Oxygen and Water Additions to a Tetrasilabuta‐1,3‐diene

The reaction of hexakis(2,4,6‐triisopropylphenyl)tetrasilabuta‐1,3‐diene R₂Si=SiR–SiR=SiR₂ ( 1 ) with atmospheric oxygen furnishes the oxidation product R₂Si(O)₂SiROSiR(O)₂SiR₂ ( 5 ) by oxygen insertion into all Si–Si bonds. However, treatment of 1 with meta‐chloroperoxobenzoic acid provides R₂Si(O)₂SiR–SiR(O)₂SiR₂ ( 7 ) with retention of the Si–Si single bond. Reaction of 1 with traces of water gives the oxatetrasilacyclopentane derivative 10 analogous to THF. With excess water a tetrasilane‐1,4‐diol is formed. The structures of 5 , 7 , and 10 were determined by X‐ray crystallography.     

1, 4‐Additions of HCl and HBr to a Tetrasilabutadiene: Formation of Unsymmetrically Substituted Disilenes [1]

The reactions of hexakis(2,4,6‐triisopropylphenyl)tetrasilabuta‐1,3‐diene R₂Si=SiR—SiR=SiR₂ ( 1 ) with HCl and HBr, slowly generated from HSiCl₃ or LiBr and CF₃COOH, respectively, furnish the unsymmetrically substituted disilenes R₂XSi—SiR=SiR—SiHR₂, X = Cl ( 2 ), Br ( 3 ), by formal 1,4‐addition of the hydrogen halides to 1 . However, passing gaseous hydrogen halides over the solution of 1 yields the 1,4‐dihalotetrasilanes by two‐fold 1,2‐additions to the double bonds of 1 . The structures of 2 and 3 which crystallize isotypically with one another have been determined by X‐ray crystallography.     

1,2‐Diaza‐3‐silacyclopent‐5‐ene – Synthese und Reaktionen

1,2‐Diaza‐3‐silacyclopent‐5‐ene – Synthesis and Reactions The dilithium salt of bis(tert‐butyl‐trimethylsilylmethylen)ketazine ( 1 ) forms an imine‐enamine salt. 1 reacts with halosilanes in a molar ratio of 1:1 to give 1,2‐diaza‐3‐silacyclopent‐5‐enes. Me₃SiCH=CCMe₃ [N(SiR,R′)‐N=C‐C]HSiMe₃ ( 2 ‐ 7 ). ( 2 : R,R′ = Cl; 3 : R = CH₃, R′ = Ph; 4 : R = F, R′ = CMe₃; 5 : R = F, R′ = Ph; 6 : R = F, R′ = N(SiMe₃)₂; 7 : R = F, R′ = N(CMe₃)SiMe₃). In the reaction of 1 with tetrafluorosilane the spirocyclus 8 is isolated. The five‐membered ring compounds 2 ‐ 7 and compound 9 substituted on the silicon‐fluoro‐ and (tert‐butyltrimethylsilyl) are acid at the C(4)‐atom and therefore can be lithiated. Experiments to prepare lithium salts of 4 with MeLi, n‐BuLi and PhLi gave LiF and the substitution‐products 10 ‐ 12 . 9 forms a lithium salt which reacts with ClSiMe₃ to give LiCl and the SiMe₃ ring system ( 13 ) substituted at the C(4)‐atom. The ring compounds 3 ‐ 7 and 10 ‐ 12 form isomers, the formation is discussed. Results of the crystal structure and analyses of 8 , 10 , 12 , and 13 are presented.     

