From a Si3‐Cyclopropene to a Si3S‐Bicyclo[1.1.0]butane to a Si3S‐Cyclopropene to a Si3S2‐Bicyclo[1.1.0]butane: Back‐and‐Forth,and In‐Between

Compact and highly reactive bicyclo[1.1.0]butanes constitute one of the most fascinating classes of organic compounds. Furthermore, interplay of bicyclo[1.1.0]butanes with their valence isomers, such as buta‐1,3‐dienes and cyclobutenes, is among the fundamental pericyclic transformations in organic chemistry. Herein we report the back‐and‐forth interconversion between the cyclotrisilenes and thiatrisilabicyclo[1.1.0]butanes, allowing for the synthesis of novel representatives of such classes of highly reactive organometallics. The peculiar structural and bonding features of the newly synthesized compounds, as well as the mechanism of their isomerization, were verified both experimentally and computationally.     

Nitridorhenium(V)‐Komplexe mit Dimercaptobernsteinsäuredimethylester. Präparation,Charakterisierung und Kristallstruktur von [Re{NC(CH3)2PPhMe2}(DMSMe2)2]

Nitridorhenium(V) Complexes with Dimercapto Succinic Acid Dimethylester. Preparation, Characterization, and Crystal Structure of [Re{NC(CH₃)₂PPhMe₂}(DMSMe₂)₂] Reaction of [ReNCl₂(Me₂PhP)₃] 1 with two equivalents of dimercaptosuccinic acid dimethylester (DMSMe₂) results in the formation of a neutral, diamagnetic rhenium(V)‐DMSMe₂ complex with a phenyldimethylphosphinoisopropyl group at the nitrido ligand as a consequence of a nucleophilic attack of the coordinated nitrido ligand on the solvent molecule. The formed complex 2 of the composition [Re{NC(CH₃)₂(Me₂PhP)}(DMSMe₂)₂] crystallizes in the triclinic space group P 1, a = 12.334(7), b = 12.412(7), c = 12.414(8) Å; α = 60.14(3)°, β = 67.98(3)°, γ = 80.63(6)°; Z = 2. Rhenium is located in a square‐pyramidal configuration of the donor atoms. The two meso‐DMSMe₂ ligands are in a syn‐endo conformation. The rhenium‐nitrogen bond (1.697(12) Å) is only slightly longer than typical Re–N bonding distances in nitrido complexes and comparable with other Re–N–C bonding distances. The addition of a solvent molecule is observed in acetone ( 2 ) as well as in methylethylketone ( 3 ). Moreover, a reaction of the nitrido group with the condensation product of ketone is found by mass spectrometry ([ReN{C(CH₃)(C₂H₅)CH₂C(O)C₂H₅(Me₂PhP)}(DMSMe₂)₂] 4 ).     

Synthese und Eigenschaften von Ph3Sn‐substituierten Telluraten – Die Kristallstrukturen von trans‐[(Ph3SnO)4Te(OH)2] und trans‐[(Ph3SnO)2Te(OMe)4]

The reaction of Te(OH)₆ with Ph₃SnOH in ethanol leads to the formation of trans‐[(Ph₃SnO)₄Te(OH)₂] ( 1 ). Compound 1 crystallizes triclinic in the space group P\bar{1} with a = 996.6(2) pm, b = 1365.4(3) pm, c = 1368.2(3) pm and α = 71.15(2)°, β = 71.48(2)°, γ = 74.81(3)° (at 220 K). The molecular structure of 1 consists of a tellurium atom, which is coordinated nearly octahedrally by four Ph₃SnO units and two hydroxyl groups that are trans to each other. The Te–O bond lengths are in the range of 190.5(2) and 193.7(2) pm. Treatment of 1 with methanol under reflux yields trans‐[(Ph₃SnO)₂Te(OMe)₄] ( 2 ). Compound 2 crystallizes triclinic in the space group P\bar{1} with a = 1012.8(1) pm, b = 1422.4(2) pm, c = 1618.1(2) pm, and α = 100.44(1)°, β = 107.92(1)°, γ = 110.66(1)° (at 220 K). 2 forms centrosymmetric molecules in which the tellurium atom is surrounded nearly octahedrally by four methoxy groups and two trans arranged Ph₃SnO units. The Te–O bond lengths of 187.9(3)–194.5(3) pm are similar to those observed in 1 .     

