Pyridine Solution Research Articles

Host–Guest Complexations of a Diastereoisomeric Mixture of cis- and trans-1,4-Bis(diphenylhydroxymethyl)cyclohexane in Pyridine and Methylpyridine Solutions: Significant Inclusion Selectivities and an Uncommon Host Conformation

Host–Guest Complexations of a Diastereoisomeric Mixture of <i>cis-</i> and <i>trans</i>-1,4-Bis(diphenylhydroxymethyl)cyclohexane in Pyridine and Methylpyridine Solutions: Significant Inclusion Selectivities and an Uncommon Host Conformation

Air-Stable Cobalt(III) and Chromium(III) Complexes as Single-Component Catalysts for the Activation of Carbon Dioxide and Epoxides.

Cobalt(III) and chromium(III) salophen chloride complexes were synthesized and tested for the cycloaddition of carbon dioxide (CO2) with epoxides to obtain cyclic carbonates. The cat1, cat2, cat4, and cat5 complexes presented high catalytic activity without cocatalysts and are solvent-free at 100 °C, 8 bar, and 9 h. At these conditions, the terminal epoxides (1a-1k) were successfully converted into the corresponding cyclic carbonates with a maximum conversion of ∼99%. Moreover, cat5 was highlighted due to its capability of opening internal epoxides such as limonene oxide (1l) with a 36% conversion to limonene carbonate (2l), and from cyclohexene oxide (1m), cyclic trans-cyclohexene carbonate (2m) and poly(cyclohexene carbonate) were obtained with 15% and 85% selectivity, respectively. A study of the coupling reaction mechanism was proposed with the aid of electrospray ionization mass spectrometry (ESI-MS) analysis, confirming the single-component behavior of the complexes through their ionization due to epoxide coordination. In addition, crystallographic analysis of cat1 single crystals grown in a saturated solution of pyridine helped to demonstrate that the substitution of chloride ion by pyridine ligands to form an octahedral coordination occurs (Py-cat1), supporting the proposed mechanism. Also, a recyclability study was performed for cat5, and a total turnover number of 952 was obtained with only minor losses in catalytic activity after five cycles.

Probing the Fermi resonance of pyridine surrounded by hydrogen bonding network by density functional theory

The Fermi resonance (FR) occurs between the ring breathing vibrational (ν1) and the triangular stretching (ν12) mode of pyridine in aqueous pyridine solution was studied using Raman spectroscopy combined with density functional theory (DFT) calculations. The effect of H-Bond on the FR in the mixture was performed by MD analysis. Combined with the FR parameters, it was found that due to the H-Bond effect the FR coupling changed significantly when the pyridine mole fractions were near 0.7 and 0.5, respectively. The water H-Bond network structure is most favorable for pyridine molecule bonding at a pyridine mole concentration around 0.5, and water preferentially affinity to the pyridine molecule at x = 0.7. In addition, we analyzed the OH vibrational region at different mole fractions and theoretically calculated Py associated OH in specific molecular bonds.

O-doped g-C3N4 prepared in pyridine for efficiently photocatalytic hydrogen production

ABSTRACT Oxygen-doped g-C3N4 with pyridine ring (POCN) was synthesized by easily thermal polymerization of urea, pyridine solution, and ammonium acetate to improve photocatalytic hydrogen production. The experimental results indicate that pyridine was incorporated into the tri-s-triazine structure of g-C3N4. The O atoms were modified to g-C3N4 by replacing the N atoms (C–N=C) of the triazine ring. The photocatalytic activity for the hydrogen production rate of optimized POCN was 1018 µmol g–1 h–1, approximately 30 times higher than that of bulk g-C3N4 (CN) under visible light irradiation (λ > 420 nm). The high stability of POCN was confirmed through cycling tests for 30-h, XRD patterns, and SEM images. The pyridine incorporation can significantly enhance surface charge transfer efficiency. The oxygen modification can greatly promote visible light absorption (600 nm) and photogenerated electron–hole pairs separation. This work provides a suitable strategy to synthesize g-C3N4 based on metal-free photocatalysts for highly efficient photocatalytic hydrogen generation performance.

