A novel metallo‐organically templated pentaborate: acetato[N,N′‐bis(2‐aminoethyl)ethane‐1,2‐diamine]zinc(II) 4,4′,6,6′‐tetrahydroxy‐2,2′‐spirobi[cyclotriboroxane](1−)

The title compound, [Zn(C₂H₃O₂)(C₆H₁₈N₄)][B₅O₆(OH)₄], contains mixed‐ligand [Zn(CH₃COO)(teta)]⁺ complex cations (teta is triethylenetetramine) and pentaborate [B₅O₆(OH)₄]⁻ anions. The [B₅O₆(OH)₄]⁻ anions are connected to one another through hydrogen bonds, forming a three‐dimensional supramolecular network, in which the [Zn(CH₃COO)(teta)]⁺ cations are located.     

A new hydrated ammonium hydroxy­borate, (NH4)2[B10O14(OH)4]·H2O

The structure of a new synthetic compound, di­ammonium tetra­hydroxy­deca­borate monohydrate, has been determined by single‐crystal X‐ray diffraction. It crystallizes in triclinic space group and all atoms occupy general sites. The title compound is composed of [B₁₀O₁₅(OH)₄]⁴⁻ ions as the fundamental building blocks, and these are linked end‐to‐end by sharing two common O atoms, thus producing infinite chains of composition [B₁₀O₁₄(OH)₄]_n^2n–. These chains are linked by hydrogen bonds, thus forming borate sheets. Water mol­ecules and ammonium ions between these sheets connect adjacent sheets via hydrogen bonds.     

Synthesis,characterization, and thermochemical property of a novel mixed alkali metal borate: NaCs[B10O14(OH)4]

A novel mixed alkali metal hydrated borate NaCs[B₁₀O₁₄(OH)₄] was synthesized under hydrothermal conditions. Its structure was determined by single-crystal X-ray diffraction and further characterized by FT-IR spectroscopy, TG-DTA, powder X-ray diffraction, and chemical analysis. NaCs[B₁₀O₁₄(OH)₄] crystallizes in monoclinic space group P2/c with a = 7.6588(3) Å, b = 9.0074(3) Å, c = 11.8708(6) Å, and β = 115.682(3)°. The crystal structure of NaCs[B₁₀O₁₄(OH)₄] consists of Na–O, Cs–O polyhedral, and [B₁₀O₁₄(OH)₄]^2? polyborate anions. [B₁₀O₁₄(OH)₄]^2? units are connected together through common oxygen atoms forming a 1D helical chain-like structure, which are further connected by O–H···O hydrogen bonds forming a 3D supramolecular structure. Through a designed thermochemical cycle, the standard molar enthalpy of formation of this borate was determined to be ?7888.6 ± 8.1 kJ mol^?1 by using a heat conduction microcalorimeter.     

Synthesis,Crystal Structure and Vibrational Spectroscopy of NH4[Co(NH3)5(H2O)][B4O5(OH)4]2·6H2O

A novel hydrated cobalt tetraborate complex NH₄[Co(NH₃)₅(H₂O)][B₄O₅(OH)₄]₂·6H₂O, was synthesized by the reaction of NH₄‐borate aqueous with CoCl₂ and its structure was determined by single crystal X‐ray diffraction. The crystal system of this complex is orthorhombic, the space group is Pnma, and the unit cell parameters are a=1.2901(2) nm, b=1.6817(3) nm, c=1.1368(2) nm, α=β=γ=90°, V=2.4742(8) nm³, and Z=4. This compound contains infinite borate layers constructed from [B₄O₅(OH)₄]^2? units via hydrogen bonds. The adjacent polyborate anion layers are further linked together with the octahedral [Co(NH₃)₅(H₂O)]³⁺ groups through hydrogen bonds to form 3D framework. The groups and guest water molecules are deposited in the empty space of this framework and interact with the layers by extensive hydrogen bonds. Infrared and Raman spectra (4000–400 cm^?1) of NH₄[Co(NH₃)₅(H₂O)][B₄O₅(OH)₄]₂·6H₂O were recorded at room temperature and analyzed. Fundamental vibrational modes were identified and band assignments were made. The middle band observed at 575 cm^?1 in Raman spectrum is the pulse vibration of [B₄O₅(OH)₄]^2?.     

