Crystals

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13 pages, 4661 KiB

Open AccessArticle

Synthesis, Crystal Structure and Photoluminescent Properties of Novel 9-Cyano-Pyrrolo[1,2-a][1,10]Phenanthrolines

by Mihaela Cristea, Mihai Răducă, Sergiu Shova, Constantin Drăghici, Vlad A. Neacșu, Maria Maganu, Loredana Albotă (Barbu), Denisa Dumitrescu and Florea Dumitrascu

Crystals 2024, 14(1), 67; https://doi.org/10.3390/cryst14010067 - 7 Jan 2024

Cited by 1 | Viewed by 1497

Abstract

Novel 9-cyano-pyrrolo[1,2-a][1,10]phenanthrolines 6a–d were obtained by an efficient one-pot regioselective reaction between 1,10-phenanthrolinium bromides 2a–d and acrylonitrile as a dipolarophile, in the presence of triethylamine and tetrakis-pyridino-cobalt(II) dichromate (TPCD) as oxidizing agents. The optical properties of the [...] Read more.

Novel 9-cyano-pyrrolo[1,2-a][1,10]phenanthrolines 6a–d were obtained by an efficient one-pot regioselective reaction between 1,10-phenanthrolinium bromides 2a–d and acrylonitrile as a dipolarophile, in the presence of triethylamine and tetrakis-pyridino-cobalt(II) dichromate (TPCD) as oxidizing agents. The optical properties of the compounds were investigated through UV–Vis spectrophotometry and steady-state photoluminescence measurements, while their structures were elucidated by single-crystal X-ray diffraction. The structural characterization revealed that the molecular structures of the four compounds were stabilized by hydrogen bonds and π–π interactions. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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20 pages, 8121 KiB

Open AccessArticle

Synthesis, Crystal Structure, Hirshfeld Surface Analysis, Energy Framework Calculations, and Halogen Bonding Investigation of Benzene-1,3,5-triyltris((4-chlorophenyl)methanone)

by Hawazen M. Hassanain, Samah Al-Sharif, Huda A. Al-Ghamdi, Layla M. Nahari, Ahlam I. Al-Sulami, Sameera M. Mousally and Khadijah M. Al-Zaydi

Crystals 2024, 14(1), 17; https://doi.org/10.3390/cryst14010017 - 24 Dec 2023

Viewed by 1651

Abstract

We synthesized 1,3,5-triyltris((4-chlorophenyl)methanone) by a condensation reaction in glacial acetic acid and studied utilizing spectroscopic and analytical techniques such as ultraviolet, infrared, mass, elemental, and nuclear magnetic resonance (NMR) spectroscopy, as well as X-ray crystallography. The effect of chlorine substitution in the 1,3,5-triaroylbenzene [...] Read more.

We synthesized 1,3,5-triyltris((4-chlorophenyl)methanone) by a condensation reaction in glacial acetic acid and studied utilizing spectroscopic and analytical techniques such as ultraviolet, infrared, mass, elemental, and nuclear magnetic resonance (NMR) spectroscopy, as well as X-ray crystallography. The effect of chlorine substitution in the 1,3,5-triaroylbenzene compound in solid-state arrangements was studied. Halogen bonds are detected in the solid-state structures of the titled compound. A dimeric structure is formed due to the presence of two C-Cl···Cl Type I halogen interactions. Additionally, a delocalized Type III C-Cl···π interaction were reported. C-Cl···H hydrogen bonding and π···π interaction were also reported. Hirshfeld surface analysis, 3D fingerprint, the energy framework, and the electro-optic potential were used to evaluate such interactions. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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21 pages, 15462 KiB

Open AccessArticle

Neutral and Ionic Form of (Benzylthio)Acetic Acid in Novel Aminopyrimidine Based Multi-Component Crystalline Phases

by Justyna Sienkiewicz-Gromiuk and Aleksandra Drzewiecka-Antonik

Crystals 2023, 13(12), 1628; https://doi.org/10.3390/cryst13121628 - 23 Nov 2023

Viewed by 1462

Abstract

(benzylthio)acetic acid (HBTA) and some aminopyrimidines, namely 2-aminopyrimidine (2-AP), 5-aminopyrimidine (5-AP), 2-amino-4,6-dimethylpyrimidine (2-A-4,6-DMP), and 2,4,6-triaminopyrimidine (2,4,6-TAP), were successfully embodied as structural units into the construction of a total of four novel supramolecular organic frameworks. The received crystalline solids were inspected by single-crystal X-ray [...] Read more.

