Ligand Exchange Processes on Solvated Beryllium Cations. IV [Be(H2O)2(imidazole‐based Chelate)]1)

The water exchange reaction of [Be(H₂O)₂(1H‐imidazole‐4,5‐dicarboxylate)] and [Be(H₂O)₂(1H‐imidazol‐3‐ium‐4,5‐dicarboxylate)]⁺ in water was studied by DFT calculations (RB3LYP/6‐311+G**) and identified as an associative interchange mechanism. The activation barriers for [Be(H₂O)₂(1H‐imidazole‐4,5‐dicarboxylate)] (16.6 kcal/mol) and [Be(H₂O)₂(1H‐imidazol‐3‐ium‐4,5‐dicarboxylate)]⁺ (13.8 kcal/mol) are similar to the barrier for [Be(H₂O)₄)]²⁺ and independent of the overall charge. NICS calculations show no indication that the aromaticity of the imidazole ring is affected during the water exchange process.     

Ligand‐Exchange Processes on Solvated Beryllium Cations. Part III

On the basis of DFT calculations (B3LYP/6‐311+G**), the possibility to include solvent effects is considered in the investigation of the H₂O‐exchange mechanism on [Be(H₂O)₄]²⁺ within the widely used cluster approach. The smallest system in the gas phase, [Be(H₂O)₄(H₂O)]²⁺, shows the highest activation barrier of +15.6 kcal/mol, whereas the explicit addition of five H‐bonded H₂O molecules in [{Be(H₂O)₄(H₂O)}(H₂O)₅]²⁺ reduces the barrier to +13.5 kcal/mol. Single‐point calculations applying CPCM (B3LYP(CPCM:H₂O)/6‐311+G**//B3LYP/6‐311+G**) on [Be(H₂O)₄(H₂O)]²⁺ lower the barrier to +9.6 kcal/mol. Optimization of the precursor and transition state of [Be(H₂O)₄(H₂O)]²⁺ within an implicit model (B3LYP(CPCM:H₂O)/6‐311+G** or B3LYP(PCM:H₂O)/6‐311+G**) reduces the activation energy further to +8.3 kcal/mol but does not lead to any local minimum for the precursor and is, therefore, unfavorable.     

Ligand Exchange Processes on Solvated Beryllium Cations V. Water Exchange on [Be(X)(H2O)3]+ (X: H–,F–, Cl–, Br–, OH–, CN–, NCNCN–)‡

The water exchange reaction of Be^II complexes in the series [Be(X)(H₂O)₃]⁺ (X = H^–, F^–, Cl^–, Br^–, OH^–, CN^–, NCNCN^–) was studied by DFT calculations (RB3LYP/6‐311+G**) and identified as an associative interchange mechanism. The influence of X on the activation energies was examined and found to be largely negligible, thus making them all act as spectator ligands. The energies for addition of a fourth water molecule, representing the second coordination sphere, were approximately half of that found for similar dicationic complexes and close to that found for monocationic species like [Li(H₂O)₄]⁺.     

Ligand‐Exchange Processes on Solvated Zinc Cations: Water Exchange on [Zn(H2O)4(L)]2+⋅2 H2O (L=Heterocyclic Ligand)

The water‐exchange mechanisms of [Zn(H₂O)₄(L)]²⁺?2 H₂O (L=imidazole, pyrazole, 1,2,4‐triazole, pyridine, 4‐cyanopyridine, 4‐aminopyridine, 2‐azaphosphole, 2‐azafuran, 2‐azathiophene, and 2‐azaselenophene) have been investigated by DFT calculations (RB3LYP/6‐311+G**). The results support limiting associative reaction pathways that involve the formation of six‐coordinate intermediates [Zn(H₂O)₅(L)]²⁺?H₂O. The basicity of the coordinated heterocyclic ligands shows a good correlation with the activation barriers, structural parameters, and stability of the transition and intermediate states.     

Ligand Exchange Processes on Solvated Zinc Cations – DFT Analysis of Hydrogen Cyanide Exchange on [Zn(HCN)6]2+

The mechanisms for hydrogen cyanide exchange on [Zn(HCN)₆]²⁺ were studied using density functional theory (B3LYP/6‐311+G**), and showed that the limiting dissociative (D) pathway is more favorable than the associative interchange (I_a) mechanism. The activation barrier for the dissociative mechanism (7 kcal · mol^–1) is clearly lower than for the interchange mechanism (15.9 kcal · mol^–1).     

(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.     

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.     