盐卤硼酸盐化学──ⅩⅩⅧ.氯柱硼镁石的激光拉曼光谱

本文研究了氯柱硼镁石硼酸和硼砂的晶体和它们在水溶液中的激光拉曼光谱,并与某些阴酸盐的谱图进行对比.初步提出硼氧配阴离子的聚合形式,为进行氯柱硼镁石结构分析提供实验依据.     

An alkoxide cluster with 18 Li+ ions encapsulating two borate anions, [(tBuO)12Li18(BO3)2]

The title compound, bis­(borato)­dodeca(tert‐butoxo)­octa­deca­lithium, [Li₁₈(BO₃)₂(C₄H₉O)₁₂], is formulated conveniently as [{(^tBuOLi)₃(Li₃BO₃)}₂(^tBuOLi)₆]. A central 12‐membered ring and two outer six‐membered rings are formed by alternating Li⁺ cations and alkoxide O atoms. Sandwiched between the central ring and each of the outer rings is a planar array of three further Li⁺ cations surrounding a [BO₃]³⁻ anion. Thus, the mol­ecule consists of a cationic [Li₁₈(O^tBu)₁₂]⁶⁺ cage encapsulating two borate anions. This compound is the first example of a structurally characterized polynuclear lithium borate, and a rare case of a lithium alkoxide cage with nuclearity greater than eight. All the alkoxide ligands are triply bridging, and the lithium ions have trigonal‐planar, trigonal‐pyramidal and fourfold coordination, all with major distortions from regular coordination geometry.     

Stable Noble Gas Compounds Based on Superelectrophilic Anions [B12(BO)11]− and [B12(OBO)11]−

Superelectrophilic monoanions [B₁₂(BO)₁₁]⁻ and [B₁₂(OBO)₁₁]⁻, generated from stable dianions [B₁₂(BO)₁₂]²⁻ and [B₁₂(OBO)₁₂]²⁻, show great potential for binding with noble gases (Ngs). The binding energies, quantum theory of atoms in molecules (QTAIM), natural population analysis (NPA), energy decomposition analysis (EDA), and electron localization function (ELF) were carried out to understand the B−Ng bond in [B₁₂(BO)₁₁Ng]⁻ and [B₁₂(OBO)₁₁Ng]⁻. The calculated results reveal that heavier noble gases (Ar, Kr, and Xe) bind covalently with both [B₁₂(BO)₁₁]⁻ and [B₁₂(OBO)₁₁]⁻ with large binding energies, making them potentially feasible to be synthesized. Only [B₁₂(OBO)₁₁]⁻ could form a covalent bond with helium or neon but the small binding energy of [B₁₂(OBO)₁₁He]⁻ may pose a challenge for its experimental detection.     

UPON SOME INORGANIC HETEROCYCLES IN THALLIUM (I) BORATES AND GERMANATES

Abstract

The structural study of some hydrated thallium (I) borates shows the existence of macroionic chains which can be considered as condensed heterocycles. In Tl [B₃O₄(OH)₂] 0.5H₂O, the unit is the well known B₃O₃ ring; it is formed by two BO₃ triangles (Δ) and one BO₄ tetrahedron (T); these units are linked to form an infinite chain; its shorthand notation is 3:∞¹ (2Δ + T). The structure of Tl₄ [B₇O₁₀(OH)₃ · OBO(OH)] H₂O contains a unit constituted by three B₃O₃ rings linked together by boron atoms; each ring is formed by two BO₄ tetrahedra and one BO₃ triangle; the corresponding fully hydrated polyanion is [B₇O₉(OH)₇]^4-. The chain is made up of units linked by BO₂(OH) triangles; the shorthand notation of this borate is: 7:∞¹ [(3Δ + 4T) + Δ].

