Ernst-Christian Koch

Metal-Fluorocarbon-Pyrolants: III. Development and Application of Magnesium/Teflon/Viton (MTV)

The development and application of pyrotechnic payloads based on magnesium, Teflon® and Viton®, so-called MTV is reviewed. MTV is applied in decoy flares, tracking flares, countermeasure torches, base bleed units, tracer units, igniters, solid rocket propellants, RAM propellants, incendiary devices and signaling applications.

Photochemical reactions of transition metal organyl complexes with olefins Part 10. Light-induced formal [5+2] cycloadditions at manganese

Abstract Tricarbonyl-η 5 -2,4-dimethyl-2,4-pentadien-1-yl-manganese ( 1 ) forms upon UV irradiation in THF at 208 K solvent stabilized dicarbonyl-η 5 -2,4-dimethyl-2,4-pentadien-1-yl-tetrahydrofurane-manganese ( 2 ). With butynedioic acid dimethyl ester ( 3 ) and diphenylacetylene ( 5 ) complex 2 yields tricarbonyl-η 5 -1,2-dimethoxycarbonyl-4,6-dimethyl- cyclohepta-2,4-dien-1-yl-manganese ( 4 ) and tricarbonyl-η-4,6-dimethyl-1,2-diphenyl-cyclohepta-2,4-dien-1-yl- manganese ( 6 ) in a formal [5+2] cycloaddition. Addition of carbon monoxide and a 1,4-H shift completes the reaction. Propynoic acid methyl ester ( 7 ) forms the 2:1 adduct dicarbonyl-η 5:2 -1,3-dimethyl-6-methoxycarbonyl-6- ( E-2 ′-methoxycarbonylvinyl)-cyclohepta-2,4-dien-1-yl-manganese ( 8 ). The crystal and molecular structure of 8 was determined by X-ray structure analysis. The molecular structures of the complexes 4 and 6 were established by IR and NMR spectroscopy. Formation mechanisms of 4 , 6 and 8 are discussed. Crystal data for 8 : monoclinic space group P 2 1 / c , a =802.6(3), b =1136.6(1), c =8872.3(3) pm, β=93.14(2)°, V =1.705 nm 3 , Z =4.

Chlorine-Free Red-Burning Pyrotechnics

The development of a red, chlorine-free pyrotechnic illuminant of high luminosity and spectral purity was investigated. Red-light emission based solely on transient SrOH(g) has been achieved by using either 5-amino-1H-tetrazole or hexamine to deoxidize the combustion flame of a Mg/Sr(NO3 )2 /Epon-binder composition and reduce the amount of both condensed and gaseous SrO, which emits undesirable orange-red light. The new formulations were found to possess high thermal onset temperatures. Avoiding chlorine in these formulations eliminates the risk of the formation of PCBs, PCDDs, and PCDFs. This finding, hence, will have a great impact on both military pyrotechnics and commercial firework sectors.

Photochemische Reaktionen von Übergangsmetall-Organyl-Komplexen mit Olefinen, XVI [1]: Photochemisch induzierte Cycloadditionen von Diphenylacetylen an Tricarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)mangan / Photochemical Reactions of Transition Metal Organyl Complexes with Olefins, XVI [1]: Photochemically Induced Cycloadditions of Diphenylacetylene to Tricarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)manganese

Upon UV irradiation in THF at 208 K tricarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)- manganese (1) yields solvent stabilized, very reactive dicarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)(tetrahydrofuran)manganese (2), which reacts in situ with one or two molecules of diphenylacetylene (3) and yields four manganese complexes and 1,3-dimethyl-5,6-diphenyl-bicyclo[3.2.1]oct-2-ene-7-one (5), which were separated by HPL chromatography. In addition to tricarbonyl η5-4,6 -dimethyl-1,2-diphenyl-cyclohepta-2,4-dien-1-yl)manganese (4) formed by [5+2]cycloaddition and successive 1,4-H shift, tricarbonyl{ 1′,2′,5′-η-5-methyl-2,3 -diphenyl-5- (2′-methyl-4′,5′-diphenyl-penta-1′,4′-dien-1′,5′-diyl)cyclopent-2-en-1 -one-κ-O}manganese (6) is isolated with a ligand, formed from 2,4-dimethyl-2,4-pentadien-1-yl, two units of 3 and one carbon monoxide. The ligands of tricarbonyl{ 1-4,2′-η-4,6 -dimethyl-1,2-diphenyl-5-(E-1′,2′- diphenyl-vinylen)cyclohepta-1,3-diene}manganese (7), and tricarbonyl{η5-4,6 -dimethyl-1,2-diphenyl-7-(E-1′,2′-diphenyl-vinyl)cyclohepta-2,4-dien-1-yl}m anganese (8) are formed from 2,4-dimethyl-2,4-pentadien-1-yl and of two molecules of 3 each. The crystal and molecular structures of 5 and 6 have been determined by single crystal X-ray diffraction. 5 crystallizes in the triclinic space group P1̅ , a = 992.0(2) pm, b = 996.8(2) pm, c = 1021.0(2) pm, a = 77.67(3)°, β = 61.17(3)°, γ = 88.68(3)°. Complex 6 crystallizes also in the triclinic space group P1̅ ,a = 1023.2(2) pm, b - 1113.8(2) pm, c = 1567.9(3) pm, α = 82.88(3)°, β = 86.93(3)°, 7 = 63.53(3)°. The constitutions of 4, 7 and 8 were elucidated from the IR, NMR and mass spectra. Possible formation mechanisms for the compounds 4-8 are proposed. Complex 7 shows hindered rotations of two phenyl groups with different barriers of energy ΔG≠316 = 68.8 kJ/mol, „ΔH≠ = 67.9 ± 0.7 kJ/mol, ΔS≠ = -2 ± 2 J/mol · K and ΔG≠296 = 60.6 kJ/mol, ΔH≠ = 57.7 ± 1.0 kJ/mol, ΔS≠ = -10 ± 2 J/mol·K due to steric interactions.

