The First Molybdenum(VI) and Tungsten(VI) Oxoazides MO2(N3)2, MO2(N3)2⋅2 CH3CN, (bipy)MO2(N3)2, and [MO2(N3)4]2− (M=Mo,W)

Molybdenum(VI) and tungsten(VI) dioxodiazide, MO₂(N₃)₂ (M=Mo, W), were prepared through fluoride–azide exchange reactions between MO₂F₂ and Me₃SiN₃ in SO₂ solution. In acetonitrile solution, the fluoride–azide exchange resulted in the isolation of the adducts MO₂(N₃)₂⋅2 CH₃CN. The subsequent reaction of MO₂(N₃)₂ with 2,2′‐bipyridine (bipy) gave the bipyridine adducts (bipy)MO₂(N₃)₂. The hydrolysis of (bipy)MoO₂(N₃)₂ resulted in the formation and isolation of [(bipy)MoO₂N₃]₂O. The tetraazido anions [MO₂(N₃)₄]²⁻ were obtained by the reaction of MO₂(N₃)₂ with two equivalents of ionic azide. Most molybdenum(VI) and tungsten(VI) dioxoazides were fully characterized by their vibrational spectra, impact, friction, and thermal sensitivity data and, in the case of (bipy)MoO₂(N₃)₂, (bipy)WO₂(N₃)₂, [PPh₄]₂[MoO₂(N₃)₄], [PPh₄]₂[WO₂(N₃)₄], and [(bipy)MoO₂N₃]₂O by their X‐ray crystal structures.     

The Molybdenum(V) and Tungsten(VI) Oxoazides [MoO(N3)3], [MoO(N3)3⋅2 CH3CN], [(bipy)MoO(N3)3], [MoO(N3)5]2−, [WO(N3)4], and [WO(N3)4⋅CH3CN]

A series of novel molybdenum(V) and tungsten(VI) oxoazides was prepared starting from [MOF₄] (M=Mo, W) and Me₃SiN₃. While [WO(N₃)₄] was formed through fluoride–azide exchange in the reaction of Me₃SiN₃ with WOF₄ in SO₂ solution, the reaction with MoOF₄ resulted in a reduction of Mo^VI to Mo^V and formation of [MoO(N₃)₃]. Carried out in acetonitrile solution, these reactions resulted in the isolation of the corresponding adducts [MoO(N₃)₃?2 CH₃CN] and [WO(N₃)₄?CH₃CN]. Subsequent reactions of [MoO(N₃)₃] with 2,2′‐bipyridine and [PPh₄][N₃] resulted in the formation and isolation of [(bipy)MoO(N₃)₃] and [PPh₄]₂[MoO(N₃)₅], respectively. Most molybdenum(V) and tungsten(VI) oxoazides were fully characterized by their vibrational spectra, impact, friction and thermal sensitivity data and, in the case of [WO(N₃)₄?CH₃CN], [(bipy)MoO(N₃)₃], and [PPh₄]₂[MoO(N₃)₅], by their X‐ray crystal structures.     

The Vanadium(V) Oxoazides [VO(N3)3], [(bipy)VO(N3)3], and [VO(N3)5]2−

Vanadium(V) oxoazide [VO(N₃)₃] was prepared through a fluoride–azide exchange reaction between [VOF₃] and Me₃SiN₃ in acetonitrile solution. When the highly impact‐ and friction‐sensitive compound [VO(N₃)₃] was reacted with 2,2′‐bipyridine, the adduct [(bipy)VO(N₃)₃] was isolated. The reaction of [VO(N₃)₃] with [PPh₄]N₃ resulted in the formation and isolation of the salt [PPh₄]₂[VO(N₃)₅]. The adduct [(bipy)VO(N₃)₃] and the salt [PPh₄]₂₃[VO(N₃)₅] were characterized by vibrational spectroscopy and single‐crystal X‐ray structure determination, making these compounds the first structurally characterized vanadium(V) azides.     