The structure of Tl₈Ge₅O₁₄ is composed of isolated Ge₅O₁₄ units; they are formed by a crown of four GeO₄ tetrahedra linked by shared oxygens; two other oxygens of two of these GeO₄ tetrahedra belong also to a fifth GeO₄ tetrahedron which is located at the center of the crown.     

A New Organic‐Inorganic Hybrid Copper Pentaborate with Free Boric Acid Group

The hydrothermal reaction of Cu(CH₃COO)₂·H₂O, H₃BO₃, ethylenediamine and H₂O in a molar ratio of 3:20:9:222 at 140°C for 5 d yields the deep blue crystals of a new copper polyborate [Cu(en)₂B(OH)₃]· [B₅O₅(OH)₇] (en?H₂NCH₂CH₂NH₂) in 70% yield. It crystallizes in monoclinic system, space group P2₁/c, with unit cell dimensions, a=1.2779(2) nm, b=1.0167(15) nm, c=1.5019(2) nm, β=90.30(2)°, Z=4. The crystal structure of this compound consists of [Cu(en)₂B(OH)₃]²⁺ cation and [B₅O₅(OH)₇]^2? anion, which are linked together through hydrogen bonding interactions and electrostatic forces, forming an interesting three‐dimensional framework. The [B₅O₅(OH)₇]^2? anion is constituted of [B₄O₅(OH)₄]^2? anion and discrete B(OH)₃ group which attaches to the side of [B₄O₅(OH)₄]^2? through intramolecular hydrogen bonds. Fundamental vibrational modes of this compound were identified and band assignments were made. The middle bands observed at 882 and 575 cm^?1 in Raman spectrum are the characteristic peak of B(OH)₃ group and [B₄O₅(OH)₄]^2? anion, respectively. Additionally the thermal behavior of title compound was recorded and its decomposition mechanism was discussed.     

Structure of Aqueous Lithium Tetraborate Solution

The structure of aqueous lithium tetraborate solutions was investigated by species distribution calculation and synchrotron X-ray scattering. It shows that the dominant species in supersaturated solution at 298.15 K is B₄O₅(OH) ₄ ^2? and the minor species are B₃O₃(OH) ₅ ^2? , B₃O₃(OH) ₄ ^? and B(OH)₃. The ‘intramolecular’ structural parameters of B₄O₅(OH) ₄ ^2? , such as bond length and coordination number, were gives out using density function theory calculation. X-ray scattering study shows that the distance Li–O(H₂O)_I of [Li(H₂O)₄]⁺ is about 0.1983 nm with the coordination number(CN) 4 in tetrahedral configuration. The B–O(H₂O) distance in hydrated anion B₄O₅(OH)₄(OH₂) ₈ ^2? is 0.3662 nm with the CN 12. The Li⁺–B distance is about 0.3364 nm with a coordination number ~1.0. The temperature effect on solution structure was also discussed.     

The Hexacyanodiborane(6) Dianion [B2(CN)6]2−

Diborane(6) dianions with substituents that are bonded to boron via carbon are very reactive and therefore only a few examples are known. Diborane(6) derivatives are the simplest catenated boron compounds with an electron‐precise B–B σ‐bond that are of fundamental interest and of relevance for material applications. The homoleptic hexacyanodiborane(6) dianion [B₂(CN)₆]²⁻ that is chemically very robust is reported. The dianion is air‐stable and resistant against boiling water and anhydrous hydrogen fluoride. Its salts are thermally highly stable, for example, decomposition of (H₃O)₂[B₂(CN)₆] starts at 200 °C. The [B₂(CN)₆]²⁻ dianion is readily accessible starting from 1) B(CN)₃²⁻ and an oxidant, 2) [BF(CN)₃]⁻ and a reductant, or 3) by the reaction of B(CN)₃²⁻ with [BHal(CN)₃]⁻ (Hal=F, Br). The latter reaction was found to proceed via a triply negatively charged transition state according to an S_N2 mechanism.     

