Anisole at 100 K: the first crystal structure determination

The simplest alkyl aryl ether, anisole (methoxybenzene), C₇H₈O, is a feedstock chemical and is widely used in the pharmaceutical industry. The structure of anisole at 100 K, as determined by single‐crystal X‐ray analysis, is reported. A crystal (m.p. 236 K) suitable for X‐ray diffraction was obtained from the melt. The title compound crystallizes in the centrosymmetric space group P2₁/c with two molecules in the asymmetric unit (Z′ = 2). Both crystallographically distinct molecules adopt a virtually flat (C_s‐symmetric) conformation. The arrangement of the molecules in the solid state appears to be governed by close packing. No face‐to‐face π–π stacking of the molecules is observed, but rather edge‐to‐face interactions result in a herringbone packing motif.     

2,4‐Dimethyl‐1,3‐thiazole‐5‐carboxylic acid: an X‐ray structural study at 100 K and Hirshfeld surface analysis

The crystal structure of the title thiazolecarboxylic acid derivative, C₆H₇NO₂S, (I), has been determined from single‐crystal X‐ray analysis at 100 K. In the crystal packing, an interplay of O—H...N and C—H...O hydrogen bonds connects the molecules to form C(6)R₂²(8) polymeric chains, which are further linked via weak C—H...O hydrogen bonds into a two‐dimensional supramolecular framework. The relative contributions of different interactions to the Hirshfeld surface in (I) and a few related thiazolecarboxylic acid derivatives indicate that the H...H, N...H and O...H contacts can account for about 50–70% of the total Hirshfeld surface area in this class of compound.     

A Novel Coordination Polymer, [Ag4^1 （bpdc）（H2bpdc）（Hbpdc）2]n （bpdc = 2,2＇-bipyridyl-3,3＇-dicarboxylate）： Coordination Models of bpdc Ligands

A novel coordination polymer, [Ag₄ppdc)(H₂bpdc)(Hbpdc)₂] (bpdc = 2,2′‐bipyridyl‐3,3′‐dicarboxylate), was hydrothermally synthesized at 403 K and structurally characterized by single crystal X‐ray diffraction analysis. The compound crystalizes in the monoclinic space group C2/c with a=1.9516(4) nm, b=1.9503(4) nm. c=1.2566(3) nm, and β=112.48(3)°. In the two‐dimensional crystal structure, Ag^I center is coordinated, in a scarce coordination environment, double‐capped tetrahedron, by one bpdc ligand to form N‐Ag‐N chelate bond via two pyridyl N atoms, and other two bpdc ligands to form two O‐Ag‐O chelate bonds, respectively, via two carboxyl O atoms. The bpdc ligands are present in one non‐protonated form, bpdc, and two protonated forms, Hbpdc and H2bpdc, which all act as μ3‐ligand in a hexadentate fashion (N, N′; O, O′; O, O′) to coordinate with three Ag centers, respectively, through the three chelate bonds. This coordinated fashion of bpdc ligand is first found in the title compound. W‐Us‐NIR reflectance spectroscopy study revealed insulator nature for the crystal with an optical energy gap of 3.1 eV.     

Polymeric potassium di­aqua­hexa‐μ‐cyano‐holmium(III)­ruthenium(II) dihydrate

The crystal structure of the title bimetallic cyanide‐bridged complex, {K[HoRu(CN)₆(H₂O)₂]·2H₂O}_n, was determined by means of single‐crystal X‐ray diffraction techniques. The coordination about the central holmium(III) ion is eightfold in a square‐antiprismatic arrangement, while the ruthenium(II) ion is octahedrally coordinated. Channels permeating the crystal lattice contain the potassium cations and two zeolitic water mol­ecules. The Ho^III and K atoms lie at sites with mm symmetry and the Ru atom is at a site with 2/m symmetry.     

Disodium[hydroxotetranitronitrosyl]ruthenate(II), a Photochromic Substance with Long‐lived Metastable States: Structure at 110 K,Spectroscopic and Thermal Properties

Disodium[hydroxotetranitronitrosyl]ruthenate(II) is a photochromic compound excitable with blue‐green light which exhibits at least one unusually long‐lived metastable state at low temperature. At 298 K, the compound crystallises in the space group C2/m. A reversible phase transition occurs at 240 K upon cooling, as detected by Differential Scanning Calorimetry and X‐ray powder diffraction which causes a lowering of the crystal symmetry to the space group P2₁/n. Synchrotron X‐ray single crystal diffraction and FT‐IR spectroscopy data obtained on the ground and the excited states of the title compound low temperature phase are presented.     

