Syntheses,Structures, and Magnetic Behavior of New Azide Linked Compounds with One‐ and Two‐Dimensional Structures

Three azide based compounds were synthesized employing aliphatic amines as site blocking agents: [Ni(N₃)(C₆H₁₆N₂)₂]ClO₄ ( I ) [C₆H₁₆N₂ = N,N′‐diethylethylenediamine (DEDA)], [Cu₈(N₃)₁₆(C₆H₁₈N₄)₂] ( II ) [C₆H₁₈N₄ = tris(2‐aminoethyl) amine (TREN)], and [Cu₇(N₃)₁₄(C₇H₁₉N₃)₂] · 2H₂O ( III ) [C₇H₁₉N₃ = 3,3′‐diamino‐N‐methyldipropylamine (DMDA)]. The compounds I and II have one‐dimensional structure and III has a two‐dimensional structure. Compound I is a simple linear cationic Ni–azide chain and compound II has Cu₆ azide units forming a column terminated by the copper‐metalloligand generated in‐situ during the course of the reaction. The charge compensation perchlorate anions occupy spaces in between the chains in I . Compound II packs in a herringbone arrangement, which is not commonly observed in low‐dimensional structures. Compound III has one‐dimensional copper‐azide chains connected through copper‐metalloligand forming the two‐dimensional structure. All the three compounds exhibit anti‐ferromagnetic behavior.     

Two Diammonium Copper Azides with Similar Layerlike Magnetic Substructures Made of Chains of Serially Connected Cu6 Rings Show Cation‐Modulated Magnetism

We present here the first examples of Cu–azide compounds synthesized by using protonated diamine ions as cationic templates: (dmenH₂)[Cu₆(N₃)₁₄] and (trimenH₂)[Cu₆(N₃)₁₄] (dmenH₂²⁺: N,N′‐dimethylethylenediammonium; trimenH₂²⁺: N,N,N′‐trimethylethylenediammonium). Both compounds possess a similar, rarely observed anionic Cu–azide layer, which consists of [Cu₆(N₃)₁₄^2?]_n anionic chains linked by asymmetric end‐to‐end azido bridges. The chain, in turn, is made up of elongated Cu₆ rings, with double and single end‐on azido linkages between the square‐planar Cu²⁺ sites within the ring and double end‐on azido bridges serially connecting the rings. The molecular geometry results in ferromagnetic interactions within the Cu–azide layer in both compounds. The interlayer separations are determined by the cations, with the shortest interlayer Cu???Cu separations being 8.016 Å for the dmenH₂²⁺ compound and 9.106 Å for the trimenH₂²⁺ compound. These different interlayer separations tune the magnetic properties of the two materials. The dmenH₂²⁺ compound displays long‐range antiferromagnetic ordering at lowtemperature and short‐range ferromagnetic interaction at high temperature, while only short‐range ferromagnetism was observed in the trimenH₂²⁺compound at 2–300 K.     

Quantification of ATRP initiator density on polymer latex particles by fluorescence labeling technique using copper‐catalyzed azide‐alkyne cycloaddition

We developed a novel fluorescence labeling technique for quantification of surface densities of atom transfer radical polymerization (ATRP) initiators on polymer particles. The cationic P(St‐CPEM‐C₄DMAEMA) and anionic P(St‐CPEM) polymer latex particles carrying ATRP‐initiating chlorine groups were prepared by emulsifier‐free emulsion polymerization of styrene (St), 2‐(2‐chloropropionyloxy)ethyl methacrylate (CPEM), and N‐n‐butyl‐N,N‐dimethyl‐N‐(2‐methacryloyloxy)ethylammonium bromide (C₄DMAEMA). ATRP initiators on the surface of polymer particles were converted into azide groups by sodium azide, followed by fluorescent labeling with 5‐(N,N‐dimethylamino)‐N′‐(prop‐2‐yn‐1‐yl)naphthalene‐1‐sulfonamide (Dansyl‐alkyne) by copper‐catalyzed azide‐alkyne cycloaddition (CuAAC). The reaction time required for both azidation of ATRP‐initiating groups and successive fluorescence labeling of azide groups with Dansyl‐alkyne by CuAAC were investigated in detail by FTIR and fluorescence spectral measurement, respectively. The ATRP initiator densities on the cationic P(St‐CPEM‐C₄DMAEMA) and anionic P(St‐CPEM) particle surfaces were estimated to be 0.21 and 0.15 molecules nm^?2, respectively, which gave close agreement with values previously determined by a conductometric titration method. The fluorescence labeling through click chemistry proposed herein is a versatile technique to quantify the surface ATRP initiator density both on anionic and cationic polymer particles. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4042–4051     