Auf dem Wege zu einem Disilin –Si≡Si–: Bildung von RHSi=SiHR und Hinweise auf die intermediäre Bildung von RSi≡SiR (R = SiH(SitBu3)2)

Compounds of Silicon. 146. Unsaturated Silicon Compounds. 59. On the Way to a Disilyne –Si≡Si–: Formation of RHSi=SiHR and Indication of the Intermediate Formation of RSi≡SiR (R = SiH(Si t Bu₃)₂) Reaction of R*₂HSi–SiHBr–SiHBr–SiHR*₂ with an equimolar amount of NaR* × 2 THF in THF at –78 °C (R* = supersilyl = SitBu₃) or reaction of R*₂ClSi–SiHBr–SiHBr–SiClR*₂ with a two‐molar amount of NaR* × 2 THF in C₆D₆ at room temperature leads in the first case to the yellow disilene (R*₂HSi)HSi=SiH(SiHR*₂) ( 1 ) and to the red cyclotetrasilene [–R*HSi–R*Si=SiR*–SiHR*–] ( 3 ), respectively, in the latter case to the colorless bicyclotetrasilane R*₄H₂Si₄ ( 4 ). The disilene 1 (for > Si= in ²⁹Si‐NMR: d of d at 141.32 ppm with ¹J_SiH = 149.9 Hz, ²J_SiH = 0.9 Hz) slowly isomerizes at room temperature (τ_1/2 ca. 3 h) under formation of the colorless trisilacyclopentane [–CH₂–SiH(SiH₂SiHR*₂)–SiHR*–SitBu₂–CMe₂–] ( 2 ) and adds methanole under formation of the colorless compound R*₂HSi–SiH₂–SiH(OMe)–SiHR*₂. As initial stage of 3 the disilyne R*₂HSi–Si≡Si–SiHR*₂ is in consideration, which by way of R*HSi=SiR*–SiR*=SiHR* may transform into 3 . The characterization of 2 and 3 results among others from X‐ray structure analyses, whereby for 3 an unexpectable long double bond (2.36 Å) has been found. The identification of 4 results from comparison with an authentic sample (formed from R*HBrSi–SiBr₂R* and NaR* × 2 THF).     

Mobility Studies on Siloxane‐Based Inorganic‐Organic Hybrid Polymers by Dynamic Solid State,Suspended State,and Deuterium NMR Spectroscopy: Supported Organometallic Complexes. XXVI [1]

Organic modified siloxanes of the type RSi(OMe₂)₂(CH₂)₃C₆D₄(CH₂)₃(OMe₂)₂SiR [R = Me ( 4 ), R = OMe ( 5 )] were sol‐gel processed employing solvents of different polarity (MeOH and THF) to yield the corresponding inorganic‐organic hybrid polymers X4a — X5b with different physical properties. These polymers were investigated by multinuclear (²H, ¹³C, and ²⁹Si) solid state and ¹H suspension state NMR spectroscopy, including dynamic NMR techniques, in order to correlate the mobilities of these xerogels with physical properties, especially with the cross‐linkage.     

Intercepting the Disilene‐Silylsilylene Equilibrium

The equilibrium between disilenes (R₂Si=SiR₂) and their silylsilylene (R₃Si?SiR) isomers has previously been inferred but not directly observed, except in the case of the parent system H₂Si=SiH₂. Here, we report a new method to prepare base‐coordinated disilenes with hydride substituents. By varying the bulk of the coordinating base and other silicon substituents, we have been able to control the rearrangement of disilene adducts to their silylsilylene tautomers. Remarkably, 1,2 migration of a trimethylsilyl group is preferred over hydrogen migration. A DFT study of the reaction mechanism provides a rationale for the observed reactivity and detailed information on the bonding situation in base‐stabilized disilenes.     

