Shedding new light on quadrupolar 1,4-dihydropyrrolo[3,2-]pyrroles: impact of electron-deficient scaffolds over emission.

In this work, we disclose a series of seven quadrupolar centrosymmetric 1,4-dihydropyrrolo[3,2-]pyrroles (DHPPs) linked to the two peripheral, strongly electron-accepting heterocycles such as benzoxadiazole, benzothiadiazole and benzoselenadiazole. This represents the first study probing the influence of electron-deficient heterocycles, rather that small electron-withdrawing substituents, on photophysics of DHPPs. These new acceptor-donor-acceptor hybrid dyes exhibit an appreciable combination of photophysical properties including absorption maxima in the range of 470-620 nm, and emission in the range of 500-720 nm with fluorescence quantum yields reaching 0.

Nanosecond-Lived Excimer Observation in a Crystal of a Rhodium(I) Complex via Time-Resolved X-ray Laue Diffraction.

The rare observation of transient Rh···Rh excimer formation in a single crystal is reported. The estimated excited-state lifetime at 100 K is 2 ns, which makes it the shortest-lived small-molecule species caught experimentally using the laser-pump/X-ray-probe time-resolved Laue method. Upon excitation with 390 nm laser light, the intermolecular Rh···Rh distance decreases from 3.

Pressure-induced single-crystal-to-single-crystal nitrite ligand isomerisation accompanied by a piezochromic effect.

High-pressure structural study of a piezochromic crystal of a rare di--nitrito nickel(II) complex supported by computational analysis is presented. The examined system is not photoswitchable, however, in the 0-6.2 GPa pressure range the crystal undergoes two phase-transitions accompanied by a colour change and the nitrite ligand isomerisation, which is unique.

Correction: Porous oligomeric materials synthesised using a new, highly active precatalyst based on ruthenium(III) and 2-phenylpyridine.

Correction for 'Porous oligomeric materials synthesised using a new, highly active precatalyst based on ruthenium(III) and 2-phenylpyridine' by Kacper Pobłocki , , 2024, , 4194-4203, https://doi.org/10.1039/D3DT04091G.

Porous oligomeric materials synthesised using a new, highly active precatalyst based on ruthenium(III) and 2-phenylpyridine.

There are few literature reports on using precatalysts based on ruthenium(II/III) ions in the polymerization of olefins. Therefore, a new coordination compound was designed based on ruthenium(III) ion and 2-phenylpyridine. The resulting monocrystal was characterized by X-ray diffraction (XRD), solid-state (photo)IR spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA).

Interrelations between Linkage Isomers of an Efficient Square-planar Nickel(II) Nitrite Photoswitch in the Solid State.

An efficient nitrite nickel(II) photoswitch, with the 1-phenyl-2-hydroxyimino-3-[(2'-dimethylamino)ethyl]imino-1-propanone moiety used as the ancillary ligand, is reported. In the ground-state ('dark') crystal structure, the studied compound exists predominantly as the nitro-(η -N(O) ) isomer, however, traces of the exo- and endo-nitrito-(η -ONO) forms are detected both at 100 K (4-5 % each) and under ambient conditions (~9 % each). When excited with the 405-530 nm LED light, the nitro-to-nitrito isomerization takes place.

Catalytic Properties of Two Complexes of chromium(III) and cobalt(II) with Nitrilotriacetate, Dipicolinate, and 4-Acetylpyridine.

In this paper, a synthesis of two innovative coordination compounds, based on chromium(III) and cobalt(II) ions with N,O-donor ligands (nitrilotriacetate, dipicolinate) and 4-acetylpyridine, is reported. The obtained metal-organic compounds were structurally characterized using the single-crystal X-ray diffraction (XRD) method. The well-defined chromium(III) and cobalt(II) complexes were used as precatalysts in the oligomerization reaction of 2-chloro-2-propen-1-ol and 2-propen-1-ol with methylaluminoxane (MMAO) as an activator.

Correction: An optically reversible room-temperature solid-state cobalt(III) photoswitch based on nitro-to-nitrito linkage isomerism.

Correction for 'An optically reversible room-temperature solid-state cobalt(III) photoswitch based on nitro-to-nitrito linkage isomerism' by Krystyna A. Deresz , , 2022, , 13439-13442, https://doi.org/10.

