Equatorial Distances Research Articles

On the Relationship Between the Banded Hiss Distribution and Plasmapause Location: A Survey of Van Allen Probes Observations

AbstractThe plasmapause is the outer boundary of the plasmasphere and plays a crucial role in the propagation of plasma waves. We statistically investigate the relationship between the distribution of banded hiss and plasmapause locations. Wave power distributions of banded hiss are analyzed in terms of two ways: (a) the distance away from the plasmapause (ΔL) and (b) the equatorial distance away from the Earth. Statistical results show both bands of banded hiss have larger wave powers and occurrence rates near the plasmapause. The frequencies of two banded hiss waves both decrease discernably with increasing L‐shell at most magnetic local time sectors and geomagnetic activities, but remain nearly constant with increasing ΔL. The highly consistent distribution suggests both bands may be generated in the plume region. The correlation between banded hiss waves and plasmapause locations sheds new light on the generation mechanisms of banded hiss waves.

Exploring the micromorphological diversity of palynomorphic flora from lesser Himalaya biodiversity hotspot

Palynology, a prominent field in plant systematics and biodiversity studies, plays a vital role in identifying and determining the plant species present in a specific region. The current study was performed to evaluate the micromorphological traits of pollen from flora of Lesser Himalaya. Pollen microstructural variations aid in the identification of species belonging to specific botanical families and various geographic habitats. Flowers of 24 selected species categorized into 16 families were collected, preserved and then acetolysis protocol followed. Pollen was examined under a light and scanning microscopy (LM and SEM) for palynomorph description. The palynomorphs characteristics such as size, shape, exine surface, and aperture orientation, were examined. Status of these plants show that herbs are being dominant (11 species), while shrubs (7 species), climbers (3 species), bulbous plants (2 species), small tree, sedge, weed (1 species each). Pollen shape determined in equatorial view were; spheroidal, sub-prolate, oblate-spheroidal, prolate, spherical and sub-oblate. The variations were seen among pollen types; tricolpate, tricolporate and polyporate in most of the species. Exine stratification was observed mostly scabrate while echinate, cristate-reticulate, granulate, punctate, rugulate-perforate, striate-rugulate, verrucate, cristate-foveolate was visualized in each different species. Palynomorph apertural patterns were observed sunken, furrowed, slightly bulged, scabrate, granulate, slit like, and perforate. The largest polar diameter was measured in Hymenocallis littoralis (138.6 µm) whereas smallest in Parthenium hysterophorus (14.70 µm). Equatorial distance was calculated maximum for Cascabela thevetia (110.1 µm) and minimum for Hibiscus rosa-sinensis (1.7 µm). P/E ratio was calculated largest in Hymenocallis littoralis (1.8) and lowest in Duranta erecta (0.89). The palynomorphs taxonomic characters investigated can be helpful in species level identification and provide a baseline to conduct more systematic research with respect to specific plant families and genera.

Scanning electron microscopic investigation on Chicory tribe (Compositae) botanical sources and their antimicrobial potential.

This study discusses the micro-level structural details of Cichorieae pollen sources elucidated by scanning electron microscopy (SEM) and explains their symmetry and morphometry. The in-depth knowledge from the electron ultrastructure of Asteraceae pollen has provided insights into enhanced pollen morphology, and the antimicrobial significance of species under study presents novel avenues for their natural defense mechanisms in the development of antimicrobial agents. In this research, both quantitative and qualitative features of pollen were examined. The pollen grains are prolate-spheroidal and oblate-spheroidal in shape, characterized by a maximum polar diameter of 55.6-61.0 μm and a maximum equatorial distance of 68.3-74.4 μm. SEM reveals various configurations such as echinate perforate-tectate, psilate, and echino-lophate perforate. The Cichorieae species have significant antimicrobial efficacy and are promising sources for the development of novel antimicrobial drugs with potential implications in pharmaceutical and healthcare industries. SEM analysis of Cichorieae pollens has provided remarkable insights into their unique structures, revealing diverse shapes and surface ornamentations, which can be used for accurate Asteraceae species identification. RESEARCH HIGHLIGHTS: SEM provides unique pollen surface structures and patterns of Chicory pollen grains. Chemical composition of Chicory botanical sources provides valuable information on their potential as antimicrobial agents. SEM imaging reveals specialized fenestrate grain structures of taxonomic importance.