Synthesis,Characterization, and Crystal Structures of Various Energetic Urotropinium Salts with Azide,Nitrate, Dinitramide and Azotetrazolate Counter Ions

Urotropinium nitrate, N‐methylurotropinium azide, dinitramide and azotetrazolate salts have been prepared and fully characterized by analytical and spectoscopic (¹H, ¹³C, ¹⁴N NMR, IR, Raman) methods. The structures of all four compounds have been determined using X‐ray diffraction techniques and represent new examples of the class of high energy density materials (HEDMs).     

Copper‐Catalyzed Cascade Cyclization Reaction of 2‐Haloaryltriazenes and Sodium Azide: Selective Synthesis of 2 H‐Benzotriazoles in Water

A new approach to the synthesis of 2 H‐benzotriazoles is described. This strategy is based on the copper‐catalyzed C?N coupling of 2‐haloaryltriazenes or 2‐haloazo compounds with sodium azide and the intramolecular addition of nitrene to N?N bonds. This approach allows the synthesis of various N‐amino‐ and N‐aryl‐2 H‐benzotriazoles in water, in good to excellent yields. The procedure is simple and the starting materials and catalyst are easily available, offering a practical and convenient synthetic route to 2‐substituted benzotriazoles.     

Crystal Structure and Spectroscopic Properties of cis‐β‐Diazido(1,4,7,11‐tetraazaundecane)chromium(III) Bromide

The new complex, cis‐β‐[Cr(2,2,3‐tet)(N₃)₂]Br (2,2,3‐tet = 1,4,7,11‐tetraazaundecane), was prepared and its structure was determined by single‐crystal X‐ray diffraction. The chromium(III) atom is in a distorted octahedral environment coordinated by four nitrogen atoms of 2,2,3‐tet and two azido ligands in a cis‐β arrangement, with bent Cr–N₃ linkages at the coordinating azide nitrogen atoms. The mean Cr–N(2,2,3‐tet) and Cr–N(azide) bond lengths are 2.084(5) and 2.021(5) Å, respectively. The crystal structure is stabilized by ionic interactions, supported by N–H ··· N(azide) and N–H ··· Br hydrogen bonds. The IR and electronic spectroscopic properties are also discussed.     

Synthesis of 5‐Aminotetrazole‐1 N‐oxide and Its Azo Derivative: A Key Step in the Development of New Energetic Materials

1‐Hydroxy‐5‐aminotetrazole ( 1 ), which is a long‐desired starting material for the synthesis of hundreds of new energetic materials, was synthesized for the first time by the reaction of aqueous hydroxylamine with cyanogen azide. The use of this unique precursor was demonstrated by the preparation of several energetic compounds with equal or higher performance than that of commonly used explosives, such as hexogen (RDX). The prepared compounds, including energetic salts of 1‐hydroxy‐5‐aminotetrazole (hydroxylammonium ( 2 , two polymorphs) and ammonium ( 3 )), azo‐coupled derivatives (potassium ( 5 ), hydroxylammonium ( 6 ), ammonium ( 7 ), and hydrazinium 5,5′‐azo‐bis(1‐N‐oxidotetrazolate ( 8 , two polymorphs)), as well as neutral compounds 5,5′‐azo‐bis(1‐oxidotetrazole) ( 4 ) and 5,5′‐bis(1‐oxidotetrazole)hydrazine ( 9 ), were intensively characterized by low‐temperature X‐ray diffraction, IR, Raman, and multinuclear NMR spectroscopy, elemental analysis, and DSC. The calculated energetic performance, by using the EXPLO5 code, based on the calculated (CBS‐4M) heats of formation and X‐ray densities confirm the high energetic performance of tetrazole‐N‐oxides as energetic materials. Last but not least, their sensitivity towards impact, friction, and electrostatic discharge were explored. 5,5′‐Azo‐bis(1‐N‐oxidotetrazole) deflagrates close to the DDT (deflagration‐to‐detonation transition) faster than all compounds that have been investigated in our research group to date.     

