha-Po net topology. Compound 3 displays a 1D rectangle-like chain structure linked by azides adopting end-on (EO) and end-to-end (EE) modes and 2-ptrz ligands. The IR and thermal stabilities of these coordination polymers 1–3 have also been studied.

Synthesis of 5‐Substituted 1H‐Tetrazoles by the Copper‐Catalyzed [3+2] Cycloaddition of Nitriles and Trimethylsilyl Azide

The copper-catalyzed [3+2] cycloaddition between various nitriles and trimethylsilyl azide in DMF/MeOH produced the corresponding 5-substituted 1H-tetrazoles in good to high yields. It was proposed that the reaction proceeds through the formation in situ of a copper azide species and subsequent [3+2] cycloaddition with the nitriles. Furthermore, we found that a copper and triethylamine combined catalyst also promoted the cycloaddition of nitriles and trimethylsilyl azide to afford the 5-substituted 1H-tetrazoles at relatively low reaction temperatures. The copper azide species would be formed by reaction of the copper catalyst with Et(3)NHN(3) generated in situ.

Synthesis, crystal engineering, and magnetic properties of an anionic 4-terpyridone based copper(II) azide supramolecule containing dinuclear–mononuclear cocrystal

Synthesis, crystal engineering, and magnetic properties of an anionic 4-terpyridone (L) based three-dimensional supramolecule, [ Cu 2 II (L) 2(μ 1,1-N 3) 2] · 2[Cu II(L)(N 3)(H 2O)] · 6H 2O ( 1), have been described in the present investigation. The title compound crystallizes in the monoclinic space group C2/ c with the following unit cell parameters: a = 27.803(7) Å, b = 14.361(4) Å, c = 16.071(4) Å, β = 99.09(2)°, and Z = 4. In this compound, one dinuclear [ Cu 2 II (L) 2(μ 1,1-N 3) 2] unit is cocrystallized with two mononuclear [Cu II (L)(N 3)(H 2O)] units. In both the dinuclear and mononuclear species, 4-terpyridone chelates to the metal centers in its anionic form. The coordination environment of the metal ions is distorted square pyramidal. Eight O–H⋯O type strong hydrogen bonds involving the oxygen of anionic 4-terpyridone ligand and water molecules link the components of 1 into a three-dimensional framework. Excluding the atoms except the water molecules and ligand oxygens, the topology is a two-dimensional network. The mononuclear [Cu II(L)(N 3)(H 2O)] moiety is appended from this sheet, while the neighboring sheets are interlinked by the dinuclear [ Cu 2 II (L) 2(μ 1,1-N 3) 2] unit to add the third dimension of the overall three-dimensional structure of the title compound.

Copper-catalyzed synthesis of 5-substituted 1H-tetrazoles via the [3+2] cycloaddition of nitriles and trimethylsilyl azide

The [3+2] cycloaddition between various nitriles and trimethylsilyl azide proceeds smoothly in the presence of a CuI catalyst in DMF/MeOH, to give the corresponding 5-substituted 1H-tetrazoles in good to high yields. The reaction most probably proceeds through the in situ formation of a copper azide species, followed by a successive [3+2] cycloaddition with the nitriles.

Heterometallic Tetrazole Coordination Polymer Formed through 2 + 3 Cycloaddition Reaction between Inorganic Complexes in the Presence of Lewis Acid

The two in situ 2 + 3 intermolecular cycloaddition reactions between inorganic complexes bis(3-cyanopyrdine)copper(II)azide (A) offer homometallic and heterometallic 3D novel tetrazole coordination polymers, (3-C5H4N-CN4)2Cu(I)2 (1) and (3-C5H4N-CN4)Cu(I)Cd(II)Cl2 (2), respectively, in the presence of Lewis acid CuCl2 and CdCl2 in which A is used to replace the organic cyano group and NaN3 during Sharplessʼs tetrazole synthesis. Their interesting luminescent properties are reported.

Ligand-directed copper(І) azide coordination polymers bridged by N-donor ligands with different lengths: azide exhibits a rare μ−1, 1, 3, 3 bridging mode

A Ligand-Directed strategy has been adopted to synthesize three novel Copper(І) coordination polymers, [Cu2(bpe)(N3)2]n (1), [Cu2(bpy)(N3)2]n(2), and [Cu4(py)(N3)4]n (3), by the reactions of NaN3 with bpe, bpy and py (bpe = 1,2-trans-(4-pyridyl)ethene, bpy = 4,4′-bipyridine, py = pyrazine) in the presence of H3PO3 under hydrothermal conditions, which proved that the length of ligands had subtle effects on overall network and the coordination mode of azide.

