Beiträge zur Chemie des Phosphors. 225 [1, 2] Lithium-pentahydrogenoctaphosphid

Contributions to the Chemistry of Phosphorus. 225. Lithium Pentahydrogen Octaphosphide Lithium pentahydrogen octaphosphide, LiH₅P₈ ( 1 ), belongs to the first reaction products of the metallation of P₂H₄ with n-butyllithium to be detected. Compound 1 is also formed in the reactions of the tricyclic heptaphosphide Li₃P₇ or the monocyclic pentaphosphide LiH₄P₅ with P₂H₄. In all cases, LiH₄P₇, LiH₈P₇, and further not yet identified polyphosphides are formed additionally. The composition and the structure of 1 have been elucidated by ³¹P-NMR studies, above all a complete analysis of its low-temperature ³¹P{¹H}-NMR spectrum. Hence, compound 1 is 7-lithium-2,5,6-trihydrogen-3-phosphino-bicyclo[2.2.1]heptaphosphide and has a norbornane-type P₇ skeleton. At room temperature 1 decomposes to furnish more phosphorus-rich lithium polyphosphides.     

Beiträge zur Chemie des Phosphors. 140. Dilithium-hydrogenheptaphosphid,Li2HP7 – ein teilmetalliertes Derivat von P7H3: Darstellung und strukturelle Charakterisierung

Contributions to the Chemistry of Phosphorus. 140. Dilithium Hydrogen Heptaphosphide, Li₂HP₇ — a Partially Metallated Derivative of P₇H₃: Preparation and Structural. Characterization Dilithium hydrogen heptaphosphide, Li₂HP₇ ( 2 ), is purely obtained as an orange-red solvent adduct by reacting P₂H₄ with n-BuLi or Li₃P₇ ( 1 ) under suitable conditions. 2 is also formed in the metalation of LiH₂P₇ ( 3 ) or P₇H₃, in the disproportionation of LiH₄P₅, in thepartial protolysis of 1 , and in the nucleophilic cleavage of P₄. The composition and the structure of 2 could be elucidated by a complete analysis of its low-temperature ³¹P{¹H}-NMR spectrum. As shown by the δ(³¹P) values, the P₇ cage in 2 is clearly distorted compared with 1 . The P₇H^2? ion has fluctuating bonds in analogy to dihydrobullvalene and can be described by two valence-tautomeric forms with identical structures. At room temperature 2 disproportionates yielding lithium polyphosphides with a greater number of phosphorus atoms.     

Beiträge zur Chemie des Phosphors. 151. Dilithium-dihydrogentetradecaphosphid,Li2H2P14: Darstellung und strukturelle Charakterisierung

Contributions to the Chemistry of Phosphorus. 151. Dilithium Dihydrogen Tetradecaphosphide, Li₂H₂P₁₄: Preparation and Structural Characterization Dilithium dihydrogentetradecaphosphide, Li₂H₂P₁₄ ( 1 ), is obtained as an orange-red solvent adduct Li₂H₂P₁₄ · 6 THF in a purity of 80–90 per cent by reacting P₂H₄ with n-BuLi under suitable conditions. 1 is also formed in the reaction of Li₃P₇ or LiH₄P₅ with P₂H₄, and in the disproportionation of LiH₄P₇. According to its 2D-³¹P-NMR spectrum 1 is a conjuncto-phosphane built up by one P₇(5)^?- and one P₉(3)^?-unit group with structures analogous to norbornane and delta-cyclane, respectively.     

Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 44. Tricäsiumheptaphosphid Cs3P7: Darstellung,Struktur und Eigenschaften

Chemistry and Structural Chemistry of Phosphides and Ployphosphides. 44. Tricesium Heptaphosphide Cs₃P₇: Preparation, Structure, and Properties Tricesium heptaphosphide is prepared from the elements by a quantitative reaction at 1200 K in Nb ampoules. Slow cooling yield the bright yellow α-Cs₃P₇, quenching the yellow orange coloured β-Cs₃P₇. The crystalline α-Cs₃P₇ transforms at 552 K in a first order phase transition to the plastically crystalline β-Cs₃P₇. Both modifications are sensitive against moisture and oxygen and are completely soluble in ethylendiamine yielding a pale yellow solution. At room temperature the ³¹P nmr spectra of such solutions show only one singulett, which corresponds to the valence tautomerism of the P₇^3? anion. α-Cs₃P₇ crystallizes in a new structure type (P4₁, a = 904.6(1) pm; c = 1671.4(4) pm; Z = 4). The structure is formed by heptaphospha-nortricyclene anions P₇^3? and Cs⁺ cations. The cs atoms connect the anions forming a three-dimensional arrangement (d?(Cs? P) = 374 pm), not allowing the fragmentation into discrete Cs₃P₇ units. The P? P distances differ by their function in the nortricyclene anion. Each P₇ group is surrounded by 12 Cs atms. β-Cs₃P₇ crystallizes in the Li₃Bi type of structure (Fm3 M; a(573 K) = 1130.5(1)pm; Z = 4). The P atoms of the P₇^3? anions surround the Bi positions with an orienational disorder. The orientation has been investigated with a mixed crystal Ca₃(P₇)_2/3(P₁₁)_1/2 (Fm3 m; a (298 K) = 1149.5(9) pm; Z = 4).     

Beiträge zur Chemie des Phosphors. 167 [1, 2]. Konstitutions- und Konfigurationsisomere von Pentaphosphan(7), P5H7

Contributions to the Chemistry of Phosphorus. 167. Constitutional and Configurational Isomers of Pentaphosphane(7), P₅H₇ Phosphane mixtures containing 10—15 P-% of pentaphosphane(7), P₅H₇, are obtained by thermolysis of diphosphane, P₂H₄, or as residue from distillation of crude diphosphane [3]. According to the complete analysis of the ³¹P{¹H}-NMR spectrum on the basis of selective population transfer experiments, P₅H₇ exists as a mixture of three diastereomers of n-P₅H₇ — 1a (erythro, erythro), 1b (erythro, threo), 1c (threo, threo) — and of the constitutional isomer 2-phosphinotetraphosphane 2 (iso-P₅H₇, largest relative isomeric abundance). The correlation between the diastereomers and the observed spin systems results from the preferred gauche orientation of neighboring free electron pairs, the dependence of ¹J(PP) on dihedral angles, and the ³J(PP) long range couplings. From the ³¹P-NMR data of the phosphane molecules P_nH_n+2 with n = 1—5 general relationships for the δ(³¹P) values and the ¹J(PP) coupling constants of chain-type phosphorus hydrides as a function of their structural parameters are derived.     

Theoretical study of one‐electron bonds in a series of high‐spin lithium–beryllium–hydrogen clusters: “Valence shell single‐electron repulsion” rule and electron localization function analysis

A series of high‐spin clusters containing Li, H, and Be in which the valence shell molecular orbitals (MOs) are occupied by a single electron has been characterized using ab initio and density functional theory (DFT) calculations. A first type (⁵Li₂, ⁿ⁺¹LiH_n+ (n = 2–5), ⁸Li₂H) possesses only one electron pair in the lowest MO, with bond energies of ～3 kcal/mol. In a second type, all the MOs are singly occupied, which results in highly excited species that nevertheless constitute a marked minimum on their potential energy surface (PES). Thus, it is possible to design a larger panel of structures (⁸LiBe, ⁷Li₂, ⁸Li, ⁴LiH⁺, ⁶BeH, ⁿ⁺³LiH (n = 3, 4), ⁿ⁺²LiH (n = 4–6), ⁸Li₂H, ⁹Li₂H, ²²Li₃Be₃ and ²²Li₆H), single‐electron equivalent to doublet “classical” molecules ranging from CO to C₆H₆. The geometrical structure is studied in relation to the valence shell single‐electron repulsion (VSEPR) theory and the electron localization function (ELF) is analyzed, revealing a striking similarity with the corresponding structure having paired electrons. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Zur thermischen Dehydratisierung von Lithiumdihydrogenphosphat, -hydrogendiphosphat und -cyclophosphat-Hydraten