Synthesis of well‐defined azide‐terminated poly(vinyl alcohol) and their subsequent modification via click chemistry

A new azide‐functionalized xanthate, S‐(4‐azidomethylbenzyl) O‐(2‐methoxyethyl) xanthate, was synthesized and used to mediate the reversible addition fragmentation chain transfer polymerization of vinyl acetate. The polymerization was demonstrated to be controlled, and well‐defined PVAc with α‐azide, ω‐xanthate groups were obtained, the xanthate groups of which were further removed by radical‐induced reduction with lauroyl peroxide in the presence of excess 2‐propanol. Hydrolysis of α‐azide‐terminated PVAc (N₃‐PVAc) led to the formation of the corresponding α‐azide‐terminated PVA (N₃‐PVA). Finally, end‐modification of N₃‐PVA by click chemistry with alkyne‐end‐capped poly(caprolactone) (A‐PCL), alkynyl‐mannose, and alkynyl‐pyrene was carried out to obtain a new block copolymer PCL‐b‐PVA, and two PVA with mannose or pyrene as the end functional groups. The polymers were characterized by gel permeation chromatography, ¹H NMR spectroscopy, and FTIR. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4494–4504, 2009     

Synthese und Kristallstruktur von 2‐Azido‐4,6‐dichloro‐s‐triazin

Synthesis and Crystal Structure of 2‐Azido‐4,6‐dichloro‐s‐triazine Single crystals of 2‐azido‐4,6‐dichloro‐s‐triazine were obtained from a reaction between cyanuric chloride and sodium azide. The structure of this compound was determined by single crystal X‐ray diffraction. 2‐Azido‐4,6‐dichloro‐s‐triazine crystallizes in the orthorhombic space group Pbca (no. 61), Z = 8, a = 746.48(8) pm, b = 952.6(1) pm, c = 2001.6(2) pm. The crystal structure contains (C₃N₃)(N₃)Cl₂ molecules being arranged in a tape‐like fashion, with tapes running along a‐axis direction. The tapes are combined with each other by interlocking azide‐ligands including an angle of approximately 90°. This arrangement leads to the formation of corrugated layers in the crystal structure.     

Identification of 2‐chloropyrazine oxidation products and several derivatives by multinuclear magnetic resonance

¹H, ¹³C, ¹⁴N and ¹⁵N NMR chemical shifts were used to prove the structures of the products of 2‐chloropyrazine oxidation. It was shown that oxidation by hydrogen peroxide in acetic acid or m‐chloroperbenzoic acid leads to the N4‐oxide, whereas potassium persulfate in sulfuric acid gives the N1‐oxide as the main product. Additionally, the results of NMR measurements of products from the nucleophilic substitution of the chlorine atom by azide anion, yielding the respective azides, and ethylation reactions of both 2‐chloropyrazine N‐oxides leading to the N‐ethyl salts confirm the structures of both isomeric N‐oxides. Protonation studies of the compounds obtained are also reported. The favoured protonation site is found to be the N atom that is not hindered by any substituents, and in some cases probably the oxygen atom of the N‐oxide function. Copyright © 2003 John Wiley & Sons, Ltd.     

