When a dream comes true: birth of the African Crystallographic Association (AfCA)

This paper summarizes brief perspectives on the historic process of establishing an African Crystallographic Association (AfCA), including appropriate role players, organizations and accompanying events. It concludes with the official admission of AfCA as the fifth Regional Associate of the IUCr at the 26th Congress and General Assembly of the IUCr in Melbourne, Australia in 2023.

JUAMI, the joint undertaking for an African materials institute: building materials science research collaborations and capabilities between continents

JUAMI, the joint undertaking for an African materials institute, is a project to build collaborations and materials research capabilities between PhD researchers in Africa, the United States, and the world. Focusing on research-active universities in the East African countries of Kenya, Ethiopia, Tanzania and Uganda, the effort has run a series of schools focused on materials for sustainable energy and materials for sustainable development.

Synthesis, structure and Hirshfeld surface analysis of 2-oxo-2H-chromen-6-yl 4-tert-butyl­benzoate: work carried out as part of the AFRAMED project

In the title coumarin derivative, the dihedral angle between the 2H-chromen-2-one ring system and the phenyl ring is 89.12 (5)°. In the crystal, the mol­ecules are linked by C—H⋯O hydrogen bonds into [010] double chains.

Crystal structure and Hirshfeld surface analysis of (E)-2-[2-(2-amino-1-cyano-2-oxo­ethyl­idene)hydrazin-1-yl]benzoic acid N,N-di­methylformamide monosolvate

In the crystal, N—-H⋯O and O—H⋯O hydrogen bonds connect the two independent mol­ecules, forming (8) ring motifs. Weak C—H⋯O inter­actions link the mol­ecules, forming layers parallel to the (12) plane. The DMF solvent mol­ecules are also connected to the main mol­ecules N—H⋯O hydrogen bonds. π–π stacking inter­actions between the layers are also observed.

Crystal structure of a layered phosphate molybdate K₂Gd(PO₄)(MoO₄)

Dipotassium gadolinium(III) phosphate(V) molybdate(VI), synthesized from a high-temperature melt starting from GdF₃ as a source of gadolinium, has a structure that is isotypic with other M^I₂M^III(M^VIO₄)(PO₄) compounds, where M^I = Na, K or Cs, and M^III = rare-earth cation, M^VI = Mo or W. The three-dimensional framework is built up from [Gd(PO₄)(MoO₄)] anionic sheets, which are organized by adhesion of [GdPO₄] layers and [MoO₄] tetra­hedra stacked above and below of these layers, and the inter­stitial space is occupied by K cations having eightfold oxygen coordination.

An unexpected tautomer: synthesis and crystal structure of N-[6-amino-4-(methyl­sulfan­yl)-1,2-di­hydro-1,3,5-triazin-2-yl­idene]benzenesulfonamide

The title compound, C₁₀H₁₁N₅O₂S₂, consists of an unexpected imino-di­hydro-triazine tautomer. Mol­ecules are linked by hydrogen bonds and by O_{sulf­on­amide}⋯(C—NH—C)_triazine contacts.

{[(E)-(1,3-Benzodioxol-5-yl)methyl­idene]amino}thio­urea

The synthesis and crystallographic analysis of [(E)-1,3-benzodioxol-5-yl­methyl­idene­amino]­thio­urea is reported, offering a comprehensive exploration of its structural features and supra­mol­ecular arrangements within the crystal.

Synthesis and crystal structure of a cadmium(II) coordination polymer based on 4,4′-(1H-1,2,4-triazole-3,5-di­yl)dibenzoate

The coordination polyhedron of the Cd²⁺ ion in the title compound is a CdN₂O₅ penta­gonal bipyramid formed by two bidentately coordinated carb­oxy­lic groups of different anions, one water mol­ecule and two pyridine mol­ecules. In the crystal, polymeric chains propagate along the [11] direction; the chains are linked by hydrogen bonds and π–π stacking inter­actions into a three-dimensional network.

Crystal structure of poly[hexa-μ-bro­mido-bis­{2-[1-(py­ridin-2-yl)ethyl­idene­amino]ethanol­ato}tetracopper(II)]

In the title Schiff base tetra­nuclear copper(II) complex, two discrete environments are present in the structure: CuN₂OBr₂ and CuBr₄. Two copper(II) cations are situated in distorted square-based pyramidal environment, while two copper(II) cations are located in distorted tetra­hedral geometry.