Thermal Dehydration of Lithium Dihydrogenphosphate, -Hydrogen-diphosphate, and -Cyclophosphate Hydrates On heating lithium dihydrogenphosphate, LiH₂PO₄, is converted to lithium polyphosphate, (LiPO₃)_n · H₂O [2–5]. Seeding LiH₂PO₄ with lithium cyclohexaphosphate, Li₆P₆O₁₈, the thermal dehydration proceeds structurally controlled to pure Li₆P₆O₁₈. On heating lithium hydrogen-diphosphate, Li₃HP₂O₇, reacts to Li₄P₂O₇ form III and lithium cyclotetraphosphate, Li₄P₄O₁₂ form II , which ist converted to Li₆P₆O₁₈ at higher temperatures. The thermal dehydration of Li₂H₂P₂O₇ and of the cyclophosphate hydrates Li₃P₃O₉ · 3 H₂O, Li₄P₄O₁₂ · (8 and 6) H₂O, Li₆P₆O₁₈ · (6 and 4) H₂O and Li₈P₈O₂₄ · (10 and 6) H₂O are described.     

Lithium and beryllium hypophosphites

The structures of monoclinic (C2/m) lithium di­hydrogenphosphate, LiH₂PO₂, and tetragonal (P4₁2₁2) beryllium bis(di­hydrogenphosphate), Be(H₂PO₂)₂, have been determined by single‐crystal X‐ray diffraction. The structures consist of layers of hypophosphite anions and metal cations in tetrahedral coordination by O atoms. Within the layers, the anions bridge four Li⁺ and two Be²⁺ cations, respectively. In LiH₂PO₂, the Li atom lies on a twofold axis and the H₂PO₂⁻ anion has the PO₂ atoms on a mirror plane. In Be(H₂PO₂)₂, the Be atom lies on a twofold axis and the H₂PO₂⁻ anion is in a general position.     

Beiträge zur Chemie des Phosphors. 171. 31P-NMR-spektroskopischer Nachweis von Heptaphosphan(9), P7H9: erythro- und threo-2,3-Diphosphino-pentaphosphan

Contributions to the Chemistry of Phosphorus. 171. ³¹P-N.M.R. Spectroscopic Detection of Heptaphosphane(9), P₇H₉: erythro- and threo-2,3-Diphosphinopentaphosphane Small amounts of heptaphosphane(9), P₇H₉, could be detected ³¹P-NMR spectroscopically in mixtures of higher phosphanes P_nH_n+2 which are obtained as residue from distillation of crude diphosphane [2] or by thermolysis of P₂H₄. According to the results of a spectrum analysis on the basis of selective population transfer experiments, the heptaphosphane(9) in question is one of the possible constitutional isomers with maximum branching, namely 2,3-diphosphinopentaphosphane ( 4 ), which is present in the erythro and threo from 4a and 4b , respectively. The correlation between the diastereomers and the observed spin systems results from the determination of the corresponding molecular conformation by means of significant ¹J(PP) and ³J(PP) coupling constants. 4 is the first structurally characterized compound with seven chain-like connected phosphorus atoms.     

