New Volatile Nitronium Nitratometalates: NO2[Fe(NO3)4] and NO2[Zr(NO3)5] — Synthesis and Crystal Structure

Crystalline NO₂[Fe(NO₃)₄] was obtained by dehydration of a solution of Fe(NO₃)₃ in 100 % HNO₃ and subsequent sublimation. NO₂[Zr(NO₃)₅] was synthesized by reaction of ZrCl₄ with N₂O₅ followed by sublimation in vacuum. X‐ray single crystal structure determination showed both compounds to consist of nitronium cations, NO₂⁺, and nitratometalate anions. N‐O distances in the linear NO₂⁺ cations are in the range of 1.08—1.13Å. In both [Fe(NO₃)₄]⁻ and [Zr(NO₃)₅]⁻ anions, all nitrate groups are coordinated bidentately with average M‐O distances 2.134 and 2.293Å, respectively. Taking into account the position of N atoms around the M atoms, the arrangement of nitrate groups can be described as tetrahedral for the Fe complex and trigonal‐bipyramidal for the Zr complex. There are four shortest N(nitronium)····O(nitrate group) contacts with average distances of 2.705 and 2.726Å in NO₂[Fe(NO₃)₄] and 2.749Å in NO₂[Zr(NO₃)₅]. Nitronium pentanitratohafnate is isotypic to the zirconium complex.     

[Sm(NO3)3(TPTZ)(H2O)]·2H2O [TPTZ is 2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine]

The title compound, aqua­tris­(nitrato)[2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine]samarium dihydrate, [Sm(NO₃)₃­(C₁₈H₁₂N₆)­(H₂O)]·­2H₂O, was prepared from Sm(NO₃)₃·6H₂O and 2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine. The metal atom is ten‐coordinate being bonded to the terdentate TPTZ ligand, three bidentate nitrates and a water mol­ecule.     

Nitrosylkomplexe des Molybdän(+II) Die Kristallstrukturen von [Mo(NO)Cl3 · POCl3]2 und von [AsPh4]2[Mo(NO)Cl5] · 2 CH2Cl2

Nitrosyl Complexes of Molybdenum (+II). Crystal Structures of [Mo(NO)Cl₃ · POCl₃]₂ and [AsPh₄]₂[Mo(NO)Cl₅] · 2 CH₂Cl₂ Solutions of MoCl₅ in POCl₃ react with NOCl forming the nitrosyl compound Mo(NO)Cl₃ · 2POCl₃ ( I ), which in CH₂Cl₂ cleaves off one solvate molecule, yielding the dimeric complex [Mo(NO)Cl₃ · POCl₃]₂ ( II ). Reaction with AsPh₄Cl in dichloro methane leads to the nitrosyl complexes AsPh₄[Mo(NO)Cl₄] · CH₂Cl₂ ( III ) and [AsPh₄]₂[Mo(NO)Cl₅] · 2CH₂Cl₂ ( IV ), respectively. The i.r. spectra are recorded and assigned. [Mo(NO)Cl₃ · POCl₃]₂ crystallizes monoclinic in the space group P2₁/c with two dimeric units per unit cell. The crystal structure was determined by X-ray diffraction methods (R = 0.040; 1391 observed, independent reflexions). Complex II is linked by chlorine bridges, forming a dimeric, centrosymmetric molecule of symmetry C_i. The N? O bond of the nitrosyl ligand is extremely short (108 pm), the Mo? N bond (181 pm) corresponds to a double bond. In trans position to the NO ligand, which is coordinated in linear array, there is the O atom of the solvate molecule POCl₃. [AsPh₄]₂[Mo(NO)Cl₅] · 2 CH₂Cl₂ crystallizes triclinic in the space group P1 with two units per unit cell (R = 0.039; 1967 observed, independent reflexions). The molybdenum atom is coordinated octahedrally by five Cl ligands and a nitrosyl group, as well coordinated in linear array (Mo? N? O 174°). The nitrosyl ligand exerts a significant trans-effect (r Mo? Cl_(trans) = 247 pm, r MoCl_4(eq)(average) = 239 pm).     

