Neues aus der Chemie des Berylliums

Recent Advances in the Chemistry of Beryllium A review of recent results in coordination chemistry of beryllium halides is given. In accordance with the editors' objective, this Research Report is not a complete review of the literature in this field, but the important literature close to it is considered. The following subjects are presented: (i) Syntheses and structural characterizations of tetraphenylphosphonium salts of [BeCl₄]²⁻, [Be₂Cl₆]²⁻, and the unique [Be₂F₆]²⁻ ion, which are soluble in organic solvents like dichloromethane or acetonitrile. (Ph₄P)₂[Be₂F₆]·2CH₃CN is also extensively studied by IR spectroscopy and quantum chemical calculations (DFT). (ii) Application of (Ph₄)₂[Be₂Cl₆] to prepare donor acceptor complexes with N‐donor ligands D to give complexes [BeCl₃(D)]⁻ which are isoelectronical with the corresponding boron compounds [BCl₃(D)], including quantum chemical calculations. (iii) Molecular complexes of the type [BeCl₂(D)₂] with D = phosphorane imines HNPR₃ or Me₃SiNPR₃. (iv) Phosphoraneiminato complexes of beryllium, among these the first example [BeCl(μ‐NPEt₃)]₄ with a Be₄N₄ heterocubane skeleton. (v) Azido complexes of several types, including the unique examples with adamantane‐like structure [Be₄X₄(μ‐N₃)₆]²⁻ with X = Cl, Br. (vi) Monocationic complexes [BeCl(12‐crown‐4)]⁺[SbCl₄]⁻ and [BeCl(PMDETA)]⁺Cl⁻ (PMDETA = pentamethyl‐diethylenetriamine). (vii) Dicationic complexes with O‐donor ligands H₂O and OSMe₂. [Be(OH₂)₄]Cl₂, [Be(OSMe₂)₄]Cl₂, and mixed ligand complexes like [Be(OH₂)₂(OSMe₂)₂]Cl₂. (viii) Molecular and anionic oxo‐complexes, particularly with μ‐OSiMe₃ groups, among these the tetramethyl‐trioxosilanato complex (Ph₄P)₂[Be₄(μ‐Cl)₂Cl₄(OSiMe₂OSiMe₂O)₂].     

Ligand Exchange Processes on Solvated Beryllium Cations. II [Be(solvent)(12‐Crown‐4)]2+

The solvation and solvent exchange mechanism of [Be(12‐crown‐4)]²⁺ in water and ammonia was studied by DFT calculations (RB3LYP/6‐311+G**). In solution, five‐fold coordinated Be²⁺ species of quadratic pyramidal [Be(H₂O)(12‐crown‐4)]²⁺ and [Be(NH₃)(12‐crown‐4)]²⁺ exist. The water and ammonia exchange reactions follow an associative interchange mechanism, similar to that found for the pure solvent complexes [Be(H₂O)₄]²⁺ and [Be(NH₃)₄]²⁺. The activation barriers are clearly smaller than for the pure solvent complexes, viz. [Be(H₂O)(12‐crown‐4)]²⁺: 6.0 kcal/mol and [Be(NH₃)(12‐crown‐4)]²⁺: 15.3 kcal/mol.     

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.     

Die Kristallstruktur von (Ph4P)2[Be4Cl4(μ‐N3)6]

Suitable single crystals for X‐ray analysis of the recently published azido beryllate (Ph₄P)₂[Be₄Cl₄(μ‐N₃)₆] ( 1 ) [1] were obtained by a modified synthetic route, and the crystal structure of 1 was determined. The compound crystallizes isotypically with the corresponding bromo derivative [1] in the space group C2/c with 12 formula units per unit cell. Lattice dimensions at 193 K: a = 4125.5(1), b = 2001.7(1), c = 2050.4(1) pm, β = 101.05 (1)°, R₁ = 0.0359. The structure contains adamantanlike dianions [Be₄Cl₄(μ‐N₃)₆]^2? with a Be₄N₆ core forming by the bridging function of the α‐nitrogen atoms of the azido groups.     