Coordination Adducts of Niobium(V) and Tantalum(V) Azide M(N3)5 (M=Nb,Ta) with Nitrogen Donor Ligands and their Self‐Ionization

Several new donor–acceptor adducts of niobium and tantalum pentaazide with N‐donor ligands have been prepared from the pentafluorides by fluoride–azide exchange with Me₃SiN₃ in the presence of the corresponding donor ligand. With 2,2′‐bipyridine and 1,10‐phenanthroline, the self‐ionization products [MF₄(2,2′‐bipy)₂]⁺[M(N₃)₆]⁻, [M(N₃)₄(2,2′‐bipy)₂]⁺[M(N₃)₆]⁻ and [M(N₃)₄(1,10‐phen)₂]⁺[M(N₃)₆]⁻ were obtained. With the donor ligands 3,3′‐bipyridine and 4,4′‐bipyridine the neutral pentaazide adducts (M(N₃)₅)₂⋅L (M=Nb, Ta; L=3,3′‐bipy, 4,4′‐bipy) were formed.     

Coordination Adducts of Niobium(V) and Tantalum(V) Azide M(N3)5 (M=Nb,Ta) with Nitrogen Donor Ligands and their Self‐Ionization

Several new donor–acceptor adducts of niobium and tantalum pentaazide with N‐donor ligands have been prepared from the pentafluorides by fluoride–azide exchange with Me₃SiN₃ in the presence of the corresponding donor ligand. With 2,2′‐bipyridine and 1,10‐phenanthroline, the self‐ionization products [MF₄(2,2′‐bipy)₂]⁺[M(N₃)₆]^?, [M(N₃)₄(2,2′‐bipy)₂]⁺[M(N₃)₆]^? and [M(N₃)₄(1,10‐phen)₂]⁺[M(N₃)₆]^? were obtained. With the donor ligands 3,3′‐bipyridine and 4,4′‐bipyridine the neutral pentaazide adducts (M(N₃)₅)₂?L (M=Nb, Ta; L=3,3′‐bipy, 4,4′‐bipy) were formed.     

Preparation of the First Manganese(III) and Manganese(IV) Azides

Fluoride‐azide exchange reactions of Me₃SiN₃ with MnF₂ and MnF₃ in acetonitrile resulted in the isolation of Mn(N₃)₂ and Mn(N₃)₃?CH₃CN, respectively. While Mn(N₃)₂ forms [PPh₄]₂[Mn(N₃)₄] and (bipy)₂Mn(N₃)₂ upon reaction with PPh₄N₃ and 2,2′‐bipyridine (bipy), respectively, the manganese(III) azide undergoes disproportionation and forms mixtures of [PPh₄]₂[Mn(N₃)₄] and [PPh₄]₂[Mn(N₃)₆], as well as (bipy)₂Mn(N₃)₂ and (bipy)Mn(N₃)₄. Neat and highly sensitive Cs₂[Mn(N₃)₆] was obtained through the reaction of Cs₂MnF₆ with Me₃SiN₃ in CH₃CN.     

Azidokomplexe des Zirkoniums: ZrCl3N3, [ZrCl4N3]22⊝, [ZrCl4(N3)2]2⊝; die Kristallstruktur von (PPh4)2[ZrCl4N3]2

Azido Complexes of Zirconium: ZrCl₃N₃, [ZrCl₄N₃]₂^2?, [ZrCl₄(N₃)₂]^2?; Crystal Structure of (PPh₄)₂ [ZrCl₄N₃]₂ Highly explosive ZrCl₃N₃ is formed by the reaction of ZrCl₄ with iodine azide in dichloromethane suspension. According to the i.r. spectra, the compound is polymeric by azide and chlorine bridges. Zirconium tetrachloride reacts with one and two moles of tetraphenylphosphonium azide respectively, forming the thermally and mechanically stable complexes (PPh₄)₂[ZrCl₄N₃]₂ and (PPh₄)₂[ZrCl₄(N₃)₂]. The crystal structure of (PPh₄)₂[ZrCl₄N₃]₂ was determined by X-ray methods (1942 reflexions, R = 6.5%). The complex crystallizes in the monoclinic space group P2₁/n with two formula units per unit cell. The structure consists of tetraphenylphosphonium cations and dimeric anions [ZrCl₄N₃]₂^2?, in which the Zr atoms are linked by the α-N atoms of the azide groups, forming a centrosymmetric Zr₂N₂ ring with symmetry D_2h. According to the i.r. spectra, the azide groups in the complex (PPh₄)₂[ZrCl₄(N₃)₂] are covalently bonded at the Zr atom in trans positions.     