Ligand Exchange Processes on Solvated Lithium Cations. II. Complexation by Cryptands in γ-Butyrolactone as Solvent

Kinetic studies on Li⁺ exchange between the cryptands C222 and C221, and γ-butyrolactone as solvent were performed as a function of ligand-to-metal ratio, temperature and pressure using ⁷Li NMR. The thermal rate and activation parameters are: C222: k ₂₉₈ = (3.3 ± 0.8)×10⁴ M⁻¹ s⁻¹, ΔH ^# = 35 ± 1 kJ mol⁻¹ and ΔS ^# = −41 ± 3 J K⁻¹ mol⁻¹; C221: k ₂₉₈ = 105 ± 32 M⁻¹ s⁻¹, ΔH ^# = 48 ± 1 kJ mol⁻¹ and ΔS ^# = −45 ± 2 J K⁻¹ mol⁻¹. Temperature and pressure dependence measurements were performed in the presence of an excess of Li⁺. The influence of pressure on the exchange rate is insignificant for both ligands, such that the value of activation volume is around zero within the experimental error limits. The activation parameters obtained in this study indicate that the exchange of Li⁺ between solvated and chelated Li⁺ ions follows an associative interchange mechanism. Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at . For Part I see: R. Puchta, M. Galle, N.J.R. van Hommes, E. Pasgreta and R. van Eldik: Inorg. Chem. 43, 8227 (2004).     

(Ph4P)2[Be2F6]·2CH3CN: Synthese,Schwingungsspektrum, Kristallstruktur und quantenchemische Rechnungen

(Ph₄P)₂[Be₂F₆]·2CH₃CN: Synthesis, IR Spectra, Crystal Structure, and Quantum Chemical Calculations The hexafluorodiberyllate (Ph₄P)₂[Be₂F₆]·2CH₃CN ( 1 ) was prepared by the reaction of (Ph₄P)₂[Be₂Cl₆] with excess silver(I) fluoride in acetonitrile solution. According to the IR spectra and to the X‐ray crystal structure determination, 1 contains isolated [Be₂F₆]^2? ions of symmetry C_i, which is very close to symmetry D_2h. 1 crystallizes triclinically in space group with one formula unit per unit cell. Lattice dimensions at 193 K: a = 950.5(2), b = 1016.1(2), c = 1305.2(2) pm, α = 101.04(2)°, β = 110.83(2)°, γ = 96.85(2)°, R₁ = 0.0354. DFT (BP86) and ab initio (CCSD(T)) calculations with large basis sets provide the picture of an intrinsically unstable molecule stabilized by solvent and solid state effects.     

[Fe2(μsb‐CO)(CO)3(NO)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)]: Synthese,Kristallstruktur und Koordinationsisomerie

[Fe₂(μ_sb‐CO)(CO)₃(NO)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)]: Synthesis, X‐ray Crystal Structure and Isomerization Na[Fe₂(μ‐CO)(CO)₆(μ‐P^tBu₂)] ( 1 ) reacts with [NO][BF₄] at —60 °C in THF to the nitrosyl complex [Fe₂(CO)₆(NO)(μ‐P^tBu₂)] ( 2 ). The subsequent reaction of 2 with phosphanes (L) under mild conditions affords the complexes [Fe₂(CO)₅(NO)L(μ‐P^tBu₂)], L = PPh₃, ( 3a ); η‐dppm (dppm = Ph₂PCH₂PPh₂), ( 3b ). In this case the phosphane substitutes one carbonyl ligand at the iron tetracarbonyl fragment in 2 , which was confirmed by the X‐ray crystal structure analysis of 3a . In solution 3b loses one CO ligand very easily to give dppm as bridging ligand on the Fe‐Fe bond. The thus formed compound [Fe₂(CO)₄(NO)(μ‐P^tBu₂)(μ‐dppm)] ( 4 ) occurs in solution in different solvents and over a wide temperature range as a mixture of the two isomers [Fe₂(μ_sb‐CO)(CO)₃(NO)(μ‐P^tBu₂)(μ‐dppm)] ( 4a ) and [Fe₂(CO)₄(μ‐NO)(μ‐P^tBu₂)(μ‐dppm)] ( 4b ). 4a was unambiguously characterized by single‐crystal X‐ray structure analysis while 4b was confirmed both by NMR investigations in solution as well as by means of DFT calculations. Furthermore, the spontaneous reaction of [Fe₂(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 5 ) with NO at —60 °C in toluene yields a complicated mixture of products containing [Fe₂(μ‐CO)(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 6 ) as main product beside the isomers 4a and 4b occuring in very low yields.     

Synthese und Kristallstruktur des Azidoberyllats (Ph4P)2[Be(μ‐OSiMe3)(N3)2]2

Synthesis and Crystal Structure of the Azido Beryllate (Ph₄P)₂[Be(μ‐OSiMe₃)(N₃)₂]₂ (Ph₄P)₂[Be₂F₆] reacts with excess trimethylsilylazide in acetonitrile solution, accompanied by a hydrolytic side‐reaction to give the azido beryllate (Ph₄P)₂[Be(μ‐OSiMe₃)(N₃)₂]₂ ( 1 ) as colourless, non‐explosive crystals. 1 was characterized by IR spectroscopy and by single crystal X‐ray determination. 1 : Space group , Z = 1, lattice dimensions at 193 K: a = 1026.9(1), b = 1184.0(1), c = 1352.1(1) pm, α = 73.50(1)°, β = 74.35(1)°, γ = 64.66(1)°, R₁ = 0.0543. The complex anion of 1 forms centrosymmetric units with symmetry C_i via Be₂O₂ four‐membered rings with Be–O distances of 159.2(7) and 168.7(7) pm, and terminally bonded azide 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)°.     