Syntheses,Characterization and Crystal Structures of Three Structurally Similar Dinuclear Schiff Base Cadmium(II) Complexes with Bridging Azide or Thiocyanate Ligands

Three novel Schiff base cadmium(II) complexes, derived from the end‐on (μ‐1,1‐N₃) azide or end‐to‐end (μ‐1,3‐NCS) thio cyanate bridges and similar tridentate Schiff base ligands, have been synthesized under similar synthetic procedures and their crystal structures determined by X‐ray diffraction methods. They are the dinuclear double end‐on azide‐bridged [Cd₂(L1)₂(N₃)₂(μ‐1,1‐N₃)₂] ( 1 ), the dinuclear double end‐on azide‐bridged [Cd₂(L2)₂(N₃)₂(μ‐1,1‐N₃)₂] ( 2 ), and the dinuclear double end‐to‐end thiocyanate‐bridged [Cd₂(L3)₂(NCS)₂(μ_1,3‐NCS)₂] ( 3 ), where L1, L2 and L3 are three similar tridentate Schiff bases obtained by condensation of 2‐pyridylaldehyde with N,N‐diethylethane‐1,2‐diamine, of 2‐pyridylaldehyde with N‐isopropylethane‐1,2‐diamine, and of 2‐pyridylaldehyde with N,N‐dimethylpropane‐1,3‐diamine, respectively. Each cadmium(II) centre in the complexes is in a distorted octahedral coordination. There is a crystallographic inversion centre in each of the complexes. The similar small ligands used as the secondary ligands in the preparation of the cadmium(II) complexes with similar Schiff bases can result in similar structures.     

Low‐Valent Iron(I) Amido Olefin Complexes as Promotors for Dehydrogenation Reactions

Fe^I compounds including hydrogenases show remarkable properties and reactivities. Several iron(I) complexes have been established in stoichiometric reactions as model compounds for N₂ or CO₂ activation. The development of well‐defined iron(I) complexes for catalytic transformations remains a challenge. The few examples include cross‐coupling reactions, hydrogenations of terminal olefins, and azide functionalizations. Here the syntheses and properties of bimetallic complexes [MFe^I(trop₂dae)(solv)] (M=Na, solv=3 thf; M=Li, solv=2 Et₂O; trop=5H‐dibenzo[a,d]cyclo‐hepten‐5‐yl, dae=(N‐CH₂‐CH₂‐N) with a d⁷ Fe low‐spin valence‐electron configuration are reported. Both compounds promote the dehydrogenation of N,N‐dimethylaminoborane, and the former is a precatalyst for the dehydrogenative alcoholysis of silanes. No indications for heterogeneous catalyses were found. High activities and complete conversions were observed particularly with [NaFe^I(trop₂dae)(thf)₃].     

Can Cyclen Bind Alkali Metal Azides? A DFT Study as a Precursor to Synthesis

Can cyclen (1,4,7,10‐tetraazacyclododecane) bind alkali metal azides? This question is addressed by studying the geometric and electronic structures of the alkali metal azide‐cyclen [M(cyclen)N₃] complexes using density functional theory (DFT). The effects of adding a second cyclen ring to form the sandwich alkali metal azide‐cyclen [M(cyclen)₂N₃] complexes are also investigated. N₃^? is found to bind to a M⁺(cyclen) template to give both end‐on and side‐on structures. In the end‐on structures, the terminal nitrogen atom of the azide group (N1) bonds to the metal as well as to a hydrogen atom of the cyclen ring through a hydrogen bond in an end‐on configuration to the cyclen ring. In the side‐on structures, the N₃ unit is bonded (in a side‐on configuration to the cyclen ring) to the metal through the terminal nitrogen atom of the azide group (N1), and through the other terminal nitrogen atom (N3) of the azide group by a hydrogen bond to a hydrogen atom of the cyclen ring. For all the alkali metals, the N₃‐side‐on structure is lowest in energy. Addition of a second cyclen unit to [M(cyclen)N₃] to form the sandwich compounds [M(cyclen)₂N₃] causes the bond strength between the metal and the N₃ unit to decrease. It is hoped that this computational study will be a precursor to the synthesis and experimental study of these new macrocyclic compounds; structural parameters and infrared spectra were computed, which will assist future experimental work.     