Beiträge zur Chemie des Phosphors. 236. Über einige physikalische und chemische Eigenschaften von Diphosphan(4)

Contributions to the Chemistry of Phosphorus. 236. On Several Physical and Chemical Properties of Diphosphane(4) The density of diphosphane(4) has been measured between ?78°C and +18°C and the value d₄²⁰ = 1.014 · 0.002 extrapolated. The refractive index of P₂H₄ was determined to be n²⁰ = 1.66 ± 0.01. The surface tension at 0°C and ?50°C was measured to be σ = 34 and 42 dyn · cm^?1, respectively. In the UV absorption spectrum, gaseous P₂H₄ exhibits a broad absorption band at λ_max = 2 220 Å, in n-hexane solution, this band is shifted somewhat to shorter wave-lengths. The molar extinction coefficient was determined to be ? ≈? 900 1 · mol^?1 · cm^?1. As a result of photolytic decomposition, absorptions for PH₃ and more phosphorus-rich hydrides also occur. The solubility behavior of P₂H₄ in various organic solvents and the stabilities of the resultant solutions have been investigated. At 0°C, the solubility of diphosphane(4) in water was found to be ± 035 ± 0.003 g P₂H₄/100 g solution and that of water in diphosphane(4) to be 43.2 ± 1.6 g H₂O/100 g solution. The system diphosphane(4)/methanol also exhibits a miscibility anomaly. The IR spectra of liquid P₂H₄ and of its solutions in various solvents revealed, in accord with the results of nuclear magnetic resonance spectroscopy [7], that diphosphane(4) is practically not associated. Weak interactions through hydrogen bridging bonds occur with pyridine and methanol in which P₂H₄ serves as the proton donor and, in the latter case, also as proton acceptor. For the thermolysis of diphosphane(4), it has been found that the primary step comprises a disproportionation with inter-molecular elimination of PH₃ and formation of triphosphane(5). With further progress of the thermolysis, in dependence on the reaction conditions, mixtures of various phosphanes of differing composition are formed. Photolysis gives rise to phosphane mixtures having similar compositions. With aqueous silver salt and iodine solutions, diphosphane(4) reacts as a reducing agent; with sodium hydroxide solution, it reacts by a slow disproportionation as well as by formation and degradation of the subsequently formed polyphosphides. On reaction with triphenylmethyl, triphenylmethane and a yellow solid of varying composition are formed. The reaction of diazomethane with diphosphane(4) leads to the preferential insertion of the carbene in the P? P bond and formation of methylenebis(phosphane).     

Wellenmechanische Absolutrechnungen an Molekülen und Atomsystemen mit der SCF?MO?LC(LCGO) Methode. VII. Das System (LiH2)−

The system (LiH₂)^? has been investigated for several nuclear positions, taking all six electrons into account, using the Allgemeines Programmsystem/SCF ? MO ? LC (LCGO ) Methode. A metastable molecule was found having a linear configuration (R_LiH = 3.5 ± 0.2 a.u.) and a total energy 0.12 a.u. lower than that of the separated atoms. On the other hand, (LiH₂)^? can dissociate into Li^? + H₂; the total energy of which is 0.01 a.u. smaller. The potential barrier for this process is found to be 0.15 a.u. The energy hypersurface is given graphically and the formation (as well as the decomposition) of (LiH₂)^? is discussed.     

Induced Protic Behaviour in Aprotonic Ionic Liquids by Anion Basicity for Efficient Carbon Dioxide Capture

The interactions between aprotonic tetrabutylphosphonium carboxylate ionic liquids (ILs), [P_{4 4 4 4}][C_nCOO] (n=1, 2 and 7), and water were investigated. The cation-anion interactions occur via the α-¹H on [P_{4 4 4 4}]⁺ and the carboxylate headgroup of the anion. Upon addition, H₂O localises around the carboxylate headgroups, inducing an electron inductive effect towards the oxygens, leading to ion-pair separation. Studies with D₂O and [P_{4 4 4 4}][C_nCOO] revealed protic behaviour of the systems, with proton/deuterium exchange occurring at the α-¹H of the cation, promoted by the basicity of the anion, forming an intermediate ylide. The greater influence of van der Waals forces of the [P_{4 4 4 4}][C₇COO] system allows for re-orientation of the ions through larger interdigitation. The protic behaviour of the neat ILs allows for CO₂ to be chemically absorbed on the ylide intermediate, forming a phosphonium-carboxylate zwitterion, signifying proton exchange occurs even in the absence of H₂O. The absorption of CO₂ in equimolar IL-H₂O mixtures forms a hydrogen carbonate, through a proposed reaction of the CO₂ with an intermediate hydroxide, and carboxylic acid.     