A novel alkaline earth strontium(II) coordination polymer: poly[hexaaquatetrakis(μ5‐pyridine‐2,6‐dicarboxylato)bis(μ4‐pyridine‐2,6‐dicarboxylato)(μ7‐sulfato)heptastrontium(II)]

The title compound, [Sr₇(C₇H₃NO₄)₆(SO₄)(H₂O)₆]_n, has been synthesized by an ionothermal method using the ionic liquid 1‐ethyl‐3‐methylimidazolium ([Emim]Br) as solvent, and characterized by elemental analysis, energy‐dispersive X‐ray spectroscopy, IR and single‐crystal X‐ray diffraction. The structure of the compound can be viewed as a three‐dimensional coordination polymer composed of Sr²⁺ cations, pyridine‐2,6‐dicarboxylate anions, sulfate anions and water molecules. The compound not only exhibits a three‐dimensional structure with a unique coordination mode of the sulfate anion, but also features the first example of a heptanuclear strontium(II) coordination polymer. The structure is further stabilized by O—H...O hydrogen bonds and π–π stacking interactions.     

Synthesis and Structure of Potassium 1‐Benzylimidazole‐2‐carboxylate · 2/3Hydrate

The title compound, K[bimCO₂] · 2/3H₂O (C₁₁H₁₉N₂O₂K · 2/3H₂O), has been synthesized, and characterized by a single crystal X‐ray study; it has the grouping cross‐linked into a polymeric sheet in which potassium environments are diverse and unsymmetrical, containing six‐coordinate and seven‐coordinate geometries.     

N‐Triazolylpropanamide – an Acrylamide‐Derived Multifunctional Ligand for the Construction of Supramolecular Hydrogen‐Bonded Networks

The synthesis and single crystal X‐ray structure of the multifunctional acrylamide‐derived ligand N‐triazolylpropanamide ( 1 , = NTPA) are reported. The title compound was prepared in 72 % yield by Michael addition of 1, 2, 4‐triazole and acrylamide in the presence of Triton B (= trimethylbenzylammonium hydroxide) as catalyst. Treatment of 1 with FeCl₃(H₂O)₆ in MeOH/MeCN led to reduction and formation of the iron(II) complex (NTPA)₂FeCl₂(MeOH)₂ ( 2 , yellow prisms, 52 % yield). Both 1 and 2 were structurally characterized by X‐ray diffraction. Surprisingly, the NTPA ligands in 2 are coordinated to iron in a monodentate fashion through a triazole ring nitrogen atom. In the crystal, both compounds form supramolecular hydrogen‐bonded networks.     

Powder X‐ray study of racemic (2RS,3RS)‐5‐amino‐3‐[4‐(3‐methoxyphenyl)piperazin‐1‐yl]‐1,2,3,4‐tetrahydronaphthalen‐2‐ol

The structure of the title benzovesamicol analogue, C₂₁H₂₇N₃O₂, an important compound for the diagnosis of Alzheimer's disease, has been determined by X‐ray powder diffraction. The title compound was firstly synthesized and characterized by spectroscopic methods (FT–IR, and ¹³C and ¹H NMR). The compound is a racemic mixture of enantiomers which crystallizes in the monoclinic system in a centrosymmetric space group (P2₁/c). Crystallography, in particular powder X‐ray diffraction, was pivotal in revealing that the enantio‐resolution did not succeed. The piperazine ring is in a chair conformation, while the cyclohexene ring assumes a half‐chair conformation. The crystal packing is dominated by intermolecular O—H...N hydrogen bonding which links molecules along the c direction.     

Ethylenediammonium bis{bis[N‐(2‐aminoethyl)glycinato‐κ3N,N′,O]chromium(III)} tetrachloride dihydrate at 293 and 100 K

The crystal structure of the title compound, (C₂H₁₀N₂)[Cr(C₄H₉N₂O₂)₂]₂Cl₄·2H₂O, has been determined by single‐crystal X‐ray diffraction studies at 293 and 100 K. The analyses demonstrated that the crystal consists of ethyl­enedi­ammonium dications (which lie about inversion centres), bis­[N‐(2‐amino­ethyl)­glycin­ato]­chromium(III) monocations, Cl^? anions and hydrate water mol­ecules, in a molecular ratio of 1:2:4:2. The complex cation unit has a slightly distorted octahedrally coordinated Cr atom, with two Cr—O and four Cr—N bonds in the ranges 1.951 (1)–1.953 (1) and 2.054 (1)–2.089 (2) Å, respectively, at 293 K. The geometry of the bis­[N‐(2‐amino­ethyl)­glycinato]­chromium(III) moiety was found to be trans,cis,cis with respect to the carboxyl­ate O atom and the primary and secondary amine N atoms. The two analyses, at 293 and 100 K, exhibited no remarkable structural differences, although the colour of the crystals did differ, being red at 293 K and orange at 100 K.     

