Nuclear Magnetic Resonance Spectroscopy Experiments Research Articles

Mechanistic and Structural Insights on Difluoromethyl-1,3,4-Oxadiazole Inhibitors of HDAC6

Histone deacetylase 6 (HDAC6) is increasingly recognized for its potential in targeted disease therapy. This study delves into the mechanistic and structural nuances of HDAC6 inhibition by difluoromethyl-1,3,4-oxadiazole (DFMO) derivatives, a class of non-hydroxamic inhibitors with remarkable selectivity and potency. Employing a combination of nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS) kinetic experiments, comprehensive enzymatic characterizations, and X-ray crystallography, we dissect the intricate details of the DFMO-HDAC6 interaction dynamics. More specifically, we find that the chemical structure of a DMFO and the binding mode of its difluoroacetylhydrazide derivative are crucial in determining the predominant hydrolysis mechanism. Our findings provide additional insights into two different mechanisms of DFMO hydrolysis, thus contributing to a better understanding of the HDAC6 inhibition by oxadiazoles in disease modulation and therapeutic intervention.

ABC block copolymer micelles driving the thermogelation: Scattering, imaging and spectroscopy

Thermoresponsive polymers have attracted much scientific attention due to their capacity for temperature-driven hydrogel formation. For biomedical applications, such as drug delivery, this transition should be tuned below body temperature to facilitate controlled and targeted drug release. We have recently developed a thermoresponsive polymer that forms gel at low concentrations (2 w/w%) in aqueous media and offers a cost-effective alternative to thermoresponsive systems currently being applied in clinics. This polymer is an ABC triblock terpolymer, where A, B, and C correspond to oligo(ethylene glycol) methyl ether methacrylate with average Mn 300 g mol−1 (OEGMA300), n-butyl methacrylate (BuMA), and di(ethylene glycol) methyl ether methacrylate (DEGMA). To investigate the self-assembly and the gelation mechanism in diluted solutions, we used small-angle neutron scattering (SANS) on 1 w/w% (below the gelation concentration) and 5 w/w% solutions (above the gelation concentration). As a comparison, we also investigated the solutions of the most studied thermoresponsive polymer, namely, Pluronic F127, an ABA triblock bipolymer made of ethylene glycol (A) and propylene glycol (B) blocks. SANS revealed that the in-house synthesised polymer forms elliptical cylinders, whose length increases significantly with temperature. In contrast, Pluronic F127 solutions form core-shell spherical micelles, which slightly elongate with temperature. Transmission electron microscopy images support the SANS findings, with tubular/worm structures being present. Variable-temperature circular dichroism (CD) and proton nuclear magnetic resonance (1H NMR) spectroscopy experiments reveal insights on the tacticity, structural changes, and molecular origin of the self-assembly.

Chemical composition of soil humin in an organic soil profile

Humin is identified as the most recalcitrant fraction of soil organic matter, but its synthesis and depth variability in the soil profile are unknown. Here, we suggest that carboxyl-rich alicyclic structures (CRAM) and fused aromatic ring structures (FAR) can process significant components of the humin structure. We conducted molecular-level characterization of humin using advanced solid-state nuclear magnetic resonance spectroscopy (SSNMR) experiments and calculated the proportion of FAR and functionalities of CRAM (OCq, –C(CH)n, –CH3) structures. Dipolar dephased (dd) direct polarization magic angle spinning (DPMAS) NMR experiments provided insights into non-protonated carbon and mobile quaternary carbons. We calculated the proportions of non-protonated aromatic carbon and non-polar aliphatic C in the organic layers of the topsoil (Oa), mid-soil (Om), and mineral subsoil (Cg). It was evident that the total aliphatic carbon constitutes a significant proportion of humin, as is the non-protonated C attached to CH3. The 13C dd/DPMAS NMR spectrum of Cg humin clearly showed the formation and preservation of hydrophobic OCq, which is indicative of CRAM structures. CRAM structures could be attached to FAR, which makes the whole structure relatively more hydrophobic, a critical humin functionality in deeper soil. The findings from our research can be successfully utilized in terrestrial carbon sequestration studies to amplify the potential of humin as a recalcitrant carbon reservoir.

The lasting impact of formation cycling on the Li-ion kinetics between SEI and the Li-metal anode and its correlation with efficiency.