Darstellung und Kristallstruktur des Lithium‐Strontium‐Hydridnitrids LiSr2H2N

Synthesis and Crystal Structure of the Lithium Strontium Hydride Nitride LiSr₂H₂N LiSr₂H₂N was synthesized by the reaction of LiH and Li₃N with elemental strontium in sealed tantalum tubes at 650 °C within seven days. This second example of a quaternary hydride nitride crystallizes orthorhombically in space group Pnma (no. 62) with the lattice constants a = 747.14(5) pm, b = 370.28(3) pm and c = 1329.86(9) pm (Z = 4). Its crystal structure contains both kinds of anions H^? and N^3? in a sixfold distorted octahedral metal cation coordination each. The coordination polyhedra [(H1)Sr₅Li]¹⁰⁺, trans‐[(H2)Sr₄Li₂]⁹⁺ and [NSr₅Li]⁸⁺ are connected via edges and corners to form a three‐dimensional network. Two crystallographically different Sr²⁺ cations exhibit a sevenfold monocapped trigonal prismatic coordination by H^? and N^3? with [(Sr1)H₅N₂]^9? and [(Sr2)H₄N₃]^11? polyhedra, wheras Li⁺ shows a nearly planar fourfold coordinative environment ([LiH₃N]^5?). Cationic double chains of edge‐shared [NSr₅Li]⁸⁺ octahedra dominate the structure according to . Running parallel to the [0 1 0] direction, they are bundled like a hexagonal rod‐packing which is interconnected by H^? anions within the (0 0 1) plane first and finally even in the third dimension (i. e. along [0 0 1]). Therefore the structure of LiSr₂H₂N is compared to that one of the closely related quaternary hydride oxide LiLa₂HO₃.     

Thermodynamics of hydrogen-isotope-exchange reactions. Proton solvation inn-hexanol and water

This paper reports our results for the direct experimental determination of the equilibrium constant for the hydrogen-isotope-exchange reaction, 1/2D₂(g)+HCl(hexOH)=1/2H₂(g)+DCl(hexOD), where hexOH isn-hexanol and hexOD isn-hexanol with deuterium substitution in the alcohol function. The reaction was studied in electrochemical double cells without liquid junction for which the net cell reaction is the above isotope-exchange reaction. The experimentally determined value of ε° (296.0°K) for this cell is 4.03±0.95 mV (strong electrolyte standard states, mole-fraction composition scale); the value of the equilibrium constant for the reaction is 1.17±0.05. The contributions of isotope-exchange and transfer effects to the magnitude of the standard Gibbs energy change for the above reaction and for the analogous reaction 1/2D₂(g)+HCl(aq)=DCl(daq)+1/2H₂(g) are considered. Our results support the conclusion of Heinzinger and Weston that the formulation of the solvated proton in water as H₃O⁺, as opposed to H₉O₄ ⁺, is sufficient for the interpretation of the thermodynamics of hydrogen-isotope-exchange reactions in water. We also find that the formulation of the solvated proton inn-hexanol as ROH ₂ ⁺ is sufficient for the interpretation of our results on the thermodynamics of hydrogen-isotope-exchange inn-hexanol.     