4‐(3,5‐Dimethyl‐1H‐pyrazol‐4‐ylmethyl)‐3,5‐dimethyl‐1H‐pyrazol‐2‐ium dihydrogen phosphate: a combined X‐ray and DFT study

The molecular structure of the title salt, C₁₁H₁₇N₄⁺·H₂PO₄⁻, has been determined from single‐crystal X‐ray analysis and compared with the structure calculated by density functional theory (DFT) at the BLYP level. The crystal packing in the title compound is stabilized primarily by intermolecular N—H...O, O—H...N and O—H...O hydrogen bonds and π–π stacking interactions, and thus a three‐dimensional supramolecular honeycomb network consisting of R₄²(10), R₄⁴(14) and R₄⁴(24) ring motifs is established. The HOMO–LUMO energy gap (1.338 eV; HOMO is the highest occupied molecular orbital and LUMO is the lowest unoccupied molecular orbital) indicates a high chemical reactivity for the title compound.     

Hydrogen‐Bonding in Cyclic 2‐(3‐Oxo‐3‐phenylpropyl)‐Substituted 1,3‐Diketones: 17O‐NMR Spectra and X‐Ray Structure Determination

Structures of cyclic 2‐(3‐oxo‐3‐phenylpropyl)‐substituted 1,3‐diketones 4a – c were determined by ¹⁷O‐NMR spectroscopy and X‐ray crystallography. In CDCl₃ solution, compounds 4a – c form an eight‐membered‐ring with intramolecular H‐bonding between the enolic OH and the carbonyl O(11)‐atom of the phenylpropyl group, as demonstrated by increased shielding of specifically labeled 4a – c in the ¹⁷O‐NMR spectra (Δδ(¹⁷O(11))=36 ppm). In solid state, intermolecular H‐bonding was observed instead of intramolecular H‐bonding, as evidenced by the X‐ray crystal‐structure analysis of compound 4b . Crystals of compound 4b at 293 K are monoclinic with a=11.7927 (12) Å, b=13.6230 (14) Å, c=9.8900 (10) Å, β=107.192 (2)°, and the space group is P2₁/c with Z=4 (refinement to R=0.0557 on 2154 independent reflections).     

Synthesis and structure of a µ‐oxo diiron(III) complex with an N‐pyridylmethyl‐N,N‐bis(4‐methylbenzimidazol‐2‐yl)amine ligand and its catalytic property for hydrocarbon oxidation

A µ‐oxo diiron(III) complex [{Fe(pbba)Cl}₂(µ‐O)]Cl₂ (1, pbba = N‐pyridylmethyl‐N,N‐bis(4‐methylbenzimidazol‐2‐yl)amine) bearing multi‐imidazolyl motifs was synthesized and characterized by X‐ray crystallography to closely mimic the structural features of methane monooxygenase. As shown by its X‐ray crystal structure, complex 1 is a centrosymmetric dimer with an Fe? O? Fe angle of 180° , and pseudo‐octahedral around each iron(III) center. The catalytic ability of title compound in the oxidation of alkane and alkene is investigated by employing tert‐butylhydroperoxide and m‐chloroperbenzoic acid as oxidants under mild conditions. The catalytic oxidation results showed that radical intermediate dominates the oxidation process. Copyright © 2008 John Wiley & Sons, Ltd.     

l‐Alanylglycyl‐l‐alanine monohydrate at 20 K

The X‐ray crystal structure of the title compound, C₈H₁₅N₃O₄·H₂O, at 20 K (space group P2₁) reveals that the mol­ecular conformation of the tripeptide is remarkably different from the water‐free form (space group P2₁2₁2₁) reported previously [Padiyar & Seshadri (1996), Acta Cryst. C 52 , 1693–1695].     

K5.76Ga5.76Si10.24O32·3.4H2O,a gallosilicate with the zeolite gismondine topology

The title compound, K–GaSi–GIS, potassium gallium silicon oxide hydrate, was synthesized hydro­thermally and its crystal structure was determined from data collected on a single crystal of dimensions 10 × 10 × 8 µm at a synchrotron X‐ray source. The compound, which has the aluminosilicate (AlSi) zeolite gismondine (GIS) topology, Ca₄[Al₈Si₈O₃₂]·16H₂O, crystallizes in the tetragonal space group I4₁/a. A disordered distribution of the framework Si/Ga sites leads to higher symmetry of the GIS‐type network compared with the usual monoclinic symmetry in AlSi–GIS. Framework Ga substitution for Al in AlSi–GIS leads to substantial distortion of the crankshaft chains, reducing the effective pore dimensions and suggesting the possibility of pore‐dimension control via partial framework‐cation substitution.     