(benzylthio)acetic acid (HBTA) and some aminopyrimidines, namely 2-aminopyrimidine (2-AP), 5-aminopyrimidine (5-AP), 2-amino-4,6-dimethylpyrimidine (2-A-4,6-DMP), and 2,4,6-triaminopyrimidine (2,4,6-TAP), were successfully embodied as structural units into the construction of a total of four novel supramolecular organic frameworks. The received crystalline solids were inspected by single-crystal X-ray diffraction (SC XRD) in order to obtain insight into the structural and supramolecular facets. The SOFs deriving from 2-AP, 5-AP, and 2-A-4,6-DMP crystallize in the form of co-crystals (1–3), while the one originating from 2,4,6-TAP crystallizes as a salt solvate (4). The SC XRD results indicated the different contents of structural residues present in the asymmetric units of the crystals 1–4 despite using the same molar ratio of molecular co-former components in each case. The molecular structures of co-crystals 1–3 consist of either one neutral residue of each starting component (1 and 3) or one nonionized residue of the aminopyrimidine ingredient and two neutral residues of the acidic component (2). The asymmetric unit of salt solvate 4 is composed of two ionized residues of each co-former (two 2,4,6-TAP⁺ cations and two BTA⁻ anions) and one MeOH solvent molecule. The most extensive H-bonding network is observed in the crystal structure of salt solvate 4. The relevant molecular ingredients in co-crystals 1–3 are mainly held together by the neutral O_carboxylic–H···N_pyrimidine and N_amine–H···O_carboxylic H-bonds. In the case of aggregate 4, the corresponding ionic residues are predominantly sustained by the charged-assisted N_pyrimidinium–H···O_carboxylate and N_amine–H···O_carboxylate hydrogen interactions. The MeOH solvent, incorporated into the crystal lattice of adduct 4, is also involved in H-bonding by simultaneously serving as the single donor in O_MeOH–H···S and the single acceptor in N_amine–H···O_MeOH H-bonds, which afforded the structural diversity within the 2,4,6-TAP⁺ cations and BTA⁻ anions. Other weaker sets of additional non-covalent contacts existing in the crystal structures of analyzed conglomerates are involved in the self-assembly, stabilization, and expansion of total supramolecular organic frameworks. The fact of the formation of non-covalent bonded supramolecular organic frameworks in question is also reflected in corresponding results obtained through elemental analysis (EA), Fourier transform infrared spectroscopy (FT–IR), and thermal analysis (TG/DSC). Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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13 pages, 3057 KiB

Open AccessFeature PaperArticle

The Crystal Structure of Pb₁₀(PO₄)₆O Revisited: The Evidence of Superstructure

by Sergey V. Krivovichev and Günther Engel

Crystals 2023, 13(9), 1371; https://doi.org/10.3390/cryst13091371 - 13 Sep 2023

Cited by 5 | Viewed by 2176

Abstract

The crystal structure of Pb₁₀(PO₄)₆O, the proposed matrix for the potential room-temperature superconductor LK-99, Pb_10−xCu_x(PO₄)₆O (x = 0.9–1.0), has been reinvestigated via single-crystal X-ray diffraction using crystals prepared by [...] Read more.

The crystal structure of Pb₁₀(PO₄)₆O, the proposed matrix for the potential room-temperature superconductor LK-99, Pb_10−xCu_x(PO₄)₆O (x = 0.9–1.0), has been reinvestigated via single-crystal X-ray diffraction using crystals prepared by Merker and Wondratschek (Z. Anorg. Allg. Chem. 1960, 306, 25–29). The crystal structure is trigonal, P

\bar{3}

, a = 9.8109(6), c = 14.8403(12) Å, V = 1237.06(15), R₁ = 0.0413 using 3456 unique observed reflections. The crystal structure of Pb₁₀(PO₄)₆O is a superstructure with regard to the ‘standard’ P6₃/m apatite structure type. The doubling of the c parameter is induced through the ordering of the split sites of ‘additional’ O’ atoms within the structure channels running parallel to the c axis and centered at (00z). The O’ atoms form short bonds to the Pb1 atoms, resulting in splitting the Pb1 site into two, Pb1A and Pb1B. The structural distortions are further transmitted to the Pb phosphate framework formed by four Pb2 sites and PO₄ groups. The structure data previously reported by Krivovichev and Burns (Z. Kristallogr. 2003, 218, 357–365) may either correspond to the Pb₁₀(PO₄)₆O_x(OH)_2−2x (x ~ 0.4) member of the Pb₁₀(PO₄)₆O—Pb₁₀(PO₄)₆(OH)₂ solid solution series, or to the high-temperature polymorph of Pb₁₀(PO₄)₆O (with the phase with doubled c parameter being the low-temperature polymorph). Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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16 pages, 6126 KiB