Exploring microscopic pollen morphology in herbaceous Flora: Insights and analysis using scanning electron microscopy.

Microscopic techniques can be applied to solve taxonomic problems in the field of plant systematic and are extremely versatile in nature. This study was focused on the new approaches to visualizing the imaging, tool to cover the micro-structural techniques applied to the pollen study of flowers. The current research was proposed to evaluate microscopic pollen morphological attributes using light and scanning electron microscopy of herbaceous flora from Samarkand, Uzbekistan. A total of 13 herbaceous species, classified into 11 different families were collected, pressed, and identified, and then acetolyzed their pollen to visualize under light and scanning electron microscopy. Herbaceous flora can be characterized by small to very large-sized pollen morphotypes presenting four types of pollen shapes, prolate spheroidal (six species), spheroidal (three species) and prolate and oblate (two species each). The polar diameter and equatorial distance were calculated maximum in Hibiscus syriacus 110.55 and 111.2 μm respectively. Pollen of six different types was found namely tricolporate pollen observed in seven species, tricolpate and pantoporate in two species each, sulcate in Gagea olgae and hexacolpate pollen was examined in Salvia rosmarinus. Exine ornamentation of pollen was examined tectate perforate, verrucate-reticulate, micro-reticulate, reticulate, reticulate-cristatum, gemmate-echinate, echinate-perforate, perforate-striate, rugulate, rugulate-striate, bi-reticulate, reticulate-perforate and perforate-micro-reticulate showing great variations. Exine thickness was noted highest for Rosa canina 2.9 μm and minimum in Punica granatum 0.65 μm. This study of pollen imaging visualization of herbaceous flora contributes to the opportunity for the taxonomic evaluation of and fills knowledge gaps in studies of herbaceous flora identification using classical microscopic taxonomic tools for their accurate identification. RESEARCH HIGHLIGHTS: Pollen in unexplored herbaceous flora of the Samarkand region was studied with light and scanning electron microscopic pollen study. There is a high variation in observed pollen micromorphological characters. Pollen microscopic morphology has important taxonomic value for the identification of herbaceous species.

Plasma Wave and Particle Dynamics During Interchange Events in the Jovian Magnetosphere Using Juno Observations

AbstractInterchange instability is known to drive fast radial transport of particles in Jupiter's inner magnetosphere. Magnetic flux tubes associated with the interchange instability often coincide with changes in particle distributions and plasma waves, but further investigations are required to understand their detailed characteristics. We analyze representative interchange events observed by Juno, which exhibit intriguing features of particle distributions and plasma waves, including Z‐mode and whistler‐mode waves. These events occurred at an equatorial radial distance of ∼9 Jovian radii on the nightside, with Z‐mode waves observed at mid‐latitude and whistler‐mode waves near the equator. We calculate the linear growth rate of whistler‐mode and Z‐mode waves based on the observed plasma parameters and electron distributions and find that both waves can be locally generated within the interchanged flux tube. Our findings are important for understanding particle transport and generation of plasma waves in the magnetospheres of Jupiter and other planetary systems.

Field-Induced Single-Ion Magnet Behavior in Nickel(II) Complexes with Functionalized 2,2':6'-2″-Terpyridine Derivatives: Preparation and Magneto-Structural Study.