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.     

[Be3(μ3‐O)3(MeCN)6{Be(MeCN)3}3](I)6 – ein Berylliumkomplex mit Cyclo‐(Be3O3)‐Kern und sein Hydrolyseprodukt [Be(H2O)4](I)2·2MeCN

Single crystals of [Be₃(μ₃‐O)₃(MeCN)₆{Be(MeCN)₃}₃](I)₆·4CH₃CN ( 1 ·4CH₃CN) were obtained in low yield by the reaction of beryllium powder with iodine in acetonitrile suspension, which probably result from traces of beryllium oxide containing the applied beryllium metal. The compound 1 ·4CH₃CN forms moisture sensitive, colourless crystal needles, which were characterized by IR spectroscopy and X‐ray diffraction (Space group Pnma, Z = 4, lattice dimensions at 100(2) K: a = 2317.4(1), b = 2491.4(1), c = 1190.6(1) pm, R₁ = 0.0315). The hexaiodide complex cation 1 ⁶⁺consists of a cyclo‐Be₃O₃ core with slightly distorted chair conformation, stabilized by coordination of two acetonitrile ligands at each of the beryllium atoms and by a {Be(CH₃CN)₃}²⁺ cation at each of the oxygen atoms. This unique coordination behaviour results in coplanar OBe₃ units with short Be–O distances of 155.0 pm and 153.6 pm on average of bond lengths within the cyclo‐Be₃O₃ unit and of the peripheric BeO bonds, respectively. Exposure of compound 1 ·4CH₃CN to moist air leads to small orange crystal plates of [Be(H₂O)₄]I₂·2CH₃CN ( 3 ·2CH₃CN). According to the crystal structure determination (Space group C2/c, Z = 4, lattice dimensions at 100(2) K: a = 1220.7(1), b = 735.0(1), c = 1608.5(1) pm, β = 97.97(1)°, R₁ = 0.0394), all hydrogen atoms of the dication [Be(H₂O)₄]²⁺ are involved to form O–H ··· N and O–H ··· I hydrogen bonds with the acetonitrile molecules and the iodide ions, respectively. Quantum chemical calculations (B3LYP/6‐311+G**) at the model [Be₃(μ₃‐O)₃(HCN)₆{Be(HCN)₃}₃]⁶⁺ show that chair and boat conformation are stable and that the distorted chair conformation is stabilized by packing effects.     

[Be(OH2)4]Cl2 – Herstellung,IR‐Spektrum und Kristallstruktur

[Be(OH₂)₄]Cl₂ – Preparation, IR spectrum, and Crystal Structure Single crystals of [Be(OH₂)₄]Cl₂ were prepared by the reaction of thionyl chloride at 20 °C with samples which result from evaporated, HCl containing, aqueous solutions of BeCl₂. With excess of boiling thionyl chloride BeCl₂ is formed. [Be(OH₂)₄]Cl₂ is characterized by IR spectroscopy and by X‐ray crystal structure determination: Space group P2₁/c, Z = 4, lattice dimensions at 193 K: a = 653.53(5), b = 1298.15(14), c = 789.52(6) pm, β = 103.005(9)°, R1 = 0.027. The structure consists of slightly distorted tetrahedral [Be(OH₂)₂]²⁺ ions, which are connected with the chloride ions via nearly linear O–H···Cl hydrogen bonds to give a 3D network.     

Die Kristallstruktur von [BeCl2(15‐Krone‐5)]

Crystal Structure of [BeCl₂(15‐Crown‐5)] Single crystals of [BeCl₂(15‐crown‐5)] ( 1 ) were obtained from dichloromethane solutions of BeCl₂ in the presence of the equivalent amount of 15‐crown‐5 and characterized by IR spectroscopy and X‐ray diffraction. Space group P2₁/c, Z = 4, lattice dimensions at 100 K: a = 1036.2(1), b = 1071.1(1), c = 1360.1(1) pm, β = 109.86(1)°, R₁ = 0.0225. The structure determination shows no disorder, all hydrogen positions were refined isotropically. The results are in contrast to the previously reported crystal structure determination in the space group P2₁nb. The beryllium atom of 1 forms a BeO₂C₂ five‐membered heterocycle with terminal chlorine atoms to give a distorted tetrahedral coordination with distances Be–O 166.5(2), 169.9(2) pm, and Be–Cl 195.8(2), 197.8(2) pm. The structural results are in good agreement with DFT calculations on B3LYP/6‐311+G** level.     

[p‐tBu‐calix[4](OMe)2(OBeCl)2]: The First Structually Characterized Beryllium Calixarene Complex

Treatment of [p‐^tBu‐calix[4](OMe)₂(OLi)₂] with two equivalents of BeCl₂ gave the unprecedented dinuclear beryllium complex [p‐p‐^tBu‐calix[4](OMe)₂(OBeCl)₂], which was structurally characterized, both in solution (NMR) and in the solid state (X‐ray structure analysis).     

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.     

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.