Copper(II) azide complexes of [Cu(acac)(N 3)(dpyam)] and [Cu(μ-N 3-κ N1)(C 2N 3-κ N1)(dpyam)] 2: Synthesis, crystal structure and magnetism

Two new compounds, [Cu(acac)(N 3)(dpyam)] ( 1), (acac = acetylacetonate; dpyam = di-2-pyridylamine) and [Cu(μ-N 3-κ N1)(C 2N 3- κ N1) (dpyam)] 2 ( 2), have been synthesized and characterized by single-crystal X-ray diffraction and magnetic analyses. Compound 1 is a mononuclear compound in which each of two independent Cu(II) ions is penta-coordinated with a distorted square pyramidal geometry with distortion parameters τ = 0.21 and 0.16. In contrast, compound 2 is an azido-bridged dinuclear compound with monodentate dicyanamide anions and the Cu(II) ions display a distorted trigonal bipyramidal geometry with τ = 0.73 and end-on azido bridges providing an equatorial–axial position between the metal ions. The EPR spectra of powdered samples for 1 and 2 have also been investigated. Magnetic susceptibility measurements of compound 2 reveal a very weak ferromagnetic interaction between the Cu(II) ions with a J value of +5.8 cm −1.

Electronic structure of CuN3(I)

Self-consistent calculations of the electronic structure of monovalent copper azide CuN3(I) are carried out in the framework of the density functional theory in the basis set of pseudoatomic orbitals. The specific features of the band structure and the effect of Cu d states on the formation of the energy spectrum of CuN3(I) are considered. The structure of chemical bonding is analyzed using electron density maps.

Solvothermal Synthesis of Nanocrystalline Copper Nitride from an Energetically Unstable Copper Azide Precursor.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Solvothermal Synthesis of Nanocrystalline Copper Nitride from an Energetically Unstable Copper Azide Precursor

Nonaqueous solvothermal chemical reactions have found extensive utility in the growth of inorganic non-oxide materials. This report describes the successful use of organic solvothermal environments to synthesize energetically unstable copper azide precursors that are then decomposed in situ to crystalline metastable copper nitride at temperatures below 200 degrees C. A comparison of Cu3N products formed from nonpolar (toluene) and coordinating (THF) solvents is described. The cubic Cu3N products are nanocrystalline with aggregated particle-like extended structures and were characterized by X-ray diffraction, electron microscopy, IR spectroscopy, and mass spectrometry. The thermal stability and composition of Cu3N was examined by thermogravimetric analysis and bulk elemental analysis. The particle surfaces contain bound residual solvent species that can be removed by heating. The poorly coordinating solvent, toluene, lead to a more crystalline product containing less residual organic content. Benchtop reactions were performed to follow the temporal formation and decomposition of metal azide intermediates. These studies provided more detailed information on the progression of metal azide to metal nitride materials in a solvothermal environment.

Mono, di and polynuclear Cu(II)–azido complexes incorporating N, N, N reduced schiff base: syntheses, structure and magnetic behavior