Phosphanimin‐ und Phosphaniminato‐Komplexe von Beryllium. Kristallstrukturen von [BeCl2(HNPPh3)2], [BeCl(HNPPh3)2(Py)]Cl und [Be3Cl2(NPPh3)4]

Phosphanimine and Phosphoraneiminato Complexes of Beryllium. Crystal Structures of [BeCl₂(HNPPh₃)₂], [BeCl(HNPPh₃)₂(Py)]Cl, and [Be₃Cl₂(NPPh₃)₄] Tetraphenylphosphonium hexachlorodiberyllate, (Ph₄P)₂[Be₂Cl₆], reacts with lithium phosphoraneiminate, [LiNPPh₃]₆, in dichloromethane to give the three‐nuclear beryllium phosphoraneiminate [Be₃Cl₂(NPPh₃)₄] ( 3 ). As a by‐product the phosphaneimine complex [BeCl₂(HNPPh₃)₂] ( 1 ) can be isolated, which reacts with pyridine to give the ionic complex [BeCl(HNPPh₃)₂(Py)]Cl ( 2 ). On the other hand, the silylated phosphanimine Me₃SiNP(p‐tolyl)₃ ( 5 ) does not react with BeCl₂ or (Ph₄P)₂[Be₂Cl₆] forming the expected phosphoraneiminates. From CH₂Cl₂ solutions only the amino‐phosphonium salt [(C₇H₇)₃PNH₂]Cl ( 4 ) can be obtained. The compounds 1 ‐ 5 are characterized by single X‐ray analyses and by IR spectroscopy. 1 ·C₇H₈: Space group C2/c, Z = 4, lattice dimensions at 193 K: a = 1408.9(2), b = 1750.9(2), c = 1633.2(2) pm, β = 106.50(1)°; R₁ = 0.0385. 1 forms a molecular structure with short Be—N distances of 169.8(3) pm. 2 ·Py: Space group P1¯, Z = 4, lattice dimensions at 193 K: a = 969.5(1), b = 2077.1(2), c = 2266.4(2) pm, α = 72.24(1)°, β = 87.16(1)°, γ = 77.42(2)°, R₁ = 0.0776. 2 forms ion pairs in which the NH atoms of the phosphaneimine ligands act as hydrogen bridges with the chloride ion. The HNPPh₃ ligand realizes short Be—N bonds of 169.0(6) pm, the Be—N distance of the pyridine molecule is 182.5(6) pm. 3 ·3CH₂Cl₂: Space group P1¯, Z = 2, lattice dimensions at 193 K: a = 1333.2(2), b = 1370.2(2), c = 2151.8(3) pm, α = 107.14(1)°, β = 91.39(1)°, γ = 105.15(1)°, R₁ = 0.0917. The structure of the three‐nuclear molecule 3 corresponds with a Be²⁺ ion which is tetrahedrally coordinated by the nitrogen atoms of two {ClBe(NPPh₃)₂}^— chelates. 4 ·CH₂Cl₂: Space group P2₁/c, Z = 4, lattice dimensions at 193 K: a = 1206.6(2), b = 1798.0(2), c = 1096.2(1) pm, β = 97.65(1)°, R₁ = 0.0535. 4 forms dimeric units in which the NH₂ groups of the [(C₇H₇)₃PNH₂]⁺ cations act as hydrogen bridges with the chloride ions to give centrosymmetric eight‐membered rings. 5 : Space group P2₁/n, Z = 4, lattice dimensions at 193 K: a = 1074.3(2), b = 2132.2(3), c = 1075.5(2) pm, β = 110.68(1)°, R₁ = 0.0664. 5 forms molecules with distances PN of 154.6(3), SiN of 168.8(3) pm, and bond angle SiNP of 134.4(2)°.     

Dimethylsulfoxid‐Komplexe von Beryllium(II)‐chlorid. Kristallstrukturen von [Be(OSMe2)4]Cl2, [Be(OSMe2)3(H2O)]Cl2 und [Be(OSMe2)2(H2O)2]Cl2

