Ionic Ferrocenyl Coordination Compounds Derived from Imidazole and 1,2,4‐Triazole Ligands and Their Catalytic Effects During Combustion

Alkylferrocene‐based burning‐rate catalysts (BRCs) show conspicuous migration tendency and volatility during prolonged storage and fabrication process of a composite solid propellant. To enhance anti‐migration ability of the BRCs, forty novel ionic coordination compounds, [M(L)₄(H₂O)₂]_mX_n (M = Mn²⁺, Co²⁺, Cu²⁺, Ni²⁺, Zn²⁺, Fe²⁺, Pb²⁺, Cr³⁺, Bi³⁺, or Cd²⁺; L = ferrocenylmethyl imidazole or ferrocenylmethyl‐1,2,4‐triazole; X = picrate or trinitroresorcinolate), were synthesized and characterized by FT‐IR, UV/Vis, and elementary analysis. Additionally, the crystal structures of six compounds were confirmed by single‐crystal X‐ray diffraction. The TG analyses revealed that the new compounds show high thermal stability. Cyclic voltammetry studies suggested that theyare irreversible redox systems. Their catalytic activities in the thermal degradation of ammonium perchlorate (AP), 1,3,5‐trinitro‐1,3,5‐triazacyclo‐hexane (RDX) and 1,2,5,7‐tetranitro‐1,3,5,7‐tetraazacyclooctane (HMX) were examined by DSC technique. The results indicated that all the new compounds exert great effects on the thermal decomposition of AP and RDX, among them some compounds are more active than catocene. Compound 26 has good catalytic ability in the thermal decomposition of HMX, representing a rare example of the reported ferrocene‐based BRCs which show catalytic activity during combustion of HMX.     

Synthesis,Characterization and Migration of Ionic Polyferrocenyl Compounds of 5‐Ferrocenyl‐1H‐tetrazole and Their Effects During Combustion

Eighteen ionic polyferrocenyl compounds with 5‐ferrocenyl‐1H‐tetrazolate as anion and mono‐ and dinuclear ferrocenyl‐alkylammonium as cations were synthesized and characterized by ¹H NMR, ¹³C NMR, FT‐IR, and UV/Vis spectroscopy, and elemental analysis. Molecular structures of three compounds were further confirmed by single‐crystal X‐ray diffraction. Their thermal stability was evaluated by TG and DSC and found that they are of high thermal stability. The cyclic voltammetry analysis suggested that each of the compounds exhibits only an irreversible redox wave of the ferrocene units in the molecule. Both migration and volatility test results showed that, on comparison with those of Catocene, all tested compounds exhibit much more excellent anti‐migration ability and most of the tested compounds have lower volatility. Their effects on the thermal disintegration of ammonium perchlorate (AP), 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX), and 1,2,5,7‐tetranitro‐1,3,5,7‐tetraazacyclooctane (HMX) were measured by DSC. The results revealed that most of the compounds exhibit significant catalytic effects on the thermal degradation of AP and RDX. Particularly, most of the compounds containing one ferrocene unit in their cations show higher activity than that of Catocene. These compounds can be used as alternatives to Catocene in the composite solid propellants.     

Mono‐ and Dinuclear Ferrocenyl Ionic Compounds with Polycyano Anions. Characterization,Migration, and Catalytic Effects on Thermal Decomposition of Energetic Compounds

Neutral ferrocene‐based burning rate (BR) catalysts show strong migration trends and volatility during long‐time storage and curing of the composite solid propellants. To reduce these disadvantages thirty‐two ferrocenyl quaternary ammonium compounds, paired with polycyano anions, were synthesized and characterized by ¹H NMR, ¹³C NMR, and UV/Vis spectroscopy, as well as elemental analysis. Additionally, crystal structures of eight compounds were confirmed by single‐crystal X‐ray diffraction. TG and DSC analyses indicated that the compounds containing 1,1,2,3,3‐pentacyanopropenide anions show high thermal stability. Cyclic voltammetry studies suggested that they are quasi‐reversible or irreversible redox systems. Anti‐migration tests verified that the tested compounds show very low migration tendency and some of them exhibit no migration after 30 days aging at 70 °C. Their catalytic efficiency in the thermal decomposition of ammonium perchlorate (AP), 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX), and 1,2,5,7‐tetranitro‐1,3,5,7‐tetraazacyclooctane (HMX) were examined by DSC analyses. The results revealed that most of the compounds exhibit distinct effects on the thermal degradation of AP and RDX. Two compounds have good catalytic ability in the thermal decomposition of HMX, representing rare examples of the reported ferrocenyl ionic compounds, which display catalytic property during combustion of HMX.     