Two mononuclear nickel(II) complexes of the formula [Ni(terpyCOOH)2](ClO4)2∙4H2O (1) and [Ni(terpyepy)2](ClO4)2 MeOH (2) [terpyCOOH = 4'-carboxyl-2,2':6',2″-terpyridine and terpyepy = 4'-[(2-pyridin-4-yl)ethynyl]-2,2':6',2″-terpyridine] have been prepared and their structures determined by single-crystal X-ray diffraction. Complexes 1 and 2 are mononuclear compounds, where the nickel(II) ions are six-coordinate by the six nitrogen atoms from two tridentate terpy moieties. The mean values of the equatorial Ni-N bond distances [2.11(1) and 2.12(1) Å for Ni(1) at 1 and 2, respectively, are somewhat longer than the axial ones [2.008(6) and 2.003(6) Å (1)/2.000(1) and 1.999(1) Å (2)]. The values of the shortest intermolecular nickel-nickel separation are 9.422(1) (1) and 8.901(1) Å (2). Variable-temperature (1.9-200 K) direct current (dc) magnetic susceptibility measurements on polycrystalline samples of 1 and 2 reveal a Curie law behavior in the high-temperature range, which corresponds to magnetically isolated spin triplets, the downturn of the χMT product at lower temperatures being due to zero-field splitting effects (D). Values of D equal to -6.0 (1) and -4.7 cm-1 (2) were obtained through the joint analysis of the magnetic susceptibility data and the field dependence of the magnetization. These results from magnetometry were supported by theoretical calculations. Alternating current (ac) magnetic susceptibility measurements of 1 and 2 in the temperature range 2.0-5.5 K show the occurrence of incipient out-phase signals under applied dc fields, a phenomenon that is characteristic of field-induced Single-Molecule Magnet (SMM) behavior, which herein concerns the 2 mononuclear nickel(II) complexes. This slow relaxation of the magnetization in 1 and 2 has its origin in the axial compression of the octahedral surrounding at their nickel(II) ions that leads to negative values of D. A combination of an Orbach and a direct mechanism accounts for the field-dependent relation phenomena in 1 and 2.

Structures, temperature effect, binding and clustering energies of Cu2+(MeOH)n=1-8 clusters and extrapolations

• The structure of solvated copper (II) ion in methanol is tetra and hexa-coordinated, depending on the temperature. • Compact and high coordinated structures dominate the population at all temperatures. • Absolute clustering free energies of solvated metal ions neither depend on the metal, nor on the ligand type. Copper plays an important role in many physiological biochemical and biological processes. This work sets out to investigate structures, relative stabilities, temperature-dependence of the relative population, saturated binding and clustering energies of the solvated Cu 2 + ion in methanol, using ab initio MP2 method associated with the 6-31++G** basis set. The isomers of the Cu 2 + ( MeOH ) n = 1 - 8 clusters are reported here for the first time in the whole literature, and relative stability obeys a well-defined stability rule. It is worth mentioning that the solvated Cu 2 + ion in methanol is tetra- or hexa-coordinated, depending on the temperature. The theoretical approach used in this work, combined with the structures pointed out and their corresponding relative populations leads to equatorial distances d Cu 2 + - O in methanol, in excellent agreement with experimental results. As far as temperature dependence isomers distribution are concerned, compact and high coordinated structures dominate the population of the studied clusters at all temperatures. We also predicted binding and clustering energies as a function of the cluster size, up to n = ∞ . The convergence, called the saturation, happens around n = 18 for clustering energies of Cu 2 + ion in methanol. For the case as ammonia and water as solvent, this saturation is reached at n = 20 and n = 25 , respectively. Thus, accurate solvation energies of Cu 2 + ion in those media using cluster continuum model could be derived clustering at least up to n = 18 , 20 and 25 respectively for methanol, ammonia and water as solvent. The corresponding binding electronic energy, binding enthalpy and binding free energy per methanol molecule are respectively, −158.9, −166.2 and −134.6 kJ mol −1 . As far as clustering energies per solvent molecule at the saturation are concerned, we reported −7.0, −6.5 and −2.9 kJ mol −1 for respectively the clustering electronic energy, clustering enthalpy and clustering free energy per methanol molecule of the solvated Cu 2 + ion.

Pollen characters and their evolutionary and taxonomic significance: using light and confocal laser scanning microscope to study diverse plant pollen taxa from central India