Dimethylsulfoxide Complexes of Beryllium(II) Chloride. Crystal Structures of [Be(OSMe₂)₄]Cl₂, [Be(OSMe₂)₃(H₂O)]Cl₂ and [Be(OSMe₂)₂(H₂O)₂]Cl₂ Single crystals of the mixed ligand complexes [Be(OSMe₂)₃(H₂O)]Cl₂ ( 2 ) and [Be(OSMe₂)₂(H₂O)₂]Cl₂ ( 3 ) were obtained from saturated solutions of [Be(OSMe₂)₄]Cl₂ ( 1 ) in acetonitrile and dichloromethane, respectively, in the presence of traces of water, while single crystals of 1 were available by reaction of the carbodiphosphorane complex [BeCl₂{C(PPh₃)₂}] with DMSO/toluene solution. All complexes are characterized by X‐ray diffraction and IR spectroscopy. 1 : Space group Pbca, Z = 8, lattice dimensions at 193 K: a = 962.4(1), b = 1888.8(2), c = 2115.8(2) pm, R₁ = 0.0344. 1 consists of [Be(OSMe₂)₄]²⁺ cations with distorted tetrahedral coordination of the oxygen atoms of the DMSO molecules with Be–O distances of 161.9 pm on average, and chloride ions. 2 : Space group , Z = 2, lattice dimensions at 193 K: a = 903.9(2), b = 925.2(3), c = 1121.3(3) pm, α = 93.65(3)°, β = 108.03(3)°, γ = 115.20(3)°, R₁ = 0.0472. 3 : Space group , Z = 2, lattice dimensions at 173 K: a = 788.2(2), b = 801.6(2), c = 1070.7(3) pm, α = 86.66(2)°, β = 83.80(2)°, γ = 71.00(2)°, R₁ = 0.0699. 2 and 3 also form dications with distorted tetrahedral coordination of the Be²⁺ ions by the oxygen atoms of DMSO and water molecules, respectively. The chloride ions are associated by strong hydrogen bonds O–H···Cl to give three‐dimensional networks.     

(Ph4P)2[Be3(μ‐OH)3(H2O)6]Cl5: Kristallstruktur und DFT‐Rechnungen

Bis(tetraphenylphosphonium)‐tris(μ‐hydroxo)hexaaquatriberylliumpentachloride, (Ph₄P)₂[Be₃(μ‐OH)₃(H₂O)₆]Cl₅ ( 1 ), was surprisingly obtained by reaction of (Ph₄P)N₃ · n H₂O with BeCl₂ in dichloromethane suspension and subsequent crystallization from acetonitrile to give single crystals of composition 1· 5.25CH₃CN. According to the crystal structure determination space group P , Z = 2, lattice dimensions at 100 K: a = 1354.8(2), b = 1708.7(2), c = 1753.2(2) pm, α = 114.28(1)°, β = 94.80(1)°, γ = 104.51(1)°, R₁ = 0.0586] the [Be₃(μ‐OH)₃(H₂O)₆]³⁺ cations form six‐mem‐bered Be₃O₃ rings with boat conformation and distorted tetrahedrally coordinated beryllium atoms with the terminally coordinated H₂O molecules. The structure ist characterized by a complicated three dimensional hydrogen‐bridging network including O–H ··· O, O–H ··· Cl, and O–H ··· NCCH₃ contacts. DFT calculations result in nearly planar [Be₃(OH)₃] six‐membered ring conformations.     

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.     

Die Kristallstruktur von Berylliumamid,Be(NH2)2

Inhaltsübersicht. Die röntgenographische Untersuchung von Einkristallen des Beryllium-amids ergab, daß die Verbindung tetragonal kristallisiert. a = 10.170 ± 0.005 Å. c = 16,137 ± 0,008 Å und c/a = 1,587, in der Raumgruppe I4₁/acd mit 32 Formeleinheiten in der Elementarzelle. Es wurden die Lagen aller Atome einschließlich derer des Wasserstoffs bestimmt. Die Struktur des Be(NH₂)₂ leitet sich von einem stark verzerrten, kubisch dichten Anionenteilgitter ab. Die Kationen befinden sich derart in Tetraederlürken. daß jeweils 4 Be²⁺-Ionen ein regulärs Tetraeder mit den kürzesten Be — Be-Abständen bilden. Dadurch entstehen Einheiten, die sich als Be₄(NH₂)₆(NH₂)_4/2 wiedergeben lassen, wobei die äußeren 4 Amidionen als Brückenanionen für die dreidimensionale Verknüpfung wirken. Die Ausrichtung der Amidionen wird beschrieben und mit den Ergebnissen früherer Untersuchungen an venvandten Metallamiden verglichen. Crystal Structure of Beryllium Amide, Be(NH₂)₂ Abstract. The x-ray investigation of single crystals of beryllium amide led to the following results. The compound crystallizes tetragonally a = 10.170 ± 0.005 Å, c = 16.137 ± 0.008 Å, and c/a = 1.587. The space group is I4₁/acd. The lattice contains 32 formula units. The positions of all atoms including hydrogen were determined. The structure of Be(NH₂)₂ can be described by a strongly deformed cubic closepacking of anions. The cations occupy tetrahedral interstices so that 4 Be²⁺ ions form a regular tetrahedron with the shortest Be—Be distances. This causes units, which can be described by Be₄(NH₂)₆(NH₂)_4/2 Whereas the outer 4 amide ions serve as bridging anions to give a threedimensional arrangement. The orientation of the amide ions is given and compared with earlier results on similar metal amides.     