An optically reversible room-temperature solid-state cobalt(III) photoswitch based on nitro-to-nitrito linkage isomerism.

A simple trinitro cobalt complex [Co(3,3'-diamino--methylpropanediamine)(NO)] was proven to be photoswitchable at room temperature as the 2 polymorph with the maximum nitro-to-nitrito conversion reaching 55%. Solid-state IR, UV-vis and XRD indicate that the transformation can be triggered optically in both ways 470 nm and 570-660 nm LED light, respectively.

Exploring Photoswitchable Properties of Two Nitro Nickel(II) Complexes with (,,)-Donor Ligands and Their Copper(II) Analogues.

Two photoswitchable nickel(II) nitro coordination compounds and their copper(II) analogues are reported. In all these systems, the metal center is chelated by (,,)-donor ligands containing either 2-picolylamine or 8-aminoquinoline fragments. The studied compounds were thoroughly investigated using crystallographic and spectroscopic techniques supplemented by computational analysis.

Photocrystallographic and spectroscopic studies of a model (N,N,O)-donor square-planar nickel(II) nitro complex: in search of high-conversion and stable photoswitchable materials.

A new, cheap, easy-to-synthesize and air-stable photoswitchable nickel(II) complex, QTNiNO, is reported. The metal centre in QTNiNO is coordinated by a nitro group and a [2-methyl-8-amino-quinoline]-1-tetralone ligand. The compound crystallizes in the tetragonal space group 4/ with one complex molecule comprising the asymmetric unit, and the crystals are stable under ambient conditions.

Instrument-model refinement in normalized reciprocal-vector space for X-ray Laue diffraction.

A simple yet efficient instrument-model refinement method for X-ray diffraction data is presented and discussed. The method is based on least-squares minimization of differences between respective normalized ( unit length) reciprocal vectors computed for adjacent frames. The approach was primarily designed to work with synchrotron X-ray Laue diffraction data collected for small-molecule single-crystal samples.

Boronate Covalent and Hybrid Organic Frameworks Featuring P and P=O Lewis Base Sites.

Invited for the cover of this issue is Sergiusz Luliński and his co-workers from Warsaw University of Technology and University of Warsaw. The image depicts a journey through the interior of the porous Covalent Organic Framework containing phosphorus and boron centres with carbon dioxygen trapped inside an imagined cave. Read the full text of the article at 10.

Formylation of a metathesis-derived [4]-ferrocene: a simple route to anticancer organometallics.

Formylation of ansa[4]-ferrocene, obtained through the ruthenium-catalysed olefin metathesis, yields two separable, planar chiral 1,3- and 1,2-ansa-ferrocene aldehydes. Single-crystal X-ray structure analysis reveals that both regioisomers crystallize with spontaneous resolution of the racemate in the chiral P212121 space group with one molecule in the asymmetric unit. The major 1,3-isomer was further transformed into a conjugate with 1,2,3-triazole and uracil using "click" chemistry as the key synthetic step.

Boronate Covalent and Hybrid Organic Frameworks Featuring P and P=O Lewis Base Sites.

Two covalent organic frameworks comprising Lewis basic P centers and Lewis acidic boron atoms were prepared by poly-condensation reactions of newly obtained tris(4-diisopropoxyborylphenyl)phosphine with 2,3,6,7,10,11-hexahydroxytriphenylene and 2,3,6,7-tetrahydroxy-9,10-dimethylanthracene. Obtained materials exhibit significant sorption of dihydrogen (100 cm  g at 1 bar at 77 K), methane (20 cm  g at 1 bar at 273 K) and carbon dioxide (50 cm  g at 1 bar at 273 K). They were exploited as solid-state ligands for coordination of Pd centers.

Seed-skewness algorithm for X-ray diffraction signal detection in time-resolved synchrotron Laue photocrystallography.

A one-dimensional seed-skewness algorithm adapted for X-ray diffraction signal detection is presented and discussed. The method, primarily designed for photocrystallographic time-resolved Laue data processing, was shown to work well for the type of data collected at the Advanced Photon Source and European Synchrotron Radiation Facility. Nevertheless, it is also applicable in the case of standard single-crystal X-ray diffraction data.

Photo- and Thermoswitchable Half-Sandwich Nickel(II) Complex: [Ni(η-CH)(IMes)(η-NO)].