Synthese und Eigenschaften von Triphenylzinnmolybdaten mit kettenförmigen Anionen des Typs 1∞[(Ph3Sn)MoO4]–. Die Kristallstrukturen von (nPr4N)[(Ph3Sn)MoO4]·CH3CN, (nBu4N)[(Ph3Sn)MoO4], [Zn(en)2(Ph3Sn)2(MoO4)2]·2DMF·EtOH und [Cu(en)2(Ph3Sn)2(MoO4)2]·2DMF·EtOH

The reaction of Ph₃SnCl, (R₄N)₂[Mo₆O₁₉] and (R₄N)OH in a molar ratio of 6:1:10 leads to the formation of (R₄N)[(Ph₃Sn)MoO₄] (R = ⁿPr ( 1 ), ⁿBu ( 2 )). Compounds 1· CH₃CN and 2 have been charactarized by IR spectroscopy and single crystal X‐ray diffraction. 1· CH₃CN forms orthorhombic crystals, space group P2₁2₁2₁ with a = 1339.9(2), b = 1508.9(2), c = 1733.2(3) pm. 2 crystallizes in the monoclinic space group P2₁ with a = 1342.6(2), b = 2280.3(4), c = 1344.0(2) pm, β = 118.34(1). Both compounds 1 and 2 consist of isolated R₄N⁺ cations and polymeric $\rm^{1}_{\infty}$ [(Ph₃Sn)MoO₄]^– chains with an alternating arrangement of Ph₃Sn⁺ and MoO₄^2– groups. Treatment of (Ph₃Sn)₂MoO₄ with bis(ethylenediamine)copper(II) succinate yields [Cu(en)₂(Ph₃Sn)₂(MoO₄)₂] ( 3 ). The zinc derivative [Zn(en)₂(Ph₃Sn)₂(MoO₄)₂] ( 4 ) is obtained similarly by reaction of (Ph₃Sn)₂MoO₄ with bis(ethylenediamine)zinc(II) formiate. Compounds 3· 2DMF · EtOH and 4· 2DMF · EtOH crystallize in the monoclinic space group P2₁/n with a = 1998.0(2), b = 1313.3(1), c = 2181.6(2) pm, β = 90.97(1)° for 3 and a = 2015.4(1), b = 1316.7(1), c = 2157.0(1) pm, β = 90.40(1)° for 4 . Like in the cases of 1 and 2, polymeric $\rm^{1}_{\infty}$ [(Ph₃Sn)MoO₄]^– chains are observed. The [M(en)₂]²⁺ units (M = Cu, Zn) act as linkers between the $\rm^{1}_{\infty}$ [(Ph₃Sn)MoO₄]^– chains to give 2D layer structures with (6, 3) net topology.     

Synthese und Koordinationsverhalten neuer Schiffscher Basen aus 3‐Formylacetylaceton und natürlichen L‐Aminosäuren

Three novel chiral Schiff Base ligands (H₂L) were prepared from the condensation reaction of 3‐formyl acetylacetone with the amino acids L ‐alanine, L ‐phenylalanine, and L ‐threonine. X‐ray single crystal analyses revealed that the Schiff Base compounds exist as enamine tautomers in the solid state. The molecular structure of the compounds is stabilized by an intramolecular hydrogen bridge between the enamine NH function and a carbonyl oxygen atom of the pentandione residue. Treatment of the ligands H₂L with copper(II) actetate in the presence of pyridine led to the formation of copper complexes [CuL(py)]. In each of the complexes the copper atoms adopt a distorted square‐pyramidal coordination. Three of the basal coordination sites are occupied by the doubly deprotonated Schiff Bases L^2– which act as tridentate chelating O, N, O‐ligands. The remaining coordination sites are occupied by a pyridine ligand at the base and a carboxyl oxygen atom of a neighboring complex at the apical position. The latter coordination is responsible for a catenation of the complexes in the solid state.     

Synthese und Kristallstruktur von iso‐Butylimidogalliummethyl, [CH3Ga–NCH2CH(CH3)2]6

Synthesis and X‐Ray Structure Determination of iso ‐Butylimido Galliummethyl, [CH₃Ga–NCH₂CH(CH₃)₂]₆ The thermal decomposition of [Me₂Ga–N(ⁱBu)SnMe₃]₂ (prepared by the reaction of [Me₂SnNⁱBu]₃ with GaMe₃ in a 1:3 molar ratio) in an evacuated, sealed tube at 160°C forms [MeGaNⁱBu]₆ in high yield and SnMe₄. Mass, ¹H and ¹³C NMR as well as some IR and Raman spectroscopic data are given and the crystal structure of this cage molecule with a hexagonal prismatic Ga₆N₆ skeleton has been determined.     