Photochemische reaktionen von übergangsmetall-organyl-komplexen mit olefinen XI. Photochemisch induzierte CC-verknüpfung von tricarbonyl-η5-2,4-dimethyl-2,4-pentadien-1-yl-mangan mit 1-dimethylamino-2-propin—Synthese eines η5-7-dimethylamino-N-2,4-heptadien-1-yl-chelatkomplexes

Abstract UV irradiation of tricarbonyl-η5-2,4-dimethyl-2,4-pentadien-1-yl-manganese (2) in THF at 208 K yields solvent-stabilized dicarbonyl-η5-2,4-dimethyl-2,4-pentadien-1-yl-tetrahydrofurane-manganese (3), which reacts in situ with two equivalents of 1-dimethylamino-2-propyne (4) to dicarbonyl-1–5-η-2,4-dimethyl-(6-dimethylaminomethyl-N)-10-dimethylamino-deca-2,4,6,8- tetraen-1-yl-manganese (5). The crystal and molecular structure was determined by an X-ray diffraction analysis. Complex 5 crystallizes in the monoclinic space group P21/c, a = 1109.9(2) pm, b = 836.0(2) pm, c = 2156.9(4) pm, β = 93.23(3)°, V = 1.9982(7) nm3, Z = 4. Complex 5 was also studied in solution by IR and NMR spectroscopy. A possible formation mechanism of 5 will be discussed.

2,4,6‐Trinitrotoluene: A Surprisingly Insensitive Energetic Fuel and Binder in Melt‐Cast Decoy Flare Compositions

Aircraft are facing a steadily increasing threat by infraredguided ground-to-air and air-to-air missiles working in the l = 1–5 mm range. To fight these threats, aerial platforms eject pyrotechnic flares, which create an intense infrared signature to distract the seeker of the incoming missile and causes it to lose track of the target. Common firstand secondgeneration missile seekers track the hottest spot in the field of view (FOV) in the 1.9–2.6 mm range (a-band). Hence they are most advantageously countered by pyrotechnic flares that yield hot flames (T= 2000–2500 K) and a graybody type signature. Typical payloads of this type comprise magnesium/ fluorocarbon compositions. However, true aerial targets do not exhibit a graybody-type signature but radiate selectively in the range of the combustion products H2O (1.87, 2.7 mm) and CO2 (2.7, 4.3 mm). Thus so-called two-color seekers have been devised for advanced missiles that are able to distinguish between hot spot flares and true targets. These seekers evaluate the intensity ratio qb/a in two spectral ranges, a-band and b-band (3.5–4.8 mm). Thus hot graybodies yield qb/a< 1, whereas aircraft yield values between qb/a 5–20. To fight these threats, pyrotechnic flares which generate predominantly CO2 and little H2O have been described in the literature; Table 1 shows the composition of typical formulations. These formulations often comprise potassium perchlorate (KClO4) as oxidizer and oxygenated aromatic compounds, such as potassium benzoate (C7H5O2K; 1) or pyromellitic dianhydride (1,2,4,5-benzenetetracarboxylic anhydride, C10H2O6; 2), as fuel. [4] Mixtures of potassium benzoate and perchlorates are extremely sensitive to friction and impact and have caused disastrous explosions while mixing and handling. Pyromellitic dianhydride and potassium benzoate have a large negative enthalpy of formation DfH8 ( 954 and 529 kJmol , respectively), and thus yield insufficient spectral efficiency El (J g 1 s r ). In moist air, compound 2 is prone to undergo hydrolysis to give the tetracarboxylic acid, C10H6O8, which does not burn well with KClO4. The color ratio qb/a increases with increasing oxygen balance L (wt %) of a fuel; however, the spectral efficiency El decreases with the oxygen balance of the fuel. Thus it was hitherto impossible to increase both El and qb/a. Other payload types used in spectral flares resemble double base propellants and are based on nitroglycerine, (NG, C3H5N3O9), diethylene glycol dinitrate, (DEGN, C4H8N2O7), and nitrocellulose (NC, C6H7N3O11)n). [7] Payloads of this type are very sensitive and can detonate when struck by a bullet or nearby shock. In view of the deficiencies of current payloads, there is an urgent need for spectrally matched compositions that are safer to produce and less vulnerable to accidental stimuli and that prove to be at least equally or even more powerful than prior formulations. 2,4,6-Trinitrotoluene (TNT) was probably the most widely used explosive in military stores in the 20th century. Today it still plays an important role as energetic binder in melt-cast explosives based on nitroguanidine (NQ) and guanylurea dinitramide (FOX-12). TNT has been proposed as a component for detonating obscurant charges. However, owing to its character as a high explosive, it has never been considered as an energetic fuel and binder in slow burning pyrotechnic compositions. Herein, we report the findings on the use of TNT as both energetic fuel and melt-cast binder in pyrotechnic formulations. In the present study, mixtures of TNT and KClO4 were considered for use in spectrally matched decoy flare compositions. Table 2 shows the compositions investigated. The stoichiometry was varied between 35–50 wt% TNT to investigate the effect of oxygen balance of the composition, and Lx [Eq. (1)] on burn rate, color ratio, and spectral Table 1: Common spectral flare formulations A–C.