Open AccessEditor’s ChoiceArticle

Red and Blue-Black Tin Monoxide, SnO: Pitfalls, Challenges, and Helpful Tools in Crystal Structure Determination of Low-Intensity Datasets from Microcrystals

by Hans Reuter

Crystals 2023, 13(8), 1281; https://doi.org/10.3390/cryst13081281 - 19 Aug 2023

Cited by 1 | Viewed by 1517

Abstract

The crystal structures of red and blue-black tin(II) oxide, SnO, have been determined for the first time by single-crystal X-ray diffraction. Blue-black SnO crystallizes in the tetragonal space group P4/nmm, representing a layer structure consisting of the square–pyramidally coordinated tin [...] Read more.

The crystal structures of red and blue-black tin(II) oxide, SnO, have been determined for the first time by single-crystal X-ray diffraction. Blue-black SnO crystallizes in the tetragonal space group P4/nmm, representing a layer structure consisting of the square–pyramidally coordinated tin and slightly distorted tetrahedrally coordinated oxygen atoms, in accordance with previous results. In contrast, red SnO crystallizes in the orthorhombic centrosymmetric space group Pbca rather than in the non-centrosymmetric space group Cmc2₁, as assumed for a long time. Its layer structure consists of very regular, trigonal–pyramidally coordinated tin atoms as well as trigonal–planar coordinated oxygen atoms. Special care was taken on space group determination, including lattice centering. C-centering could be excluded because of systematic absence violations detected when collecting and processing a primitive triclinic dataset and by generating precession images. In the absence of meaningful extinction conditions resulting from the very small crystal under examination, the structure was initially solved and refined in the triclinic space group P1. Subsequently, the observed atom coordinates were used to reconstruct the actual symmetry skeleton. The various possibilities to identify the correct space group starting from the triclinic solution are demonstrated, and the unique structural features of the crystal structure are visualized. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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17 pages, 4552 KiB

Open AccessEditor’s ChoiceArticle

The High-Pressure Phase Transition in Jamesonite: A Single-Crystal Synchrotron X-ray Diffraction Study

by Paola Comodi, Tonci Balić-Žunić, Maximiliano Fastelli, Michael Hanfland, Ines Collings and Azzurra Zucchini

Crystals 2023, 13(8), 1258; https://doi.org/10.3390/cryst13081258 - 15 Aug 2023

Viewed by 1258

Abstract

The high-pressure behavior of jamesonite (FePb₄Sb₆S₁₄, a = 4.08(3) Å, b = 19.08(3) Å, c = 15.67(3) Å, β= 91.89°, space group P2₁/c) has been investigated using in situ HP synchrotron X-ray [...] Read more.

The high-pressure behavior of jamesonite (FePb₄Sb₆S₁₄, a = 4.08(3) Å, b = 19.08(3) Å, c = 15.67(3) Å, β= 91.89°, space group P2₁/c) has been investigated using in situ HP synchrotron X-ray single-crystal diffraction up to ~17 GPa with a diamond anvil cell under hydrostatic conditions. Results of the volume isothermal equation of state (EoS), determined by fitting the P-V data with a third-order Birch–Murnaghan (BM) EoS, are V₀ = 1207.1(4) Å³, K₀ = 36(1) GPa and K’ = 5.7(7). At high pressure, jamesonite undergoes a phase transition to an orthorhombic structure with a Pmcb space group (β-jamesonite). The analysis of β-jamesonite’s compressibility up to 16.6 GPa, studied by fitting the data with a second-order BM-EoS, gives V₀ = 1027(2) Å³, K₀ = 74(2) GPa. The comparison of the structural refinements at different pressures indicates that Fe, Pb and Sb do not change their coordination number over the whole investigated P range, respectively, 6 for Fe, 7 and 8 for Pb and 5 + 2 for Sb. However, a significant change occurs on the orientation of Sb lone electron pairs upon the phase transition in accordance with the change in symmetry. Furthermore, a discontinuity in the Fe chain evolution at the transition pressure is observed. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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20 pages, 2082 KiB