Increasing the taxonomic resolution of fossil pollen identification and establishing the kinship and similarity among phylogenetically related plant groups are inevitable for advancing the Quaternary palaeoecological, palaeoclimatological and palaeoenvironmental research. We, in the present study, examined and determined the pollen morphological characteristics of nine plant taxa belonging to seven families from central India by a combined light microscopic (LM) and confocal laser scanning microscopic (CLSM) study. The prime object was to observe, document and describe, as well as illustrate the prevalent variation in pollen shape, size, aperture number and diameter, diameter of the polar axis and equatorial distance, as well as exine thickness and pattern (i.e. pollen wall architecture) of the studied plant taxa. Pollen identification key was developed to demonstrate variations in pollen features and delimit taxa for correct identification. Principal component analysis (PCA) suggests exine and aperture number as dominant characters, as well as hierarchical clustering analysis (HCA), applied to the pollen morphological characters of nine plant taxa to understand the variability among the taxa, and to cluster them, respectively, suggest three clusters. The cophenetic correlation coefficient also substantiates the three group of clustering. The present study has significance in taxonomy and systematics, as well as in phylogeny and evolution. In addition, the preservation potential of different pollen grains has been ascertained, based on the pollen wall architecture. The study, moreover, will improve the precise fossil pollen identification, which is critical for advancing Quaternary palaeoecology in India and also in similar tropical and subtropical areas of the globe.

Radial Transport of Energetic Electrons as Determined From the “Zebra Stripes” Measured in the Earth’s Inner Belt and Slot Region

The “zebra stripes” are drift-periodic structures present in the form of peaks and valleys in energetic (tens to hundreds of keV) electron spectrograms in the Earth’s inner belt and slot region. Their characteristics inform of preceding electric field disturbances. Specifically, their amplitude contains information on the radial transport of trapped particles generated by azimuthal electric field disturbances. We introduce a method to quantify radial transport from the measured amplitude of the zebra stripes, and we apply it to the zebra stripes observed on 16 February 2014. The findings are compared with results from a particle tracing code that leverages an empirical analytical model for the electric field disturbances. The measured amplitude of the zebra stripes indicates that the electric field disturbances transported the trapped population coherently, over radial distances spanning several hundreds to thousands of kilometers. The magnitude of radial transport is shown to depend on angular drift frequency and initial location (equatorial radial distance and magnetic local time) in the disturbance. The model-observation comparison suggests that the timing for electric field variations provided by the model is valid for studying radial transport in the inner belt and slot region. On the other hand, we found discrepancies when comparing radial transport magnitudes. When assuming that radial transport varies as L3, as weakly suggested by the data for set angular drift frequencies, and extrapolating observations to L = 1, the amount of experimental transport obtained is two to three times greater than numerical estimates. Outputs from the standalone version of the Rice Convection Model (RCM) suggests that the electric field disturbances are likely greater than the estimates provided by the empirical model. RCM also supports the idea that radial transport driven by the prompt penetration of magnetospheric convection varies as L3 in the inner belt and slot region.

Magnetic resonance imaging of the normal canine eye using a T1‐weighted volumetric acquisition

MRI is becoming increasingly available within the veterinary profession, and eyes are frequently included as part of a cranial study. The advantages of volumetric imaging are numerous, when compared to traditional two-dimensional imaging, and could be utilised within the veterinary setting. This report describing the normal MRI appearance of the canine eye, aimed to establish a standard reference range on a T1w volumetric acquisition. This study retrospectively assessed 62 eyes from 31 dogs that had undergone MRI at the Small Animal Hospital, Langford Vets, University of Bristol between 2016 and 2018 using a standardised MRI protocol. Dogs were excluded if they had presented with any reported ocular or orbital abnormalities. Measurements were performed from the 3D T1w volumetric sequence by a single observer using a previously published technique. Mean axial globe length was 2.13 cm and equatorial width 2.16 cm. Mean anteroposterior depth of the anterior chamber was 0.40 cm and 0.97 cm for the vitreous chamber. The mean anteroposterior and equatorial distance of the lens was 0.75 cm and 1.15 cm, respectively. Mean optic nerve width was 0.15 cm, and the mean width of the entire optic nerve sheath was 0.43 cm. Statistically significant relationships were noted between age and axial globe length and both lens dimensions. Highly significant relationships were noted between all variables, except lens dimensions and body weight Conclusion: This study provides reference values to assist in the interpretation of ocular structures during MRI on a T1w volumetric acquisition.