Über Reaktionen von Hexachlorodiberyllat mit Trimethylsilyl‐N‐dimethylamid. Die Kristallstrukturen von (Ph4P)3[Be2Cl5(OSiMe3)][BeCl3(Me2NSiMe3)], (Ph4P)[BeCl3(HNMe2)] und (Ph4P)(H2NMe2)[BeCl4]

On Reactions of Hexachlorodiberyllate with Trimethylsilyl‐N‐dimethylamide. Crystal Structures of (Ph₄P)₃[Be₂Cl₅(OSiMe₃)][BeCl₃(Me₂NSiMe₃)], (Ph₄P)[BeCl₃(HNMe₂)], and (Ph₄P)(H₂NMe₂)[BeCl₄] Reactions of bis‐tetraphenylphosphonium hexachlorodiberyllate, (Ph₄P)₂[Be₂Cl₆], with trimethylsilyl‐N‐dimethylamide under different conditions lead to the novel chloroberyllate derivatives (Ph₄P)₃[Be₂Cl₅(OSiMe₃)][BeCl₃(Me₂NSiMe₃)] ( 1 ), (Ph₄P)[BeCl₃(HNMe₂)] ( 2 ), and (Ph₄P)(H₂NMe₂)[BeCl₄] ( 3 ). 1 ‐ 3 were characterized by IR spectroscopy and crystal structure determinations. 1· 4CH₂Cl₂: Space group P1¯, Z = 2, lattice dimensions at 193 K: a = 1115.6(1), b = 2110.7(2), c = 2145.0(3) pm, α = 71.38(1)°, β = 85.66(1)°, γ = 85.24(1)°, R₁ = 0.0732. The [Be₂Cl₅(OSiMe₃)]^2— ion in the structure of 1 is derived from the [Be₂Cl₆]^2— ion by substitution of a μ‐Cl ligand by the oxygen atom of the (OSiMe₃)^— group. The second anion, [BeCl₃(Me₂NSiMe₃)]^—, can be described as donor acceptor complex with a short Be—N bond of 179(1) pm. 2 : Space group P1¯, Z = 2, lattice dimensions at 193 K: a = 1063.1(1), b = 1072.0(1), c = 1238.3(1) pm, α = 87.55(1)°, β = 74.86(1)°, γ = 69.73(1)°, R₁ = 0.0299. The anion of 2 forms a centrosymmetric dimer [BeCl₃(HNMe₂)]₂^2— via N—H···Cl bridges of the two donor acceptor complex units with Be—N separations of 175.2(2) pm. 3 : Space group Pbca, Z = 8, lattice dimensions at 193 K: a = 926.9(1), b = 2164.7(1), c = 2732.7(1) pm, R₁ = 0.0495. The structure of 3 contains centrosymmetric ion quadrupoles [(Me₂NH₂)(BeCl₄)]₂^2— forming by N—H···Cl bridges between (Me₂NH₂)⁺ and [BeCl₄]^2— ions.     

Synthese,Schwingungsspektrum und Kristallstruktur des Disiloxanato‐Chloroberyllats (Ph4P)2[Be4Cl6(OSiMe2OSiMe2O)2]