Molecular Modeling Study of Bis-sulfonamide Derivatives Synthesis Targeting Aromatase Enzyme as Anticancer

Most studies indicate the important role of estrogen in the mechanism of occurrence and development of breast cancer. The importance of our research is the synthesis of bis-sulfonamide compounds that inhibit the aromatase enzyme, which is the main enzyme in the biosynthesis of estrogen. Molecular modeling of studied compounds was carried out by Molegro Virtual Docker (MVD) targeting aromatase enzyme and binding energy calculated to select the most encouraging compound. The highest binding energy among the studied compounds was -118.52 kcal/mol (compound A5) comparing with the aromatase substrate androstenedione -132.51 kcal/mol and the aromatase inhibitor letrozole -136.52 kcal/mol. Several of these compounds were synthesized in a simple way with good yields by reacting sulfonyl chloride derivatives with amino derivatives in an alkaline aqueous solution, or in a pyridine solution. The physicochemical characteristics and identification of synthesized compounds were determined by various analytical methods such as Mass spectrometry, Infrared spectroscopy and Nuclear Magnetic Resonance.

Daylight-driven catalytic removal of pyridine over Ag-embedded ZnO porous nanosheets

Structure of heterogeneous photocatalyst with adequate coupling interface has an important effect on energy transfer and photoinduced electron-hole pairs separation. In this work, Ag-embedded ZnO heterogeneous porous nanosheets (PNSs) have been synthesized by thermal pyrolyzing of Ag2CO3-modified Zn5(CO3)2(OH)6 nanosheets at 400 °C. Photoelectron spectra and X-ray diffraction measurements demonstrate that there exists an adequate coupling between Ag and ZnO phase. Ag-embedded ZnO PNSs, in contrast to bare ZnO PNSs, performs 6-fold enhancement in natural-daylight-driven degradation of pyridine which requires participation of ·OH radicals. This result demonstrates that the adequate coupling interface between Ag and ZnO for Ag-embedded ZnO PNSs promotes an energy transfer from local surface plasma resonance of Ag nanoparticles to bound excitons in ZnO region, activating them to dissociate into free photoinduced carriers. In addition, external control experiments indicate that the best photocatalytic degradation is obtained in the 7–10 pH range of 10 mg/L pyridine solution in presence of 0.5 g/L photocatalyst dosage. The optimal Ag-embedded ZnO PNSs under outdoor daylight irradiation also performs an efficiently photocatalytic degradability for pyridine present in ground water. Our work provides a new approach to fabricate ZnO-based photocatalyst with efficient energy transfer for treating stubborn organics present in polluted water.

Synthesis and Characterization of Homoleptic Zintl Anions [(Pn7)M(Pn7)]4− (M/Pn=Pb/As, Zn/Bi)

AbstractThe formation and follow‐up chemistry of P73− has been intensely studied in the recent decades. In contrast, corresponding investigations of its heavier polycyclic polypnictide congeners Pn73− (Pn=As, Sb, Bi), especially Bi73−, have been done to a much lesser extent. In our report, we add to these rare studies, by reporting new coordination compounds with As73− and Bi73−, respectively. Addition of PbI2 to a solution of K3As7 in ethane‐1,2‐diamine (en) afforded the heterometallic cluster anion [(As7)Pb(As7)]4− (with an 8 % co‐crystallization of [PbAs15]3− on the same site), in compound [K3.92(crypt‐222)4][(As7)Pb(As7)]0.92[PbAs15]0.08 ⋅ 3en (1). A similar reaction of [ZnPh2] with a pyridine (py) solution of the ternary solid ‘K5Ga2Bi4’, which was previously shown to release Ga and polybismuthide units in situ under certain reaction conditions, resulted in the formation of [K(crypt‐222)]4[(Bi7)Zn(Bi7)] ⋅ 2.5py (2), comprising the related heterometallic anion [(Bi7)Zn(Bi7)]4−. The former represents the first Pb−As binary Zintl anions obtained via solution chemistry, and the latter adds one more piece to the remarkably rare coordination compounds reported for Bi73−.

Tensile and Surface Wettability Properties of the Solvent Cast Cellulose Fatty Acid Ester Films.