Open AccessArticle

Molecular Structures and Intermolecular Hydrogen Bonding of Silylated 2-Aminopyrimidines

by Marcus Herbig, Edwin Kroke and Jörg Wagler

Crystals 2023, 13(7), 990; https://doi.org/10.3390/cryst13070990 - 21 Jun 2023

Viewed by 1161

Abstract

A series of silylated 2-aminopyrimidines Me_(4−n)Si(NHpyr)_n (Me = methyl, NHpyr = pyrimid-2-ylamino, n = 1, 2, 3, 4), i.e., compounds 1, 2, 3, and 4, respectively, was prepared from a series of the respective [...] Read more.

A series of silylated 2-aminopyrimidines Me_(4−n)Si(NHpyr)_n (Me = methyl, NHpyr = pyrimid-2-ylamino, n = 1, 2, 3, 4), i.e., compounds 1, 2, 3, and 4, respectively, was prepared from a series of the respective chlorosilanes Me_(4−n)SiCl_n and 2-aminopyrimidine. Triethylamine was used as a sacrificial base. Compounds 1, 2, 3, and 4 are solid at room temperature. They were analyzed using ¹H, ¹³C, ²⁹Si NMR, and Raman spectroscopy, and their molecular structures were confirmed by single-crystal X-ray diffraction analyses. All structures exhibit intramolecular van der Waals contacts between the silicon atom and one nitrogen atom of the pyrimidine moiety. Thus, their Si coordination spheres can be interpreted as [4+n] coordinated capped tetrahedra. Intermolecular hydrogen bonds (N–H···N bridges between the Si-bound amino groups and the non-Si-capping pyrimidine N atoms) are a constant contributor to the solid-state structures of these compounds. Furthermore, compounds 2 and 4 exhibit N–H···N bridges which involve 50% of their Si-capping N atoms as hydrogen bridge acceptors. Consequently, 50% of the non-Si-capping pyrimidine N atoms are stabilized by C–H···N contacts. As a result of a particularly dense network of intermolecular hydrogen bridges, the melting point of Si(NHpyr)₄ (compound 4) is higher than 300 °C. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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12 pages, 3420 KiB

Open AccessEditor’s ChoiceArticle

C–H…X (X = F, Cl, Br, I) Versus π-Stacking in the Crystal Packing of Compounds Containing the {M(tpy)X₃} Motif

by Catherine E. Housecroft and Edwin C. Constable

Crystals 2023, 13(6), 885; https://doi.org/10.3390/cryst13060885 - 28 May 2023

Viewed by 1383

Abstract

Analysis of the data in the Cambridge Structural Database (CSD) for compounds containing an {M(tpy)X₃} motif (tpy = 2,2’:6’,2”-terpyridine, M = any metal, X = F, Cl, Br, I) reveals 17 isostructural mononuclear [M(tpy)X₃] compounds crystallizing without lattice solvent; [...] Read more.

Analysis of the data in the Cambridge Structural Database (CSD) for compounds containing an {M(tpy)X₃} motif (tpy = 2,2’:6’,2”-terpyridine, M = any metal, X = F, Cl, Br, I) reveals 17 isostructural mononuclear [M(tpy)X₃] compounds crystallizing without lattice solvent; both face-to-face π-stacking of pyridine rings and C–H3/H3’…X hydrogen bonding appear to be equally important. Regardless of coordination number (CN = 6, 7 or 8) and nuclearity (mono- or dinuclear), a recurring packing feature in other compounds containing an {M(tpy)X₃} unit is the presence of bifurcated Cl…H3/H3’ interactions, complemented in some cases by Cl…H5’/H3” interactions, consistent with the acidic H3, H3’, H5’, and H3” atoms of a coordinated tpy ligand. Octahedral [M(tpy)F₃] complexes crystallize as hydrates with strong F…H–OH hydrogen bonding dominating the crystal packing. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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15 pages, 6216 KiB

Open AccessArticle

M₆O₄(OH)₄ of M = Sn, Pb: Single Crystal Growth and Crystal Structure Determinations Far Away from Routine

by Hans Reuter, Dirk Schröder and Kristina Peckskamp

Crystals 2023, 13(5), 739; https://doi.org/10.3390/cryst13050739 - 27 Apr 2023

Cited by 1 | Viewed by 1592

Abstract

Single crystals of Sn₆O₄(OH)₄ have been grown over a period of more than a decade in hermetically sealed flasks of various triorganotin(IV)-trihydrides in toluene/N,N-dimethylformamide and those of Pb₆O₄(OH)₄ on [...] Read more.