Computation of aromatic C3N4 networks and synthesis of the molecular precursor N(C3N3)3Cl6

The successful synthesis and structural characterization of molecules that represent segments of extended solids is a valuable strategy for learning metric and stereochemical characteristics of those solids. This approach has been useful in cases in which the solids are particularly difficult to crystallize and thus their atomic connectivity and overall structures become difficult to deduce with X-ray diffraction techniques. One such class of materials is the covalently linked C(x)N(y) extended solids, where molecular analogues remain largely absent. In particular, structures of C(3)N(4) solids are controversial. This report illustrates the utility of a simple molecule, N(C(3)N(3))(3)Cl(6), in answering the question of whether triazine based C(3)N(4) phases are layered or instead they adopt 3D structures. Here, we present density functional calculations that clearly demonstrate the lower stability of graphitic C(3)N(4) relative to 3D analogues.     

4‐Nitro‐3‐(5‐tetrazole)furoxan and Its Salts: Synthesis,Characterization, and Energetic Properties

A series of new energetic salts based on 4‐nitro‐3‐(5‐tetrazole)furoxan (HTNF) has been synthesized. All of the salts have been fully characterized by nuclear magnetic resonance (¹H and ¹³C), infrared (IR) spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). The crystal structures of neutral HTNF ( 3 ) and its ammonium ( 4 ) and N‐carbamoylguanidinium salts ( 9 ) have been determined by single‐crystal X‐ray diffraction analysis. The densities of 3 and its nine salts were found to range from 1.63 to 1.84 g cm^?3. Impact sensitivities have been determined by hammer tests, and the results ranged from 2 J (very sensitive) to >40 J (insensitive). Theoretical performance calculations (Gaussian 03 and EXPLO 5.05) provided detonation pressures and velocities for the ionic compounds 4 – 12 in the ranges 25.5–36.2 GPa and 7934–8919 m s^?1, respectively, which make them competitive energetic materials.     

N‐Methylimidazolkomplexe des Berylliums: [Be(Me‐Im)4]I2 und [Be3(μ‐OH)3(Me‐Im)6]Cl3

Tetra(N‐methylimidazole)‐beryllium‐di‐iodide, [Be(Me‐Im)₄]I₂ ( 1 ), was prepared from beryllium powder and iodine in N‐methylimidazole suspension to give yellow single crystal plates, which were characterized by X‐ray diffraction and IR spectroscopy. Compound 1 crystallizes tetragonally in the space group I 2d with four formula units per unit cell. Lattice dimensions at 100(2) K: a = b = 1784.9(1), c = 696.2(1) pm, R₁ = 0.0238. The structure consists of homoleptic dications [Be(Me‐Im)₄]²⁺ with short Be–N distances of 170.3(3) pm and iodide ions with weak interionic C–H ··· I contacts. Experiments to yield crystalline products from reactions of N‐methylimidazole with BeCl₂ and (Ph₄P)₂[Be₂Cl₆], respectively, in dichloromethane solutions were unsuccessful. However, single crystals of [Be₃(μ‐OH)₃(Me‐Im)₆]Cl₃ ( 2 ) were obtained from these solutions in the presence of moisture air. According to X‐ray diffraction studies, two different crystal individuals ( 2a and 2b ) result, depending on the starting materials BeCl₂ and (Ph₄P)₂[Be₂Cl₆], respectively [ 2a : Space group P2₁/n, Z = 4; 2b : Space group P , Z = 2]. As a side‐product from the reaction of N‐methylimidazole with (Ph₄P)₂[Be₂Cl₆] single crystals of (Ph₄P)Cl·CH₂Cl₂ ( 3 ) were identified crystallographically (P2₁/n, Z = 4) which are isotypical with the corresponding known bromide (Ph₄P)Br·CH₂Cl₂.     

Synthese und Struktur eines Pentaalkylchlorohexastibans Sb6R5Cl [R = (Me3Si)2CH]

Synthesis and Structure of Pentaalkylchlorohexastibane Sb₆R₅Cl [R = (Me₃Si)₂CH] The reaction of RSbCl₂ [R = (Me₃Si)₂CH] with Na‐K alloy in tetrahydrofuran gives besides the known rings Sb_nR_n (n = 3, 4), (Me₃Si)₂CH₂ and the pentaalkylchlorohexastibane Sb₆R₅Cl ( 1 ). 1 was characterized by spectroscopic methods (MS, ¹H‐, ¹³C‐NMR, X‐ray diffraction). The structure of 1 consists of a folded four membered antimony ring in the all‐trans configuration with three alkyl groups and one Sb(R)—Sb(R)Cl fragment as substituents.     