Crystal structure, Hirshfeld surface analysis and energy frameworks of 1-[(E)-2-(2-fluoro­phen­yl)di­azan-1-yl­idene]naphthalen-2(1H)-one

In the crystal, mol­ecules of the title compound are linked into infinite sinusoidal chains along the [001] direction. The study demonstrated that dispersion energy was the most influential factor in the crystal organization of the compound.

Synthesis and crystal structures of boryl ortho-silylaryl tri­fluoro­methane­sulfonates

The preparation and solid-state structures of three borylated ortho-silylaryl tri­fluoro­methane­sulfonates are reported. All compounds show the expected connectivity and unexceptional metric parameters as well as weak intra­molecular inter­actions.

Synthesis and crystal structure of N¹,N²-di­methyl­ethane­dihydrazide

In the title compound, the two hydrazide planes make a dihedral angle of 86.5 (2)°. In the crystal, C—H⋯O, N—H⋯O and N—H⋯N hydrogen bonds lead to the formation of a three-dimensional supra­molecular network.

Synthesis, crystal structure and thermal properties of di­bromido­bis­(2-methyl­pyridine N-oxide-κO)cobalt(II)

The crystal structure of the title compound consists of discrete tetra­hedral complexes that are linked by weak inter­molecular hydrogen bonding. Upon heating, melting before decomposition is observed.

Crystal structures of five gold(I) complexes with methyl­piperidine ligands

Five structures with methyl­piperidine ligands and gold(I) centres all exhibit linear geometry at the Au atom, and equatorial and axial positions, respectively, for the methyl groups and Au atoms at the piperidine rings. The packing involves hydrogen bonding and aurophilic inter­actions.

Synthesis and crystal structure of [1,3-bis­(2,6-diiso­propyl­phen­yl)imidazol-2-yl­idene](iso­cyanato-κN)gold(I)

The title complex was synthesized by ligand metathesis from [1,3-bis­(2,6-diiso­propyl­phen­yl)imidazol-2-yl­idene]gold(I) chloride and sodium cyanate in anhydrous tetra­hydro­furan and crystallized from toluene at 233 K as a neutral complex with the central Au atom di-coordinated by an N-heterocyclic carbene and an iso­cyanate, with a linear CAuNCO moiety.

Crystal structures of the alkali aluminoboracites A₄B₄Al₃O₁₂Cl (A = Li, Na)

Single crystals of cubic alkali aluminoboracites A₄B₄Al₃O₁₂Cl (A = Li, Na) were grown from a self-flux and their crystal structures were determined and compared in two space group types, F3c and F23. Na₄B₄Al₃O₁₂Cl is the first sodium boracite and its lattice parameter is the largest among boracites with a cation–oxygen framework.

Synthesis and crystal structure of diiso­thio­cyanato­tetra­kis­(4-methyl­pyridine N-oxide)cobalt(II) and diiso­thio­cyanato­tris­(4-methyl­pyridine N-oxide)cobalt(II) showing two different metal coordination polyhedra

In the crystal structure of the title compounds, the Co^II cations are either sixfold or fivefold coordinated by two thio­cyanate anions and four or three 4-methyl­pyridine N-oxide coligands within a slightly distorted octa­hedral or a trigonal–bipyramidal coordination polyhedron.

Synthesis, crystal structure and Hirshfeld surface analysis of sodium bis­(malonato)borate monohydrate

The asymmetric unit of the title salt, Na⁺·C₆H₄BO₈⁻·H₂O, com­prises a five-coordinate sodium cation, a bis­(malonato)borate anion and a water mol­ecule of crystallization.

Crystal structures and Hirshfeld surface analyses of methyl 4-{2,2-di­chloro-1-[(E)-phenyl­diazen­yl]eth­enyl}benzoate, methyl 4-{2,2-di­chloro-1-[(E)-(4-methyl­phen­yl)diazen­yl]ethen­yl}benzoate and methyl 4-{2,2-di­chloro-1-[(E)-(3,4-di­methyl­phen­yl)diazen­yl]ethen­yl}benzoate

In the crystal of methyl 4-{2,2-di­chloro-1-[(E)-phenyl­diazen­yl]ethen­yl}benzoate, mol­ecules are linked by C—H⋯N hydrogen bonds, forming chains with C(6) motifs parallel to the b axis. In methyl 4-{2,2-di­chloro-1-[(E)-(4-methyl­phen­yl)diazen­yl]ethen­yl}benzoate, mol­ecules are linked by C—H⋯O hydrogen bonds and C—Cl⋯π inter­actions, forming layers parallel to (010). In methyl 4-{2,2-di­chloro-1-[(E)-(3,4-di­methyl­phen­yl)diazen­yl]ethen­yl}benzoate, mol­ecules are linked by C—H⋯π and C—Cl⋯π inter­actions, forming chains parallel to [011].