Three kinds of copper(II) azide complexes have been synthesised in excellent yields by reacting Cu(ClO 4) 2 · 6H 2O with N, N-bis(2-pyridylmethyl)amine (L 1); N-(2-pyridylmethyl)- N′, N′-dimethylethylenediamine (L 2); and N-(2-pyridylmethyl)- N′, N′-diethylethylenediamine (L 3), respectively, in the presence of slight excess of sodium azide. They are the monomeric Cu(L 1)(N 3)(ClO 4) ( 1), the end-to-end diazido-bridged Cu 2(L 2) 2(μ-1,3-N 3) 2(ClO 4) 2 ( 2) and the single azido-bridged (μ-1,3-) 1D chain [Cu(L 3)(μ-1,3-N 3)] n (ClO 4) n ( 3). The crystal and molecular structures of these complexes have been solved. The variable temperature magnetic moments of type 2 and type 3 complexes were studied. Temperature dependent susceptibility for 2 was fitted using the Bleaney–Bowers expression which led to the parameters J = −3.43 cm −1 and R = 1 × 10 −5. The magnetic data for 3 were fitted to Baker’s expression for S = 1/2 and the parameters obtained were J = 1.6 cm −1 and R = 3.2 × 10 −4. Crystal data are as follows. Cu(L 1)(N 3)(ClO 4): Chemical formula, C 12H 13ClN 6O 4Cu; crystal system, monoclinic; space group, P2 1/ c; a = 8.788(12), b = 13.045(15), c = 14.213(15) Å; β = 102.960(10)°; Z = 4. Cu(L 2)(μ-N 3)(ClO 4): Chemical formula, C 10H 17ClN 6O 4Cu: crystal system, monoclinic; space group, P2 1/ c; a = 10.790(12), b = 8.568(9), c = 16.651(17) Å; β = 102.360(10)°; Z = 4. [Cu(L 3)(μ-N 3)](ClO 4): Chemical formula, C 12H 21ClN 6O 4Cu; crystal system, monoclinic; space group, P2 1/ c; a = 12.331(14), b = 7.804(9), c = 18.64(2) Å; β = 103.405(10)°; Z = 4.

Synthesis and characterization of copper(II) azide complexes containing polyamines as co-ligands

Two new copper(II) azide complexes Cu 2(pn) 2(N 3) 4 ( 1) and Cu 3(dien) 2(N 3) 6 ( 2) (pn=1,3-diaminopropane and dien=diethylenetriamine) have been synthesized and characterized by single crystal X-ray diffraction. In complex 1 each copper(II) atom is coordinated to six nitrogen atoms from four azide anions and one 1,3-diaminopropane molecule in a distorted octahedral geometry. Successive pairs of copper(II) atoms are linked by two end-on azide bridges to form a polymeric chain. In centrosymmetric complex 2 the central copper(II) is coordinated by two monodentate azide anions and linked to two terminal copper atoms by double end-on azide bridges to give a linear trinuclear unit. The coordination geometry around each of the terminal copper atoms is square pyramidal, being surrounded by two nitrogen atoms of the bridging azide anions and three nitrogen atoms of the diethylenetriamine ligand. Magnetic susceptibility measurement of complex 2 in the range 2–300 K showed weak antiferromagnetic exchange between the copper(II) ions ( J=−2.09(8) cm −1) through the double end-on azide bridges.

Synthesis, spectral, magnetic and crystal structural characterization of two new copper(II) azido complexes: catena-[μ(N 3)Cu(pyridine) 3] n(PF 6) n and dimeric [Cu(4-ethylpyridine)(N 3) 2] 2

Two new copper(II) azide complexes, namely [Cu(pyridine) 3(N 3)](PF 6) ( 1) and Cu(4-ethylpyridine)(N 3) 2 have been synthesized and characterized by spectroscopic and crystallographic methods. The structure of 1 contains a polymeric cation [Cu(pyridine) 3(N 3)] + and PF 6 − anion. Each copper atom, in the cation, is five coordinated by three nitrogen atoms from the pyridine ligands and two nitrogens from two μ(1,3) azide bridges forming a 1D structure. The geometry around each copper atom is best described as a square pyramid, and the azide group is asymmetric. The structure of complex 2 features dimeric molecules, copper atoms coordinated by three nitrogen atoms from two μ(1,1) azide bridges forming a Cu 2N 2 unit and a third azide group, the fourth site is occupied by the pyridine nitrogen. The third azide group links another two different copper atoms from an adjacent dimer at CuN distances of 2.729(12) and 3.206(12) Å. Thus this azide group functions as a μ(1,1,3) tridentate bridging ligand. The IR and electronic spectra are reported. Strong absorption bands due to N 3→Cu II CT transitions are observed in spectra of solids and solutions of both complexes. Magnetic susceptibilities at different temperatures of both complexes are presented and discussed.

Copper(II) azide complexes of aliphatic and aromatic amine based tridentate ligands: novel structure, spectroscopy, and magnetic properties.