Formation cycling is a critical process aimed at improving the performance of lithium ion (Li-ion) batteries during subsequent use. Achieving highly reversible Li-metal anodes, which would boost battery energy density, is a formidable challenge. Here, formation cycling and its impact on the subsequent cycling are largely unexplored. Through solid-state nuclear magnetic resonance (ssNMR) spectroscopy experiments, we reveal the critical role of the Li-ion diffusion dynamics between the electrodeposited Li-metal (ED-Li) and the as-formed solid electrolyte interphase (SEI). The most stable cycling performance is realized after formation cycling at a relatively high current density, causing an optimum in Li-ion diffusion over the Li-metal-SEI interface. We can relate this to a specific balance in the SEI chemistry, explaining the lasting impact of formation cycling. Thereby, this work highlights the importance and opportunities of regulating initial electrochemical conditions for improving the stability and life cycle of lithium metal batteries.

1H and 13C chemical shift-structure effects in anhydrous β-caffeine and four caffeine-diacid cocrystals probed by solid-state NMR experiments and DFT calculations.

By using density functional theory (DFT) calculations, we refined the H atom positions in the structures of β-caffeine (C), α-oxalic acid (OA; (COOH)2), α-(COOH)2·2H2O, β-malonic acid (MA), β-glutaric acid (GA), and I-maleic acid (ME), along with their corresponding cocrystals of 2 : 1 (2C-OA, 2C-MA) or 1 : 1 (C-GA, C-ME) stoichiometry. The corresponding 13C/1H chemical shifts obtained by gauge including projector augmented wave (GIPAW) calculations agreed overall very well with results from magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy experiments. Chemical-shift/structure trends of the precursors and cocrystals were examined, where good linear correlations resulted for all COO1H sites against the H⋯O and/or H⋯N H-bond distance, whereas a general correlation was neither found for the aliphatic/caffeine-stemming 1H sites nor any 13C chemical shift against either the intermolecular hydrogen- or tetrel-bond distance, except for the 13COOH sites of the 2C-OA, 2C-MA, and C-GA cocrystals, which are involved in a strong COOH⋯N bond with caffeine that is responsible for the main supramolecular stabilization of the cocrystal. We provide the first complete 13C NMR spectral assignment of the structurally disordered anhydrous β-caffeine polymorph. The results are discussed in relation to previous literature on the disordered α-caffeine polymorph and the ordered hydrated counterpart, along with recommendations for NMR experimentation that will secure sufficient 13C signal-resolution for reliable resonance/site assignments.

Synergistic dopa-reinforced fluid hydrosol as highly efficient coal dust suppressant

A highly efficient coal dust suppressant with low initial viscosity and high adhesion-solidification properties was fabricated by reinforcing a polyacrylic acid hydrosol with dopa and glutathione (DG) redox system. The synthesis mechanism and dust suppression properties of the dust suppressant were investigated by ultraviolet–visible spectroscopy, high-performance liquid chromatography, and nuclear magnetic resonance spectroscopy experiments combined with density functional theory calculations. The polyacrylic acid hydrosol was synthesized by free radical polymerization with an optimal concentration ratio of 0.36 % ammonium persulfate to 9 % acrylic acid; the DG redox system presented a catechol-quinone dynamic equilibrium, and the dopa polymer reinforcing adhesion was synthesized by the reverse dismutation and polymerization of dopa and dopaquinone. Results revealed that the dust suppressant system formed a multiple hydrogen bonding cross-linking network, dominated by strong double hydrogen bonding interaction formed between the carboxyl groups of dopa polymer and polyacrylic acid, and synergized by hydrogen bonds between the carboxyl groups of glutathione and PAA, and between the hydroxyl and carboxyl groups of dopa and dopaquinone. Moreover, the − OH and − COOH groups in the dust suppressant system were more tightly bonded after dehydration and can form a mesh film to effectively adhere and solidify coal dust, and the coal crust film did not raise dust at 20.526 ± 0.083 m/s wind speed.

Diamine-appended metal-organic framework for carbon capture from wet flue gas: Characteristics and mechanism

