Joel Bernstein: a crystal engineer's crystal engineer

Joel Bernstein was a gentle giant in the field of organic solid-state chemistry and a person who inspired anyone who was in his presence and attended his charismatic lectures over the five decades of his academic career. This commentary looks at his scientific publishing career.

The design of novel metronidazole benzoate structures: exploring stoichiometric diversity

The imidazole–hy­droxy synthon was explored by combining benzoyl­metronidazole with several coformers containing phenol and carb­oxy­lic acid groups. Based on a rational design strategy, two salts and eleven cocrystals were obtained, with predefined stoichiometries (1:1, 2:1 and 3:1).

One-dimensional copper(II) coordination polymers based on 1,3-bis­(pyridin-4-yl)propane and di­imine ligands

Two one-dimensional coordination polymers have been synthesized using [Cu(NO₃)(NN)(H₂O)]NO₃, where NN is 2,2′-bi­pyridine or 1,10-phenanthroline, with 1,3-bis­(pyridin-4-yl)propane as a linker, and have been structurally characterized.

A fourfold inter­penetrating diamond-like three-dimensional zinc(II) coordination polymer: synthesis, crystal structure and physical properties

A zinc(II) compound, prepared by reaction of Zn(NO₃)₂·6H₂O with furan-2,5-di­carb­oxy­lic acid and bis­[4-(2-methyl-1H-imidazol-1-yl)phen­yl] ether, possesses a fourfold inter­penetrating diamond-like three-dimensional framework. The compound exhibits a strong fluorescence emission in the solid state at room temperature.

A 4′-(4-carb­oxy­phen­yl)-3,2′:6′,3′′-terpyridine-based luminescent cadmium(II) coordination polymer for the detection of 2,4,6-tri­nitro­phenol

The two-dimensional coordination polymer poly[bis­[μ-4-(3,2′:6′,3′′-terpyridin-4′-yl)benzoato]cadmium(II)] displays strong luminescence and good thermal stability, indicating that it can potentially be used as a luminescence sensor. The compound also shows a highly selective and sensitive response to 2,4,6-tri­nitro­phenol through the luminescence quenching effect.

The rich crystal chemistry of the AMM′(PO₄)₂ morphotropic series: NaZnAl(PO₄)₂, the first Na representative with a new structure type

NaZnAl(PO₄)₂ was synthesized hydro­thermally and refined in the space group P2₁/c (C_2h⁵). The new phosphate presents a first sodium member of the AMM′PO₄ morphotropic series and demonstrates an original structure type.

A triangular palladium(II) supra­molecular coordination complex based on 1,4-bis­(1H-imidazol-1-yl)benzene and (2,2′-bipyrid­yl)palladium(II) nitrate: synthesis and crystal structure

The self-assembly of ditopic bis­(1H-imidazol-1-yl)benzene ligands and the palladium(II) complex [Pd(NO₃)₂(2,2′-bi­pyridine)] affords a supra­molecular coordination complex in the form of a triangular Pd₃ framework associated with PF₆⁻ counter-ions and aceto­nitrile solvent mol­ecules.

Asymmetric diosmium sawhorse complexes

The crystal structures of eight diosmium(I) carbonyl sawhorse complexes are reported, two with two axial CO ligands, two with one axial CO ligand and one axial phosphane ligand, and four with two axial phosphane ligands. One of the latter complexes also has two different bridging carboxyl­ate groups and is the first example of a sawhorse complex with mixed carboxyl­ate ligands.

The crystal and mol­ecular structures of three copper-containing complexes and their activities in mimicking galactose oxidase

The structures of three copper-containing complexes are reported and tests for their activity in the oxidation of D-galactose suggest that, unlike the enzyme galactose oxidase, due to the precipitation of Cu₂O, this reaction is not catalytic as would have been expected.

Crystal structures and properties of two hydrated conglomerate forms of the heart-rate-lowering agent ivabradine hydro­chloride

The crystal structures of two hydrated conglomerate forms of ivabradine hydro­chloride are described. The stabilities of the two crystal forms are experimentally and theoretically investigated.

The effect of water-mediated catalysis on the intra­molecular proton-transfer reactions of the isomers of 5-chloro­uracil: a theoretical study

The geometrical structures and thermal energies, enthalpies and Gibbs free energies of 13 isomers of 5-chloro­uracil (5ClU) in the gas and water phases were investigated using the density functional theory (DFT) method. The results indicate that the catalytic effect of two H₂O mol­ecules is much greater than that of one H₂O mol­ecule in isomerizations of 5ClU.

Structural analysis of Gd₆FeBi₂ from single-crystal X-ray diffraction methods and electronic structure calculations

The crystal structure of the ternary phase Gd₆FeBi₂ is established from single-crystal X-ray diffraction data and the structural details are used to understand its high magnetic-ordering temperature. The combined structural analysis and first-principles electronic structure calculations suggest the enhanced magnetic-exchange inter­actions to be due to the significant Gd 5d–Fe 3d hybridization. Strong Gd—Gd bonding is present in this Gd-rich material, but the Gd—Bi inter­actions are shown to be weak.

More crystal field theory in action: the metal–4-picoline (pic)–sulfate [M(pic)_x]SO₄ complexes (M = Fe, Co, Ni, Cu, Zn, and Cd)

Crystal structures of first-row transition metal (Fe, Co, Ni, Cu, and Zn) and cadmium–4-picoline (pic) complexes of the form [M(pic)_x]SO₄ are presented. The structural variation of the complexes in relation to crystal field theory and the related pyridine structures is discussed.

Cadmium(II) three-dimensional coordination polymers constructed from 1,3,5-tris­(4-carb­oxy­phen­oxy)benzene: synthesis, crystal structure, fluorescence and I₂ sorption characterization

Two three-dimensional Cd^II coordination polymers (CPs) were obtained by the hydro­thermal method under similar conditions except for the presence of an auxiliary 1,4-bis­(imidazol-1-yl)benzene ligand in one of them. It was found that mol­ecular I₂ can move in and out of this latter CP freely without changes to the skeleton.

Crystal structure variations in the series SrLnCuS₃ (Ln = La, Pr, Sm, Gd, Er and Lu)

In the crystal structures of the complex sulfides SrLnCuS₃, as the ionic radius (Ln³⁺) decreases, the structure type changes consecutively in the order BaLaCuS₃ (La, Pr) → Eu₂CuS₃ (Sm, Gd) → KZrCuS₃ (Er, Lu).

Structural and spectroscopic investigations on the quenching free luminescence of europium oxalate nanocrystals

The structural features leading to the intense quenching free luminescence exhibited by europium oxalate nanocrystals is the focal point of this report. The various spectroscopic parameters were evaluated by Judd–Ofelt theoretical analysis and the results are discussed on the basis of crystal structure analysis.

Completing the picture of tolaza­mide polymorphism under extreme conditions: a low-temperature study

The detailed study of the polymorphs of tolaza­mide on cryogenic cooling has completed previous research on the same compound on hydro­static compression.