Single crystals of Sn₆O₄(OH)₄ have been grown over a period of more than a decade in hermetically sealed flasks of various triorganotin(IV)-trihydrides in toluene/N,N-dimethylformamide and those of Pb₆O₄(OH)₄ on a petri dish within some days from the reaction of Pb(ClO₄)₂ with Sr(OH)₂·8H₂O. High-resolution X-ray diffraction data of the tetragonally crystallizing compounds have been collected conventionally at 100 K. Crystal structure determinations have been performed in space groups P4/mnc and P

\bar{4}

2₁c with different structure models because of a pretended specific systematic extinction condition. Its violation was routinely overseen because of the very low intensities of the respective reflections, an effect reinforced by crystal size. The non-existence of this systematic extinction was experimentally confirmed by studying the datasets in more detail, including the simulation of layer photographs. The importance of additional information obtained from dataset analysis tools and structure validation programs to assess the different structure models is demonstrated. Structures of both molecules are analyzed with respect to the molecules as a whole as well as to their constructive building units: two crystallographic different prototypes of {MO₄} coordination polyhedra with a bent seesaw conformation, one μ₃-OH- and one μ₃-O- group, each trigonal-pyramidally coordinated. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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19 pages, 5744 KiB

Open AccessArticle

Crystal Structure, Hirshfeld Surface Analysis, and Computational Study of Quinolin-8-yl 4-Chlorobenzoate: Insights from Spectroscopic, Thermal, and Antitumor Properties

by Juan-Carlos Castillo, Diana Becerra and Mario A. Macías

Crystals 2023, 13(4), 694; https://doi.org/10.3390/cryst13040694 - 18 Apr 2023

Cited by 4 | Viewed by 2065

Abstract

We report the time-efficient synthesis of quinolin-8-yl 4-chlorobenzoate (3) via an O-acylation reaction between 8-hydroxyquinoline (1) and 4-chlorobenzoyl chloride (2) mediated by triethylamine in acetonitrile under heating at 80 °C for 20 min in the Monowave [...] Read more.

We report the time-efficient synthesis of quinolin-8-yl 4-chlorobenzoate (3) via an O-acylation reaction between 8-hydroxyquinoline (1) and 4-chlorobenzoyl chloride (2) mediated by triethylamine in acetonitrile under heating at 80 °C for 20 min in the Monowave 50 reactor. This protocol is distinguished by its short reaction time, operational simplicity, and clean reaction profile. The structure of 3 was fully characterized through a combination of analytical techniques, including NMR, IR, and UV–Vis spectroscopy, MS spectrometry, differential scanning calorimetry (DSC), thermogravimetry (TG), and crystallographic studies. Interestingly, X-ray diffraction analyses of 3 show that the crystal structure is characterized by C-H···N, C-H···O, Cl···π, and π···π interactions. The molecular conformation presents an orthogonal orientation between aromatic rings in the solid state. The calculated interaction energies using the CE-B3LYP model show that dispersion forces act in a higher proportion to build the crystal, which is consistent with the few short hydrogen interactions detected. Electrostatic potential maps suggest the formation of σ-holes over the Cl atoms. Although they can behave as both Lewis acid and base sites, Cl··Cl interactions are absent due to the shallow depth of these σ-holes. Quantum chemical descriptors and global reactivity descriptors were examined using the B3LYP method with the 6-31G(d,p) basis set implemented in CrystalExplorer. Finally, compound 3 exhibited low activity against HOP-92 and EKVX non-Small-cell lung and UO-31 Renal cancer cell lines, with a growth inhibition percentage (GI%) ranging from 6.2% to 18.1%. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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15 pages, 5178 KiB

Open AccessEditor’s ChoiceArticle

Packing Motifs in [M(bpy)₂X₂] Coordination Compounds (bpy = 2,2′-bipyridine; X = F, Cl, Br, I)

by Edwin C. Constable and Catherine E. Housecroft

Crystals 2023, 13(3), 505; https://doi.org/10.3390/cryst13030505 - 15 Mar 2023

Cited by 3 | Viewed by 1605

Abstract

Packing motifs within structurally characterized cis-[M(bpy)₂X₂] (M = any metal, bpy = 2,2′-bipyridine, X = F, Cl, Br, I) coordination compounds have been investigated using data from the Cambridge Structural Database. Compounds fall into two classes: non-solvated cis- [...] Read more.