“One‐Step” Synthesis of Ionic Ferrocenyl Compounds of Ferrocenylmethyldimethylamine. Characterization,Migration, and Catalytic Properties During Combustion

Alkylferrocene‐based burning rate catalysts exhibit high migration tendency and volatility during prolonged storage and fabrication process of the solid propellants. To retard the migration problems, eight ionic compounds composed of ferrocenylmethyldimethylammonium cation paired with a common energetic anion, were synthesized by “one‐step” procedure. The compounds were characterized by FT‐IR, NMR, and UV/Vis spectroscopy as well as elementary analysis. Their crystal structures were confirmed by single‐crystal X‐ray diffraction. The TG and DSC analyses indicated that they exhibit high thermal stability. Cyclic voltammetry studies suggested that most of them show reversible or quasi‐reversible redox waves. The anti‐migration results revealed that 1 – 4 are low‐migratory compounds, but 5 exhibits high migration trends. The TG curves at 70 °C for 24 h showed that all of them have low volatility. They have from high to low impact sensitivity depending on the anions of the compounds. They all exhibit significant effect on the thermal decomposition of ammonium perchlorate (AP) and some of them accelerate the thermal degradation of 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX). Among them 4 is the best one. Unexpectedly, compound 5 , with 1H‐tetrazolate as anion, can decompose into its original reactants at the temperature just higher than its melting point and could show smart‐material functionality in solid propellants.     

Ferrocenyl Ionic Compounds Based on 5‐Ferrocenyl‐1H‐tetrazole. Synthesis,Characterization, Migration,and Catalytic Effects During Combustion

Ferrocenyl ionic compounds, consisting of the 5‐ferrocenyltetrazolate anion and a guanidinium or a 1‐alkyl‐3‐methylimidazolium cation, were synthesized and characterized by ¹H NMR, ¹³C NMR, and UV/Vis spectroscopy, as well as elementary analysis. The molecular structures of four compounds were additionally confirmed by single‐crystal X‐ray diffraction. Results of the TG and DSC analyses showed that some compounds display high thermal stability. Cyclic voltammetry investigations suggested that the compounds exhibit redox waves for the ferrocenyl groups and are considered as irreversible redox systems. Migration studies revealed that migration trends of the compounds are much lower than that of 2, 2‐bis(ethylferrocenyl)propane (Catocene), extensively used in composite solid propellants. Their catalytic performances for thermal decomposition of ammonium perchlorate (AP), 1, 3,5‐trinitro‐1, 3,5‐triazacyclohexane (RDX), and 1, 2,5, 7‐tetranitro‐1, 3,5, 7‐tetraazacyclooctane (HMX) were evaluated by DSC and/or TG techniques. Most of the compounds exhibit high catalytic efficiency in the thermal degradation of AP and RDX. Those of the guanidine‐containing compounds 1 – 3 are better, implying that nitrogen‐rich moieties are beneficial to enhancing released heats of some energetic materials. These guanidine salts could be used as ferrocene‐based burning rate catalyst candidates in composite solid propellants.     