Crystal structure and Hirshfeld surface analysis of (2E)-1-phenyl-3-(1H-pyrrol-2-yl)propen-1-one

In the title crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, forming ribbons parallel to (020) in zigzag C(7) chains along the a axis. These ribbons are connected via C—H⋯π inter­actions, forming a three-dimensional network.

A triclinic polymorph of miconazole

A second polymorphic form of solvent-free miconazole, a triclinic form (MIC-tri), is reported, and compared with the anhydrous monoclinic form of miconazole (MIC-mono).

(E)-N,N-Di­ethyl-4-{[(4-meth­oxy­phen­yl)imino]­meth­yl}aniline: crystal structure, Hirshfeld surface analysis and energy framework

In the title com­pound, a benzyl­ideneaniline Schiff base, the planes of the p-substituted aromatic rings subtend a dihedral angle of 46.01 (6)°.

Cadmium phosphates Cd₂(PO₄)OH and Cd₅(PO₄)₂(OH)₄ crystallizing in mineral structures

Cd₂(PO₄)OH and Cd₅(PO₄)₂(OH)₄ crystallize in the mineral structures of triplite and arsenoclasite, respectively.

(S)-(+)-1-(4-Bromo­phen­yl)-N-[(4-methoxyphen­yl)methyl­idene]ethyl­amine and bis­{(S)-(+)-1-(4-bromo­phen­yl)-N-[(4-methoxyphen­yl)methyl­idene]ethyl­amine-κN}di­chlorido­palladium(II)

The synthesis, crystal structure and analysis of a chiral Schiff base (S)-(+)-1-(4-bromo­phen­yl)-N-[(4-methoxyphen­yl)methyl­idene]ethyl­amine ligand along with its corresponding palladium(II) com­plex are detailed. The crystal structures exhibit monoclinic P2₁ and ortho­rhom­bic P2₁2₁2₁ symmetries, respectively. The structure of the palladium(II) com­plex reveals C—H⋯O and C—H⋯Br hydrogen-bonding inter­actions involving two distinct mol­ecules within the asymmetric unit.

Synthesis, crystal structure and Hirshfeld surface analysis of 2-({5-[(naphthalen-1-yl)meth­yl]-4-phenyl-4H-1,2,4-triazol-3-yl}sulfan­yl)-1-(4-nitro­phen­yl)ethanone

In the title compound, C₂₇H₂₀N₄O₃S, the three aromatic rings are oriented almost perpendicular to the plane of the central 1,2,4-triazole ring.

Crystal structure and Hirshfeld surface analysis of 4-(2-chloro­eth­yl)-5-methyl-1,2-di­hydro­pyrazol-3-one

In the crystal, mol­ecular pairs form dimers through N—H⋯O hydrogen bonds. These dimers are linked into ribbons parallel to the (100) plane by further N—H⋯O hydrogen bonds. In addition, π–π and C—Cl⋯π inter­actions between the ribbons form layers parallel to the (100) plane.

Crystal structure and characterization of a new lanthanide coordination polymer, [Pr₂(pydc)(phth)₂(H₂O)₃]·H₂O

The crystal structure and thermogravimetric stability of [Pr₂(pydc)(phth)₂(H₂O)₃]·H₂O, a two-dimensional coordination polymer with a novel coordination mode of pyridine-2,5-di­carboxyl­ate (pydc²⁻), are reported.

Crystal structure, Hirshfeld surface analysis, crystal voids, inter­action energy calculations and energy frameworks, and DFT calculations of 1-(4-methyl­benz­yl)in­doline-2,3-dione

In the crystal of 1-(4-methyl­benz­yl)in­do­line-2,3-dione, a layer structure is generated by C—H⋯O hydrogen bonds and C—H⋯π(ring), π-stacking and C=O⋯π(ring) inter­actions.

Crystal structure, Hirshfeld surface analysis, crystal voids, inter­action energy calculations and energy frameworks and DFT calculations of ethyl 2-cyano-3-(3-hy­droxy-5-methyl-1H-pyrazol-4-yl)-3-phen­ylpropano­ate

In the title mol­ecule, the five- and six-membered rings are oriented at a dihedral angle of 75.88 (8)°. In the crystal, N—H⋯N hydrogen bonds form chains of mol­ecules extending along the c-axis direction that are connected by inversion-related pairs of O—H⋯N into ribbons. The ribbons are linked by C—H⋯π(ring) inter­actions, forming layers parallel to the ab plane.