2,2‐Difluor‐1,3‐diaza‐2‐sila‐cyclopenten – Synthese und Reaktionen

2,2‐Difluor‐1,3‐diaza‐2‐sila‐cyclopentene – Synthesis and Reactions N,N′‐Di‐tert‐butyl‐1,4‐diaza‐1,3‐butadiene reacts with elemental lithium under reduction to give a dilithium salt, which forms with fluorosilanes the diazasilacyclopentenes 1 – 4 ; (HCNCMe₃)₂SiFR, R = F ( 1 ), Me ( 2 ), Me₃C ( 3 ), N(CMe₃)SiMe₃ ( 4 ). As by‐product in the synthesis of 1 , the tert‐butyl‐amino‐methylene‐tert‐butyliminomethine substituted compound 5 was isolated, R = N(CMe₃)‐CH₂‐CH = NCMe₃. 5 is formed in the reaction of 1 with the monolithium salt of the 1,4‐diaza‐1,3‐butadiene in an enamine‐imine‐tautomerism. 1 reacts with lithium amides to give (HCNCMe₃)₂SiFNHR, 6 – 12 , R = H ( 6 ), Me ( 7 ), Me₂CH ( 8 ), Me₃C ( 9 ), H₅C₆ ( 10 ), 2,6‐Me₂C₆H₃ ( 11 ), 2,6‐(Me₂CH)₂C₆H₃ ( 12 ). The reaction of 12 with LiNH‐2.6‐(Me₂CH)₂C₆H₃ leads to the formation of (HCNCMe₃)₂Si(NHR)₂, ( 13 ). In the presence of n‐BuLi, 12 forms a lithium salt which looses LiF in boiling toluene. Lithiated 12 adds this LiF and generates a spirocyclic tetramer with a central eight‐membered LiF‐ring ( 14 ), [(HCNCMe₃)₂Si(FLiFLiNR)]₄, R = 2,6‐(Me₂CH)₂C₆H₃. ClSiMe₃ reacts with lithiated 12 to yield the substitution product (HCNCMe₃)₂SiFN(SiMe₃) R, ( 15 ). The crystal structures of 1 , 5 , 6 , 9 , 11 , 13 , 14 are reported.     

Reduction of Disilane (tBu3Si)Br2Si‐SiBr2(SitBu3) in Presence of C2H4: A Mechanistic Approach

The reduction of R*–SiBr₂–SiBr₂–R* ( 2 ) with NaR* (R* = supersilyl = SitBu₃) in presence of C₂H₄ provides a white crystalline solid (η²‐C₂H₄)R*Si–SiR*(Br)(CH₂–CH₂–R*) ( 3 ) characterized by X‐ray diffraction analysis. Compound 3 is accompanied with an impurity of R*(Br)₂Si–Si(Br)(R*)(CH₂–CH₂–R*) ( 4 ). The formation of 3 and 4 runs complicated because of several reactive partners. However, reduction of 2 with sodium naphthalenide in presence of ethene runs straightforward with formation of a mixture of tetrahedrane R*₄Si₄ ( 1 ) and bis(silirane) R*(η²‐C₂H₄)Si–Si(η²‐C₂H₄)R* ( 5 ). The latter is formed by [1+2]‐cycloaddition reaction of intermediate disilyne R*Si≡SiR* with ethene. Compound 5 has been characterized by X‐ray structure determination. The ¹H NMR spectrum of the silacyclopropane ring protons shows AA′BB′ complex spectrum comprising of 2 sets each of 12 transitions.     

Synthesis of trans‐disubstituted cyclam ligands appended with two 6‐hydroxymethylpyridin‐2‐ylmethyl sidearms: Crystal structures of the 1,8‐dimethyl‐4,ll‐di(6‐hydroxymethylpyridin‐2‐ylmethyl)cylam ligand and its Co(II) and Ni(II) complexes

Two new trans‐disubstituted cyclam ligands; 1,8‐di(6‐hydroxymethylpyridin‐2‐ylmethyl)‐1,4,8,11‐tetra‐azacyclotetradecane ( 5 ) and 1,8‐dimethyl‐4, 11‐di(6‐hydroxymethylpyridin‐2‐ylmethyl)‐1,4,8,11 ‐tetraaza‐cyclotetradecane ( 6 ); have been synthesized and characterized. The crystal structures of ligand 6 and its Ni(II) and Co(II) complexes have been determined. Crystal data are given for 6 , space group, P2₁/c, a = 11.095 (6) Å, b = 9.467 (5) Å, c = 13.283 (8) Å; β = 106.95 (5)°, Z = 2, R = 0.0715; for [Ni 6 ](C10₄)₂, space group P2₁/c, a = 9.4848 (14) Å, b = 33.941(6) Å, c = 9.793(2) A, β = 95.264(14)°, Z = 4, R = 0.0567; for [Co 6 ](C10₄)₂, space group, P2₁/c, a = 9.440 (6) Å, b = 33.848 (13) Å, c = 9.820 (3) Å, β = 95.16(3)°, Z = 4, R = 0.0718. In both complexes, the metal atoms are six‐coordinate with only one of the pendants interacting with the central metal atom and the other pendant remaining uncoordinated.     

