Anna J. Lehner

The Reaction of White Phosphorus with NO+/NO2+[Al(ORF)4]−: The [P4NO]+ Cluster Formed by an Unexpected Nitrosonium Insertion†

Despite decades of intense research into polyphosphorus chemistry, our knowledge of homoleptic polyphosphorus cations is still limited to the results of mass spectrometry and quantum chemical calculations. In general, the diamagnetic cage cations with an odd number of phosphorus atoms are more stable, with P9 , composed of two C2v symmetric P5 cages joined by a common phosphonium atom having special stability. This cage was found in one of the few types of simple inorganic phosphorus cluster cations that are known, that is, [P5R2] + (R = Cl, Br, I, Ph, DippN(Cl)NDipp (Dipp = 2,6-diisopropylphenyl)). Those P5 cages are formed by the formal insertion of carbene-analogous PR2 + fragments into the P P bond of P4 (see Ref. [9, 10] for Reviews on P4 activation). Stable carbenes also interact with P4, leading to compounds including P1 up to P12 moieties, depending on the electronic nature of the carbene. Larger cationic P7 cages were recently prepared, but all preparative approaches to true Pn + ions remained futile. However, we expected that an appropriate one-electron oxidant should be able to oxidize P4 (ionization energy (IE) 9.34 eV) and lead to phosphorus cluster cations Pn . Herein we give an account of the reaction of P4 with the salts [NO] [Al(OC(CF3)3)4] [13] (1; IE NO = 9.26 eV) and [NO2] [Al(OC(CF3)3)4] (2 ; IE NO2 = 9.59 eV. At least 2 was expected to be a strong enough oxidant to yield Pn + cations. The novel salt 2 was synthesized in 94 % yield from NO2[BF4] and Li[Al(OC(CF3)3)4] in SO2 solution with precipitation of insoluble Li[BF4]; it was fully characterized by X-ray diffraction and vibrational and NMR spectroscopy (for details, see the Supporting Information). Unexpectedly, the reactions of 1 and 2 with P4 in CH2Cl2 show an analogous process, regardless of the ratios of phosphorus to oxidant employed (between 3P:1 NOx + and 9P:1 NOx ). They form a red intermediate and yield the same yellow final product ([P4NO] [Al(OC(CF3)3)4] (3 ; Scheme 1). Compound 3 may be viewed as the insertion

In‐Between Complex and Cluster: A 14‐Vertex Cage in [Ag2Se12]2+

Numerous cyclic sulfur and selenium allotropes En (E = S: n = 6–15, 18, 20 etc.; E = Se: n = 6, 7, 8) are known, while hexagonal Te1 remains the only accessible allotrope of tellurium. For Se, the stability of the allotropes increases from Se7< Se6< Se8< Se1. Although being structurally related to crown ethers, only a few examples of chalcogen rings coordinated to a metal ion exist, including [Agn(Se6)] n+ (n = 1, 2), 3] [M(S8)n] + (M = Cu; Ag), [Cu(S12)] , [Cu(S8)(S12)] . All of these cations are partnered with weakly coordinating anions (WCA). Related salts containing almost non-interacting cationic stacks are [Rb(Se8) ]1 [8] and [Rb(Se6)2 ]1. [9] The neutral selenium complexes [PdX2(Se6)] [10] (X = Cl, Br), [(AgI)2Se6], [11] [Re2I2(CO)6(Se7)], [12]

Kristallstrukturen der Alkalimetall-Thiosulfate A2S2O3 nH2O (A/n = K/0, K/⅓ , Rb=1) / Crystal Structures of the Alkali Thiosulfates A2S2O3 · nH2O (A/n = K/0, K/⅓ , Rb=1)

The potassium and rubidium thiosulfates (hydrates) considered in this work were originally obtained as by-products during several syntheses of mixed sulfido=oxido metallates. The interesting complexity of their structural chemistry has motivated us to investigate them in detail. The crystal structures of all title compounds have been determined using single-crystal X-ray data. The structure of the anhydrous potassium thiosulfate K2S2O3 (monoclinic, space group P21/c, a=1010.15(14), b=910.65(12), c=1329.4(2) pm, b =111.984(11)º, Z =8, R1=0.0665) exhibits two crystallographically different thiosulfate anions, overall coordinated by 9=10 potassium cations. Their packing in the structure leads to a complex structure with a pseudo orthorhombic unit cell. The structure of the anhydrous salt is discussed in comparison with the known even more complicated 1=3 hydrate K2S2O3·1/3H2O (monoclinic, space group P21/c, a=938.27(6), b=602.83(4), c=3096.0(2) pm, b =98.415(6)º, Z =12, R1=0.0327). Under the chosen experimental conditions, rubidium forms the monohydrate Rb2S2O3 ·H2O, which also crystallizes with a new, in this case less complex structure (monoclinic, space group C2/m, a=1061.4(1), b=567.92(4), c=1096.4(1) pm, b =97.40(1)º, Z =4, R1=0.0734). Its thiosulfate ions form double layers of equally oriented tetrahedral units. The bond lengths and angles of the thiosulfate ions in all title compounds and in the sodium salts used for comparison vary only very slightly (dS-S =199.8 - 203.0 pm, dS-O =144.8 - 147.4 pm), and the deviation from the ideal C3v symmetry is very small, despite their complex packing. The overall coordination number of the thiosulfate ions by the alkali cations (and water molecules) increases systematically with the ionic radius of the counter cations and the amount of water molecules. For all known alkali thiosulfates, both the conventional and the calculated effective coordination numbers (ECoN) of the alkali cations as well as the partial molar volumes of the cations and the water molecules are compared and discussed. Graphical Abstract Kristallstrukturen der Alkalimetall-Thiosulfate A2S2O3 nH2O (A/n = K/0, K/⅓ , Rb=1) / Crystal Structures of the Alkali Thiosulfates A2S2O3 · nH2O (A/n = K/0, K/⅓ , Rb=1)