Thermoplastic cellulose esters are promising materials for bioplastic packaging. For that usage, it is important to understand their mechanical and surface wettability properties. In this study, a series of cellulose esters are prepared, such as laurate, myristate, palmitate, and stearate. The aim of the study is to investigate the tensile and surface wettability properties of the synthesized cellulose fatty acid esters to understand their suitability as a bioplastic packaging material. Cellulose fatty acid esters are first synthesized from microcrystalline cellulose (MCC), then dissolved in pyridine solution, and after the solvent cast into thin films. The cellulose fatty acid ester acylation process is characterized by the FTIR method. Cellulose esters hydrophobicity is evaluated with contact angle measurements. The mechanical properties of the films are tested with the tensile test. For all the synthesized films, FTIR provides clear evidence of acylation by showing the presence of characteristic peaks. Films' mechanical properties are comparable to those of generally used plastics such as LDPE and HDPE. Furthermore, it appears that with an increase in the side-chain length, the water barrier properties showed improvement. These results show that they could potentially be suitable materials for films and packaging materials.

Metabolomics analysis of plasma samples of patients with fibromyalgia and electromagnetic sensitivity using GC–MS technique

Fibromyalgia (FM) is a chronic and systemic condition that causes widespread chronic pain, asthenia, and muscle stiffness, as well as in some cases depression, anxiety, and disorders of the autonomic system. The exact causes that lead to the development of FM are still unknown today. In a percentage of individuals, the symptoms of FM are often triggered and/or exacerbated by proximity to electrical and electromagnetic devices. Plasma metabolomic profile of 54 patients with fibromyalgia and self-reported electromagnetic sensitivity (IEI-EMF) were compared to 23 healthy subjects using gas chromatography-mass spectrometry (GC–MS) coupled with multivariate statistical analysis techniques. Before the GC–MS analysis the plasma samples were extracted with a modified Folch method and then derivatized with methoxamine hydrochloride in pyridine solution and N-trimethylsilyltrifuoroacetamide. The combined analysis allowed to identify a metabolomic profile able of distinguishing IEI-EMF patients and healthy subjects. IEI-EMF patients were therefore characterized by the alteration of 19 metabolites involved in different metabolic pathways such as energy metabolism, muscle, and pathways related to oxidative stress defense and chronic pain. The results obtained in this study complete the metabolomic "picture" previously investigated on the same cohort of IEI-EMF patients with 1H-NMR spectroscopy, placing a further piece for better understanding the pathophysiological mechanisms in patients with IEI-EMF.

Polymer Gel with Tunable Conductive Properties: A Material for Thermal Energy Harvesting.

The spontaneous gelation of poly(4-vinyl pyridine)/pyridine solution produces materials with conductive properties that are suitable for various energy conversion technologies. The gel is a thermoelectric material with a conductivity of 2.2-5.0 × 10-6 S m-1 and dielectric constant ε = 11.3. On the molecular scale, the gel contains various types of hydrogen bonding, which are formed via self-protonation of the pyridine side chains. Our measurements and calculations revealed that the gelation process produces bias-dependent polymer complexes: quasi-symmetric, strongly hydrogen-bonded species, and weakly bound protonated structures. Under an applied DC bias, the gelled complexes differ in their capacitance/conductive characteristics. In this work, we exploited the bias-responsive characteristics of poly(4-vinyl pyridine) gelled complexes to develop a prototype of a thermal energy harvesting device. The measured device efficiency is S = ΔV/ΔT = 0.18 mV/K within the temperature range of 296-360 K. Investigation of the mechanism underlying the conversion of thermal energy into electric charge showed that the heat-controlled proton diffusion (the Soret effect) produces thermogalvanic redox reactions of hydrogen ions on the anode. The charge can be stored in an external capacitor for heat energy harvesting. These results advance our understanding of the molecular mechanisms underlying thermal energy conversion in the poly(4-vinyl pyridine)/pyridine gel. A device prototype, enabling thermal energy harvesting, successfully demonstrates a simple path toward the development of inexpensive, low-energy thermoelectric generators.