Neue Polyiodide des Caesiums mit Doppel‐ und Tripeldecker‐Kationen, [Cs(Benzo‐18‐Krone‐6)2]Ix und [Cs2(Benzo‐18‐Krone‐6)3](Ix)2 (x = 3, 5)

New Polyiodides of Cesium containing Double and Triple Decker Cations, [Cs(benzo‐18‐crown‐6)₂]I_x and [Cs₂(benzo‐18‐crown‐6)₃](I_x)₂ (x = 3, 5) [Cs(b18c6)₂]I_x (x = 3 (1) , 5 (3) ) and [Cs₂(b18c6)₃](I_x)₂ (x = 3 (2) , 5 (4) ) (b18c6 = benzo‐18‐crown‐6) have been synthesized by the reaction of benzo‐18‐crown‐6 (C₁₆H₂₄O₆), cesium iodide (CsI) and iodine (I₂) in acetonitrile ( 1 ), ethanol/dichloromethane ( 2 , 4 ) and 2‐methoxyethanol ( 3 ). Their crystal structures were determined on the basis of single crystal X‐ray data {( 1 ): monoclinic, C2/c, Z = 4, a = 2048.8(5), b = 1329.5(5), c = 1588.7(5) pm, β = 110.23(1)°; ( 2 ): monoclinic, C2/c, Z = 4, a = 2296.0(1), b = 2092.7(1), c = 1373.6(1) pm, β = 100.21(1)°; ( 3 ): monoclinic, P2₁/n, Z = 4, a = 1586.3(1), b = 1745.5(1), c = 1608.6(1) pm, β = 92.37(1)°; ( 4 ): triclinic, , Z = 2, a = 1241.7(1), b = 1539.8(2), c = 1938.4(2) pm, α = 91.15(1), β = 100.53(1), γ = 95.26(1)°}. As expected, double decker cations centered by Cs atoms, [Cs(b18c6)₂]⁺, are found in the structures of ( 1 ) and ( 3 ). In contrast, the triple decker cation found in ( 2 ) and ( 4 ) is less common. The triiodide anions of ( 1 ) and ( 2 ) can be regarded as normal and the chain‐type pentaiodide anions of ( 3 ) and ( 4 ) fall into the known systematic sequence of these anions. The differences in the connectivity of the crystallographically independent I₅^? anions in ( 4 ) are surprising with respect to the fact that, so far, independent pentaiodide anions do not show variations in their scheme of connectivity within one crystal structure.     

Kristallstrukturen „supramolekularer”︁ (Benzo‐18‐krone‐6)kaliumtetrathiocyanatometallate: Ein dimerer Komplex {[K(Benzo‐18‐krone‐6)]2[Hg(SCN)4]}2 und zwei isomere Komplexe [K(Benzo‐18‐krone‐6)][Cd(SCN)3] mit kettenförmigen Trithiocyanatocadmat‐Anionen