Binary Polyazides of Cadmium and Mercury

Following our interest in binary element–nitrogen compounds we report here on the synthesis and comprehensive characterization (M.p., IR/Raman, elemental analysis, ¹⁴N/¹³³Cd/¹⁹⁹Hg NMR) of tri‐ and tetraazido cadmate and mercurate anions [E(N₃)_(2+n)]^n? (E=Cd, Hg; n=1, 2) in a series of [Ph₄P]⁺ and [PNP]⁺ ([PNP]⁺=bis(triphenylphosphine)iminium) salts. The azide/chloride exchange in CH₂Cl₂ as well as the formation of tetrazolate salts in CH₃CN solutions of the polyazido mercurates were investigated. Single crystal X‐ray structures of all new compounds, and for comparison [Ph₄P][Cd₂(N₃)₅(H₂O)], were determined. Moreover, the synthesis of anhydrous cadmium(II) azide and its DMSO adduct is presented for the first time. For a better understanding of structure and bonding in E(N₃)₂, [E(N₃)₃]^? and [E(N₃)₄]^2?, theoretical calculations at the M06‐2X/aug‐cc‐pVDZ level were carried out.     

Plume Deposits from Bipropellant Rocket Engines: Methylhydrazinium Nitrate and N,N‐Dimethylhydrazinium Nitrate

The predominant species in the plume residues resulting from the incomplete combustion of methylhydrazine (MMH)/N,N‐dimethylhydrazine (UDMH) and N₂O₄ (NTO) in rocket engines are methylhydrazinium and N,N‐dimethylhydrazinium nitrate. Both compounds were synthesized, characterized and their crystal structures were determined. The thermal, shock and friction sensitivity of these compounds was investigated. For both compounds the products formed in their thermal decompositions were determined.     

ABC‐type hetero‐arm star terpolymers through “Click” chemistry

Hetero‐arm star ABC‐type terpolymers, poly(methyl methacrylate)‐polystyrene‐poly(tert‐butyl acrylate) (PMMA‐PS‐PtBA) and PMMA‐PS‐poly(ethylene glycol) (PEG), were prepared by using “Click” chemistry strategy. For this, first, PMMA‐b‐PS with alkyne functional group at the junction point was obtained from successive atom transfer radical polymerization (ATRP) and nitroxide‐mediated radical polymerization (NMP) routes. Furthermore, PtBA obtained from ATRP of tBA and commercially available monohydroxyl PEG were efficiently converted to the azide end‐functionalized polymers. As a second step, the alkyne and azide functional polymers were reacted to give the hetero‐arm star polymers in the presence of CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine ( PMDETA) in DMF at room temperature for 24 h. The hetero‐arm star polymers were characterized by ¹H NMR, GPC, and DSC. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5699–5707, 2006     

Studies on the syntheses of azole derivatives. Part IX. Formation of 2,4-disubstituted δ2 -1,3,4-oxadiazolin-5-one and 4-substituted 1,2,4-triazolidin-3,5-dione derivatives by thermal reaetion of N-aryl-N-benzylearbamoyl azides

The structure of the novel produets, 2,4-ltis-(N-benzy1-4-nitroanilino)-Δ²-1,3,4-oxadiazolin-5-one (VII), 2-benzy1-1-(N-benzy1-4-chloroanilino)-4-(4-chlorophenyl)-1,2,4-triazolidin-3,5-dione (XIVa), and 2-benzy1-1-(N-benzylanilino)-4-pheny1-1,2,4-triazolidin-3,5-dione (XIVb), obtained upon thermal reaction of N-bcnzyl-N-(4-nitrophenyl)carbamoyl azide (la), N-benzyl-N-(4-chloro-phenyl)carbamoyl azide (Ib) and N-benzyl-N-phcnylcarbamoyl azide (le), respectively, were determined.     