Syntheses and Structures of Trilithium Cyclotriphosphazenates Equipped with 2‐Halo‐aryl Substituents

Hexakis (2‐halo‐anilino) cyclotriphosphazenes (2‐X‐C₆H₄NH)₆P₃N₃ {X = F ( 1d ), Cl ( 1e ), Br ( 1f )} were prepared by refluxing mixtures of hexachloro cyclotriphosphazene, 2‐haloaniline and triethylamine in toluene and characterized by single crystal X‐ray diffraction. 1d , 1e and 1f were reacted with ⁿBuLi in thf. Reactions were monitored with ³¹P NMR. Addition of three equivalents of ⁿBuLi yields lithium complexes of trianionic phosphazenates [{(thf)₂Li}₃{(2‐X‐C₆H₄N)₃(2‐X‐C₆H₄NH)₃P₃N₃}] {X= F ( 2d ), Cl ( 2e ) and Br ( 2f )}. 2d , 2e and 2f were structurally characterized by X‐ray diffraction, which reveals monomeric cis‐metalated phosphazenates featuring central P₃N₃ ring systems of chair conformation. Lithium ions reside in three N(eq)‐P‐N(endo) chelation sites at one face of the P₃N₃ ring system. Li…X distances are rather long (> 3Å) indicating no Li‐X interactions.     

Assembled synthesis of luminescent mono/double‐layered 2D and 3D Zn (II)‐based coordination polymers tuned by flexible bis (pyridyl)propane‐1,2‐diamines and diverse organic dicarboxylates

Six mono/double‐layered 2D and three 3D coordination polymers were synthesized by a self‐assembly reaction of Zn (II) salts, organic dicarboxylic acids and L1/L2 ligands. These polymeric formulas are named as [Zn(L1)(C₄H₂O₄)_0.5 (H₂O)]_n·0.5n(C₄H₂O₄)·2nH₂O ( 1 ), [Zn₂(L2)(C₄H₂O₄)₂]_n·2nH₂O ( 2 ), [Zn(L1)(m‐BDC)]_n ( 3 ), [Zn₂(L2)(m‐BDC)₂]_n·2nH₂O ( 4 ), [Zn₃(L1)₂(p‐BDC)₃(H₂O)₄]_n·2nH₂O ( 5 ), [Zn₂(OH)(L2) (p‐BDC)_1.5]_n ( 6 ), [Zn₂(L1)(p‐BDC)₂]_n·5nH₂O ( 7 ), [Zn₂(L2)(p‐BDC)₂]_n·3nH₂O ( 8 ) and [Zn₂(L1)(C₄H₄O₄)_1.5(H₂O)]_n·n(ClO₄)·nH₂O ( 9 ) [L1 = N,N′‐bis (pyridin‐4‐ylmethyl)propane‐1,2‐diamine, L2 = N,N′‐bis (pyridin‐3‐ylmethyl)propane‐1,2‐ diamine, m‐BDC^2? = m‐benzene dicarboxylate, p‐BDC^2? = p‐benzene dicarboxylate]. Meanwhile, these polymers have been characterized by elemental analysis, infrared, thermogravimetry (TG), photoluminescence, powder and single‐crystal X‐ray diffraction. Polymers 1–6 present mono‐ and double (4,4)‐layer motifs accomplished by L1/L2 ligands with diverse conformations and organic dicarboxylates, and the layer thickness locates in the range of 5.8–15.0 Å. In three 3D polymers, the L1 and L2 molecules adopt the same cis‐conformations and join adjacent Zn (II) cations together with p‐BDC^2? or succinate, giving rise to different binodal (4,4)‐c nets with (4.5².8³)(4.5³.7²) ( 7 ), pts ( 8 ) topology and twofold interpenetrated binodal (5,5)‐c nets with (3².4⁴.5².6²)(3.4³.5².6⁴) ( 9 ). Therefore, the diverse conformations of the two bis (pyridyl)‐propane‐1,2‐diamines and the feature of different organic dicarboxylate can effectively influence the architectures of these polymers. Powder X‐ray diffraction patterns demonstrate that these bulk solid polymers are pure phase. TG analyses indicate that these polymers have certain thermal stability. Luminescent investigation reveals that the emission maximum of these polymers varies from 402 to 449 nm in the solid state at room temperature. Moreover, 1 , 3 and 5–8 show average luminescence lifetimes from 8.81 to 16.30 ns.     