Crystal Structures of „Supramolecular”︁ Benzo‐18‐crown‐6 Potassium Tetrathiocyanato Metallates: A Dimeric Complex {[K(Benzo‐18‐crown‐6)]₂[Hg(SCN)₄]}₂ and Two Isomeric Complexes [K(Benzo‐18‐crown‐6)][Cd(SCN)₃] Containing Trithiocyanato Cadmate Anions with Chain Structures By reaction of potassium thiocyanatomercurate(II) complexes with benzo‐18‐crown‐6 (2,3‐benzo‐1,4,7,10,13,16‐hexaoxacyclooctadec‐2‐ene) crystals of {[K(benzo‐18‐crown‐6)]₂[Hg(SCN₄)]}₂ ( 1 ) were obtained. 1 crystallizes monoclinic, space group P2₁/n (non‐standard setting of P2₁/c), a = 1737.35(2), b = 1377.16(2), c = 1984.12(3) pm, β = 100.637(1)°, Z = 2. With potassium tetrathiocyanatocadmate(II) two modifications of a complex [K(benzo‐18‐crown‐6)][Cd(SCN)₃] ( 2 , 3 ), of different symmetry were formed. 2 crystallizes monoclinic, P2₁/c, a = 1158,31(3), b = 1096,55(2), c = 2028,46(2) pm, β = 99,5261(2)°, Z = 4, 3  orthorhombic, P2₁cn, a = 1105,95(3), b = 1413,07(4), c = 1617,10(5) pm, Z = 4. 1 has a dimeric structure, built up from a dication K₂(benzo‐18‐crown‐6)₂]²⁺ and two [K(benzo‐18‐crown‐6)]⁺ cations, which are bridged by two [Hg(SCN)₄]^2– anions. In 2 and 3 triply bridged infinite [{Cd(SCN)₃^–}_n] zigzag chains, stretching along screw axes, are to be found as anions. In 2 these chains exist in two conformations related by inversion symmetry, whereas in 3 only one form can be found. [K(benzo‐18‐crown‐6)]⁺ cations are linked to the anion chains via K · · · S interactions of different lengths.     

2,5,8‐Trihydrazino‐s‐heptazine: A Precursor for Heptazine‐based Iminophosphoranes

The title compound  C₆N₇(NHNH₂)₃ ( 1 ) was obtained from melem C₆N₇(NH₂)₃ or melon [C₆N₇(NH₂)NH]_n and hydrazine by an autoclave synthesis. Upon treatment with a 10 % HCl solution it is transformed into the trihydrochloride  [C₆N₇(NHNH₃)₃]Cl₃ ( 2 ). Compounds 1 and 2 were analysed with ¹³C NMR, ¹⁵N NMR, FTIR and Raman spectroscopy. Furthermore, the single‐crystal X‐ray structure of the pentahydrate of 2 is reported (P\bar{1} , a = 674.96(3), b = 1214.17(6), c = 1272.15(6) pm, α = 66.288(2)°, β = 75.153(2)°, γ = 80.420(2)°, V = 920.30(8)·10⁶ pm³, Z = 2, T = 90(2) K). The thermal decomposition of 1 and 2 was investigated with TG/DTA. Reaction of 1 with NaNO₂/HCl yields triazido‐s‐heptazine, C₆N₇(N₃)₃ ( 3 ). Tris(tri‐n‐butylphosphinimino)‐s‐heptazine ( 4 ) was synthesised from 3 and characterised by means of ¹³C, ³¹P, ¹H NMR, FTIR and MALDI‐TOF spectroscopy. Similar to s‐heptazine derivative 3 , compounds 1 and 4 are precursors for graphitic carbon nitrides, which have attracted considerable attention recently, and to various potential applications, such as flame retardants and (photo) catalysis.     