Due to the superior CO2 adsorption capacity and selectivity, amine-functional solid adsorbents have received increasing attention. Nevertheless, amine-functionalized polyporous materials have a large performance deviation when considering carbon removal capacity under wet flue gas. Therefore, a variety of metal–organic frameworks (MOFs) with amine functionality are synthesized in this work by appending diamine with a propylene linker to Mg2(dobpdc) (dobpdc4- = 4,4′-dioxido-3,3′-biphenyldicarboxylate) and screened under the simulated flue gas environment with a high water content (7 v%). The results indicate that ndmpn-grafted Mg2(dobpdc) (ndmpn = N,N-dimethyl-1,3-propanediamine) has a high CO2 adsorption capacity of 1.72 mmol/g at 60 °C with an extremely low regeneration heat (2.26 GJ/ton CO2 at the desorption temperature of 145 °C). Adsorption property of ndmpn-Mg2(dobpdc) at high humidity is even more excellent than that of another well-reported diaminopropene-appended MOF, dmpn-Mg2(dobpdc) (dmpn = 2,2-dimethyl-1,3-propanediamine). Herein, van der Waals (vdW)-corrected density functional theory (DFT) calculations are used to quantitatively analyze binding strengths and water effects on it between diamine-appended Mg2(dobpdc) and CO2. It is revealed that the addition of water makes ammonium carbamate chains produced in ndmpn-Mg2(dobpdc) more stable. These chemisorption structures under humid conditions have also been disclosed by using 15N solid-state nuclear magnetic resonance (NMR) spectroscopy experiments and DFT calculation. To conclude, we unveil the binary adsorption characteristics and mechanism of ndmpn-Mg2(dobpdc). It enables a thorough understanding of this compound and highlights its potential as a promising adsorbent under humid conditions for post-combustion applications.

Small-Molecule Inhibition of KRAS through Conformational Selection.

Mutations in KRAS account for about 20% of human cancers. Despite the major progress in recent years toward the development of KRAS inhibitors, including the discovery of covalent inhibitors of the G12C KRAS variant for the treatment of non-small-cell lung cancer, much work remains to be done to discover broad-acting inhibitors to treat many other KRAS-driven cancers. In a previous report, we showed that a 308.4 Da small-molecule ligand [(2R)-2-(N'-(1H-indole-3-carbonyl)hydrazino)-2-phenyl-acetamide] binds to KRAS with low micro-molar affinity [Chem. Biol. Drug Des.2019; 94(2):1441-1456]. Binding of this ligand, which we call ACA22, to the p1 pocket of KRAS and its interactions with residues at beta-strand 1 and the switch loops have been supported by data from nuclear magnetic resonance spectroscopy and microscale thermophoresis experiments. However, the inhibitory potential of the compound was not demonstrated. Here, we show that ACA22 inhibits KRAS-mediated signal transduction in cells expressing wild type (WT) and G12D mutant KRAS and reduces levels of guanosine triphosphate-loaded WT KRAS more effectively than G12D KRAS. We ruled out the direct effect on nucleotide exchange or effector binding as possible mechanisms of inhibition using a variety of biophysical assays. Combining these observations with binding data that show comparable affinities of the compound for the active and inactive forms of the mutant but not the WT, we propose conformational selection as a possible mechanism of action of ACA22.

Cardiometabolic disease risk markers are increased following burn injury in children.

Burn injury in children causes prolonged systemic effects on physiology and metabolism leading to increased morbidity and mortality, yet much remains undefined regarding the metabolic trajectory towards specific health outcomes. A multi-platform strategy was implemented to evaluate the long-term immuno-metabolic consequences of burn injury combining metabolite, lipoprotein, and cytokine panels. Plasma samples from 36 children aged 4-8 years were collected 3 years after a burn injury together with 21 samples from non-injured age and sex matched controls. Three different 1H Nuclear Magnetic Resonance spectroscopic experiments were applied to capture information on plasma low molecular weight metabolites, lipoproteins, and α-1-acid glycoprotein. Burn injury was characterized by underlying signatures of hyperglycaemia, hypermetabolism and inflammation, suggesting disruption of multiple pathways relating to glycolysis, tricarboxylic acid cycle, amino acid metabolism and the urea cycle. In addition, very low-density lipoprotein sub-components were significantly reduced in participants with burn injury whereas small-dense low density lipoprotein particles were significantly elevated in the burn injured patient plasma compared to uninjured controls, potentially indicative of modified cardiometabolic risk after a burn. Weighted-node Metabolite Correlation Network Analysis was restricted to the significantly differential features (q <0.05) between the children with and without burn injury and demonstrated a striking disparity in the number of statistical correlations between cytokines, lipoproteins, and small molecular metabolites in the injured groups, with increased correlations between these groups. These findings suggest a 'metabolic memory' of burn defined by a signature of interlinked and perturbed immune and metabolic function. Burn injury is associated with a series of adverse metabolic changes that persist chronically and are independent of burn severity and this study demonstrates increased risk of cardiovascular disease in the long-term. These findings highlight a crucial need for improved longer term monitoring of cardiometabolic health in a vulnerable population of children that have undergone burn injury.