Kalium-Doppelsalze mit den gemischten Trisulfidometallat-Ionen [MoOS3]2- und [WOS3]2- / Potassium Double Salts with the Mixed Trisulfidometalate Ions [MoOS3]2- and [WOS3]2-

In the course of the synthesis of mixed oxidosulfido molybdates and tungstates by passing H2S gas through solutions of the oxido metalates, several new salts containing the metalates [MOS3]2- besides further anions (halides X-, hydrosulfide SH- or thiosulfate S2O2-3) were obtained as well-formed crystals. Their crystal structures have been determined using single crystal X-ray data. The salts containing SH- as the additional anion crystallize with a new structure type (orthorhombic, space group Pmn21, M=Mo=W, TM =20=-125 °C: a=957.7(2)/954.15(2), b=636.2(2)/636.19(1), c=812.4(2)/809.88(2) pm, Z =2, R1=0.0319=0.0185). The mixed sulfidomolybdate/ chloride K3[MoO1.25S2.75]Cl (orthorhombic, space group Pca21, a=1246.3(1), b=623.20(4), c=1230.44(8) pm, Z =4, R1=0.0472) is isotypic with the sulfidotungstate K3[WOS3]Cl, but contains 25% of the disulfido molybdate. The structures of the SH- and the Cl- salts are closely related: In both cases, the trisulfido metalates are overall coordinated by cuboctahedra of 12 K+ ions, and the small additional anions are centered in K+ octahedra. In this regard, the structures are both derivatives of the cubic perovskite (and thus the Cu3Au) type. This crystallographic group-subgroup relation is discussed in detail. Yellow hexagonal columns of the double salt K6[WOS3]2(S2O3) were obtained by the methanothermal decomposition of the disulfidotungstate K2[WO2S2]. It crystallizes with a new structure type (hexagonal, space group P63mc, a=983.78(8), c=1227.3(1) pm, Z =2, R1=0.0175). Like in the other mixed salts, the two crystallographically different [WOS3]2- anions exhibit an overall cuboctahedral coordination by 12 potassium cations. The smaller S2O2-3 anions are surrounded by nine K+ ions arranged in the form of two flat facesharing octahedra. Again similar to the mixed halides and hydrosulfides, the two K polyhedra around the anions, here present in a 2 : 1 ratio, are arranged in a space-filling packing, in this case related to the ht- BaMnO3 (and thus the Ni3Ti) structure type. According to their ‘double salt’ character, the Mo/W-O and Mo/W-S distances and the intramolecular vibrational frequencies of the tetrahedral moieties of the title compounds are similar between them and those in the pure potassium trisulfido metalates. This further becomes apparent from the additive nature of their molar volumes, which correspond to the sum of the volumes of the simple salts KCl, KSH or K2(S2O3) and K2[MoOS3]. Graphical Abstract Kalium-Doppelsalze mit den gemischten Trisulfidometallat-Ionen [MoOS3]2- und [WOS3]2- / Potassium Double Salts with the Mixed Trisulfidometalate Ions [MoOS3]2- and [WOS3]2-

Gemischte Alkalimetall-Oxidosulfidomolybdate A2[MoOxS4– x] (x = 1, 2, 3; A = K, Rb, Cs, NH4). Synthesen, Kristallstrukturen und Eigenschaften / Mixed Alkali Oxidosulfidomolybdates A2[MoOxS4−x] (x = 1, 2, 3; A = K, Rb, Cs, NH4).Synthesis, Crystal Structure and Properties