Synthesis,Structure, and Luminescent Property of the Templated Borate [C9H14N]·[B5O6(OH)4]

The templated borate, [C₉H₁₄N] · [B₅O₆(OH)₄], was synthesized under hydrothermal conditions. Single crystal X‐ray diffraction techonology reveals that it crystallizes in the triclinic system, space group P$\bar{1}$ (No. 2). The material was also characterized by element analysis, Fourier transform infrared spectroscopy (FTIR), powder X‐ray diffraction (PXRD), thermogravimetric and differential thermal analysis (TG‐DTA), and luminescence spectroscopy. The compound consisted of isolated pentaborate [B₅O₆(OH)₄]^– and N‐butylpyridinium cations [C₉H₁₄N]⁺. The [B₅O₆(OH)₄]^– anions are connected together by hydrogen bonds to form a three‐dimensional framework, in which [C₉H₁₄N]⁺ cations are located in. [C₉H₁₄N] · [B₅O₆(OH)₄] exhibits tunable luminescence emission at 415–458 nm by means of heating treatment from 100 to 300 °C.     

Aromatic Polyhedral Hydroxyborates: Bridging Boron Oxides and Boron Hydrides

No explosion , but per-B-hydroxylation occurs if the icosahedral boron hydrides [closo-B₁₂H₁₂]²⁻ (see picture), [closo-CB₁₁H₁₂]⁻, or closo-1,12-(CH₂OH)₂-1,12-C₂B₁₀H₁₀ are refluxed in 30 % hydrogen peroxide. Thus, the three isoelectronic species [closo-B₁₂(OH)₁₂]²⁻, [closo-1-H-1-CB₁₁(OH)₁₁]⁻, and closo-1,12-H₂-1,12-C₂B₁₀(OH)₁₀ were obtained. ○=BH, ○=BOH.     

Crystal structure and characterization of Rb2Ca[B4O5(OH)4]2·8H2O

Dirubidium calcium tetraborate octahydrate, Rb₂Ca[B₄O₅(OH)₄]₂·8H₂O, was prepared by reaction of Rb-borate aqueous solution with CaCl₂ and it's structure has been determined by single-crystal X-ray diffraction data. It crystallizes in the orthorhombic system, space group P2₁2₁2₁ with unit cell parameters, Z=4, The structure contains alternate layers of [B₄O₅(OH)₄]²⁻ polyanions separated by water molecules and Rb, Ca cations. The isolated [B₄O₅(OH)₄]²⁻ is constructed from two BO₃(OH) tetrahedron groups and two BO₂(OH) triangular groups joined at common oxygen atoms. The two BO₃(OH) tetrahedron groups are further linked by means of an oxygen bridge across the ring. The Ca²⁺ ion displays seven coordination, while the two non-equivalent Rb⁺ ions display nine and seven coordination, respectively. Infrared and Raman (4000-400 cm⁻¹) spectra of Rb₂Ca[B₄O₅(OH)₄]₂·8H₂O were recorded at room temperature and analyzed. Fundamental vibrational modes were identified and band assignments were made. The dehydration of this hydrated mixed borate occurs in one step and leads to an amorphous phase which undergoes a crystallization.     

Syntheses and crystal structures of two new hydrated borates, Zn8[(BO3)3O2(OH)3] and Pb[B5O8(OH)]·1.5H2O