Molecular Assessment of Metabolome Alterations in Lotus japonicus Roots Induced by Arbuscular Mycorrhiza

AbstractAn arbuscular mycorrhiza symbiosis, which is established by 80% of all vascular plants and Glomeromycota fungi, can boost the growth, stress tolerance, and yield of agricultural crop plants by increasing the mineral supply of the host plant [1]. Mineral nutrients absorbed by the fungus are exchanged for photoassimilates from the plant via highly branched fungal structures called arbuscules which are formed within root cortex cells [2]. The process of arbuscule formation and degradation is highly dynamic and accompanied by considerable cell reprogramming [3], but there is only limited knowledge on the influence of arbuscular mycorrhiza on the host metabolome.We investigated alterations of the host plant's root metabolome induced by arbuscular mycorrhizal symbiosis using the model legume Lotus japonicus. Methanol extracts of mycorrhizal (myc) and non‐mycorrhizal roots (mock) were analyzed employing ultra‐highperformance liquid chromatography–electrospray ionization–time‐of‐flight–ion mobility–mass spectrometry (UPLC–ESI–ToF–IM–MS) in an untargeted metabolomics approach. Up‐regulated marker metabolites were identified via principal components analysis (PCA) and orthogonal partial least squares–discriminant analysis (OPLS–DA) depicted as S‐plots, and their structures elucidated by co‐chromatography with authentic standards or by isolation from L. japonicus roots using preparative HPLC and one‐ and two‐dimensional nuclear magnetic resonance spectroscopy (NMR) experiments. We isolated three previously unknown mycorrhizal marker polyphenols from L. japonicus roots, one being a coumaronochromone, one pterocarp‐6a‐ene, and one aryl benzofuran carboxaldehyde. Additionally, we identified three more coumaronochromones, three flavonoids, three isoflavonoids, and one coumestan in mycorrhized L. japonicus.

Understanding cooperativity effects in RNA structure probing experiments.

Small molecule chemical probes, which form covalent bonds with atoms of flexible nucleotides, are commonly used to gain insight into the structure adopted by an RNA. In this work, we use selective 2’ hydroxyl acylation analyzed by primer extension (SHAPE) and nuclear magnetic resonance (NMR) spectroscopy experiments to explore whether the structure of an RNA is modulated by chemical probe binding events. We find that as the concentration of a chemical probe increases, modified nucleotides locally modulate the RNA structure, resulting in the increase or decrease of SHAPE reactivity in surrounding nucleotides. This cooperative effect is dependent on both chemical probe concentration and size. Critically, this effect impacts the accuracy of predicted RNA secondary structures when guided by chemical probing experiments. Altogether, our work highlights the importance of optimizing the conditions of chemical probing experiments to obtain secondary structural information about an RNA.

Optimization of Diffusion-Ordered NMR Spectroscopy Experiments for High-Throughput Automation in Human Metabolic Phenotyping.

The diffusion-ordered nuclear magnetic resonance spectroscopy (DOSY) experiment allows the calculation of diffusion coefficient values of metabolites in complex mixtures. However, this experiment has not yet been broadly used for metabolic profiling due to lack of a standardized protocol. Here we propose a pipeline for the DOSY experimental setup and data processing in metabolic phenotyping studies. Due to the complexity of biological samples, three experiments (a standard DOSY, a relaxation-edited DOSY, and a diffusion-edited DOSY) have been optimized to provide DOSY metabolic profiles with peak-picked diffusion coefficients for over 90% of signals visible in the one-dimensional 1H general biofluid profile in as little as 3 min 36 s. The developed parameter sets and tools are straightforward to implement and can facilitate the use of DOSY for metabolic profiling of human blood plasma and urine samples.

Monitoring the Solution Persistence of Porous Coordination Cages with Diffusion NMR Spectroscopy and Cryogenic Transmission Electron Microscopy

As a unique class of molecular adsorbents, porous coordination cages (PCCs) have garnered interest because of their potential solubility, which enables applications not available to activated carbons, zeolites, metal–organic frameworks (MOFs), and covalent organic frameworks (COFs), such as covalent membrane incorporation, solution-based ion binding, and facile incorporation into porous liquids. The identification of key aspects of cage behavior in solution such as the self-assembly process, structural integrity in solution, conformational changes, and cage interactions with guest molecules is necessary to broaden the utility of soluble porous cages. Many characterization strategies for permanently porous coordination cages have been limited to the solid state and have relied heavily on X-ray diffraction, electron microscopy, and infrared (IR), UV–vis, and nuclear magnetic resonance (NMR) spectroscopies. As such, definitive evidence of cage behavior while in solution has been lacking, as the often-paramagnetic nature of permanently porous coordination cages complicates one-dimensional NMR spectroscopy experiments. Here, we explore the combined use of diffusion-ordered spectroscopy NMR (DOSY NMR), transmission electron microscopy (TEM), and cryogenic transmission electron microscopy (cryo-TEM) to confirm the persistence of soluble PCCs in various solutions.