Synthesis, Vibrational Spectra, and Crystal Structure of the Disiloxanato‐chloroberyllate (Ph₄P)₂[Be₄Cl₆(OSiMe₂OSiMe₂O)₂] (Ph₄P)₂[Be₄Cl₆(OSiMe₂OSiMe₂O)₂] ( 1 ) was prepared by the reaction of (Ph₄P)₂[Be₂Cl₆] with cyclo‐hexamethyl‐trisiloxane in dichloromethane solution, forming colourless, moisture sensitive crystals, which are characterized by their vibrational spectra (IR, Raman) and by an X‐ray crystal structure determination. 1 crystallizes in the triclinic space group with Z = 1 and with the lattice dimensions at 193 K: a = 1050.0(1), b = 1248.2(1), c = 1312.5(1) pm, α = 84.37(1)°; β = 76.53(1)°; γ = 70.79(1)°; R₁ = 0.0349. 1 consists of (Ph₄P)⁺ions and centrosymmetric anions [Be₄Cl₆(OSiMe₂OSiMe₂O)₂]^2‐, in which the four beryllium atoms are connected by the terminal oxygen atoms of the (OSiMe₂OSiMe₂O)^2‐ ligands via two‐forked bonds to give Be₂O₂ four‐membered rings. The Be atoms of these units are additionally bridged by two μ‐Cl atoms. 1 is also obtained by reaction of (Ph₄P)₂[Be₂Cl₆] with Baysilon grease.     

Stable Heterometallic Cluster Ions based on Werner's Hexol

Large aqueous ions are interesting because they are useful in materials science (for example to generate thin films) but also because they serve as molecular models for the oxide–aqueous mineral interface where spectroscopy is difficult. Here we show that new clusters of the type M[(μ‐OH)₂Co(NH₃)₄]₃(NO₃)₆ (M=Al, Ga) can be synthesized using Werner's century‐old cluster as a substitutable framework. We substituted Group 13 metals into the hexol Co[(μ‐OH)₂Co(NH₃)₄]₃⁶⁺ ion to make diamagnetic heterometallic ions. The solid‐state structure of the hexol‐type derivatives were determined by single‐crystal XRD and NMR spectroscopy and confirmed that the solid‐state structure persists in solution after dissolution into either D₂O or [D₆]DMSO. Other compositions besides these diamagnetic ions can undoubtedly be made using a similar approach, which considerably expands the number of stable aqueous heteronuclear ions.     

Azidoberyllate mit Adamantanstruktur: Synthese,IR‐Spektren und Kristallstrukturen von (Ph4P)2[Be4X4(μ‐N3)6] (X = Cl,Br)

Azido Beryllates with Adamantan‐like Structures: Synthesis, IR Spectra, and Crystal Structures of (Ph₄P)₂[Be₄X₄(μ‐N₃)₆] (X = Cl, Br) The azido beryllates (Ph₄P)₂[Be₄X₄(μ‐N₃)₆] (X = Cl 1a , X = Br 1b ) have been prepared by the reaction of Me₃SiN₃ with the halogeno beryllates (Ph₄P)₂[Be₂Cl₆] and (Ph₄P)₂[Be₂Br₆], respectively, in CH₂Cl₂ and CH₂Br₂ solution, respectively. Both complexes form moisture sensitive, colourless crystals, which are nonexplosive with respect to mechanical or thermal stress. They are characterized by IR spectroscopy and by crystal structure determinations. 1a and 1b crystallize isotypically in the space group C2/c with 12 formula units per unit cell. Whereas 1a was only refined to R₁ = 0.13, which is caused by disordering, 1b could be refined to R₁ = 0.066. The structures contain adamantanlike dianions [Be₄X₄(μ‐N₃)₆]^2— with two symmetry nonequivalent individuals which differ only slightly from one another. The Be₄N₆ core is formed by bridging function of the α‐nitrogen atoms of the azide groups with BeN bond lengths of 172.5 and bond lengths N_α—N_β = 123.2 pm and N_β—N_γ = 113.1 pm on average in the structure of 1b .     

Kinetics and Mechanism of Oxidation of S2O32− by a Co‐Bound μ‐Amido‐μ‐Superoxo Complex