Packing motifs within structurally characterized cis-[M(bpy)₂X₂] (M = any metal, bpy = 2,2′-bipyridine, X = F, Cl, Br, I) coordination compounds have been investigated using data from the Cambridge Structural Database. Compounds fall into two classes: non-solvated cis-[M(bpy)₂X₂] moieties and those with additional lattice molecules (solvent or other molecules). A recurring packing motif is a dimeric unit involving intermolecular face-to-face π-stacking of bpy ligands and CH_bpy...X contacts, although in several cases, slippage of the stacked bpy units reduces the effectiveness of the face-to-face interaction leaving the CH_bpy...X contacts as the dominant crystal-packing interaction. The prevalence of the dimeric unit versus the assembly of 1D-chains in the solid state is described. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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10 pages, 1919 KiB

Open AccessArticle

Synthesis, Structure, and Luminescence of a Molecular Europium Tetracyanoplatinate Incorporating 4,5-Diazafluoren-9-One

by Richard E. Sykora

Crystals 2023, 13(2), 317; https://doi.org/10.3390/cryst13020317 - 14 Feb 2023

Cited by 1 | Viewed by 1378

Abstract

Eu₂(Pt(CN)₄)₃(H₂O)₁₂]·4C₁₁H₆N₂O·6H₂O represents a new member to the lanthanide tetracyanoplatinate family of materials. The synthesis, single-crystal X-ray structure, and photoluminescence properties of this compound are reported [...] Read more.

Eu₂(Pt(CN)₄)₃(H₂O)₁₂]·4C₁₁H₆N₂O·6H₂O represents a new member to the lanthanide tetracyanoplatinate family of materials. The synthesis, single-crystal X-ray structure, and photoluminescence properties of this compound are reported herein. The compound contains dimeric [Eu₂(Pt(CN)₄)₃(H₂O)₁₂] molecules in which the Eu³⁺ sites are connected with trans-bridging [Pt(CN)4] ²⁻ anions and co-crystallized along with 4,5-diazafluoren-9-one (dafone) and lattice water. Prominent noncovalent interactions that stabilize the structure include H-bonding as well as short stacking interactions involving the planar tetracyanoplatinate anions in conjunction with the planar dafone molecules. Photoluminescence measurements illustrate that Eu₂(Pt(CN)₄)₃(H₂O)₁₂]·4C₁₁H₆N₂O·6H₂O contains multiple emitting states and also displays enhanced Eu³⁺-based emission due to energy transfer within the compound. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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12 pages, 5427 KiB

Open AccessArticle

High pO₂ Flux Growth and Characterization of NdNiO₃ Crystals

by Xiaoli Wang, Shilei Wang, Chao Liu, Chuanyan Fan, Lu Han, Feiyu Li, Tieyan Chang, Yu-Sheng Chen, Shanpeng Wang, Xutang Tao and Junjie Zhang

Crystals 2023, 13(2), 180; https://doi.org/10.3390/cryst13020180 - 19 Jan 2023

Cited by 1 | Viewed by 2129

Abstract

Single crystals of the perovskite nickelate NdNiO₃ with dimensions of up to 50 μm on edge have been successfully grown using the flux method at a temperature of 400 °C and oxygen pressure of 200 bar. The crystals were investigated by a [...] Read more.

Single crystals of the perovskite nickelate NdNiO₃ with dimensions of up to 50 μm on edge have been successfully grown using the flux method at a temperature of 400 °C and oxygen pressure of 200 bar. The crystals were investigated by a combination of techniques, including high-resolution synchrotron X-ray single-crystal and powder diffraction and physical property measurements such as magnetic susceptibility and resistivity. Resistivity measurements revealed a metal-insulator transition (MIT) at T_MIT~180 K with apparent thermal hysteresis; however, no superlattice peaks or peak splitting below T_MIT, which corresponds to a structural transition from Pbnm to P2₁/n, was observed. The successful growth of NdNiO₃ crystals at relatively low temperatures and oxygen pressure provides an alternative approach for preparing single crystals of interesting perovskites such as RNiO₃ (R = Sm-Lu) and parent phases of superconducting square planar nickelates. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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17 pages, 3974 KiB