Bifunktionalisierte 1 H‐Phosphiren‐ und g1‐1‐Phosphaallen‐Wolframkomplexe

Bifunctionalized 1 H‐Phosphirene and g¹‐1‐Phosphaallene Tungsten Complexes The tungsten(0) complex [{(Me₃Si)₂HCPC(Ph)=N}W(CO)₅] 1 reacts upon heating with acetylene derivatives 2 a–d in toluene to form benzonitrile and the complexes [{(Me₃Si)₂HCPC(R)=COEt} · W(CO)₅] 5 a–d ( 5 a : R = SiMe₃; 5 b : R = SiPh₃; 5 c : R = SnMe₃; 5 d : R = SnPh₃) and [{(Me₃Si)₂HCP=C=C(OEt)R} · W(CO)₅] 6 a, b ( 6 a : R = SnMe₃; 6 b : R = SnPh₃), which have been isolated by chromatography; complexes 5 c and 6 a have been characterized as mixtures. Spectroscopic and mass spectrometric data are discussed. The crystal structure of the compound 5 a was determined by X‐ray single crystal structure analysis ( 5 a : space group P2₁/n, Z = 4, a = 977.6(2) pm, b = 1814.6(4) pm, c = 1628.0(4) pm, β = 93.95(2)°).     

The effect of solvent accessible surface on Hammett‐type dependencies of infinite dilution 29Si and 13C NMR shifts in ring substituted silylated phenols dissolved in chloroform and acetone

Infinite dilution ²⁹Si and ¹³C NMR chemical shifts were determined from concentration dependencies of the shifts in dilute chloroform and acetone solutions of para substituted O‐silylated phenols, 4‐R‐C₆H₄‐O‐SiR′₂R″ (R = Me, MeO, H, F, Cl, NMe₂, NH₂, and CF₃), where the silyl part included groups of different sizes: dimethylsilyl (R′ = Me, R″ = H), trimethylsilyl (R′ = R″ = Me), tert‐butyldimethylsilyl (R′ = Me, R″ = CMe₃), and tert‐butyldiphenylsilyl (R′ = C₆H₅, R″ = CMe₃). Dependencies of silicon and C‐1 carbon chemical shifts on Hammett substituent constants are discussed. It is shown that the substituent sensitivity of these chemical shifts is reduced by association with chloroform, the reduction being proportional to the solvent accessible surface of the oxygen atom in the Si‐O‐C link. Copyright © 2012 John Wiley & Sons, Ltd.     

Sigma‐ versus Pi‐Koordination in Bis‐indenyl‐ und Bis‐2‐methallyl‐Imidokomplexen des sechswertigen Molybdäns und Wolframs: DF‐Rechnungen und Kristallstrukturanalyse

Sigma‐ versus Pi‐Coordination in Bis‐indenyl‐ and Bis‐2‐methallyl Imido Complexes of Hexavalent Molybdenum and Tungsten: DF‐Calculations and Crystal Structure Analysis Bis‐indenyl and bis‐2‐methallyl imido complexes [(C₉H₇)₂M(NR)₂] (M = Mo, W; R = tert‐butyl, mesityl) 1 — 4 and [(H₃C‐C₃H₄)₂M(NtBu)₂] (M = Mo, W) 6 , 7 have been prepared starting from [Mo(NtBu)₂Cl₂] or [M(NR)₂Cl₂L₂] (M = W, R = tBu, L = py; M = Mo, W, R = Mes, L₂ = dme) and indenyl lithium or 2‐methallyl magnesium bromide, respectively. According to spectroscopic data and the crystal structure of 4 there are two different coordination modes of the indenyl ligands, [(η³‐C₉H₇)M(NR)₂(η¹‐C₉H₇)], in solution as well as in the solid state. These compounds show fluxional rearrangements in solution, namely σ, π‐exchange of η¹‐ and η³‐coordinated ligands. Similar behavior has been observed for the 2‐methallyl complexes 6 and 7 in solution. In agreement with experimental observations, DF calculations on models of 6 strongly suggest a (σ+π)‐coordination mode of the η³‐coordinated ligand.     