In acetate buffer media (pH 4.5–5.4) thiosulfate ion (S₂O₃^2?) reduces the bridged superoxo complex, [(NH₃)₄Co^III(μ‐NH₂,μ‐O₂)Co^III(NH₃)₄]⁴⁺ ( 1 ) to its corresponding μ‐peroxo product, [(NH₃)₄Co^III(μ‐NH₂,μ‐O₂)Co^III(NH₃)₄]³⁺ ( 2 ) and along a parallel reaction path, simultaneously S₂O₃^2? reacts with 1 to produce the substituted μ‐thiosulfato‐μ‐superoxo complex, [(NH₃)₄Co^III(μ‐S₂O₃,μ‐O₂)Co^III(NH₃)₄]³⁺ ( 3 ). The formation of μ‐thiosulfato‐μ‐superoxo complex ( 3 ) appears as a precipitate which on being subjected to FTIR shows absorption peaks that support the presence of Co(III)‐bound S‐coordinated S₂O₃^2? group. In reaction media, 3 readily dissolves to further react with S₂O₃^2? to produce μ‐thiosulfato‐μ‐peroxo product, [(NH₃)₄Co^III(μ‐S₂O₃,μ‐O₂)Co^III(NH₃)₄]²⁺ ( 4 ). The observed rate (k₀) increases with an increase in [T_Thio] ([T_Thio] is the analytical concentration of S₂O₃^2?) and temperature (T), but it decreases with an increase in [H⁺] and the ionic strength (I). Analysis of the log A_t versus time data (A is the absorbance of 1 at time t) reveals that overall the reaction follows a biphasic consecutive reaction path with rate constants k₁ and k₂ and the change of absorbance is equal to {a₁ exp(–k₁t) + a₂ exp(–k₂t)}, where k₁ > k₂.     

Di‐μ‐hydroxo‐bis({bis­[2‐(2‐pyridyl)ethyl]amine‐κ3N}copper(II)) dichloride hexahydrate

The title compound, [Cu₂(OH)₂(C₁₄H₁₇N₃)₂]Cl₂·6H₂O, is a crystallographically centrosymmetric dimer of square‐pyramidal Cu^II centres, with a basal–basal [Cu₂(μ‐OH)₂]²⁺ bridging motif and apical pyridyl donors. The Cl⁻ anion is hydrogen bonded to one O—H and one N—H group, and to three different water mol­ecules. Because of disorder, the network of intramolecular hydrogen bonding in the hydrated lattice is only partly resolved.     

Peroxide Coordination of Tellurium in Aqueous Solutions

Tellurium–peroxo complexes in aqueous solutions have never been reported. In this work, ammonium peroxotellurates (NH₄)₄Te₂(μ‐OO)₂(μ‐O)O₄(OH)₂ ( 1 ) and (NH₄)₅Te₂(μ‐OO)₂(μ‐O)O₅(OH)?1.28 H₂O?0.72 H₂O₂ ( 2 ) were isolated from 5 % hydrogen peroxide aqueous solutions of ammonium tellurate and characterized by single‐crystal and powder X‐ray diffraction analysis, by Raman spectroscopy and thermal analysis. The crystal structure of 1 comprises ammonium cations and a symmetric binuclear peroxotellurate anion [Te₂(μ‐OO)₂(μ‐O)O₄(OH)₂]^4?. The structure of 2 consists of an unsymmetrical [Te₂(μ‐OO)₂(μ‐O)O₅(OH)]^5? anion, ammonium cations, hydrogen peroxide, and water. Peroxotellurate anions in both 1 and 2 contain a binuclear Te₂(μ‐OO)₂(μ‐O) fragment with one μ‐oxo‐ and two μ‐peroxo bridging groups. ¹²⁵Te NMR spectroscopic analysis shows that the peroxo bridged bitellurate anions are the dominant species in solution, with 3–40 %wt H₂O₂ and for pH values above 9. DFT calculations of the peroxotellurate anion confirm its higher thermodynamic stability compared with those of the oxotellurate analogues. This is the first direct evidence for tellurium–peroxide coordination in any aqueous system and the first report of inorganic tellurium–peroxo complexes. General features common to all reported p‐block element peroxides could be discerned by the characterization of aqueous and crystalline peroxotellurates.     

Influence of the chloride counterion on the redox reactivity of tetraammineplatinum(II) cation with octacyanotungstate(V) anion: Crystal structure of [Pt(NH3)4]2[W(CN)8]

The redox reaction between [Pt(NH₃)₄]²⁺ and [W(CN)₈]³⁻ in the presence of Cl⁻ anions in aqueous solution affords single crystals of [Pt^II(NH₃)₄]₂[W^IV(CN)₈] and [Pt^IV(NH₃)₄Cl₂]Cl₂. Trapped cyano ligands of [W(CN)₈]⁴⁻ rectangular antiprisms of D₂ point symmetry between parallel Pt(II) square planes show that the inner-sphere redox pathway is prohibited. The presence of Cl⁻ counterions enables the formation of [Pt(NH₃)₄Cl₂]Cl₂ as the product of the rare outer-sphere pathway of the oxidation of Pt(II) by [W(CN)₈]³⁻.     