A new photoswitchable half-sandwich nitro Ni complex with the N-heterocyclic carbene ligand was synthesized and successfully crystallized. The compound constitutes an analogue of a known nitrate nickel(II) compound, [Ni(η-Cp)(IMes)(NO)] (Cp = cyclopentadienyl, CH; IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene), and crystallizes with two symmetry-independent molecules in the asymmetric unit. When irradiated with 470 nm light-emitting diode light, the complex molecules undergo a photoisomerization reaction in the solid state.

Impact of High Pressure on Metallophilic Interactions and Its Consequences for Spectroscopic Properties of a Model Tetranuclear Silver(I)-Copper(I) Complex in the Solid State.

Structure-property relationships were investigated via combined high-pressure spectroscopic and X-ray diffraction techniques for a model luminescent AgCuL (L = 2-diphenylphosphino-3-methylindole) complex in the crystalline state. The experimental results were contributed by theoretical calculations, compared with the previously evaluated light-induced geometrical changes, and discussed in the context of available literature to date. To the best of our knowledge, this is the first study of this kind devoted to a coinage-metal complex for which the argentophilic interactions are crucial.

Ground-State Charge-Density Distribution in a Crystal of the Luminescent ortho-Phenylenediboronic Acid Complex with 8-Hydroxyquinoline.

This contribution is devoted to the first electron density studies of a luminescent oxyquinolinato boron complex in the solid state. ortho-Phenylenediboronic acid mixed with 8-hydroxyquinoline in dioxane forms high-quality single crystals via slow solvent evaporation, which allows successful high resolution data collection (sin θ/λ = 1.2 Å) and charge density distribution modeling.

Multi-temperature study of potassium uridine-5'-monophosphate: electron density distribution and anharmonic motion modelling.

Uridine, a nucleoside formed of a uracil fragment attached to a ribose ring via a β-N1-glycosidic bond, is one of the four basic components of ribonucleic acid. Here a new anhydrous structure and experimental charge density distribution analysis of a uridine-5'-monophosphate potassium salt, K(UMPH), is reported. The studied case constitutes the very first structure of a 5'-nucleotide potassium salt according to the Cambridge Structural Database.

Axially chiral racemic half-sandwich nickel(ii) complexes by ring-closing metathesis.

A remarkable nickelacycle has been synthesised via olefin metathesis of the α,ω-diene complex [Ni(η-CHR)(Br)(NHC)] (R = C(CH)CHCH[double bond, length as m-dash]CH, NHC = 1-(6-hexenyl)-3-(2,4,6-trimethylphenyl)-imidazol-2-ylidene). Single-crystal X-ray analysis reveals a helical shape of the molecule and stretching of some interatomic distances in the Ni(ii) coordination sphere. The Cp-NHC tethered complex shows catalytic activity resembling that of the parent complexes.

First experimental charge density study using a Bruker CMOS-type PHOTON 100 detector: the case of ammonium tetraoxalate dihydrate.

The aim of this study was to test the applicability of a Bruker AXS CMOS-type PHOTON 100 detector for the purpose of a fine charge density quality data collection. A complex crystal containing oxalic acid, ammonium oxalate and two water molecules was chosen as a test case. The data was collected up to a resolution of 1.

Shedding light on the photochemistry of coinage-metal phosphorescent materials: a time-resolved Laue diffraction study of an Ag(I)-Cu(I) tetranuclear complex.

The triplet excited state of a new crystalline form of a tetranuclear coordination d(10)-d(10)-type complex, Ag2Cu2L4 (L = 2-diphenylphosphino-3-methylindole ligand), containing Ag(I) and Cu(I) metal centers has been explored using the Laue pump-probe technique with ≈80 ps time resolution. The relatively short lifetime of 1 μs is accompanied by significant photoinduced structural changes, as large as the Ag1···Cu2 distance shortening by 0.59(3) Å.

Anharmonicity and isomorphic phase transition: a multi-temperature X-ray single-crystal and powder diffraction study of 1-(2'-aminophenyl)-2-methyl-4-nitroimidazole.

The harmonic model of atomic nuclear motions is usually enough for multipole modelling of high-resolution X-ray diffraction data; however, in some molecular crystals, such as 1-(2'-aminophenyl)-2-methyl-4-nitro-1H-imidazole [Paul, Kubicki, Jelsch et al. (2011 ▶). Acta Cryst.