Komplexe einwertiger Dibenzo‐18‐Krone‐6‐Kationen mit Triiodid als Anionen

Complexes of Monovalent Dibenzo‐18‐crown‐6 Cations with Triiodide as Anions The new polyiodides [NH₄(db18c6)]₂(I₃)₂ ( 1 ), [NH₄(db18c6)](db18c6)I₃ ( 2 ), [Na_1/2(db18c6)H₂O]₂I₃ ( 3 ), [Rb(db18c6)]I₃ ( 4 ), [Rb(db18c6)]₂(I₃)₂ ( 5 ), [Cs(db18c6)]I₃ ( 6 ), and [Cs₂(db18c6)₃][Cs(db18c6)_3/2](I₃)₃ ( 7 ) were obtained from reactions of dibenzo‐18‐crown‐6 (db18c6) and iodine with NH₄I, NaI, RbI, and CsI. Their crystal structures were determined by single‐crystal X‐ray diffraction. ( 1 ) M = NH₄, ( 5 ) M = Rb: monoclinic, P2₁/n, a = 1409,67(8), b = 2211,63(14), c = 1627,16(10) pm, β = 101,030(5)°, Z = 4 (crystal data for M = NH₄); ( 2 ): monoclinic, Pn, a = 1345,26(14), b = 773,82(4), c = 2095,10(20) pm, β = 94,439(8)°, Z = 2; ( 3 ): orthorhombic, Pnaa, a = 931,59(13), b = 2213,3(5), c = 2223,9(4) pm, Z = 4; ( 4 ): monoclinic, P2₁/n, a = 999,50(6), b = 1711,33(10), c = 1517,45(9) pm, β = 99,021(5)°, Z = 4; ( 6 ): triclinic, , a = 705,16(9), b = 1137,93(14), c = 1678,90(20) pm, α = 73,719(10), β = 79,782(10), γ = 83,669(10)°, Z = 2; ( 7 ): triclinic, , a = 1519,25(6), b = 1702,49(7), c = 2136,41(9) pm, α = 102,641(3), β = 101,989(3), γ = 91,911(3)°, Z = 2. 1 : 1 cations centered by M, [M(db18c6)]⁺, are found in the structures of ( 1 – 6 ). In contrast, the triple decker cation found in ( 7 ) is less common. The crystal structures are completed by mostly asymmetrically linear I₃^? anions.     

The crystal structure of 9‐chloro‐4,5‐dihydro‐2‐ethyl‐1‐(2,4,6‐trichlorophenyl)‐1H‐1,2,4‐triazolo[3,2‐d][1,5]‐benzoxazepinium hexachloroantimonate

The title compound 4 , i.e. 9‐chloro‐4,5‐dihydro‐2‐ethyl‐1‐(2,4,6‐trichlorophenyl)‐1H‐1,2,4‐triazolo[3,2‐d]‐[1,5]benzoxazepinium hexachloroantimonate, is a novel 6‐7‐5 tricyclic heterocycle. C₁₈H₁₄Cl₄N₃O·SbCJ₆, M = 764.61, P2₁/c(#14), a = 13.457(4), b = 11.583(2), c = 18.992(3) Å α = 90, β = 110.11(1)°, Z = 4, V = 2780(1) ų, D_c = 1.827 g/cc, μ (MoKα) = 19.69 cm^?1, F(000) = 1488.00, T = 293 K, R_int = 0.055 for 3094 independent reflections with I>3.00σ(I). The five‐membered heterocyclic ring is nearly planar, with the trichlorophenyl ring at N(2) almost perpendicular to it. However, the seven‐membered ring is not planar, but adopts a twist‐boat conformation.     

Zur Reaktion der Alkin‐Kupfer(I)‐Komplexe [CuX(S‐Alkin)] (X = Cl,Br, I; S‐Alkin = 3,3,6,6‐Tetramethyl‐1‐thia‐4‐cycloheptin) mit den Phosphanen PMe3 und Ph2PCH2CH2PPh2 (dppe)