Crystal Structures of (PPh3)2Pd(N3)2, (AsPh3)2Pd(N3)2, (2‐Chloropyridine)2Pd(N3)2, [(AsPh4)2][Pd2(N3)4Cl2], [(PNP)2][Pd(N3)4], [(AsPh4)2][Pt(N3)4] · 2 H2O,and [(AsPh4)2][Pt(N3)6]

The crystal structures of the monomeric palladium(II) azide complexes of the type L₂Pd(N₃)₂ (L = PPh₃ ( 1 ), AsPh₃ ( 2 ), and 2‐chloropyridine ( 3 )), the dimeric [(AsPh₄)₂][Pd₂(N₃)₄Cl₂] ( 4 ), the homoleptic azido palladate [(PNP)₂][Pd(N₃)₄] ( 5 ) and the homoleptic azido platinates [(AsPh₄)₂][Pt(N₃)₄] · 2 H₂O ( 6 ) and [(AsPh₄)₂][Pt(N₃)₆] ( 7 ) were determined by X‐ray diffraction at single crystals. 1 and 2 are isotypic and crystallize in the triclinic space group P1. 1 , 2 and 3 show terminal azide ligands in trans position. In 4 the [Pd₂(N₃)₄Cl₂]^2– anions show end‐on bridging azide groups as well as terminal chlorine atoms and azide ligands. The anions in 5 and 6 show azide ligands in equal positions with almost local C_4h symmetry at the platinum and palladium atom respectively. The metal atoms show a planar surrounding. The [Pt(N₃)₆]^2– anions in 7 are centrosymmetric (idealized S₆ symmetry) with an octahedral surrounding of six nitrogen atoms at the platinum centers.     

The Binary Group 4 Azides [PPh4]2[Zr(N3)6] and [PPh4]2[Hf(N3)6]

The binary zirconium and hafnium polyazides [PPh₄]₂[M(N₃)₆] (M=Zr, Hf) were obtained in near quantitative yields from the corresponding metal fluorides MF₄ by fluoride–azide exchange reactions with Me₃SiN₃ in the presence of two equivalents of [PPh₄][N₃]. The novel polyazido compounds were characterized by their vibrational spectra and their X‐ray crystal structures. Both anion structures provide experimental evidence for near‐linear M‐N‐N coordination of metal azides. The species [M(N₃)₄], [M(N₃)₅]^? and [M(N₃)₆]^2? (M=Ti, Zr, Hf) were studied by quantum chemical calculations at the electronic structure density functional theory and MP2 levels.     

Bis[tris­(2,2′‐bipyridine)iron(II)] tetra­aqua­sodium(I) dodeca­tungsto­ferrate(III) dihydrate

The title compound, bis­[tris­(2,2′‐bipyridine)iron(II)] tetra­aqua­tetra‐μ₄‐oxo‐penta­cosa‐μ₂‐oxo‐undeca­oxo­iron(III)sodium(I)­dodeca­tungsten(VI) dihydrate, [Fe(C₁₀H₈N₂)₃]₂[NaFeW₁₂O₄₀(H₂O)₄]·2H₂O, consists of a dodeca­tungstoferrate(III) framework grafted on to an [Na(H₂O)₄]⁺ cation, two complex [Fe(2,2′‐bipy)₃]²⁺ cations (2,2′‐bipy is 2,2′‐bipyridine) and two uncoordinated water mol­ecules per formula unit.     