Open AccessArticle

Dicarboxylic Acid-Based Co-Crystals of Pyridine Derivatives Involving Structure Guiding Unconventional Synthons: Experimental and Theoretical Studies

by Pranay Sharma, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver and Manjit K. Bhattacharyya

Crystals 2022, 12(10), 1442; https://doi.org/10.3390/cryst12101442 - 12 Oct 2022

Cited by 1 | Viewed by 2037

Abstract

Four co-crystals involving dicarboxylic acids and pyridine derivatives, viz. (ox)_0.5(2-CNpy) (1), (adp)(4-CNpy)₂ (2), (tp)(4-CNpy)₂ (3) and (adp)(3-CNpy)₂ (4) (ox = oxalic acid, tp = terephthalic acid, adp = adipic acid, [...] Read more.

Four co-crystals involving dicarboxylic acids and pyridine derivatives, viz. (ox)_0.5(2-CNpy) (1), (adp)(4-CNpy)₂ (2), (tp)(4-CNpy)₂ (3) and (adp)(3-CNpy)₂ (4) (ox = oxalic acid, tp = terephthalic acid, adp = adipic acid, CNpy = cyanopyridine), have been synthesized at room temperature in water medium. Crystal-structure analysis of co-crystal 1 reveals the presence of unconventional O···π(oxalic acid)-hole interaction with the C-C bond of ox moiety, along with parallel nitrile–nitrile interactions. The structural topologies of co-crystals 2–4 unfold the presence of antiparallel nitrile–nitrile interactions involving the CNpy moieties. The molecular associations involving the H-bonds and other unconventional contacts among the co-formers of the multicomponent co-crystals are analyzed using density functional theory (DFT) calculations combined with molecular electrostatic potential (MEP) surface, quantum theory of atoms-in-molecules (QTAIM) and noncovalent interaction (NCI) plot computational tools. The computational studies revealed the presence of unconventional O···π-hole interaction in 1 and the H-bonded synthons with π-stacked nitrile contacts involving CNpy moieties in co-crystals 2–4. The energetic features of the noncovalent contacts reveal the crucial roles of the H-bonding synthons and π-stacking interactions in the multicomponent compounds. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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14 pages, 4205 KiB

Open AccessArticle

To Be or Not to Be a (4,4) Net: Reactions of 4′-{4-(N,N-Diethylaminophenyl)}- and 4′-{4-(N,N-Diphenylaminophenyl)}-3,2′:6′,3″- and 4,2′:6′,4″-Terpyridines with Cobalt(II) Thiocyanate

by Dalila Rocco, Anamarija Nikoletić, Alessandro Prescimone, Edwin C. Constable and Catherine E. Housecroft

Crystals 2022, 12(8), 1136; https://doi.org/10.3390/cryst12081136 - 12 Aug 2022

Cited by 2 | Viewed by 1661

Abstract

The ligands 4′-{4-(N,N-diethylaminophenyl)}-3,2′:6′,3″-terpyridine (1) and 4′{4-(N,N-diphenylaminophenyl)}-3,2′:6′,3″-terpyridine (2) were prepared and characterized, including the single crystal structure of 2. Along with their 4,2′:6′,4″-terpyridine isomers, 3 and 4, ligands 1 and 2 were reacted with [...] Read more.

The ligands 4′-{4-(N,N-diethylaminophenyl)}-3,2′:6′,3″-terpyridine (1) and 4′{4-(N,N-diphenylaminophenyl)}-3,2′:6′,3″-terpyridine (2) were prepared and characterized, including the single crystal structure of 2. Along with their 4,2′:6′,4″-terpyridine isomers, 3 and 4, ligands 1 and 2 were reacted with Co(NCS)₂ under conditions of crystal growth by layering, using solvent mixtures of MeOH and CHCl₃. The single crystal structures of [Co(NCS)₂(1)]_n·0.8nCHCl₃, [Co(NCS)₂(2)₂(MeOH)₂]·3CHCl₃, [Co(NCS)₂(3)]_n·2nCHCl₃, and [Co(NCS)₂(4)]_n were determined. The complexes with 1, 3, and 4 assemble into 2D (4,4) nets with the Co(II) centres as 4-connecting nodes, whereas [Co(NCS)₂(2)₂(MeOH)₂] is a discrete molecular species, illustrating that MeOH can act as a non-innocent solvent. The effects on the structure of changing from the 3,2′:6′,3″-terpyridine (3,2′:6′,3″-tpy) to a 4,2′:6′,4″-tpy metal-binding unit, and of introducing R₂N functionalities with different steric demands, are discussed. PXRD of bulk samples of all four products confirmed the single-crystal structures as representative of the bulk materials. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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10 pages, 1985 KiB