New DMAP meso-arylporphyrin Magnesium(II) complex. Spectroscopic, Cyclic voltammetry and X-ray molecular structure characterization. DFT, DOS and MEP calculations and Antioxidant and Antifungal activities

This study aims at first at the synthesis and the UV-visible, the infrared and the 1H Nuclear Magnetic Resonance spectroscopic characterizations of the 4-(dimethylamino)pyridine)[meso-tetra(para-chlorophenyl)porphyrinato]magnesium(II) with the formula [Mg(TClPP)(DMAP)].1/2C6H14(I). The fluorescence and cyclic voltammetry studies have also been performed. The molecular structure of (I) was determined and described by single crystal X-ray diffraction analysis and Hirshfeld surfaces computational method. Complex (I) has a distorted square pyramidal geometry with a Mg__N(DMAP) distance value of 2.130 (4) Å and the average equatorial distance between the magnesium(II) central ion and the nitrogen atoms is 2.082 (3) Å. The crystal packing of our synthetic Mg(II) porphyrinic species is made by layers perpendicular to the [010] direction and the cohesion of the crystal packing is stabilized by nonconventional C–H···Cl and by C–H···Cg intermolecular interactions involving the pyrrole and phenyl rings of the porphyrin macrocycle. DFT calculations on (I) indicated an agreement with both UV-visible and IR experimental data. To gain further insights into the reactivity of (I), a density of states (DOS) and a molecular electrostatic potential (MEP) theoretical calculation were carried out. Furthermore, the antifungal and the antioxidant activities of the free base H2TClPP porphyrin, the [Mg(TClPP)] starting material and [Mg(TClPP)(DMAP)] (I) were also tested.

Trapping an unusual pentacoordinate carbon atom in a neutral trialuminum complex.

A neutral trialuminum complex incorporates a pentacoordinate carbon through a methylidene bridge linking the three metal atoms. The rigid electron-deficient Al3 core stabilizes the hypercoordinate carbon atom resulting in the shortest equatorial Al-C distance reported for such an Al3-(μ3-CH2) unit.

Inversion of the Energetic Electron “Zebra Stripe” Pattern Present in the Earth's Inner Belt and Slot Region: First Observations and Interpretation

AbstractEnergetic electron spectra in the Earth's inner belt and slot region usually display extrema at some energies that form uninterrupted lines when color‐coded in two‐dimensional maps in which one axis represents the normalized equatorial distance, L, and the other axis represents kinetic energy. These patterns are called “zebra stripes.” This letter presents the first observations of zebra stripe inversions: Lines of local minima in the electron spectra at low L values (below L = 2) turn into lines of local maxima in the electron spectra at higher L values, and vice versa. The observations are interpreted by specifying the connection between fluctuations in directional differential fluxes and radial disturbances of trapped population drift motion. The analysis highlights the role of flux energy‐ and radial‐gradients when it comes to determining radial motion from particle data. The underlying method applies to a variety of problems, whether at Earth or at the outer planets.

Trapped Particle Motion in Magnetodisk Fields

AbstractThe spatial and temporal characterization of trapped charged particle trajectories in magnetospheres has been extensively studied in dipole magnetic field structures. Such studies have allowed the calculation of spatial quantities, such as equatorial loss cone size as a function of radial distance, the location of the mirror points along particular field lines (L‐shells) as a function of the particle's equatorial pitch angle, and temporal quantities such as the bounce period and drift period as a function of the radial distance and the particle's pitch angle at the equator. In this study, we present analogous calculations for the disk‐like field structure associated with the giant rotation‐dominated magnetospheres of Jupiter and Saturn as described by the University College London/Achilleos‐Guio‐Arridge (UCL/AGA) magnetodisk model. We discuss the effect of the magnetodisk field on various particle parameters and make a comparison with the analogous motion in a dipole field. The bounce period in a magnetodisk field is in general smaller the larger the equatorial distance and pitch angle, by a factor as large as ∼8 for Jupiter and ∼2.5 for Saturn. Similarly, the drift period is generally smaller, by a factor as large as ∼2.2 for equatorial distances ∼20–24 RJ at Jupiter and ∼1.5 for equatorial distances ∼7–11 RS at Saturn.