Binary Pnictogen Azides—An Experimental and Theoretical Study: [As(N3)4]−, [Sb(N3)4]−, and [Bi(N3)5(dmso)]2−

[PPh₄][EI₄] (E=As, Sb, Bi) salts were reacted with four and five equivalents of AgN₃ to form tetraazidopnictates and pentaazidopnictates of the type [PPh₄][E(N₃)₄] and [PPh₄]₂[E(N₃)₅], respectively. The synthesis of [PPh₄][P(N₃)₄] was also attempted from the reaction of P(N₃)₃ with [PPh₄]N₃, but it yielded only the starting materials. Herein, we report the synthesis and structure elucidation of [PPh₄][E(N₃)]₄ (E=As, Sb) and pentaazidobismuthate, stabilized as the dimethyl sulfoxide (DMSO) anion adduct, [PPh₄]₂[Bi(N₃)₅(dmso)]. Successive anion formation along the series E(N₃)₃+nN₃^? (n=1–3) and E(N₃)₅+N₃^? was studied by density functional theory.     

Bis(2,2′‐bipyridine)iodo­(oxo)tri‐μ3‐sulfido‐tricopper(I)tungsten(VI)

The title nest‐shaped cluster, [Cu₃WIOS₃(C₁₀H₈N₂)₂], has been synthesized by the reaction of (NH₄)₂[WOS₃], CuI and 2,2′‐bipyridine (bipy) in dimethyl­formamide under a purified nitro­gen atmosphere. The cluster has a neutral skeleton containing the bipy ligands, and the central W atom is tetra­hedrally coordinated by three S atoms and one O atom. The three Cu atoms are divided into two different kinds. Two Cu atoms adopt distorted tetra­hedral geometry, with each Cu atom coordinated by two S atoms and the two N atoms of a bipy ligand. The other Cu atom adopts a trigonal mode surrounded by two S atoms and one I atom.     

Natriumoxonitridometallate(VI) von Molybdän und Wolfram,Na4MO2N2 (M = Mo,W)

Sodium Oxonitridometallates(VI) of Molybdenum and Tungsten, Na₄MO₂N₂ (M = Mo, W) MoO₃ as well as WO₃ react with an excess of NaNH₂ in autoclaves at temperatures ranging from 250°C to 750°C to yield – in contrast to Ta₂O₅ [1] – oxonitridometallates of general composition Na₄MX₄ and other products like Na₅WO₄N [2]. The compounds decompose in moist air within minutes to Na₂WO₄, Na₂MoO₄ and Na₂MoO₄ · xH₂O, respectively. The structures of the Na₄MX₄ phases were determined from single crystal X-ray diffraction data. They crystallize triclinic in the Na₄CoO₄-type structure [3] P1 , Z = 2 with the following cell constants:      

The syntheses,crystal, molecular and electronic structures of two polymorphs of [ReCl2(N2COPh)(C3N2H4)(PPh3)2] and [ReCl2(N2COPh)(py)(PPh3)2] complexes

The [ReCl₂(η²-N₂COPh–N^′,O)(PPh₃)₂] complex reacts with pyridine and pyrazole to give [ReCl₂(N₂COPh)(py)(PPh₃)₂] and [ReCl₂(N₂COPh)(C₃N₂H₄)(PPh₃)₂], respectively. Two monoclinic polymers of [ReCl₂(N₂COPh)(C₃N₂H₄)(PPh₃)₂] and [ReCl₂(N₂COPh)(py)(PPh₃)₂] have been characterized by IR, UV–Vis, ¹H NMR, magnetic measurements and X-ray structure.     

Taming Tin(IV) Polyazides

The first charge‐neutral Lewis base adducts of tin(IV) tetraazide, [Sn(N₃)₄(bpy)], [Sn(N₃)₄(phen)] and [Sn(N₃)₄(py)₂], and the salt bis{bis(triphenylphosphine)iminium} hexa(azido)stannate [(PPN)₂Sn(N₃)₆] (bpy = 2,2′‐bipyridine; phen = 1,10‐phenanthroline; py = pyridine; PPN = N(PPh₃)₂) have been prepared using covalent or ionic azide‐transfer reagents and ligand‐exchange reactions. The azides were isolated on the 0.3 to 1 g scale and characterized by IR and NMR spectroscopies, microanalytical and thermal methods and their molecular structures determined by single‐crystal XRD. All complexes have a distorted octahedral Sn[N]₆ coordination geometry and possess greater thermal stability than their Si and Ge homologues. The nitrogen content of the adducts of up to 44 % exceed any Sn^IV compound known hitherto.     