Ferrocenyl Ionic Compounds Containing [Fe(CN)6]3– Anions: Synthesis,Characterization, and Catalytic Effects during Combustion

Twenty‐eight novel ferrocenyl ionic compounds, composed of mononuclear 1‐ferrocenylmethylalkyldimethylammoniums, 1‐ferrocenylmethyl‐3‐alkylimidazoliums, or their dinuclear analogs and [Fe(CN)₆]^3– anion, were designed and synthesized to tackle significant volatility and migration tendency of ferrocene‐based burning rate catalysts (BRCs) used currently in the composite solid propellants. The new compounds were characterized by UV/Vis, FT‐IR, and elementary analysis. The crystal structures of compounds 2· 5H₂O and 3· CH₂Cl₂ · 4H₂O verified the successful preparation of the desired ionic compounds. The TG tests at 70 °C for 24 h revealed that the new compounds exhibit lower volatility than catocene. The cyclic‐voltammetry results suggested that new compounds are quasi‐reversible or irreversible redox systems. TheTG/DSC analyses exhibited that the compounds are of highly thermal stability. Their catalytic effects on the thermal degradation of ammonium perchlorate (AP), 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX), and 1,3,5,7‐tetranitro‐1,3,5,7‐tetrazacyclooctane (HMX) were investigated. The results showed that most of the compounds exert great effects on the thermal degradation of AP and RDX during combustion. 11 and 2 are comparable to catocene in the thermal decomposition of AP and RDX, respectively, and can therefore be used as alternatives of catocene in a composite solid propellant. Some new compounds are unexpectedly active in promoting the thermal disintegration of HMX.     

Dinuclear (Ferrocenylmethyl)imidazolium Ionic Compounds with Polycyano Anions. Characterization,Migration, and Effects during Combustion

Alkyl‐substituted ferrocene‐based burning rate catalysts exhibit high migration and volatility during curing process and prolonged storage of the composite solid propellants. To deal with the drawbacks twenty‐one dinuclear (ferrocenylmethyl)imidazolium compounds paired with polycyano anions, were synthesized and characterized by ¹H NMR, ¹³C NMR, UV/Vis, elementary analysis, and both 2 and 11 were further characterized by single‐crystal X‐ray diffraction. The migration test revealed that the compounds have excellent anti‐migration ability. The cyclic‐voltammetry results suggested that they are quasi‐reversible or irreversible redox systems. The TG/DSC analyses showed that the compounds are highly thermal stable. Their effects on the thermal decomposition of ammonium perchlorate (AP) and 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX) were additionally examined. The results showed that the new compounds have strong effects on the thermal decomposition of both AP and RDX during combustion. Both 13 and 21 are more excellent than catocene for increasing the released heats of AP and can be used as alternatives of catocene in the composite solid propellants.     

Synthesis and Esterification of 3‐Ferrocenyl Acrylic Acid in Ionic Liquid

3‐Ferrocenyl acrylic acid, synthesized from ferrocenecarboxaldehyde and propandioic acid in water‐insoluble ionic liquid (1‐butyl‐3‐methylimidazolium hexafluorophosphate, [BMIM]PF₆) at 85 °C in high yield, was transformed to a series of 3‐ferrocenyl acrylate of alcohols and phenols in water‐soluble ionic liquid (1,3‐dimethylimidazolium dimethylphosphate, [DMIM]Me₂PO₄) at room temperature in the presence of dicyclohexylcarbodiimide (DCC) and 4‐dimethylaminopyridine (DMAP).     

以三乙烯二胺为配体的过渡金属配位化合物合成、晶体结构及荧光性质研究

采用混合溶剂热法合成出一系列以三乙烯二胺（简写dabco）为配体的新型过渡金属配位化合物[CdCl₃H（dabco）₂]（1）、[CoCl₃Hdabco]（2）、[NiCl₂（H₂O）₃Hdabco]Cl（3）和[CuCl₃H（dabco）₂]Cl·H₂O（4）。对该系列化合物进行了元素分析、红外光谱以及热重分析表征,并通过X射线单晶衍射分析确定出晶体结构。结构解析表明：化合物1具有一维直链状分子结构;化合物2具有一维左螺旋状分子结构,化合物3具有一维右螺旋链状分子结构;化合物4具有二维平面网格状分子结构。对该系列化合物的荧光光谱研究结果表明,化合物1~4均具有较好的荧光性质。     