Alkene loss from metastable methyleneimmonium ions: Unusual inverse secondary isotope effect in ion-neutral complex intermediate fragmentations

The mechanism of propene elimination from metastable methyleneimmonium ions is discussed. The first field-free region fragmentations of complete sets of isotopically labelled methyleneimmonium ions (H₂C = $ \mathop {\rm N}\limits^{\rm +} $⁺R¹R²: R¹ = R² = n-C₃H₇; R¹ = R² = i-C₃H₇; R¹ = n -C₃H₇; R² = C₂H₅; R¹ = n-C₃H₇; R² = CH₃; R¹ = n-C₃H₇; R² = H) were used to support the mechanism presented. The relative amounts of H/D transferred are quantitatively correlated to two distinct mathematical concepts which allow information to be deduced about influences on reaction pathways that cannot be measured directly. Propene loss from the ions examined proceeds via ion-neutral complex intermediates. For the di-n-propyl species rate-determining and H/D distribution-determining steps are clearly distinct Whereas the former corresponds to a 1,2-hydride shift in a 1-propyl cation coordinated to an imine moiety, the latter is equivalent to a proton transfer to the imine occurring from the 2-propyl cation generated by the previous step. For the diisopropyl-substituted ions which directly form the 2-propyl cation-containing complex, the rate-determining hydride shift vanishes. The 2-propyl cation-containing complex can decompose directly or via an intermediate proton-bridged complex. Competition of these routes is not excluded by the experimental results. Assuming a 2:1:3 distribution, a preference for the α- and β-methylene of the initial n-propyl chain as the source of the hydrogen transferred is detected for n-propylimmonium ions containing a second alkyl chain R². This preference shows a clear dependence on the steric influence of R². During the transfer step isotopic substitution is found to affect the H/D distribution strongly. For the alternative route of McLafferty rearrangement leading to C₂H₄ loss, specific γ-H transfer is observed.     

Heterometallic SrII‐MII (M=Co,Ni, Zn and Cu) Coordination Polymers: Synthesis,Temperature‐Dependent Structural Transformation,and Luminescent and Magnetic Properties

The use of pyridine‐2,4‐dicarboxylic acid (H₂pydc) in the construction of Sr^II and Sr^II‐M^II (M=Co, Ni, Zn and Cu) coordination polymers is reported. Eight complexes, that is, [Sr(pydc)H₂O]_n ( 1 ), [MSr(pydc)₂(H₂O)₂]_n (M=Co ( 2 ), Ni ( 3 ), Zn ( 4 )), [ZnSr(pydc)₂(H₂O)₇]_n?4 nH₂O ( 5 ), [SrCu(pydc)₂]_n ( 6 ), [SrCu(pydc)₂(H₂O)₃]_n?2 nH₂O ( 7 ), and [Cu₃Sr₂(pydc)₄(Hpydc)₂(H₂O)₂]_n ( 8 ), have been synthesized via dexterously choosing the appropriate strontium sources and transition metal salts, and rationally controlling the temperature of the reaction systems. Complexes 1 , 2 ( 3 , 4 ), 6 , and 8 display four types of 3‐D framework structures. Complexes 5 and 7 exhibit a 2‐D network and a 1‐D chain structure, respectively. The 2‐D complex 7 can be reversibly transformed into 3‐D compound 6 through temperature‐induced solvent‐mediated structural transformation. The luminescent property studies indicated that complex 1 shows a strong purple luminescent emission and 4 exhibits a strong violet luminescence emission. The magnetic properties of 2 , 3 , and 8 were also studied. Antiferromagnetic M^II???M^II interactions were determined for these complexes.     