BiCuI4(Pyridine)5 a neutral ligand-supported compound of BiI3 and CuI

Reaction of equimolar pyridine (Py) solutions BiI3 and CuI produces the Py-supported 1:1 bimetallic complex BiCuI4(Py)5 in quantitative yield. The title complex is only the second neutral complex to feature Cu−I−Bi bridging and shows an octahedral trans-[BiI4(Py)2] unit joined to a distorted tetrahedral CuI(Py)3 unit by an iodide bridge. The complex shows low thermal stability, decomposing under modest heating or vacuum to produce a mixture of BiI3 and CuI. Thus, it is a potential entry/precursor to BiI3/CuI chemistry. Natural Localized Molecular Orbital (NLMO) calculations were performed to analyze the nature of the Cu−I−Bi bonds, revealing that the title compound lies on the cusp of being [Cu(Py)3]+[BiI4(Py)2]−. Diffuse reflectance spectroscopy measurements show a strong absorption band with an optical bandgap energy of 1.94 eV. Theoretical density of states (DOS) and time-dependent density functional theory (TD-DFT) experiments to map the electronic structure assign the primary electronic transition as a mixed halide/metal-to-ligand charge transfer between Cu−I−Bi donor orbitals and Py π* acceptor orbitals.

A Neutral Heteroleptic Molybdenum Cluster trans-[{Mo6I8}(py)2I4

Despite that the chemistry of octahedral cluster complexes has been actively developed recently, there are still a lot of unexplored areas. For example, to date, only a few halide M6-clusters with N-heterocycles are known. Here, we obtained an apically heteroleptic octahedral iodide molybdenum cluster complex with pyridine ligands—trans-[{Mo6I8}(py)2I4] by the direct substitution of iodide apical ligands of [{Mo6I8}I6]2– in a pyridine solution. The compound co-crystalized with a monosubstituted form [{Mo6I8}(py)I5]– in the ratio of 1:4, and thus, can be described by the formula (pyH)0.2[{Mo6I8}(py)1.8I4.2]·1.8py. The composition was studied using XRPD, elemental analyses, and 1H-NMR and IR spectroscopies. According to the absorption and luminescence data, the partial substitution of apical ligands weakly affects optical properties.

Self-Assembled Fluorescent Block Copolymer Micelles with Responsive Emission.

Responsive fluorescent materials offer a high potential for sensing and (bio‐)imaging applications. To investigate new concepts for such materials and to broaden their applicability, the previously reported non‐fluorescent zinc(II) complex [Zn(L)] that shows coordination‐induced turn‐on emission was encapsulated into a family of non‐fluorescent polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) diblock copolymer micelles leading to brightly emissive materials. Coordination‐induced turn‐on emission upon incorporation and ligation of the [Zn(L)] in the P4VP core outperform parent [Zn(L)] in pyridine solution with respect to lifetimes, quantum yields, and temperature resistance. The quantum yield can be easily tuned by tailoring the selectivity of the employed solvent or solvent mixture and, thus, the tendency of the PS‐b‐P4VP diblock copolymers to self‐assemble into micelles. A medium‐dependent off–on sensor upon micelle formation could be established by suppression of non‐micelle‐borne emission background pertinent to chloroform through controlled acidification indicating an additional pH‐dependent process.

Solubility, Phase Equilibria, and Critical Phenomena in the Ternary KBr + H2O + C5H5N System from T = 283.15 to 363.15 K

The solubility of components, phase equilibria, and critical phenomena in the potassium bromide + water + pyridine system were investigated from T = 283.15 to 363.15 K by the visual polythermal method. KBr delaminates water–pyridine solutions above 323.75 K. The formation temperature of the critical tie line of the monotectic state (323.75 K) and the compositions of the solutions corresponding to the critical solubility points of liquid–liquid equilibrium at three temperatures were determined. The distribution coefficients Kd of pyridine between the organic and aqueous phases of the monotectic state at 328.15, 343.15, and 363.15 K were calculated. The salting-out effect of KBr relative to pyridine from solutions is shown to be enhanced with an increase in the temperature. A comparative analysis of the results of our polythermal study of the salting-out action of potassium salts (iodide, bromide, nitrate, and chloride) on the binary water + pyridine system was done. It has been found that a decrease in the crystallographic radius of the salt anion in the KI–KBr–KNO3–KCl series leads to a decreased formation temperature of the critical tie line of the monotectic state of the ternary salt + water + pyridine systems and an enhanced salting-out effect of pyridine from aqueous solutions.

Hierarchical Co3(PO4)2/CuI/g-CnH2n-2 S-Scheme Heterojunction for Efficient Photocatalytic Hydrogen Evolution.