Experimental and computational studies on the structure and properties of a novel low-spin iron(III) macrocyclic complex

Synthesis of a new iron(III) metalloporphyrin complex is achieved. Molecular structure, supramolecular assembly and physico-chemical properties have been explored by means of experiments and computational tools. The mean equatorial distance between the iron(III) metal center and N-pyrrolic nitrogens is appropriate for a low-spin (S = 1/2) derivative. Magnetic data confirm the low-spin state (S = 1/2) of our ferric derivative. The planarity of the porphyrin macrocycle is confirmed by the shift of the value of the half potential E1/2[Fe(III)/Fe(II)] of (I) toward more negative value in the cyclic voltammogram. Metal–ligand interactions has been also described via natural bond orbital analysis.

An Empirical Model for the Dayside Magnetospheric Plasma Mass Density Derived From EMMA Magnetometer Network Observations

AbstractA local time dependent empirical model of the equatorial plasma mass density in the inner magnetosphere is derived from field line resonance (FLR) observations at the European quasi‐Meridional Magnetometer Array (EMMA). Models of the plasmasphere, plasmatrough, and plasmapause are derived separately and then combined. The whole model is limited to the local time (LT) sector 06:00‐18:00 and to the range of equatorial distances . It is also dependent on the geomagnetic activity but only in determining the plasmapause position. It well describes the recovery phase following a plasmasphere erosion but is not intended to reproduce highly dynamical phases. The plasmasphere model is limited to the range and predicts a mass density increase in the daytime sector (10–18 LT) which becomes more evident with increasing (up to a factor of 2). A comparison with previous models of plasmaspheric electron density suggests that the diurnal variation is mainly contributed by the heavy ions. The plasmatrough model is limited to the range and predicts a diurnal variation even more pronounced. Comparison with electron density models suggests that the average ion mass density can increase from 2.0 to 4–5 amu during daytime hours. An automated algorithm to search for plasmapause signatures in the radial mass density profiles derived from experimental observations is also presented. It could represent a useful space weather tool when included in a real‐time monitoring system of the plasmasphere.

Probing the Excited State of Methylcobalamin Using Polarized Time-Resolved X-ray Absorption Spectroscopy.

We use picosecond time-resolved polarized X-ray absorption near-edge structure (XANES) measurements to probe the structure of the long-lived photoexcited state of methylcobalamin (MeCbl) and the cob(II)alamin photoproduct formed following photoexcitation of adenosylcobalamin (AdoCbl, coenzyme B12). For MeCbl, we used 520 nm excitation and a time delay of 100 ps to avoid the formation of cob(II)alamin. We find only small spectral changes in the equatorial and axial directions, which we interpret as arising from small (<∼0.05 Å) changes in both the equatorial and axial distances. This confirms expectations based on prior UV-visible transient absorption measurements and theoretical simulations. We do not find evidence for the significant elongation of the Co-C bond reported by Subramanian [ J. Phys. Chem. Lett. 2018 , 9 , 1542 - 1546 ] following 400 nm excitation. For AdoCbl, we resolve the difference XANES contributions along three unique molecular axes by exciting with both 540 and 365 nm light, demonstrating that the spectral changes are predominantly polarized along the axial direction, consistent with the loss of axial ligation. These data suggest that the microsecond "recombination product" identified by Subramanian et al. is actually the cob(II)alamin photoproduct that is produced following bond homolysis of MeCbl with 400 nm excitation. Our results highlight the pronounced advantage of using polarization-selective transient X-ray absorption for isolating structural dynamics in systems undergoing atomic displacements that are strongly correlated to the exciting optical polarization.

Diffuse Auroral Electron and Ion Precipitation Effects on RCM-E Comparisons With Satellite Data During the 17 March 2013 Storm.