Structural Characterization and Cardioprotective Effect of Water-Soluble Polysaccharides Extracted from Clematis flammula

Clematis flammula is widely used for its pharmacological properties in Tunisia. This work aimed to explore, in a rat model, the cardiopreventive capacity of polysaccharides extracted from C. flammula (CFPS) after a myocardial injury caused by isoproterenol. Structural analyses suggested that the average molecular weight of CFPS was 1.82 × 105 g/mol, being mainly composed of glucuronide (41.53%), galacturonic acid (19.06%), arabinose (16.10%), galactose (6.15%), glucose (5.49%), and rhamnose (3.55%). Fourier transform–infrared spectroscopy and nuclear magnetic resonance spectroscopy experiments showed that CFPS was rich with carbohydrates containing pectic materials with glycosidic bonds. In addition, results show that pretreatment with CFPS (150 mg/kg) could improve the electrocardiogram pattern by decreasing the elevated ST segment and ameliorating the relative heart weights and the biochemical profile content (creatine phosphokinase-MB, lactate dehydrogenase, and cardiac troponin I). Furthermore, pretreatment with CFPS reduced the amount of malondialdehyde and restored the genotoxicity induced by isoproterenol. The histopathological study revealed that CFPS pretreatment diminished the level of cardiac tissue injury. Based on these data, CFPS presents a broad biological effect as a cardioprotective and can be used for the exploration of novel natural products for the treatment of cardiac disease.

Evolutionary Role of Water-Accessible Cavities in Src Homology 2 (SH2) Domains.

Protein excited states are fundamental in the understanding of biological function, despite the fact they are hardly observed using traditional biophysical methodologies. Pressure perturbation coupled with nuclear magnetic resonance (NMR) spectroscopy is a powerful physicochemical tool to glance at these low-populated high-energy states on a residue-by-residue basis and underpin mechanistic insights into protein functionalities. Here we performed pressure titrations using NMR spectroscopy and relaxation dispersion experiments to identify the low-lying energetic states of the c-Abl SH2 domain. By showing that the SH2 excited state contains a hydrated hydrophobic cavity, fast-exchange motions, and highly conserved residues facing the water-accessible hole, we discuss the implications of water-protein interactions in SH2 modules achieving high-affinity binding and promiscuous phospho-Tyr peptide recognition.

A holistic NMR framework to understand environmental impact: Examining the impacts of superparamagnetic iron oxide nanoparticles (SPIONs) in Daphnia magna via imaging, spectroscopy, and metabolomics.

Superparamagnetic iron oxide nanoparticles (SPIONs) are a contaminant of emerging interest, often used in the medical field as an imaging contrast agent, with additional uses in wastewater treatment and as food additives. Although the use of SPIONs is increasing, little research has been conducted on the toxic impacts to living organisms beyond traditional lethal concentration endpoints. Daphnia magna are model organisms for aquatic toxicity testing with a well understood metabolome and high sensitivity to SPIONs. Thus, as environmental concentrations continue to increase, it is becoming critical to understand their sub-lethal toxicity. Due to the paramagnetic nature of SPIONs, a range of potential nuclear magnetic resonance spectroscopy (NMR) experiments are possible, offering the potential to probe the physical location (via imaging), binding (via relaxation weighted spectroscopy), and the biochemical pathways impacted (via in vivo metabolomics). Results indicate binding to carbohydrates, likely chitin in the exoskeleton, along with a decrease in energy metabolites and specific biomarkers of oxidative stress. The holistic NMR framework used here helps provide a more comprehensive understanding of SPIONs impacts on D. magna and showcases NMR's versatility in providing physical, chemical, and biochemical insights.