Graphdiyne (GD), a new type of carbon allotrope formed by sp and sp2 hybrid carbon atoms, has attracted wide attention due to its high π-conjugation degree, special band structure, and uniformly distributed pores. In traditional synthesis methods, hexaethylbenzene was coupled on the substrate catalytic material (copper foil or foamed copper) to generate graphdiyne. In this work, CuI was used as the substrate catalytic material, and the CuI-GD composite was synthesized by cross-coupling in the pyridine solution of hexaethylbenzene. For the first time, Co3(PO4)2 was modified by the CuI-GD composite material to prepare a Co3(PO4)2/CuI-GD S-scheme heterojunction catalyst, which avoided the complicated process of removing the substrate catalytic material. Under the action of the internal electric field, electrons are induced to move quickly and directionally, and the powerful photogenerated electrons in the conduction band (CB) of GD and the holes in the valence band (VB) of CuI are retained to participate in the photocatalytic reaction. These advantages were combined with the high-energy acetylene bond in GD, which accelerated the catalytic reaction of the Co3(PO4)2/CuI-GD heterostructure. Electrochemical and fluorescence analysis showed that Co3(PO4)2/CuI-GD has faster electron and hole separation efficiency, lower hydrogen evolution overpotential, and higher carrier utilization. Therefore, Co3(PO4)2/CuI-GD exhibited good hydrogen evolution activity. This work shows that GD has broad prospects in designing high-performance photocatalyst systems.

Bis(CBT)palladium(II) Derivatives (CBT = m-carborane-1-thiolate): Synthesis, Molecular Structure, and Physicochemical Properties of cis-[(bipy)Pd(CBT)2] and trans-[(py)2Pd(CBT)2

The new synthesized PdII complex cis-[(bipy)Pd(CBT)2] (bipy = 2,2'-bipyridyl; CBT = m-carborane-1-thiolate anion), which is a potential BNCT (boron neutron capture therapy) agent and of structure elucidated by single-crystal X-ray work, has been studied by infrared (IR) and ultraviolet-visible light (UV-vis) spectra and its properties compared with those of the previously reported and also the structurally characterized analogue trans-[(py)2Pd(CBT)2]. This trans species, prepared via a direct method, was previously isolated from a pyridine solution, consequent to the occurring releasing of the external Pd(CBT)2 moieties of the porphyrazine macrocycle [{Pd(CBT)2}4LZn]·xH2O (L = tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazinato anion), which is an active photosensitizer in photodynamic therapy (PDT) and a potential bimodal PDT/BNCT agent. The UV-vis spectral behavior of both cis and trans species in CHCl3 solution and in the gas phase has been examined in detail by density functional theory (DFT) and time-dependent density functional theory (TDDFT) studies devoted to explain their distinct behavior observed in the region of 400-500 nm, as determined by the presence in the cis structure of a vicinal arrangement of the two CBT groups, an ensemble of results closely similar to those observed for the macrocycles [{Pd(CBT)2}4LM]·xH2O (M = MgII(H2O), ZnII, PdII). It has also been experimentally proved the tendency of the cis isomer in CHCl3/pyridine solution to be changed to the respective trans analogue, with conversion occurring in two steps, as interpreted by detailed DFT studies.

Design, preparation, characterization, and application of MnxCu1-xOy/γ-Al2O3 catalysts in ozonation to achieve simultaneous organic carbon and nitrogen removal in pyridine wastewater

In the process of treating high-concentration pyridine wastewater, problems such as low treatment efficiency and total nitrogen (TN) residues are always encountered. Catalytic ozonation can degrade pyridine wastewater well, and it also has the potential to remove TN. However, limited research has been conducted on the development of ozonation catalysts that can simultaneously remove the total organic carbon (TOC) and TN. Density functional theory (DFT) technology can determine the number of active components on the catalyst based on its composition; therefore, it can be used to guide the research and development of such catalysts. Here, we presented a strategy to guide the preparation of two-component Mn and Cu catalysts using DFT technology. By characterising and applying the prepared MnxCu1-xOy/γ-Al2O3 catalysts, it was confirmed that the DFT accurately predicted the changes in the active site content. The selected catalyst also achieved strong TOC and TN removal rates during the catalytic ozonation of high-concentration pyridine wastewater. A Box-Behnken design and response surface methodology was used to optimise the process conditions of catalytic ozonation and verify its stability. Under the optimal reaction conditions, the TOC and TN removal efficiencies from a 500 mg/L pyridine solution were 99.8% and 45.8%, respectively. This work indicated that the use of DFT for the design of catalytic materials was an effective method, which can provide a theoretical basis for material design and reduce the time for material screening.