Synthese und Struktur von Cs11[(WN2,5O1,5)2](N3)2, ein Caesiumoxonitridomonowolframat(VI)-azid

Synthesis and Structure of Cs₁₁[(WN_2,5O_1,5)₂](N₃)₂, a Cesium Oxo Nitrido Monotungstate(VI) Azide Cs₁₁[(WN_2,5O_1,5)₂](N₃)₂ results from the reaction of a mixture of CsNH₂, W and WO₃ at 620 °C in autoclaves. It crystallizes monoclinic in the space group C2/m with the lattice parameters a = 12.421(4) Å, b = 11.568(6) Å, c = 10.516(4) Å, β = 118.71(3)° and Z = 4. The crystal structure is built up by isolated tetrahedra [WX₄] with X = N, O, which are connected by cesium cations. Between the cesium ions lie azide ions separated from the anions [WX₄]. The tungsten atoms and azide ions together build up the motif of a distorted arrangement of the CsCl structure type.     

Organoimido complexes of tungsten and rhenium: Oxo-imido and bis-imido complexes of tungsten(VI), and phenylimido complexes of rhenium(VI) and (V). The X-ray crystal structures of [W(NCMe3)(NPh)Cl2(bipy)] and [Re(NPh)Cl3(NH2CMe3)2]

Reaction of Me₃CNH₂ or Me₃SiNHCMe₃ with WOCl₄ gives a mixture containing [W(O)(NCMe₃)Cl₂(NH₂CMe₃)]_x which on further reaction with 2,2′-bipyridyl (bipy) gives [W(NCMe₃)₂Cl₂(bipy)] and insoluble oxo complexes. Reaction of WOCl₄ with p-MeC₆H₄N(SiMe₃)₂ and then bipy gives [W(NC₆H₄Me-p)₂Cl₂(bipy)] and [W(O)(NC₆H₄Me-p)Cl₂(bipy)]; [W(NPh)Cl₄]₂ reacts with p-MeC₆H₄N(SiMe₃)₂ and then bipy to give [W(NPh)(NC₆H₄Me-p)Cl₂(bipy)]. [W(NCMe₃)(μ-NPh)Cl₂(NH₂CMe₃)]₂ and bipy give [W(NCMe₃)(NPh)Cl₂(bipy)] (6). ReOCl₄ reacts with PhNCO to give [Re(NPh)Cl₄]_x which in tetrahydrofuran (THF) or MeCN give the adducts [Re(NPh)Cl₄(THF)] and [Re(NPh)Cl₄(MeCN)]. [Re(NPh)Cl₄]_x reacts with Me₄NCl to give [Me₄N][Re(NPh)Cl₅], with PPh₃ to give [Re(NPh)Cl₃(PPh₃)₂] and with Me₃ SiNHCMe₃ gives [Re(NPh)Cl₃(NH₂CMe₃)₂] (12). The complexes were characterized by elemental analysis, IR, ¹H and ¹³C NMR spectroscopy. The structures of [W(NCMe₃)(NPh)Cl₂(bipy)] (6) and [Re(NPh)Cl₃(NH₂CMe₃)₂] (12) were determined by single-crystal X-ray diffraction methods. Crystals of (6) are orthorhombic, space group P2₁2₁2₁, with a = 8.879(3) Å, b = 13.036(3) Å, c = 18.837(4) Å; crystals of (12) are orthorhombic, space group Pbcn with a = 14.140(1) Å, b = 11.806(1), Å, c = 11.936(3) Å. Both structures were solved by Patterson and Fourier methods and refined to R values of 0.053 for the 2138 observed data for (6) and 0.035 for the 1108 observed data for (12). In complex (6) the tungsten atom is in a distorted octahedral environment comprising cis-t-butylimido and phenylimido groups, trans chlorides and bidentate bipy. The bipy nitrogens lie trans to the imid o functions. Observed distances are: WN_phenylimido 1.774(8) Å, WN_t-butylimido 1.754(10) Å, WCl 2.412(3) and 2.390(3) Å and WN_bipy 2.312(10) Å and 2.333(9) Å. Interaction between the t-butylimido methyl groups and bipy is relieved by lengthening of one WN_bipy bond. In complex (12) the rhenium atom is in a distorted octahedral environment comprising three chloride ligands, two trans-t-butylamine ligands and a phenylimido ligand. Observed distances are: ReN_phenylimido 1.709(11) Å, ReN_t-butylamine 2.187(7) Å, and ReCl 2.404(2) and 2.411(5) Å. The complex attains an 18-electron count without π-bonding from the chloro ligands.     

