Noble-Gas-Inserted Fluoro(sulphido)boron (FNgBS, Ng = Ar, Kr, and Xe): A Theoretical Prediction

The possibility of the existence of a new series of neutral noble gas compound, FNgBS (where Ng = Ar, Kr, Xe), is explored theoretically through the insertion of a Ng atom into the fluoroborosulfide molecule (FBS). Second-order Møller–Plesset perturbation theory, density functional theory, and coupled cluster theory based methods have been employed to predict the structure, stability, harmonic vibrational frequencies, and charge distribution of FNgBS molecules. Through energetics study, it has been found that the molecules could dissociate into global minima products (Ng + FBS) on the respective singlet potential energy surface via a unimolecular dissociation channel; however, the sufficiently large activation energy barriers provide enough kinetic stability to the predicted molecules, which, in turn, prevent them from dissociating into the global minima products. Moreover, the FNgBS species are thermodynamically stable, owing to very high positive energies with respect to other two two-body dissociation channels, leading to FNg + BS and F^– + NgBS⁺, and two three-body dissociation channels, corresponding to the dissociation into F + Ng + BS and F^– + Ng + BS⁺. Furthermore, the Mulliken and NBO charge analysis together with the AIM results reveal that the Ng–B bond is more of covalent in nature, whereas the F–Ng bond is predominantly ionic in character. Thus, these compounds can be better represented as F^–[NgBS]⁺. This fact is also supported by the detail analysis of bond length, bond dissociation energy, and stretching force constant values. All of the calculated results reported in this work clearly indicate that it might be possible to prepare and characterize the FNgBS molecules in cryogenic environment through matrix isolation technique by using a mixture of OCS/BF₃ in the presence of large quantity of noble gas under suitable experimental conditions

Magneto-Structural Properties and Theoretical Studies of a Family of Simple Heterodinuclear Phenoxide/Alkoxide Bridged Mn^IIILn^III Complexes: On the Nature of the Magnetic Exchange and Magnetic Anisotropy

A family of Mn^IIILn^III strictly dinuclear complexes of general formula [Mn^III(μ-L)­(μ-OMe)­(NO₃)­Ln^III(NO₃)₂(MeOH)] (Ln^III = Gd, Dy, Er, Ho) has been assembled in a one pot synthesis from a polydentate, multipocket aminobis­(phenol)­ligand [6,6′-{(2-(1-morpholyl)­ethylazanediyl)­bis­(methylene)}­bis­(2-methoxy-4-methylphenol)], Mn­(NO₃)₂·4H₂O, Ln­(NO₃)₃·<i>n</i>H₂O, and NEt₃ in MeOH. These compounds represent the first examples of fully structurally and magnetically characterized dinuclear Mn^IIILn^III complexes. Single X-ray diffraction studies reveal that all complexes are isostructural, consisting of neutral dinuclear molecules where the Mn^III and Ln^III metal ions, which exhibit distorted octahedral MnN₂O₄ and distorted LnO₉ coordination spheres, are linked by phenoxide/methoxide double bridging groups. Static magnetic studies show that the Mn^IIIGd^III derivative exhibits a weak antiferromagnetic interaction between the metal ions, with a negative axial zero-field splitting <i>D</i> parameter. The Mn^IIIGd^III complex shows a notable magnetocaloric effect with magnetic entropy change at 5 T and 3 K of −Δ<i>S</i>_m = 16.8 J kg^–1 K^–1. Theoretical studies were performed to support the sign and magnitude of the magnetic anisotropy of the Mn^III ion (<i>ab initio</i>), to predict the value and nature of <i>J</i>_MnGd, to disclose the mechanism of magnetic coupling, and to establish magneto-structural correlations (DFT calculations). The results of these calculations are corroborated by quantum theory of atoms in molecule analysis (QTAIM). Finally, Mn^III–Dy^III and Mn^III–Er^III complexes show field-induced slow relaxation of the magnetization but without reaching a maximum above 2 K in the out-of-phase ac susceptibility. <i>Ab initio</i> calculations were also performed on Mn^III–Dy^III/Ho^III systems to unravel the origin behind the weak SMM characteristics of the molecules possessing two strongly anisotropic ions. The mechanism of magnetic relaxation was developed, revealing a large QTM/tunnel splitting at the single-ion level. Furthermore, the anisotropy axes of the Mn^III and Ln^III ions were calculated to be noncollinear, leading to reduction of the overall anisotropy in the molecules. Hence, the herein reported complexes demonstrate that a combination of two anisotropic metal ions does not guarantee SMM behavior

Interior Engineering of a Viral Nanoparticle and Its Tumor Homing Properties

The development of multifunctional nanoparticles for medical applications is of growing technological interest. A single formulation containing imaging and/or drug moieties that is also capable of preferential uptake in specific cells would greatly enhance diagnostics and treatments. There is growing interest in plant-derived viral nanoparticles (VNPs) and establishing new platform technologies based on these nanoparticles inspired by nature. <i>Cowpea mosaic virus</i> (CPMV) serves as the standard model for VNPs. Although exterior surface modification is well-known and has been comprehensively studied, little is known of interior modification. Additional functionality conferred by the capability for interior engineering would be of great benefit toward the ultimate goal of targeted drug delivery. Here, we examined the capacity of empty CPMV (eCPMV) particles devoid of RNA to encapsulate a wide variety of molecules. We systematically investigated the conjugation of fluorophores, biotin affinity tags, large molecular weight polymers such as poly­(ethylene glycol) (PEG), and various peptides through targeting reactive cysteines displayed selectively on the interior surface. Several methods are described that mutually confirm specific functionalization of the interior. Finally, CPMV and eCPMV were labeled with near-infrared fluorophores and studied side-by-side in vitro and in vivo. Passive tumor targeting via the enhanced permeability and retention effect and optical imaging were confirmed using a preclinical mouse model of colon cancer. The results of our studies lay the foundation for the development of the eCPMV platform in a range of biomedical applications