Two new hydrated borates, Zn₈[(BO₃)₃O₂(OH)₃] and Pb[B₅O₈(OH)]·1.5H₂O, have been prepared by hydrothermal reactions at 170 °C. Single-crystal X-ray structural analyses showed that Zn₈[(BO₃)₃O₂(OH)₃] crystallizes in a non-centrosymmetric space group R32 with a=8.006(2) Å, c=17.751(2) Å, Z=3 and Pb[B₅O₈(OH)]·1.5H₂O in a triclinic space group P1¯ with a=6.656(2) Å, b=6.714(2) Å, c=10.701(2) Å, α=99.07(2)°, β=93.67(2)°, γ=118.87(1)°, Z=2. Zn₈[(BO₃)₃O₂(OH)₃] represents a new structure type in which Zn-centered tetrahedra are connected via common vertices leading to helical ribbons _∞¹[Zn₈O₁₅(OH)₃]¹⁷⁻ that pack side by side and are further condensed through sharing oxygen atoms to form a three-dimensional _∞³[Zn₈O₁₁(OH)₃]⁹⁻ framework. The boron atoms are incorporated into the channels in the framework to complete the final structure. Pb[B₅O₈(OH)]·1.5H₂O is a layered compound containing double ring [B₅O₈(OH)]²⁻ building units that share exocyclic oxygen atoms to form a two-dimensional layer. Symmetry-center-related layers are stacked along the c-axis and held together by interlayer Pb²⁺ ions and water molecules via electrostatic and hydrogen bonding interactions. The IR spectra further confirmed the existence of both triangular BO₃ and OH groups in Zn₈[(BO₃)₃O₂(OH)₃], and BO₃, BO₄, OH groups as well as guest water molecules in Pb[B₅O₈(OH)]·1.5H₂O.     

Structural and Oxidation State Alternatives in Platinum and Palladium Complexes of a Redox-Active Amidinato Ligand

Reaction of [Pt(DMSO)₂Cl₂] or [Pd(MeCN)₂Cl₂] with the electron-rich LH=N,N’-bis(4-dimethylaminophenyl)ethanimidamide yielded mononuclear [PtL₂] ( 1 ) but dinuclear [Pd₂L₄] ( 2 ), a paddle-wheel complex. The neutral compounds were characterized through experiments (crystal structures, electrochemistry, UV-vis-NIR spectroscopy, magnetic resonance) and TD-DFT calculations as metal(II) species with noninnocent ligands L⁻. The reversibly accessible cations [PtL₂]⁺ and [Pd₂L₄]⁺ were also studied, the latter as [Pd₂L₄][B{3,5-(CF₃)₂C₆H₃}₄] single crystals. Experimental and computational investigations were directed at the elucidation of the electronic structures, establishing the correct oxidation states within the alternatives [Pt^II(L⁻)₂] or [Pt^.(L )₂], [Pt^II(L^0.5−)₂]⁺ or [Pt^III(L⁻)₂]⁺, [(Pd^II)₂(μ-L⁻)₄] or [(Pd^1.5)₂(μ-L^0.75−)₄], and [(Pd^2.5)₂(μ-L⁻)₄]⁺ or [(Pd^II)₂(μ-L^0.75−)₄]⁺. In each case, the first alternative was shown to be most appropriate. Remarkable results include the preference of platinum for mononuclear planar [PtL₂] with an N-Pt-N bite angle of 62.8(2)° in contrast to [Pd₂L₄], and the dimetal (Pd₂⁴⁺→Pd₂⁵⁺) instead of ligand (L⁻→L ) oxidation of the dinuclear palladium compound.     

Low Temperature Flux Synthesis and Characterizations of a New Layered Barium Borate BaB8O11(OH)4

The new hydroxyl barium borate BaB₈O₁₁(OH)₄ was synthesized by using a low‐temperature molten salt technique with boric acid as flux at 458 K. Its crystal structure was determined from single‐crystal X‐ray data. The compound crystallizes in the monoclinic space group P12₁/n1 (No.14) with unit cell of a = 790.80(16) pm, b = 1393.9(3) pm, c = 1004.7(2) pm, β = 90.00(3)°, V = 1107.6(4) × 10⁶ pm³, Z = 2. It is isostructural to PbB₈O₁₁(OH)₄, but obviously different from AB₈O₁₁(OH)₄ (A = Ca, Sr) in cell. The crystal structure of BaB₈O₁₁(OH)₄ is built from corrugated borate layers,{[B₈O₁₁(OH)₄]^2–}_n parallel to (010), which are stacked along the b axis and are linked by barium atoms. The borate layer consists of [B₆O₉(OH)] clusters as fundamental building blocks (FBBs), which are connected with surrounding four FBBs by sharing common oxygen vertices to form a sheet, and the sheet is further decorated with the flanking [B₂O₂(OH)₃] dimers. FT‐IR and Raman spectroscopy, DTA‐TG, and the identification of an intermediate phase are presented.     