Identification of the Structural Boundary between [Ln(18‐crown‐6)(NO3)3] and [Ln(NO3)3(H2O)3] · 18‐crown‐6 Motifs in the Lanthanide Series

Recrystallization of Ln(NO₃)₃ (Ln = Sm, Eu, Yb) in the presence of 18‐crown‐6 under aqueous conditions yielded [Ln(NO₃)₃(H₂O)₃] · 18‐crown‐6. X‐ray crystallography revealed isomorphous structures for each of the lanthanide complexes where [Ln(NO₃)₃(H₂O)₃] is involved in hydrogen bonding interactions with 18‐crown‐6. The transition point where the structural motif changes from [Ln(18‐crown‐6)(NO₃)₃] (with the metal residing in the crown cavity) to [Ln(NO₃)₃(H₂O)₃] · 18‐crown‐6 has been identified as at the Nd/Sm interface. A similar investigation involving [Ln(tos)₃(H₂O)₆] (tos = p‐toluenesulfonate) and 18‐crown‐6 were resistant to crown incorporation. X‐ray studies show extensive intra‐ and intermolecular hydrogen bonding is present.     

IV Dodekaedrische [Mo(CN)8]‐Koordination in den cyanoverbrückten Cobalt‐ und Nickel‐Amminkomplexen MII2(NH3)8[Mo(CN)8] · 1,5 H2O (MII = Co,Ni) und Ni2(NH3)9[Mo(CN)8] · 2 H2O

Crystal Structures of Octacyanomolybdates(IV). IV Dodecahedral [Mo(CN)₈] Coordination of the Cyano‐Bridged Cobalt and Nickel Ammin Complexes M^II₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (M^II = Co, Ni) and Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O At single crystals of the hydrated cyano complexes Co₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 910.0(4), b = 1671(2), c = 1501(1) pm, β = 93.76(6)°) and Ni₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 899.9(9), b = 1654.7(4), c = 1488(1) pm, β = 94.01°), isostructurally crystallizing in space group P2₁/c, Z = 4, and of trigonal Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O (a = 955.1(1), c = 2326.7(7) pm, P3₁, Z = 3), X‐ray structure determinations were performed at 168 resp. 153 K. The [Mo(CN)₈]^4– groups of the three compounds, prepared at about 275 K and easily decomposing, show but slightly distorted dodecahedral coordination (mean distances Mo–C: 216.3, 215.4 and 216.1 pm). Within the monoclinic complexes the anions twodimensionally form cyano bridges to the ammin cations [M(NH₃)₄]²⁺ and are connected with the resulting [MN₆] octahedra (Co–N: 215.1 pm, Ni–N: 209.8 pm) into strongly puckered layers. The trigonal complex exhibits a chain structure, as one [Ni(NH₃)₅]²⁺ cation is only bound as terminal octahedron (Ni–N: 212.0 pm). Details and the influence of hydrogen bridges are discussed.     

Oxo-Phosphaniminato-Komplexe von Molybdän und Wolfram. Die Kristallstrukturen von [Mo(O)2(NPPh3)2] und [WO(NPPh3)3]2[W6O19]

Oxo-phosphoraneiminato Complexes of Molybdenum and Tungsten. Crystal Structures of [Mo(O)₂(NPPh₃)₂] and [WO(NPPh₃)₃]₂[W₆O₁₉] The dioxo-phosphoraneiminato complexes [Mo(O)₂(NPPh₃)₂] ( 1 ) and [W(O)₂(NPPh₃)₂] ( 2 ) originate from hydrolysis of the nitrido complexes [MN(NPPh₃)₃] (M = Mo, W). They form colourless crystals, which are characterized by IR and NMR spectroscopy as well as by mass spectrometry. According to the crystal structure analysis of 1 (space group Fdd2, Z = 8; lattice dimensions at –83 °C: a = 1953.3(1), b = 3275.8(3), c = 953.4(1) pm) there are monomeric molecules with tetrahedrally coordinated molybdenum atoms. The distances MoO of 171.2 pm and MoN of 185.9 pm correspond to double bonds. In dichloromethane solution 2 undergoes further hydrolysis with colourless crystals of [WO(NPPh₃)₃]₂[W₆O₁₉] ( 3 ) originating, which are characterized crystallographically (space group Pbcn, Z = 4; lattice dimensions at –50 °C: a = 3225.1(6), b = 1803.6(3), c = 1811.9(3) pm). 3 consists of cations [WO(NPPh₃)₃]⁺ with tetrahedrally coordinated tungsten atoms and of the known [W₆O₁₉]^2– anions. The tungsten atoms of the cations show distances WO of 171.8 pm and WN of 182 pm which correspond to double bonds as in 1 .