On the Oxidation of [Ge9]4− – Crystal Structures and Raman Spectroscopic Investigation of Linked Ge9 Clusters

AbstractOxidation of Ge9 Zintl clusters can afford condensed cluster species in the form of dimers, oligomers and polymers. In this work, we present a new route for the synthesis of Ge9 tetramers present in the compound [K(18‐crown‐6)]8[Ge9=Ge9=Ge9=Ge9] ⋅ 4 pyr. The reaction of a pyridine solution of K4Ge9 with 18‐crown‐6 first leads to the formation of green needles of yet unknown composition, which convert into the reported tetramer over time. In this reaction pyridine acts as oxidation reagent. Raman studies on the green needles as well as on tetrameric and polymeric Ge9 feature complex vibrational patterns. Furthermore, we present the crystal structure of a new type of Ge9 dimer in the compound K4[K(2.2.2‐crypt)]2[Ge9−Ge9] ⋅ 4 en ⋅ 2 thf, which represents an intermediate between the two established conformers.

The emergence of intense near-infrared photoluminescence by photoactivation of silver nanoclusters.

Photoirradiation of a pyridine solution of Ag29 nanoclusters (NCs) with red photoluminescence (PL) at 680 nm activated intense PL in the near infrared (NIR) region, giving a PL quantum yield (PLQY) of 33% at 770 nm. The use of Au-doped silver NCs further boosted the PLQY to more than 45% at 800 nm. Photoirradiation is considered to induce a change in the charge localization in the NCs, leading to the formation of NIR emitting sites.

Solvation and coordination chemistry of manganese(II) in some solvents. A transfer thermodynamic, complex formation, EXAFS spectroscopic and crystallographic study

The solvation and coordination chemistry of the manganese(II) ion in water, methanol, dimethylsulfoxide (dmso), N,N’-dimethylpropylene urea (dmpu), acetonitrile and N,N-dimethylthioformamide (dmtf) have been studied from solvation thermodynamic, structural and complex formation ability point of view by calorimetry and EXAFS spectroscopy. The heats of transfer from water to methanol, dmso, acetonitrile and dmtf have been determined to −37.7, −71.6, –23.1 and −36.3 kJ mol−1, respectively, from the heats dissolution of anhydrous manganese(II) trifluoromethanesulfonate by ampoule calorimetry in the neat solvents. Refinement of the EXAFS data of the hydrated and methanol and dmso solvated manganese(II) ions in solution show octahedral configuration and mean Mn-O bond distances of 2.165(3), 2.161(2) and 2.157(3) Å, respectively. The Mn-O bond distance is significantly shorter in dmpu solution, 2.087(3) Å. As dmpu is a space-demanding solvent upon coordination, the manganese(II) ion is only allowed to bind five dmpu molecules in the solvate complex. The acetonitrile solvated manganese(II) ion is six-coordinate in octahedral fashion in solution with a mean Mn-N bond distance of 2.193(3) Å. The relative permittivity of pyridine is too low to allow dissociation of salts of divalent metal ions and neutral pyridine solvated complexes are formed in pyridine solution. In concentrated manganese(II) trifluoromethanesulfonate dmtf solution a contact ion-pair is formed with one trifluoromethanesulfonate ion. In this complex manganese(II) binds five dmtf molecules and a trifluoromethanesulfonate oxygen with Mn-S and Mn-O bond distances of 2.598(6) and 2.16(1) Å, respectively, in an octahedral complex. Complex formation studies performed by titration calorimetry of the manganese(II)-bromide system show significantly more stable complexes in dmpu than in solvents where the solvated manganese(II) ion has regular octahedral symmetry. The dmpu solvated MnBr2 complex in dmpu solution is five coordinate with mean Mn-Br and Mn-O bond distances of 2.494(3) and 2.076(3) Å, respectively. The structure of the [MnBr2(dmpu)2] complex in solid state has distorted tetrahedral geometry with mean Mn-Br and Mn-O bond distances of 2.473(3) and 2.014(3) Å, respectively, and a Br-Mn-Br bond angle of 116.3(1) degrees.