Organometallic Compounds of Copper. XVIII. On the Reaction of the Alkyne Copper(I) Complexes [CuX(S‐Alkyne)] (X = Cl, Br, I; S‐Alkyne = 3,3,6,6‐Tetramethyl‐1‐thiacyclohept‐4‐yne) with the Phosphanes PMe₃ and Ph₂PCH₂CH₂PPh₂ (dppe) The alkyne copper(I) halide complexes [CuX(S‐Alkyne)]_n ( 2 ) ( 2 a : X = Cl, 2 b : X = Br, 2 c : X = I; S‐Alkyne = 3,3,6,6‐tetramethyl‐1‐thiacyclohept‐4‐yne; n = 2, ∞) add the phosphanes PMe₃ and Ph₂PCH₂CH₂PPh₂ (dppe) to form the mono‐ and dinuclear copper compounds [(S‐Alkyne)CuX(PMe₃)] ( 6 ) ( 6 a : X = Cl, 6 b : X = Br) and [(S‐Alkyne)CuX(μ‐dppe)CuX(S‐Alkyne)] ( 7 a : X = Cl, 7 b : X = Br, 7 c : X = I), respectively. By‐product in the reaction of 2 a with dppe is the tetranuclear complex [(S‐Alkyne)Cu(μ‐X)₂Cu(μ‐dppe)₂Cu(μ‐X)₂Cu(S‐Alkyne)] ( 8 ). In case of the compounds 7 prolonged reaction times yield the alkyne‐free dinuclear copper complexes [Cu₂X₂(dppe)₃] ( 9 ) ( 9 a : X = Cl, 9 b : X = Br, 9 c : X = I)). X‐ray diffraction studies were carried out with the new compounds 6 a , 6 b , 7 b , 8 , and 9 c .     

Disilynes. III [1] A Relatively Stable Disilyne RSi≡SiR (R = SiMe(SitBu3)2)

The disilyne R**Si≡SiR** (R** = SiMe(SitBu₃)₂), prepared as the first isolable and realtively stable silicon compound with a SiSi triple bond two years ago by dehalogenation of trans‐R**ClSi=SiClR** with LiC₁₀H₈ in thf at ‐78 °C (calc.: Si≡Si distance 2.072Å, Si‐Si≡Si bond angle 148°), forms with CH₂=CH₂ a [2+2] and with CH₂=CH‐CH=CH₂ a [2+4] cycloadduct. The ethene adduct takes up oxygen very easily with change of the Si=Si group into a SiOSiO ring with formation of R**Si(μ‐O)(μ‐O)(μ‐C₂H₄)SiR**. By heating the disilyne in heptane to ca. 50 °C in the presence of traces of thf it transforms into a monoxide of the ethene adduct with formation of R**Si(μ‐O)(μ‐C₂H₄)SiR**. In thf, the disilyne rearranges at r.t. and below by migration of a SitBu₃ group with formation of a silyl substituted cyclotrisilene. X‐ray structure determinations of the ethene adduct and its mono‐ and dioxide are presented.     

Synthesis,Characterization, and Crystal Structure of 1,3‐Dipentafluorophenyl‐2,2,2,4,4,4‐hexazido‐1,3‐diaza‐2,4‐diphosphetidine

1,3‐Dipentafluorophenyl‐2,2,2,4,4,4‐hexazido‐1,3‐diaza‐2,4‐diphosphetidine ( 1 ) was synthesized by the reaction of [(C₆F₅)NPCl₃]₂ with trimethylsilyl azide in CH₂Cl₂ and characterized by multinuclear NMR and vibrational spectroscopy. The molecular structure of the compound was determined by single‐crystal X‐ray structure analysis. [(C₆F₅)NP(N₃)₃]₂ crystallizes in the monoclinic space group P2₁/n with a = 9.6414(2), b = 7.4170(1) and c = 15.9447(4) Å, β = 94.4374(9)°, with 2 formula units per unit cell. The bond situation in [(C₆F₅)NP(N₃)₃]₂ has been studied on the basis of NBO analysis. The antisymmetric stretching vibration of the azide groups is discussed. The structural diversity of 1 and 1,3‐diphenyl‐2,2,2,4,4,4‐hexazido‐1,3‐diaza‐2,4‐diphosphetidine in solution and in the solid state depending on the aryl substituent at the nitrogen atom is discussed.