以三乙烯二胺为配体的过渡金属配位化合物合成、晶体结构及荧光性质研究

采用混合溶剂热法合成出一系列以三乙烯二胺(简写dabco)为配体的新型过渡金属配位化合物[CdCl3H(dabco)2](1)、[CoCl3Hdabco](2)、[NiCl2(H2O)3Hdabco]Cl(3)和[CuCl3H(dabco)2]Cl·H2O(4)。对该系列化合物进行了元素分析、红外光谱以及热重分析表征,并通过X射线单晶衍射分析确定出晶体结构。结构解析表明:化合物1具有一维直链状分子结构;化合物2具有一维左螺旋状分子结构,化合物3具有一维右螺旋链状分子结构;化合物4具有二维平面网格状分子结构。对该系列化合物的荧光光谱研究结果表明,化合物1~4均具有较好的荧光性质。     

Investigations on the Structure Diversity and Thermal Degradation Behavior of CdII and ZnII Thiocyanato Coordination Compounds based on 3‐Acetylpyridine as Neutral Co‐Ligand

Reaction of Cd^II and Zn^II thiocyanate with 3‐acetylpyridine leads to the formation of the new Cd^II and Zn^II coordination compounds [Cd(NCS)₂(3‐acetylpyridine)₄] ( 1A ), [Cd(NCS)₂(3‐acetylpyridine)₂]_n ( 1B ), [Cd(NCS)₂(3‐acetylpyridine)]_n ( 1C ) and [Zn(NCS)₂(3‐acetylpyridine)₂] ( 2A ). Compound 1A consists of discrete complexes, in which the metal centers are octahedrally coordinated by four terminal bonded N‐donor co‐ligands and two terminal N‐bonded thiocyanato anions. In compound 2A the metal centers are only tetrahedrally coordinated by two terminal bonded N‐donor co‐ligands and two terminal N‐bonded thiocyanato anions. In compound 1B the Cd^II cations are octahedrally coordinated by two terminal bonded N‐donor co‐ligands and four thiocyanato anions. The metal centers are linked by μ‐1, 3 bridging thiocyanato anions into chains. In compound 1C the metal cations are octahedrally coordinated by two μ‐1, 5 bridging 3‐acetyl‐pyridine ligands and four μ‐1, 3 bridging thiocyanato anions building up a three‐dimensional coordination network. Investigations on the thermal degradation behavior of all compounds using simultaneous differential thermoanalysis and thermogravimetry as well as X‐ray powder diffraction and IR spectroscopy prove that on heating compound 2A decompose without the formation of 3‐acetylpyridine‐deficient intermediates. In contrast, for compound 1A a stepwise decomposition is observed, leading to the formation of the 3‐acetylpyridine‐deficient compound [Cd(NCS)₂(3‐acetylpyridine)₂]_n ( 1B ) which decomposes on further heating     

Synthesis and Characterization of 1,2-Dimethyl Imidazolium Ionic Liquids and Their Catalytic Activities

The synthesis of substituted imidazolium-type ionic liquids via a simple method is described. Our synthesized ionic liquids are more useful in the catalytic behavior of the Mannich reaction.     

Some Polynuclear Coordination Compounds Precursors of Chromites Synthesis,Physicochemical Characterization and Thermal Stability

The polynuclear coordination compounds LnCr(tartrate)₃·nH₂O where Ln(III)=La-Er, obtained through a precipitation method, were characterized on the basis of elemental analysis, their electronic and vibrational spectra and magnetic susceptibility measurements. The possibility of obtaining chromites through the transformations of the polynuclear coordination compounds in the solid state was considered. The thermal decompositions of these compounds, studied by TG and DTA methods, were found to follow an almost uniform pattern. The decompositions occurred in six-eight steps. The first two steps involved dehydration, and the third the transformation of tartrate anions to oxalate, followed by conversion to carbonate and oxocarbonate intermediates. The final product in each case was LnCrO₃. A non-isothermal kinetic analysis of the first decomposition steps was performed, the most probable decomposition mechanism being selected and the kinetic parameters evaluated. The final products of the transformations were characterized. This revised version was published online in August 2006 with corrections to the Cover Date.     