Mixed sulfido/oxidomolybdate anions [MoOxS4−x]2− (x = 1, 2, 3) have been prepared by passing H2S gas through a solution of oxidomolybdates. The alkali salts of K+, Rb+, Cs+, and NH+4 precipitate as crystalline salts from these solutions depending on the pH, the polarity of the solvent, the educt concentrations and the temperature. Their structures have been determined by means of X-ray single-crystal diffraction data. All trisulfidomolybdates A2[MoOS3] (A = NH4/K/Rb/Cs) are isotypic with the tetrasulfido salts, exhibiting the β -K2[SO4] type (orthorhombic, space group Pnma, Z = 4; for A = Rb: a = 940.62(4), b = 713.32(4), c = 1164.56(5) pm, R1 = 0.0281). In contrast, the disulfidomolybdates exhibit a rich crystal chemistry, forming three different structure types depending on the preparation conditions and the size of the A cation: All four cations form salts crystallizing with the (NH4)2[WO2S2] structure type (monoclinic, space group C2/c, Z = 4, for A = Rb: a = 1144.32(11), b = 732.60(4), c = 978.99(10) pm, β = 120.324(7)°, R1 = 0.0274). For the three alkali metal cations a second polymorph with a new structure type (monoclinic, space group P21/c, Z = 4) is observed in addition (for A = Rb: a = 674.83(2), b = 852.98(3), c = 1383.10(9) pm, β = 115.19(1)°, R1 = 0.0216). The cesium salt also crystallizes with a third modification of another new structure type (orthorhombic, space group Pbcn, Z = 4, a = 915.30(6), b = 777.27(7), c = 1120.02(7) pm, R1 = 0.0350). Only for K, an anhydrous monosulfidomolybdate could be obtained (K2[MoO4] structure type, monoclinic, space group C2/m, Z = 4, a = 1288.7(3), b = 615.7(2), c = 762.2(1) pm, β = 109.59(1)°, R1 = 0.0736). The intramolecular chemical bonding in the molybdate anions is discussed and compared with the respective vanadates. Hereby aspects like bond lengths, bond strengths and force constants derived from Raman spectroscopy, are taken into account. Especially for the polymorphic disulfido salts, in-depth analyses of the local coordination numbers and the packing of the ions are presented. The gradual bathochromic shift of the crystal color with increasing S content and increasing size of the counter cations A and molar volumes (for the polymorphic forms), respectively, is in accordance with the increase of the experimental (UV/Vis spectroscopy) and calculated (FP-LAPW band structure theory) band gaps. Graphical Abstract Gemischte Alkalimetall-Oxidosulfidomolybdate A2[MoOxS4– x] (x = 1, 2, 3; A = K, Rb, Cs, NH4). Synthesen, Kristallstrukturen und Eigenschaften / Mixed Alkali Oxidosulfidomolybdates A2[MoOxS4−x] (x = 1, 2, 3; A = K, Rb, Cs, NH4).Synthesis, Crystal Structure and Properties

Hydrates of the Alkali Trioxidomonosulfidomolybdates and -tungstates: K2[(Mo/W)O3S] · 1.5H2O and (Rb/Cs)2[(Mo/W)O3S] · H2O

Abstract The trioxidomonosulfidomolybdate and -tungstate anions [(Mo/W)O3S]2– are the first products formed when passing H2S gas through a solution of the oxidometalates. Their potassium, rubidium and cesium salt hydrates form as crystalline precipitates from these solutions depending on pH, the polarity of the solvent, educt concentrations and temperature. The structures of the sesqui- (K) and mono- (Rb, Cs) hydrates have been determined by means of X-ray single crystal diffraction data. The potassium sesquihydrates K2[(Mo/W)O3S] · 1.5H2O are isotypic and crystallize with a new structure type (monoäclinic, space group C2/c, M = Mo/W: a = 987.0(2)/993.13(11), b = 831.75(14)/831.10(11), c = 1868.9(4)/1865.2(2) pm, β = 99.34(2)/99.153(8)°, R1 = 0.0352/0.0390). In the crystal structure the [(Mo/W)O3S]2– anions are connected via hydrogen bonds to form columns along the c direction. Channels containing only water molecules run along the [101] direction. The dehydration process proceeds in a topotactic reaction between 60 to 95 °C and yields crystals of the anhydrous salts K2[(Mo/W)O3S]. The two different K+ cations exhibit a 5 + 3 and 5 + 2 O/S coordination. The heavier alkali metal cations form the four monohydrates (Rb/Cs)2[(Mo/W)O3S] · H2O (trigonal rhombohedral, space group R-3m) with lattice parameters for the Rb/Cs molybdates of a = 621.17(6)/624.62(10), c = 3377.9(4)/3388.6(8) pm (R1 = 0.0505/0.0734) and the tungstates of a = 642.80(3)/643.3(4), c = 3532.8(3)/3566(4) pm (R1 = 0.0348/0.0660). In the structures the 3m symmetrical tetrahedra are arranged to form double layers in such a way, that the O3 bases of the tetrahedra are pointing towards each other in a staggered conformation. These double layers are stacked in the c direction in a rhombohedral sequence. In these hydrates, there are no distinct hyrdogen bonds. Instead, partially disordered pairs of H2O molecules are situated in large cavities between the double layers. With a number of 10, the cation coordination sphere is increased compared to the K salts. The crystallographic results are confirmed by vibrational spectroscopy (Raman/IR) and thermal analytical studies of the new compounds.