Open AccessArticle

Unexpected Formation of a Silicon-Centered Spirocyclic Oligosiloxane Bearing Eight Pendant Ferrocene Units

by Sonia Bruña, Isabel Cuadrado and Josefina Perles

Crystals 2022, 12(8), 1122; https://doi.org/10.3390/cryst12081122 - 11 Aug 2022

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Abstract

An intriguing but rare silicon-centered spirocyclic compound, spiro[5.5]octaferrocenylpentasiloxane (4) featuring silicon fused six-membered ferrocenyl-functionalized siloxane rings, has been obtained during the thermally induced transformation of triferrocenylsilane Fc₃Si–H (1) into triferrocenylsilanol Fc₃Si–OH (2), when [...] Read more.

An intriguing but rare silicon-centered spirocyclic compound, spiro[5.5]octaferrocenylpentasiloxane (4) featuring silicon fused six-membered ferrocenyl-functionalized siloxane rings, has been obtained during the thermally induced transformation of triferrocenylsilane Fc₃Si–H (1) into triferrocenylsilanol Fc₃Si–OH (2), when N,N-dimethylformamide (DMF) was used as a solvent in the presence of the metal carbonyl Mo(CO)₆. The unexpected formation of the maximally ferrocenyl substituted silicon centered spirocyclic 4 involves the obtention, and subsequent condensation, of different ferrocenylsilanol intermediates. Spirocyclic silicate 4 has been characterized using a combination of MALDI-TOF mass spectrometry, elemental analysis, and single crystal X-ray diffraction analysis. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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12 pages, 1993 KiB

Open AccessArticle

Influence of the Reaction Conditions in the Crystal Structures of Zn(II) and Ni(II) Coordination Compounds with a Dissymmetric Bis(Thiosemicarbazone) Ligand

by Luis Alonso, Rodrigo Burón, Elena López-Torres and Maria Antonia Mendiola

Crystals 2022, 12(3), 310; https://doi.org/10.3390/cryst12030310 - 23 Feb 2022

Cited by 6 | Viewed by 2296

Abstract

The new ligand HMeATSM, derived from condensation of 2-3-butanedione with 4-methyl-3-thiosemicarbazide and 2,4-dimethyl-3-thiosemicarbazide, has been synthesized. Its reactivity with nickel(II) and zinc(II) nitrates was explored and the resulting complexes were thoroughly characterized by elemental analysis, conductivity, mass spectrometry, IR, ¹H and ¹³ [...] Read more.

The new ligand HMeATSM, derived from condensation of 2-3-butanedione with 4-methyl-3-thiosemicarbazide and 2,4-dimethyl-3-thiosemicarbazide, has been synthesized. Its reactivity with nickel(II) and zinc(II) nitrates was explored and the resulting complexes were thoroughly characterized by elemental analysis, conductivity, mass spectrometry, IR, ¹H and ¹³C NMR spectroscopies and their structures were confirmed by single-crystal X-ray diffraction. The results showed that the complex [Ni(MeATSM)]NO₃ 1 is formed under every reaction condition. In contrast, the reaction with zinc(II) nitrate depends on the temperature and the presence of LiOH·H₂O, leading to the obtaining of complexes [Zn(MeATSM)(OH₂)](NO₃) 2 and [Zn(Me₂TS)₂(OH₂)](NO₃)₂ 3. The crystal structures of complexes 1 and 2 show that the dissymmetric ligand acts as a N₂S₂ tetradentate monoanionic ligand. The structural preferences of the metals also determine the structure of the complexes: whereas nickel(II) is in a square-planar environment, the zinc atom prefers a distorted square-base pyramid geometry imposed by the coordination mode and the planarity of the bis(thiosemicarbazone) ligand. In contrast, in complex 3, containing two bidentate Me₂TS ligands, the Zn(II) is in a trigonal bipyramid arrangement. In all the complexes, the nitrate ion is not coordinated to the metal and acts as a counterion. Full article

(This article belongs to the Special Issue Characterisation and Study of Compounds by Single Crystal X-ray Diffraction)

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