Thermal Decomposition of New Mononuclear NiII Complexes with ONNO Type Reduced Schiff Bases and Pseudo Halogens

Mononuclear nickel(II) complexes were prepared by reaction of the three ONNO type reduced Schiff bases bis‐N,N′‐(2‐hydroxybenzyl)‐1,3‐propanediamine (L^HH₂), bis‐N,N′‐(2‐hydroxybenzyl)‐2,2′‐dimethyl‐1,3‐propanediamine (LDM^HH₂), and bis‐N,N′‐[1‐(2‐hydroxyphenyl)ethyl]‐1,3‐propanediamine (LAC^HH₂) with Ni^II ions in the presence of pseudo halides (OCN^–, SCN^– and N₃^–). The complexes were characterized with the use of elemental analyses, IR spectroscopy, and thermal analyses. The molecular structure of one of the complexes was obtained by single‐crystal X‐ray diffraction. The obtained complexes are mononuclear, and a pseudo halide molecule is attached. One of the oxygen atoms of the ligand is in phenolate and the other was in phenol form. According to the thermogravimetry results, it was thought that the pseudo halide thermally detaches from the structure as hydropseudo halide. In azide‐containing complexes an endothermic reaction was observed although the azide group usually decomposes with an exothermic reaction.     

Dual thermo‐ and pH‐sensitive network‐grafted hydrogels formed by macrocrosslinker as drug delivery system

Dual thermo‐ and pH‐sensitive network‐grafted hydrogels made of poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA) network and poly(N‐isopropylacrylamide) (PNIPAM) grafting chains were successfully synthesized by the combination of atom transfer radical polymerization (ATRP), reversible addition‐fragmentation chain transfer (RAFT) polymerization, and click chemistry. PNIPAM having two azide groups at one chain end [PNIPAM‐(N₃)₂] was prepared with an azide‐capped ATRP initiator of N,N‐di(β‐azidoethyl) 2‐chloropropionylamide. Alkyne‐pending poly(N,N‐dimethylaminoethyl methacrylate‐co‐propargyl acrylate) [P(DMAEMA‐co‐ProA)] was obtained through RAFT copolymerization using dibenzyltrithiocarbonate as chain transfer agent. The subsequent click reaction led to the formation of the network‐grafted hydrogels. The influences of the chemical composition of P(DMAEMA‐co‐ProA) on the properties of the hydrogels were investigated in terms of morphology and swelling/deswelling kinetics. The dual stimulus‐sensitive hydrogels exhibited fast response, high swelling ratio, and reproducible swelling/deswelling cycles under different temperatures and pH values. The uptake and release of ceftriaxone sodium by these hydrogels showed both thermal and pH dependence, suggesting the feasibility of these hydrogels as thermo‐ and pH‐dependent drug release devices. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

One‐pot double click reactions for the preparation of H‐shaped ABCDE‐type quintopolymer

We employed for the first time double click reactions: Cu(I) catalyzed azide‐alkyne 1,3‐dipolar cycloaddition and Diels–Alder (4 + 2) reactions for the preparation of H‐shaped polymer possessing pentablocks with different chemical nature (H‐shaped quintopolymer) using one‐pot technique. H‐shaped quintopolymer consists of poly(ethylene glycol) (PEG)‐poly(methylmethacrylate) (PMMA) and poly(ε‐caprolactone) (PCL)‐polystyrene (PS) blocks as side chains and poly (tert‐butylacrylate) (PtBA) as a main chain. For the preparation of H‐shaped quintopolymer, PEG‐b‐PMMA and PCL‐b‐PS copolymers with maleimide and alkyne functional groups at their centers, respectively, were synthesized and simply reacted in one‐pot with PtBA with α‐anthracene‐ω‐azide end functionalities in N,N‐dimethylformamide (DMF) using CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) as catalyst at 120 °C for 48 h. The precursors and the target H‐shaped quintopolymer were characterized comprehensively by ¹H NMR, UV, FTIR, GPC, and triple detection GPC. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3409–3418, 2009