Room Temperature Synthesis and Crystal Structure of mer‐[MoBr3Py3], the Vibrational Spectra of mer‐[MoBr3Py3], mer‐[MoI3Py3] and trans,trans‐[MoBr2Py4][MoBr4Py2]

The reaction of MoBr₃ and pyridine at room temperature provided single crystals of mer‐[MoX₃Py₃]. mer‐[MoBr₃Py₃] crystallizes in P2₁/n monoclinic space group with cell dimensions a = 9.2297(5) Å, b = 12.911(8) Å, c = 15.7022(9) Å and β = 90.479(3)°. There are four formula units in a unit cell. Mo–N distances are in the range 2.196(8)–2.214(8) Å and Mo–Br distances are 2.573(1) Å and 2.574(1) Å. Fundamental vibrational frequencies of pyridine molecules are strongly affected upon coordination in all three coordination compounds: mer‐[MoBr₃Py₃], mer‐[MoI₃Py₃] and trans,trans‐[MoBr₂Py₄][MoBr₄Py₂].     

Kristallstrukturen der iso‐Thiocyanatoberyllate (Ph4P)2[Be(NCS)4] und (Ph4P)4[{Be2(NCS)4(μ‐NCS)2}{Be2(NCS)6(μ‐H2N2C2S2)}]

Bis(tetraphenylphosphonium) hexachloridodiberyllate, (Ph₄P)₂[Be₂Cl₆], reacts with excess trimethylsilyl‐iso‐thiocyanate to give a mixture of colourless single crystals of (Ph₄P)₂[Be(NCS)₄] ( 1 ) and (Ph₄P)₄[{Be₂(NCS)₄(μ‐NCS)₂}{Be₂(NCS)₆(μ‐H₂N₂C₂S₂)}] ( 2 ), which can be separated by selection. Both complexes were characterized by X‐ray diffraction. Compound 1 can be prepared without by‐products by treatment of (Ph₄P)₂[BeCl₄] with excess Me₃SiNCS in dichloromethane solution. 1 : Space group I4₁/a, Z = 4, lattice dimensions at 100(2) K: a = b = 1091.2(1), c = 3937.1(3) pm, R₁ = 0.0474. The [Be(NCS)₄]^2– ion of 1 forms tetragonally distorted tetrahedral anions with Be–N distances of 168.4(2) pm and weak intermolecular S ··· S contacts along [100] and [010]. 2 ·4CH₂Cl₂: Space group P , Z = 1, lattice dimensions at 100(2) K: a = 919.5(1), b = 1248.3(1), c = 2707.0(2) pm, α = 101.61(1) °, β = 95.08(1) °, γ = 94.52(1) °, R₁ = 0.103. Compound 2 contains two different anionic complexes in the ratio 1:1. In {Be₂(NCS)₄(μ‐NCS)₂}^2–, the beryllium atoms are connected by (NCS)^– bridging groups forming centrosymmetric eight‐membered Be₂(NCS)₂ rings with distances Be–N of 168(1) pm and Be–S of 235.2(9) pm. The second anion {Be₂(NCS)₆(μ‐H₂N₂C₂S₂)}^2– consists of two {Be(NCS)₃}^– units, which are linked by the nitrogen atoms of the unique dimeric cyclo‐addition product of HNCS with Be–N distances of 179(1) pm.     

Pentagermapyramidane: Crystallizing the “Transition‐State” Structure

The first example of the homonuclear pyramidanes, pentagermapyramidane, was synthesized, fully characterized, and computationally studied to reveal its peculiar structural features and the nature of its apex‐to‐base bonding interactions. Both solid‐state and solution structures of pentagermapyramidane are discussed based on the computed stabilities of its square‐pyramidal and distorted forms.     

Silver Salt and Derivatives of 5‐Azido‐1H‐1, 2, 4‐triazole‐3‐­carbonitrile

This study features the preparation of three new energetic C‐azido‐1, 2, 4‐triazoles, with the anion of one being a new binary C–N compound. 5‐Azido‐1H‐1, 2, 4‐triazole‐3‐carbonitrile ( 1 ) was prepared from 5‐amino‐1H‐1, 2, 4‐triazole‐3‐carbonitrile and further derivatized to 5‐azido‐1H‐1, 2, 4‐triazole‐3‐carbohydroximoyl chloride ( 5 ) with 3‐azido‐1H‐1, 2, 4‐triazole‐5‐carboxamidoxime ( 3 ) as an intermediate. The ability of 1 and 3 for salt formation was shown with the respective silver salts 2 and 4 . All compounds were well characterized by various means, including IR and multinuclear NMR spectroscopy, mass spectrometry, and DSC. The molecular structures of 1 , 3 , and 5 in the solid state were determined by single‐crystal X‐ray diffraction. The sensitivities towards various outer stimuli (impact, friction, electrostatic discharge) were determined according to BAM standards. The silver salts were additionally tested for their potential as primary explosives.     