Microstructural Analysis of Poly(ethylene-co-propylene-co-1-butene) terpolymers by Multidimensional NMR Spectroscopy

Physical, rheological and optical properties of polymer depend on its molecular microstructure. Specifically, the monomer content and sequence distribution of polymer significantly affect the mechanical performance of the final product. To this base, Nuclear Magnetic Resonance Spectroscopy (NMR) has been introduced as a very powerful technique to study the microstructure of polymer. The purpose of this study was to develop a methodology to investigate the microstructure of poly(ethylene-co-propylene-co-butene) terpolymer by using multidimensional NMR spectroscopy, including pulsed-field-gradient (PFG) 1H-13C heteronuclear single quantum coherence (GHSQC), heteronuclear multiple bond coherence (gHMBC), and heteronuclear single quantum coherence-total correlation spectroscopy (GHSQC-TOCSY). The combination of 1D and 2D NMR experiments, permit the characterization of the complex structure of poly(ethylene-co-propylene-co-butene) terpolymer. The completed 13C NMR assignments provided in this work allow more accurate quantitative determination of the microstructure in these polymers.

Off-the-Shelf Gd(NO3)3 as an Efficient High-Spin Metal Ion Polarizing Agent for Magic Angle Spinning Dynamic Nuclear Polarization

Magic angle spinning nuclear magnetic resonance spectroscopy experiments are widely employed in the characterization of solid media. The approach is incredibly versatile but deleteriously suffers from low sensitivity, which may be alleviated by adopting dynamic nuclear polarization methods, resulting in large signal enhancements. Paramagnetic metal ions such as Gd3+ have recently shown promising results as polarizing agents for 1H, 13C, and 15N nuclear spins. We demonstrate that the widely available and inexpensive chemical agent Gd(NO3)3 achieves significant signal enhancements for the 13C and 15N nuclear sites of [2-13C,15N]glycine at 9.4 T and ∼105 K. Analysis of the signal enhancement profiles at two magnetic fields, in conjunction with electron paramagnetic resonance data, reveals the solid effect to be the dominant signal enhancement mechanism. The signal amplification obtained paves the way for efficient dynamic nuclear polarization without the need for challenging synthesis of Gd3+ polarizing agents.

Implementing High Q-Factor HTS Resonators to Enhance Probe Sensitivity in 13C NMR Spectroscopy

Nuclear magnetic resonance spectroscopy (NMR) probes using thin-film high temperature superconducting (HTS) resonators provide exceptional mass sensitivity in small-sample NMR experiments for natural products chemistry and metabolomics. We report improvements in sensitivity to our 1.5 mm 13C-optimized NMR probe based on HTS resonators. The probe has a sample volume of 35 microliters and operates in a 14.1 T magnet. The probe also features HTS resonators for 1H transmission and detection and the 2H lock. The probe utilizes a 13C resonator design that provides greater efficiency than our previous design. The quality factor of the new resonator in the 14.1 T background field was measured to be 4,300, which is over 3x the value of the previous design. To effectively implement the improved quality factor, we demonstrate the effect of adding a shorted transmission line stub to increase the bandwidth and reduce the rise/fall time of 13C irradiation pulses. Initial NMR measurements verify 13C NMR sensitivity is significantly improved while preserving detection bandwidth. The probe will be used for applications in metabolomics.

Molecular mechanics of glove‐like re(I) metallacycles: Toward light‐activated molecular catchers

AbstractTwo novel glove‐shaped rhenium(I)‐based metallacycle complexes, composed of two bidentate ligands α,α′‐bis(benzimidazol‐1‐yl)‐meta(orortho)‐xylene(bbim) and a tetradentate ligand, 2,5‐pyrazinedicarboxylate(pzdc) with two Re(I) metal centers each are developed and reported. The opening and closure motion of the metaxylene‐linked metallacycle complex were studied via variable temperature proton nuclear magnetic resonance spectroscopy experiment, as well as density functional theory calculation. Our results indicate that the motion of the “capping” phenyl moiety in bbim is accompanied by the swing of the two benzimidazol groups. Both complexes show two different emission bands when excited at two different wavelengths, a violation of the Kasha's rule. Theoretical calculation indicate that the lower‐energy transitions are metal–ligand charge transfer bands, arising from electrons localized to one of the two Re(I) centers to the pzdc ligand, while the higher‐energy ones are assigned to a ligand–ligand charge‐transfer excitation from bbim to pzdc. Results from excited‐state optimized structures confirm that the higher‐energy excitation leads to a closure of the molecule with meta‐bbim, a desirable “molecular catcher” behavior. Our findings provide an important insight for a strategy to design a light‐activated molecular catcher for many interesting applications.