Pr(BO2)3 und PrCl(BO2)2: Zwei meta‐Borate des Praseodyms im Vergleich

Pr(BO₂)₃ and PrCl(BO₂)₂: Two Praseodymium meta‐Borates in Comparison Single‐crystalline PrCl(BO₂)₂ can be obtained by the reaction of praseodymium, Pr₆O₁₁ and PrCl₃ with a small excess of B₂O₃ in evacuated silica tubes after seven days at 850 °C. If NaCl is additionally used as flux, single crystals of Pr(BO₂)₃ dominate the main product. Both praseodymium(III) meta‐borates are air and water stable. The crystals of PrCl(BO₂)₂ emerge as long, thin, pale green needles which tend to severe twinning due to their fibrous habit. The crystal structure (triclinic, P1¯; a = 420.56(4), b = 655.42(7), c = 808.34(8) pm, α = 82.361(8), β = 89.173(9), γ = 71.980(7)°, Z = 2) exhibits zigzag chains {[(B1)o^t_1/1O^e_2/2(B2)O^t_1/1O^e_2/2]²⁻} (≡ {[BO₂]⁻}) of corner‐linked [BO₃]³⁻ triangles with syndiotactic orientation of the terminal oxygen atoms which are running parallel to the [100] direction. The Pr³⁺ cations are surrounded by three Cl⁻ and seven O²⁻ anions with the shape of a tetracapped trigonal prism. The green, transparent crystals of Pr(BO₂)₃ (monoclinic, C2/c; a= 984.98(9), b = 809.57(8), c = 641.02(6) pm, β = 126.783(9)°, Z = 4) appear either lath‐shaped or rather spherical. In the crystal structure the B³⁺ cations reside both in trigonal planar as well as in tetrahedral coordination of oxygen atoms. Both types of borate polyhedra ([BO₃]³⁻ and [BO₄]⁵⁻) are linked via corners to form chains of the composition {[(B2)‐O^t_1/1O^e_2/2(B1)O^e_4/2(B2)O^t_1/1O^e_2/2]³⁻} (≡ {[BO₂]⁻}) which run parallel [101]. The coordination sphere of the Pr³⁺ cations consists of ten oxide anions which build up a bicapped square antiprism.     

The Borosulfates K4[BS4O15(OH)], Ba[B2S3O13], and Gd2[B2S6O24]

K₄[BS₄O₁₅(OH)], Ba[B₂S₃O₁₃], and Gd₂[B₂S₆O₂₄] were obtained by a new synthetic approach. The strategy involves initially synthesizing the complex acid H[B(HSO₄)₄] which is subsequently reacted in an open system with anhydrous chlorides of K, Ba, and Gd to the respective borosulfates and a volatile molecule (HCl). Furthermore, protonated borosulfates should be accessible by appropriate stoichiometry of the starting materials, particularly in closed systems, which inhibit deprotonation of H[B(HSO₄)₄] via condensation and dehydration. This approach led to the successful synthesis of the first divalent and trivalent metal borosulfates (Ba[B₂S₃O₁₃] with band‐silicate topology and Gd₂[B₂S₆O₂₄] with cyclosilicate topology) and the first hydrogen borosulfate K₄[BS₄O₁₅(OH)].     

Vibrational spectra of alkali metal peroxoborates

Raman and i.r. spectra of solid Na₂[B₂(O₂)₂(OH)₄]·6H₂O (normal, ¹⁰B, ¹¹B, and ²H-substituted), Na₂[B₂(O₂)₂(OH)₄]·nH₂O (n=4, 0), Li₂[B₂(O₂)₂(OH)₄] and M^I₂[B₂(O₂)₂(OOH)₂(OH)₂] (M^I= K, Rb, Cs) are reported and the vibrational modes assigned.