Effects of scattering of electrons from whistler chorus waves and of ions due to field line curvature on diffuse precipitating particle fluxes and ionospheric conductance during the large 17 March 2013 storm are examined using the self-consistent Rice Convection Model Equilibrium (RCM-E) model. Electrons are found to dominate the diffuse precipitating particle integrated energy flux, with large fluxes from ~21:00 magnetic local time (MLT) eastward to ~11:00 MLT during the storm main phase. Simulated proton and oxygen ion precipitation due to field line curvature scattering is sporadic and localized, occurring where model magnetic field lines are significantly stretched on the night side at equatorial geocentric radial distances r 0 ≳8 R E and/or at r 0 ~5.5 to 6.5 R E from dusk to midnight where the partial ring current field has perturbed the magnetic field. The precipitating protons likewise contribute sporadically to the storm time Hall and Pedersen conductance in localized regions whereas the precipitating electrons are the dominate storm time contributor to enhanced Hall and Pedersen conductance at auroral magnetic latitudes on the night and morning side. The RCM-E model can reproduce general features of the Van Allen Probe/MagEIS observed trapped electron differential flux spectrograms over energies of ~37 to 150 keV. The simulations with a parameterized electron loss model also reproduce reasonably well the storm time Defense Meteorological Satellite Program integrated electron energy flux at 850 km at satellite crossings from predawn to midmorning. However, model-data agreement is not as good from dusk to premidnight where there are large uncertainties in the electron loss model.

Stable Platinum(IV) Corroles: Synthesis, Molecular Structure, and Room-Temperature Near-IR Phosphorescence.

A series of stable Pt(IV) corrole complexes with the general formula PtIV[TpXPC](m/p-C6H4CN)(py), where TpXPC3– is the trianion of a tris(p-X-phenyl)corrole and X = CF3, H, and CH3, has been synthesized, affording key physicochemical data on a rare and elusive class of metallocorroles. Single-crystal X-ray structures of two of the complexes revealed very short equatorial Pt–N distances of 1.94–1.97 Å, an axial Pt–C distance of ∼2.03 Å, and an axial Pt–N distance of ∼2.22 Å. The complexes exhibit Soret maxima at ∼430 nm, which are essentially independent of the meso-aryl para substituents, and strong Q bands with the most intense peak at 595–599 nm. The substituent-independent Soret maxima are consistent with an innocent PtIV–corrole3– description for the complexes. The low reduction potentials (−1.45 ± 0.08 V vs saturated calomel reference electrode) also support a highly stable Pt(IV) ground state as opposed to a noninnocent corrole•2– description. The reductions, however, are irreversible, which suggests that they involve concomitant cleavage of the Pt–aryl bond. Unlike Pt(IV) porphyrins, two of the complexes, PtIV[TpXPC](m-C6H4CN)(py) (X = CF3 and CH3), were found to exhibit room-temperature near-IR phosphorescence with emission maxima at 813 and 826 nm, respectively. The quantum yield of ∼0.3% is comparable to those observed for six-coordinate Ir(III) corroles.

A new high-spin iron(III) bis(aqua) complex with the meso-tetra(para-chlorophenyl)porphyrin: X-ray crystallography, Hirshfeld surface analysis, magnetic, EPR and electrochemical properties

Chemical preparation of the bis(aqua) iron(III) metalloporphyrin [FeIII(TClPP)(H2O)2](SO3CF3)·2(Pnz)·3/4(C6H12)·2H2O (TClPP = TClPP = 5,10,15,20-tetra(para-chlorophenyl)porphyrinato and Pnz = phenazine) coordination complex (I) was made. The crystal structure of (I) was determined by X-ray single-crystal diffraction and elucidated by Hirshfeld surface approach. Magnetic, spectroscopic and electrochemical properties were also reported and discussed. The mean equatorial distance (Fe–Np) between the iron(III) atom and porphyrin nitrogen atoms is appropriate to a high-spin (S = 5/2) iron(III) complex. The high-spin state is also confirmed by both magnetic and electron paramagnetic resonance (EPR) spectroscopy data. The repetitive building unit of the crystal structure provides [FeIII(TClPP)(H2O)2]+ ion complexes, two non-coordinated Pnz molecules and two water molecules which are interconnected by O–H···O/N/Cl, C–H···O/F/Cl hydrogen bonds, and by C–X···π, C–H···π and π–π stacking intermolecular contacts, forming a 3D supramolecular network. The role and nature of these intermolecular interactions were quantitatively analysed by 3D Hirshfeld surface analysis and associated 2D fingerprint plots. Cyclic voltammetry measurements indicate a one-electron reversible reduction wave with an E1/2 (Fe(III)/Fe(II) half-potential value of −0.24 V, which confirms the high-spin S = 5/2 state of the studied complex.