Methyl 3,6‐di‐O‐pivaloyl‐α‐d‐manno­pyran­oside

The X‐ray crystal structure analysis of the title compound, C₁₇H₃₀O₈, revealed a ⁴C₁ conformation of the pyran­osyl ring [Cremer–Pople puckering parameters of Q = 0.568 (2) Å, θ = 5.1 (2) and ϕ = 218 (3)°]. The structure shows no deviations from the geometric parameters of pyran­oside carbohydrates. The hydroxyl groups participate in O—H⃛O hydrogen bonds, forming a two‐dimensional pattern [O⃛O = 2.811 (3) and 2.995 (3) Å].     

Synthesis,crystal structure and magnetic properties of a two‐dimensional cyanide‐based heterometallic coordination polymer with cationic piperazinium ligands: poly[aquatetra‐μ2‐cyanido‐κ8C:N‐dicyanido‐κ2C‐(piperazinium‐κN4)cobalt(III)copper(II)]

Cyanide as a bridge can be used to construct homo‐ and heterometallic complexes with intriguing structures and interesting magnetic properties. These ligands can generate diverse structures, including clusters, one‐dimensional chains, two‐dimensional layers and three‐dimensional frameworks. The title cyanide‐bridged Cu^II–Co^III heterometallic compound, [Cu^IICo^III(CN)₆(C₄H₁₁N₂)(H₂O)]_n, has been synthesized and characterized by single‐crystal X‐ray diffraction analysis, magnetic measurement, thermal study, vibrational spectroscopy (FT–IR) and scanning electron microscopy/energy‐dispersive X‐ray spectroscopy (SEM–EDS). The crystal structure analysis revealed that it has a two‐dimensional grid‐like structure built up of [Cu(Hpip)(H₂O)]³⁺ cations (Hpip is piperazinium) and [Co(CN)₆]³⁻ anions that are linked through bridging cyanide ligands. The overall three‐dimensional supramolecular network is expanded by a combination of interlayer O—H...N and N—H...O hydrogen bonds involving the coordinated water molecules and the N atoms of the nonbridging cyanide groups and monodentate cationic piperazinium ligands. A magnetic investigation shows that antiferromagnetic interactions exist in the title compound.     

catena‐Poly[[tetra­aqua­manganese(II)]‐μ‐4‐(carboxyl­ato­methyl­sulfanyl)­phenoxy­acetato]

The title compound, [Mn(C₁₀H₈O₅S)(H₂O)₄]_n, a one‐dimensional manganese(II) complex comprising helical chains bridged by 4‐(carboxylatomethylsulfanyl)phenoxyacetate ligands has been characterized by single‐crystal X‐ray diffraction analysis. Hydrogen‐bonding inter­actions between adjacent chains extend the complex into a three‐dimensional supra­molecular architecture.     

A Sequential Method to Prepare Polymorphs and Solvatomorphs of [Fe(1,3‐bpp)2](ClO4)2⋅nH2O (n=0, 1, 2) with Varying Spin‐Crossover Behaviour

Two polymorphs of the spin crossover (SCO) compound [Fe(1,3‐bpp)₂](ClO₄)₂ ( 1 and 2 ; 1,3‐bpp=2‐(pyrazol‐1‐yl)‐6‐(pyrazol‐3‐yl)pyridine) were prepared using a novel, stepwise procedure. Crystals of 1 deposit from dry solvents, while 2 is obtained from a solid‐state procedure, by sequentially removing lattice H₂O molecules from the solvatomorph [Fe(1,3‐bpp)₂](ClO₄)₂?2 H₂O ( 2 ?2 H₂O), using single‐crystal‐to‐single‐crystal (SCSC) transformations. Hydrate 2 ?2 H₂O is obtained through the same reaction as 1 , now with 2.5 % of water added. Compounds 2 and 2 ?2 H₂O are unstable in the atmosphere and absorb or lose one equivalent of water, respectively, to both yield the stable solvatomorph [Fe(1,3‐bpp)₂](ClO₄)₂?H₂O ( 2 ?H₂O), also following SCSC processes. The four derivatives have been characterised by single‐crystal X‐ray diffraction (SCXRD). Furthermore, the homogeneity of the various compounds as well as their SCSC interconversions have been confirmed by powder X‐ray diffraction (PXRD). Polymorphs 1 and 2 exhibit abrupt SCO behaviour near room temperature with T_1/2↑=279/316 K and T_1/2↓=276/314 K (near 40 K of shift) and different cooperativity.