Safer pyrotechnic obscurants based on phosphorus(V) nitride

The potential of phosphorus(V) nitride, P3 N5  , as a replacement for red phosphorus, PR , in pyrotechnic obscurants has been theoretically and experimentally investigated. P3 N5 can be safely mixed with KNO3 and even KClO3 and KClO4  . The corresponding formulations are surprisingly insensitive to friction and only mildly impact-sensitive. P3 N5  /KNO3 pyrolants with ξ=20-80 wt % P3 N5 burn 200 times faster than the corresponding mixtures based on PR and generate a dense smoke. Hence obscurants based on P3 N5  /KNO3 have a figure of merit that by far exceeds that of current state-of-the-art PR -based obscurants. Furthermore, unlike PR , which slowly degrades in moist air to phosphoric acids and phosphine (PH3 ), P3 N5 is stable under these conditions and does not produce any acids or PH3  . P3 N5 is hence a safe, stable, and powerful replacement for PR for use in insensitive munitions.

Photochemisch induzierte C–C-Verknüpfungen zwischen einem Mangan-koordinierten Pentadienylliganden und Acetylen

Abstract Irradiation of tricarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)manganese (1) in tetrahydrofuran (THF) at 208 K affords the carmine solvent complex dicarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)(THF)manganese (2). Complex 2 thermally reacts with acetylene (3) to give tricarbonyl(η3:2-1,3-dimethyl-bicyclo[3.3.1]-3,6-nonadien-2-yl)manganese (4) and dicarbonyl(5-7,10-13-η-6,8-dimethyl-1,3,5,8,10,12-tridecahexaen-5-yl)manganese (5). The crystal structure of complex 4 was determined at room temperature [triclinic space group P1¯,

Metal-Fluorocarbon Pyrolants. XII: Calciumsalze der 5-perfluoroalkylierten Tetrazole – Synthese, Charakterisierung und Leistungsbewertung als Oxidationsmittel in ternären Mischungen mit Magnesium und VitonTM/ Metal-Fluorocarbon Pyrolants. XII: Calcium Salts of 5-Perfluoroalkylated Tetrazoles – Synthesis, Characterization and Performance Evaluation as Oxidizers in Ternary Mixtures with Magnesium and VitonTM

P\bar 1,

Metal-Fluorocarbon-Pyrolants IV: Thermochemical and Combustion Behaviour of Magnesium/Teflon/Viton (MTV)

a=7.6891(9), b=8.3860(8), c=10.5252(13) Å, α=93.000(9)°, β=93.390(10)°, γ= 108.032(8)°, V=642.43(13) Å3]. The manganese atom is trigonal-bipyramidally coordinated by three carbonyl ligands, one ethenylic and one allylic fragment. Consequently, the bicyclic olefin ligand 1,3-dimethyl-bicyclo[3.3.1]-3,6-nonadiene coordinates the manganese atom in a η3:2 mode. The constitution of complex 5 was deduced from IR data, elemental analysis, and 1H NMR spectra. For the formation of complexes 4 and 5, a reaction mechanism is proposed.