Copper(II) azide complexes of three tridentate ligands namely 2,6-(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L), 2,6-(pyrazol-1-ylmethyl)pyridine (L'), and dipropylenetriamine (dpt) yield three kinds of complexes with different azide-binding modes. The ligand L forms two end-on-end (mu-1,3) diazido-bridged binuclear complexes, [CuL(mu-N(3))](2)(ClO(4))(2) (1) and [CuL(mu-N(3))(ClO(4))](2).2CH(3)CN (2), and L' forms a perchlorato-bridged quasi-one-dimensional chain complex, [CuL'(N(3))(ClO(4))](n)() (3) with monodentate azide coordination. The ligation of dipropylenetriamine (dpt) gives a end-on (mu-1,1) diazido-bridged binuclear copper complex [Cu(dpt)(mu-N(3))](2)(ClO(4))(2) (4). The crystal and molecular structures of these complexes have been solved. Variable-temperature EPR results of 1 and 2 are identical and indicate the presence of both ferromagnetic and antiferromagnetic interactions within the dimer, the former dominating at low temperatures and the latter at high temperatures. The unusual temperature-dependent magnetic moment and EPR spectra of this dimer reveal the presence of temperature-dependent population of two triplet states, one being caused by antiferromagnetic and the other by ferromagnetic interaction, the former transforming to the latter on cooling. While the interaction of ground spin doublets of the two metal centers gives rise to a ferromagnetic coupling of J(g) = 90.73 cm(-1), the other coupling of J(e) = -185.64 cm(-1) is suggested to be caused by the interaction between an electron in one metal center and an electron from the azide of the other monomer by excitation of a d-electron to the empty ligand orbital. The ferromagnetic state is energetically favored by 104.39 cm(-1). Compound 3 exhibits axial spectra at room temperature and 77 K, and variable-temperature magnetic susceptibility data indicate that the copper centers form a weakly antiferromagnetic one-dimensional chain with J = -0.11 cm(-1). In the case of 4, the unique presence of two nonidentical dimeric units with different bond lengths and bond angles within the unit cell as inferred by crystal structure is proved by single-crystal EPR spectroscopy.

1D Polymeric copper(II) azido complexes. Synthesis, spectral and structural studies of [Cu(ethyl isonicotinate)2(N3)2]n and [Cu(methyl isonicotinate)2(NO3)(N3)]n complexes

Two new 1:2 polymeric complexes of copper(II) azide with ethyl isonicotinate (1) and methyl isonicotinate (2) have been synthesized and characterized by spectroscopic and crystallographic methods. The polymeric structure of complex (1) features six coordinated copper centers, a pair of trans-coordinated ligand molecules, and asymmetric μ2-1,1 and μ2-1,3-azido bridges resulting in a 1D chain structure. In complex (2), each copper atom which is located at an inversion center, is coordinated to a pair of trans ligand molecules, to the nitrogen atom of two μ-1,1-azido ligand and to an oxygen atom of a bridging (μ-O,O′) nitrogen group. The i.r., electronic and e.s.r. spectra of the complexes are reported.

Syntheses, X-ray structures, spectroscopic and magnetic studies of two new polymeric copper (II) azide complexes; [Cu (3-ethylpyridine) 2 (N 3) 2] n and [Cu (4-ethylpyridine) 2 (N 3) 2] n

Two new 1:2 polymeric complexes of copper (II) azide with 3-ethylpyridine (1) and 4-ethylpyridine (2), have been synthesized and characterized by spectroscopic and crystallographic methods. The structure of complex (1) contains a dimeric [Cu (3-Etpy) 2 (N 3) 2] 2 unit and a monomeric [Cu (3-Etpy) 2 (N 3) 2] unit. Each copper atom in the dimeric unit attains a five coordination environment, whereas the copper atom in the second unit has an elongated octahedral geometry. In complex (2), each copper atom in the asymmetric unit is coordinated to the end nitrogens of two μ 2-1,3 azido ligands, a pair of trans 4-Etpy molecules and a nitrogen atom of a terminal azide group. This same nitrogen atom further links a neighboring copper atom at a long Cu–N distance of 2.920 (7) Å, thus connecting the asymmetric units giving rise to a 2D structure. The IR and electronic spectra are reported. Strong absorption bands due to N 3 → Cu IIMLCT transitions are observed in spectra of solids and solutions of both complexes. Magnetic susceptibility and EPR data of both complexes are presented and discussed.