μ‐4,4′‐Bipyridine‐κ2N:N′‐bis[triaqua(4,4′‐bipyridine‐κN)cadmium(II)] bis(3‐aminobenzoate) bis(perchlorate) dihydrate: a novel supramolecular system constructed by π–π and hydrogen‐bonding interactions

The title dicadmium compound, [Cd₂(C₁₀H₈N₂)₅(H₂O)₆](C₇H₆NO₂)₂(ClO₄)₂·2H₂O, is located around an inversion centre. Each Cd^II centre is coordinated by three N atoms from three different 4,4′‐bipyridine ligands and three O atoms from three coordinating water molecules in a distorted octahedral coordination environment. In the dicadmium cation unit, one 4,4′‐bipyridine (4,4′‐bipy) molecule acts as a bidentate bridging ligand between two Cd metal ions, while the other four 4,4′‐bipy molecules act only as monodentate terminal ligands, resulting in a rare `H‐type' [Cd₂(C₁₀H₈N₂)₅(H₂O)₆] host unit. These host units are connected to each other viaπ–π stacking interactions, giving rise to a three‐dimensional supramolecular grid network with large cavities. The 3‐aminobenzoate anions, perchlorate anions and water molecules are encapsulated in the cavities by numerous hydrogen‐bonding interactions. To the best of our knowledge, this is the first example of a coordination compound based on both 4,4′‐bipyridine ligands together with discrete 3‐aminobenzoate anions.     

Heterometall-Komplexe mit Dithiometallaten des Typs [M′(MO2S2)2]2− (M  Mo,W; M′  Co,Ni); Darstellung und spektroskopische Eigenschaften

Heterometal Complexes with Dithiometallates of the Type [M′(MO₂S₂)₂]²⁻ (M  Mo, W; M′  Co, Ni); Preparation and Spectroscopic Properties The preparation of R₂[Co(MoO₂S₂)₂], R₂[Co(WO₂S₂)₂], R₂[Ni(MoO₂S₂)₂], and R₂[Ni(WO₂S₂)₂] (R = [(C₆H₅)₄P]) is described in detail. The compounds can be isolated under certain conditions inspite of the instability of the dithiometallates in solution. The i. r. and electronic absorption spectra as well as the reversible redox behaviour (from preliminary CV data) are discussed in relation to the molecular and electronic structure of the complexes.     

Azidocuprate(II). Die Kristallstruktur von (PPh4)2[Cu2(N3)6]

Azidocuprates(II). Crystal Structure of (PPh₄)₂[Cu₂(N₃)₆] (PPh₄)₂[Cu(N₃)₄] and (PPh₄)₂[Cu₂(N₃)₆], which is already known, are prepared from the corresponding chloro cuprates and excess silver azide in dichloro methane suspension. The azido cuprates form nonexplosive brown crystals of low sensitivity to moisture and are characterized by i.r. spectroscopy. (PPh₄)₂[Cu₂(N₃)₆] was submitted to a X-ray crystallographic structural analysis (4284 observed, independent reflexions, R = 0.034). The compound crystallizes triclinic in the space group P1 with one formula unit per unit cell. The lattice parameters are a = 1047.4 pm; b = 1131.1 pm; c = 1179.4 pm; α = 101.26°; β = 109.31°; γ = 103.42°. The compound consists of PPh₄^⊕ cations and centrosymmetric anions [Cu₂(N₃)₆]^2?, which meet D_2h-symmetry fairly well. In the anions the copper atoms are linked to a planar Cu₂N₂ four-membered ring by the N α atoms of two azide groups. The other azido ligands are bonded terminally and complete coordination number 4 at the Cu atoms which show planar geometry.