A Facile Route for the Synthesis of Polycationic Tellurium Cluster Compounds: Synthesis in Ionic Liquid Media and Characterization by Single‐Crystal X‐ray Crystallography and Magnetic Susceptibility

An innovative soft chemical approach was applied, using ionic liquids as an alternative reaction medium for the synthesis of tellurium polycationic cluster compounds at room temperature. [Mo₂Te₁₂]I₆, Te₆[WOCl₄]₂, and Te₄[AlCl₄]₂ were isolated from the ionic liquid [BMIM]Cl/AlCl₃ ([BMIM]⁺: 1‐n‐butyl‐3‐methylimidazolium) and characterized. Black, cube‐shaped crystals of [Mo₂Te₁₂]I₆, which is not accessible by conventional chemical transport reaction, were obtained by reaction of the elements at room temperature in [BMIM]Cl/AlCl₃. The monoclinic structure (P2₁/n, a = 1138.92(2) pm, b = 1628.13(2) pm, c = 1611.05(2) pm, β = 105.88(1) °) is homeotypic to the triclinic bromide [Mo₂Te₁₂]Br₆. In the binulear complex [Mo₂Te₁₂]⁶⁺, the molybdenum(III) atoms are η⁴‐coordinated by terminal Te₄²⁺ rings and two bridging η²‐Te₂^2– dumbbells. Despite the short Mo···Mo distance of 297.16(5) pm, coupling of the magnetic moments is not observed. The paramagnetic moment of 3.53 μ_B per molybdenum(III) atom corresponds to an electron count of seventeen. Black crystals of monoclinic Te₆[WOCl₄]₂ are obtained by the oxidation of tellurium with WOCl₄ in [BMIM]Cl/AlCl₃. Tellurium and tellurium(IV) synproportionate in the ionic liquid at room temperature yielding violet crystals of orthorhombic Te₄[AlCl₄]₂.     

新型Salen型配合物的合成和表征及轴向配位热力学

采用金属模板法合成了四个新型Salen型单、双核金属配合物,并用元素分析、核磁共振(1HNMR)、电喷雾质谱(ESI-MS)、傅里叶变换红外光谱(FT-IR)等手段进行了表征.使用紫外-可见(UV-Vis)光谱滴定法和圆二色(CD)光谱研究了主体金属镍配合物与咪唑类含氮小分子的轴向配位反应热力学性质.结果表明:主体与咪唑(Im)和N-甲基咪唑(N-MeIm)的配位数是2,而与2-Et-4-MeIm和2-MeIm的配位数是1;轴配体系的热力学数据显示主体与咪唑类配体的平衡常数按K苓(Im)K苓(N-MeIm)K苓(2-Et-4-MeIm)K苓(2-MeIm)顺序依次减小;测得的△rHm苓和△rSm苓数据表明该轴向配位反应为放热、熵增加过程.     

Salen‐Based Coordination Polymers of Manganese and the Rare‐Earth Elements: Synthesis and Catalytic Aerobic Epoxidation of Olefins

Treatment of N,N′‐bis(4carboxysalicylidene)ethylenediamine (H₄L), with MnCl₂ ? (H₂O)₄, and Ln(NO₃)₃ ? (H₂O)_m (Ln=Nd, Eu, Gd, Dy, Tb), in the presence of N,N‐dimethylformamide (DMF)/pyridine at elevated temperature resulted (after work up) in the formation of 1D coordination polymers {[Ln₂(MnLCl)₂(NO₃)₂(dmf)₅] ? 4 DMF}_n ( 1 – 5 ). In these coordination polymers the rare earth ions are connected through carboxylate groups from Mn–salen units in a 1D chain structure. Thus, the Mn–salen complex acts as a “metalloligand” with open coordination sites. All compounds were used as catalysts in the liquid‐phase epoxidation of trans‐stilbene with molecular oxygen, which resulted in the formation of stilbene oxide. Since the choice of the lanthanide had virtually no influence on the performance of the catalyst, only the manganese–gadolinium was studied in detail. The influence of solvent, catalyst concentration, reaction temperature, oxidant, and oxidant flow rate on conversion, yield, and selectivity was analyzed. A conversion of up to 70 %, the formation of 61 % stilbene oxide (88 % selectivity), and a TON of 84 were observed after 24 h. A hot filtration test confirmed that the reaction is mainly catalyzed through a heterogeneous pathway, although a minor contribution of homogeneous species could not be completely excluded. The catalyst could be reused without significant loss of activity.     