Synthese und Kristallstruktur des Lewis‐Säure/Base‐Addukts AlCl3·C3N3Cl3

Synthesis and Crystal Structure of the Lewis Acid‐Base Adduct AlCl₃·C₃N₃Cl₃ The reaction between cyanuric chloride (C₃N₃Cl₃) and the strong Lewis acid AlCl₃ yielded colorless crystals of the adduct AlCl₃·C₃N₃Cl₃. The crystal structure was determined by single crystal X‐ray diffraction at room temperature and was solved in the space group with Z = 4, a = 7.3802(7) Å, b = 9.688(1) Å, c = 16.272(2) Å, α = 72.80(1)°, β = 89.97(1)°, γ = 87.23(1)°, and V = 1110.0(2) ų. In the crystal structure, AlCl₃ is closely associated to the triazine ring with Al–N distances of 2.042(3) Å and 2.067(4) Å, respectively. The AlCl₃·C₃N₃Cl₃ units are connected with each other via intermolecular N···Cl donor–acceptor interactions, forming tape‐like arrangements in the ac‐plane, with tapes running parallel to the a‐axis.     

A Study of 5‐(1,2,4‐Triazol‐C‐yl)tetrazol‐1‐ols: Combining the Benefits of Different Heterocycles for the Design of Energetic Materials

The synthesis and full structural and spectroscopic characterization of three 5‐(1,2,4‐triazol‐C‐yl)tetrazol‐1‐ol compounds with selected energetic moieties including nitrimino ( 5 ), nitro ( 6 ) and azido ( 7 ) groups are reported. The influence of those energetic moieties as well as the C? C connection of a tetrazol‐1‐ol and a 1,2,4‐triazole on structural and energetic properties has been investigated. All compounds were well characterized by various means, including IR and multinuclear NMR spectroscopy, mass spectrometry, and DSC. The molecular structures of 5 – 8 were determined in the solid state by single‐crystal X‐ray diffraction. The standard heats of formation were calculated on the CBS‐4M level of theory utilizing the atomization energy method, revealing highly positive values for all compounds. The detonation parameters were calculated with the EXPLO5 program and compared to the common secondary explosive RDX. Additionally, sensitivities towards impact, friction and electrostatic discharge were determined.     

[μ‐(Me3SiCH2Sb)5–Sb1,Sb3–{W(CO)5}2] und [{(Me3Si)2CHSb}3Fe(CO)4] – zwei cyclische Komplexe mit Antimon‐Liganden

Syntheses and Crystal Structures of [μ‐(Me₃SiCH₂Sb)₅–Sb¹,Sb³–{W(CO)₅}₂] and [{(Me₃Si)₂CHSb}₃Fe(CO)₄] – Two Cyclic Complexes with Antimony Ligands cyclo‐(Me₃SiCH₂Sb)₅ reacts with [(THF)W(CO)₅] (THF = tetrahydrofuran) to form cyclo‐[μ‐(Me₃SiCH₂Sb)₅–Sb¹,Sb³–{W(CO)₅}₂] ( 1 ). The heterocycle cyclo‐ [{(Me₃Si)₂CHSb}₃Fe(CO)₄] ( 2 ) is formed by an insertion reaction of cyclo‐[(Me₃Si)₂CHSb]₃ and [Fe₂(CO)₉]. The crystal structures of 1 and 2 are reported.     

Synthesis and Structure of LaSc2N@Cs(hept)‐C80 with One Heptagon and Thirteen Pentagons

The synthesis and single‐crystal X‐ray structural characterization of the first endohedral metallofullerene to contain a heptagon in the carbon cage are reported. The carbon framework surrounding the planar LaSc₂N unit in LaSc₂N@C_s(hept)‐C₈₀ consists of one heptagon, 13 pentagons, and 28 hexagons. This cage is related to the most abundant I_h‐C₈₀ isomer by one Stone–Wales‐like, heptagon/pentagon to hexagon/hexagon realignment. DFT computations predict that LaSc₂N@C_s(hept)‐C₈₀ is more stable than LaSc₂N@D_5h‐C₈₀, and suggests that the low yield of the heptagon‐containing endohedral fullerene may be caused by kinetic factors.