The First Examples of Selenidogermanate Salts with Lanthanide Complex Counter Cations: Solvothermal Syntheses and Characterizations of [{Ln(en)3}2(μ‐OH)2]Ge2Se6 (Ln = Eu,Ho) and [{Ho(dien)2}2(μ‐OH)2]Ge2Se6

The lanthanide selenidogermanates [{Eu(en)₃}₂(μ‐OH)₂]Ge₂Se₆ ( 1 ), [{Ho(en)₃}₂(μ‐OH)₂]Ge₂Se₆ ( 2 ), and [{Ho(dien)₂}₂(μ‐OH)₂]Ge₂Se₆ ( 3 ) (en = ethylenediamine, dien = diethylenetriamine) were solvothermally prepared by the reactions of Eu₂O₃ (or Ho₂O₃), germanium, and selenium in en and dien solvents respectively. Compounds 1 – 3 are composed of selenidogermanate [Ge₂Se₆]^4– anion and dinuclear lanthanide complex cation [{Ln(en)₃}₂(μ‐OH)₂]⁴⁺ (Ln = Eu, Ho) or [{Ho(dien)₂}₂(μ‐OH)₂]⁴⁺. The [Ge₂Se₆]^4– anion is composed of two GeSe₄ tetrahedra sharing a common edge. The dinuclear lanthanide complex cations are built up from two [Ln(en)₃]³⁺ or [Ho(dien)₂]³⁺ ions joined by two μ‐OH bridges. All lanthanide(III) ions are in eight‐coordinate environments forming distorted bicapped trigonal prisms. In 1 – 3 , three‐dimensional supramolecular networks of the anions and cations are formed by N–H ··· Se and N–H ··· O hydrogen bonds. To the best of our knowledge, 1 – 3 are the first examples of selenidogermanate salts with lanthanide complex counter cations.     

Die Deprotonierung von Metall-Aquoionen I.: Be · aq2+ Solvatations-Isomerie

The reaction of Be · aq²⁺ with OH^? leeds not only to loss of protons by the metalaquo ion but also to structural changes in the solvation sphere. These can be studied by following the pH variations during the first decisecond after mixing the solutions of metal salt and alkali hydroxide. The equilibrium Be²⁺ ? BeOH⁺ is reached within 5 milliseconds if acid free Beryllium solutions are used. If the metal solution is strongly acidic, however, the establishment of the equilibrium needs more time because of the slowness of the process H⁺ + BeOH⁺ → Be²⁺ (k ～ 10⁵ M^?1, s^?1). The extraction of two protons produces in the first instance an unstable Be(OH) species which transforms into the stable isomer Be(OH)₂ (solvatation isomerism) in a first-order reaction of half-life of 7 ms. This isomerisation causes almost complete disappearance of BeOH⁺ from the equilibrium Be²⁺ ? BeOH⁺ ? Be(OH)₂. (KAKIHANA & SILLEN state that the relaxed solutions contain only Be²⁺, Be(OH)₂, Be₃(OH) and some Be₂OH³⁺.) The formation of the polynuclear species Be₃(OH) needs about 30 seconds to go to completion.     

A re-interpretation of the crystal structure of ‘(NH4)2(NH3)[Ni(NH3)2Cl4]’ in terms of (NH4)2−2z[Ni(NH3)2]z[Ni(NH3)2Cl4]

A re-interpretation and re-evaluation of single-crystal X-ray diffraction data of a previously reported ‘(NH₄)₂(NH₃)[Ni(NH₃)₂Cl₄]’ (J. Solid State Chem. 162 (2001) 254) give a new formula (NH₄)_2−2z[Ni(NH₃)₂]_z[Ni(NH₃)₂Cl₄] with z=0.152. This new formula results from defects in an idealized ‘(NH₄)₂[Ni(NH₃)₂Cl₄]’ basic structure, where two adjacent NH₄⁺ cations are replaced by one Ni(NH₃)₂²⁺ unit. Cl⁻ anions from the basic structure complete the coordination sphere of the new Ni²⁺ to [Ni(NH₃)₂Cl₄]²⁻.