Design and Assembly of a Chiral Metallosalen‐Based Octahedral Coordination Cage for Supramolecular Asymmetric Catalysis

Supramolecular containers featuring both high catalytic activity and high enantioselectivity represent a design challenge of practical importance. Herein, it is demonstrated that a chiral octahedral coordination cage can be constructed by using twelve enantiopure Mn(salen)‐derived dicarboxylic acids as linear linkers and six Zn₄‐p‐tert‐butylsulfonylcalix[4]arene clusters as tetravalent four‐connected vertices. The porous cage features a large hydrophobic cavity (≈3944 ų) decorated with catalytically active metallosalen species and is shown to be an efficient and recyclable asymmetric catalyst for the oxidative kinetic resolution of racemic secondary alcohols and the epoxidation of olefins with up to >99 % enantiomeric excess. The cage architecture not only prevents intermolecular deactivation and stabilizes the Mn(salen) catalysts but also encapsulates substrates and concentrates reactants in the cavity, resulting in enhanced reactivity and enantioselectivity relative to the free metallosalen catalyst.     

Synthesis of Silsesquioxanes with Substituted Triazole Ring Functionalities and Their Coordination Ability

A synthesis of a series of mono-T₈ and difunctionalized double-decker silsesquioxanes bearing substituted triazole ring(s) has been reported within this work. The catalytic protocol for their formation is based on the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) process. Diverse alkynes were in the scope of our interest—i.e., aryl, hetaryl, alkyl, silyl, or germyl—and the latter was shown to be the first example of terminal germane alkyne which is reactive in the applied process’ conditions. From the pallet of 15 compounds, three of them with pyridine-triazole and thiophenyl-triazole moiety attached to T₈ or DDSQ core were verified in terms of their coordinating properties towards selected transition metals, i.e., Pd(II), Pt(II), and Rh(I). The studies resulted in the formation of four SQs based coordination compounds that were obtained in high yields up to 93% and their thorough spectroscopic characterization is presented. To our knowledge, this is the first example of the DDSQ-based molecular complex possessing bidentate pyridine-triazole ligand binding two Pd(II) ions.     

Syntheses,Structures, and Thermal Reactivity of New ZnII and CdII Thio‐ and Selenocyanato Coordination Compounds

Reaction of Zn^II and Cd^II thiocyanate or selenocyanate with pyrazine leads to the formation of new Zn^II and Cd^II coordination compounds. The structures of [Zn(NCSe)₂(pyrazine)₂]_n ( 1A ), [Cd(NCS)₂(pyrazine)₂]_n ( 2A ) and [Cd(NCSe)₂(pyrazine)₂]_n ( 3A ) consist of octahedrally coordinated metal cations which are surrounded by two terminal N‐bonded anions and two μ₂‐bridging pyrazine molecules. The metal cations are connected via the pyrazine ligands into layers, which are further linked by weak intermolecular S···S respectively Se···Se interactions. Investigations on the thermal degradation behavior of 1A , 2A , and 3A using simultaneous differential thermoanalysis and thermogravimetry as well as X‐ray powder diffraction, IR‐ and Raman spectroscopy prove that on heating, the pyrazine‐rich compound 1A decomposes in one step into zinc selenocyanate without the formation of a pyrazine‐deficient intermediate. In contrast, for compounds 2A and 3A a stepwise decomposition is observed, leading to the formation of the pyrazine‐deficient compounds [Cd(NCS)₂(pyrazine)]_n ( 2B‐I and 2B‐II ) and [Cd(NCSe)₂(pyrazine)]_n ( 3B ) as intermediates. The structures and the thermal reactivity are discussed and compared with that of related transition metal thiocyanates and selenocyanates with pyridine as N‐donor ligand.