Synthesis, structural and spectral characterization of two polymeric complexes of 2-chloropyridine and 3-benzoylpyridine with copper(II) azide; [Cu(2-chloropyridine(N 3) 2] n and [Cu(3-benzoylpyridine) 2(N 3) 2] n

Two new polymeric mixed ligand complexes of copper(II) azide with 2-chloropyridine ( 1) and 3-benzoylpyridine ( 3) have been prepared and characterized by crystallographic and spectroscopic methods. The 1:1 complex of 2-chloropyridine features penta-coordinate copper centers and two μ(1,1) bridging azido ligands forming chains of polyhedra along the a-axis of the unit cell. In the 1:2 complex, 2, two copper atoms are located at different inversion centers. The coordination geometries of both copper atoms may be described as distorted tetragonal bipyramids and both azides serve as μ(1, 3) bridging ligands giving rise to chains of polyhedra. The IR and Raman spectra are reported and vibrational bands of diagnostic values compared with those of parent ligands and correlated with the structures of the complexes. The solid and solution electronic spectra of 1 and 2 display strong absorptions due to N 3 − → Cu II charge transfer transitions. The EPR spectra of powder samples and DMF solutions are recorded at both room temperature and 77 K.

A copper(II) azide compound of pyrazinic acid containing a new dinuclear complex anion [Cu 2(N 3) 6] 2−. Synthesis, spectral and study of KCu 2(pyrazinato) (N 3) 4

A new complex of copper(II) azide with pyrazinic acid, of general formula KCu 2(pyrazinato)(N 3) 4 has been synthesized and characterized by spectroscopic and crystallographic methods. The structure of the complex consists of a new dinuclear complex anion [Cu 3(N 3) 6] 2−, potassium cations and neutral polymeric complex [Cu(pyrazinato)(N 3)]. Each distorted square-planar copper centre [Cu(1)] in the complex anion is coordinated to four nitrogen atoms from two terminal and two μ-(1,1) bridging azido ligands [CuN distances 1.940(6)–2.011(5) Å]. In the polymeric complex, each copper atom, Cu(2), is coordinated to N(41) of a terminal azido group and N(61), N(62) and O(31) from pyrazinato anions to form infinite, “neutral” chains of polyhedra with orientations along [010]. The potassium cations are located in broad channels which are a consequence of stacking of the copper complexes. The IR spectrum confirms the presence of different asymmetric azido ligands. The absorption frequencies of diagnostic values are given and discussed. The electronic spectrum displays three absorption bands associated with N 3 −Cu II charge transfer transitions. The EPR spectrum of the solid complex suggests an axial structure with non-coupled copper(II) atoms.

Polymeric complexes of copper(II) azide and 2,5-dimethylpyridine without and with solvent molecules. Synthesis, spectral and structural characterization of [Cu(2,5-dimethylpyridine) (N 3) 2] n and [Cu(2,5-dimethylpyridine) (N 3) 2(H 2N-CHO)] 2

Catina di-μ(1,1)-azido[di-μ(1,1)-azidobis(2,5-dimethylpyridine)dicopper(II)] ( 1) and di-μ(1,1)-azidobis[azido(2,5-dimethylpyridine)(formamide)]dicopper(II) ( 2) were synthesized and characterized by spectroscopic and crystallographic methods. In the triclinic complex 1 the copper(II) centres are penta-coordinated by four nitrogen atoms from the azido ligands [CuN distances = 1.980(3)-2.249(4) Å] and a fifth nitrogen from the organic molecule at a CuN bond length of 2.038(4) Å. Both azido ligands function as μ(1,1) bridges to form chains of polyhedra along the crystallographic a axis. The dimeric molecule 2, which possesses a crystallographic inversion centre, contains both terminal and μ(1,1) bridging azido ligands. Each copper(II) atom is further coordinated by a 2,5-dimethylpyridine molecule [ Cu O = 1.998(4) A ̊ ] and a formamide molecule via its carbonyl oxygen atom [ Cu O = 2.356(4) A ̊ ] to give a distorted square pyramid. The IR absorption spectra reveal asymmetric azido ligands in both complexes, O-bonded formamide and hydrogen bonds as well, in 2. The solid and solution electronic spectra of both complexes exhibit more than one strong N 3 − → Cu II charge-transfer transition band. The room-temperature EPR spectra of powdered samples and DMF solutions were recorded and discussed.