Beiträge zur Chemie des Phosphors. 117. Synthese und Eigenschaften der Hexaorganyl-octaphosphane(6) P8R6, R = Me,Et, Pri

Contributions to the Chemistry of Phosphorus. 117. Synthesis and Properties of the Hexaorganyl-octaphosphanes(6) P₈R₆, R = Me, Et, Prⁱ The Hexaorganyl-octaphosphanes(6) P₈Me₆ ( 1 ), P₈Et₆ ( 2 ), and P₈Pr ( 3 ) have been obtained by reacting mixtures of the corresponding organyldichlorophosphanes and phosphorus(III) chloride with magnesium. In the case of 1 and 2 the organyl-cyclophosphanes (PR)_n can also be used in the reaction with phosphorus(III) chloride and magnesium. Besides, mainly P₇R₅ as well as other polycyclic organylphosphanes are formed. 2 and 3 have been isolated as pure substances, whereas 1 was concentrated to ?50 mol-% in the product mixture. According to their ³¹P-NMR spectra the three compounds possess a pentalane-analogous P₈-skeleton with the substituents within each five-membered ring in trans position and the substituents of different five-membered rings next to the zero bridge in cis position; the organyl groups in the 3, 7 position are trans oriented with respect to the free electron pairs of the bridgehead atoms. Therefore, the structures of 1 – 3 differ from the known tert-butyl compound P₈Bu, whereas the corresponding phosphorus hydride P₈H₆ has the same pentalane-analogous P₈-skeleton, thus being a bicyclo[3.3.0]octaphosphane.     

Synthesis and Structural Characterization of New Divanada‐ and Diniobaboranes Containing Chalcogen Atoms

The reaction of [Cp_nMCl_4?x] (M=V: n=2, x=2; M=Nb: n=1, x=0; Cp=η⁵‐C₅H₅) with LiBH₄ ? THF followed by thermolysis in the presence of dichalcogenide ligands E₂R₂ (E=S, Te; R=2,6‐(tBu)₂‐C₆H₂OH, Ph) and 2‐mercaptobenzothiazole (C₇H₅NS₂) yielded dimetallaheteroboranes [{CpV(μ‐TePh)}₂(μ₃‐Te)BH ? thf] ( 1 ), [(CpV)₂(BH₃S)₂] ( 2 ), [(CpNb)₂B₄H₁₀S] ( 3 ), [(CpNb)₂B₄H₁₁S(tBu)₂C₆H₂OH] ( 4 ), and [(CpNb)₂B₄H₁₁TePh] ( 5 ). In cluster 1 , the V₂BTe atoms define a tetrahedral framework in which the boron atom is linked to a THF molecule. Compound 2 can be described as a dimetallathiaborane that is built from two edge‐fused V₂BS tetrahedron clusters. Cluster 3 can be considered as an edge‐fused cluster in which a trigonal‐bipyramidal unit (Nb₂B₂S) has been fused with a tetrahedral core (Nb₂B₂) by means of a common Nb₂ edge. In addition, thermolysis of an in‐situ‐generated intermediate that was produced from the reaction of [Cp₂VCl₂] and LiBH₄ ? THF with excess BH₃ ? THF yielded oxavanadaborane [(CpV)₂B₃H₈(μ₃‐OEt)] ( 6 ) and divanadaborane cluster [(CpV)₂B₅H₁₁] ( 7 ). Cluster 7 exhibits a nido geometry with C_2v symmetry and it is isostructural with [(Cp*M)₂B₅H_9+n] (M=Cr, Mo, and W, n=0; M=Ta, n=2; Cp*=η⁵‐C₅Me₅). All of these new compounds have been characterized by ¹H NMR, ¹¹B NMR, and ¹³C NMR spectroscopy and elemental analysis and the structural types were established unequivocally by crystallographic analysis of compounds  1 – 4 , 6 , and 7 .