Apical Position Research Articles

Effects of Bromine Doping on the Structural Properties and Band Gap of CH3NH3Pb(I1-x Br x )3 Perovskite.

An experimental and theoretical study is reported to investigate the influence of bromine doping on CH3NH3Pb(I1–xBrx)3 perovskite for Br compositions ranging from x = 0 to x = 0.1, in which the material remains in the tetragonal phase. The experimental band gap is deduced from UV–vis absorption spectroscopy and displays a linear behavior as a function of bromine concentration. Density functional theory calculations are performed for five different series of randomly doped structures in order to simulate the disorder in bromine doping sites. The computations predict a linear variation of the lattice parameters, supercell volume, density, band gap, and formation energy in the considered doping range. The calculated evolution of the band gap as the function of Br doping is in excellent agreement with the experimental data, provided that different Br doping configurations are included in the simulations. The analysis of the structural and electronic properties shows a correlation between the increase of the band gap and the increased distortion of the Pb(I1–xBrx)6 octahedrons. Additionally, the simulations suggest that in CH3NH3Pb(I1–xBrx)3 bromine doping is likely to occur at both the equatorial and apical positions of the octahedrons.

CARDIAC RHYTHM MANAGEMENTPredictors and management of cardiac perforation caused by cardiac rhythm device implantation

Abstract Background Cardiac perforation caused by cardiac rhythm device implantation is uncommon but potentially lethal. Methods All patients presenting to a single referral centre with cardiac perforation after implantation between December 2017 and July 2019 were identified. Patient demographics, time to diagnosis, the method of lead extraction and 30-day complications were examined. Results Thirteen cases of cardiac perforation were identified, 4 of which were implanted at other hospitals. The incidence of perforation for devices implanted at our institution was 9/1031 (0.87%). Median time from implantation to diagnosis was 8 days (IQR = 3–21). Compared with implantations during the same time period, patients with perforation were older (80 ± 10 years vs. 73 ± 15 years, P = 0.005) and predominantly females (9/13 vs. 355/1031, P = 0.009). In all cases, the perforating lead was an active fixation model, an ICD coil in one case. 10 leads were in the right ventricle (3 of which in apical position) and 3 in the right atrium (all in the lateral wall). There was no greater proportion of a particular lead type compared with implantations during the same time period. All had abnormal electrical parameters at device interrogation. Nine patients (69%) had pericardial effusion and four (31%) developed tamponade. Transvenous lead extraction was successfully performed in all 13 patients, with no 30-day mortality. Conclusion Older age and female gender were more prevalent in patients with lead perforation. Transvenous lead extraction was safely performed in all patients.

69-YEAR-OLD MALE WITH ENTRAPPED CHEST TUBE: COMPLICATION OF CPR

SESSION TITLE: Medical Student/Resident Critical Care Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Cardiopulmonary resuscitation (CPR) is a lifesaving intervention routinely performed in medical institutions. However, it is associated with multiple complications including rib fractures requiring thoracostomy tube (TT) insertion. Additionally, there is a paucity of evidence identifying complications of CPR with a TT present. Here we describe a case of a patient who had their TT break due to CPR. CASE PRESENTATION: A 69-year-old male presented as a level two trauma status post motor vehicle collision. His initial injury severity score was 29 with injuries including: left-sided rib fractures with flail segment of ribs 1-6, left hemopneumothorax, comminuted fracture of the left scapular body and spine, left clavicle fracture with emphysema and hematoma. The patient was admitted to the surgical intensive care unit with management including a thoracotomy for rib plating and evacuation of the hematoma. Preoperative imaging is shown in Figure 1. The patient underwent left posterolateral thoracotomy with open reduction and internal fixation of left ribs 3-7 with evacuation of subcutaneous hematoma and left hemothorax. A 28 French TT was placed in the left posterior apical position, and a curved 28 French TT was placed in the left posterior inferior position. A postoperative chest x-ray confirmed lung re-expansion (Figure 2). On post-operative day 1, the patient became hypoxic, hypotensive, and bradycardic leading to cardiac arrest. Advanced cardiac life support was initiated including CPR and epinephrine for eight minutes until return of spontaneous circulation was achieved. A chest x-ray post arrest was taken showing the rib plating was intact. On post-operative day 2, removal of the TT was attempted. The distal portion of the left TT broke and remained within the thoracic cavity. A computed tomography of the chest (Figure 3) showed the broken portion of the tube. On post-operative day 3, the patient underwent left mini thoracotomy, removal of the retained TT under ultrasound guidance, and replacement of the apical TT. The distal end of the curved chest tube was found to be entrapped within the anterior rib fractures that resulted from CPR and successfully removed. The rest of the patient’s admission was unremarkable and he was discharged to a rehabilitation facility. DISCUSSION: To our knowledge this is one of the first cases to describe entrapment of a TT as a result of CPR. Additionally, this is one of the few cases to describe the use of a thoracotomy for removal of an entrapped tube. Thoracotomy has been reported as a management strategy in a similar case in which a nasogastric tube became entrapped intratracheally following lobectomy. There remains a paucity of data on the true incidence of abnormal positioning of tubes and the role of thoracotomy in the management of these patients. CONCLUSIONS: We present the case of a broken entrapped TT and successful removal via thoracotomy. Reference #1: Hoke RS, Chamberlain D. (2004). Skeletal chest injuries secondary to cardiopulmonary resuscitation. Resuscitation, 63(3):327-38. Reference #2: Deliliga A, Chatzinikolaou F, Koutsoukis D, Chrysovergis I, Voultsos P. (2009). Cardiopulmonary resuscitation (CPR) complications encountered in forensic autopsy cases. BMC Emergency Medicine, 28;19(1):23. DISCLOSURES: No relevant relationships by Jordan Debbrecht, source=Web Response No relevant relationships by Katherine Foerster, source=Web Response no disclosure on file for Brian Gilbert; No relevant relationships by Michael Nguyen, source=Web Response no disclosure on file for George Philip; No relevant relationships by William Waswick, source=Web Response

Changes in mucogingival junction after an apically positioned flap with collagen matrix at sites with or without previous guided bone regeneration: A prospective comparative cohort study.

To assess changes in the position of the mucogingival junction (MGJ) after an apically positioned flap (APF) with collagen matrix performed at sites with or without previous guided bone regeneration (GBR). Dental implants were placed with or without GBR (group GBR or non-GBR) depending on the available ridge width in 30 patients with a limited width of keratinized mucosa (MGJ placed more coronally than the expected prosthetic margin). An apically positioned flap with collagen matrix was performed in both groups. Changes in the position of the MGJ from the day of an apically positioned flap up to 1, 3, and 12months thereafter were assessed on digital scans (primary endpoint). Secondary endpoints were the width and thickness of the keratinized mucosa, and the position of the mucosal margin. The position of the MGJ changed significantly from baseline to the first month, by 5.25±2.10 and 4.40±1.41mm in groups GBR and non-GBR, respectively. Thereafter, the position remained stable in both groups up to 1year (changes from baseline of 5.46±2.28 and 4.58±1.92 mm, respectively; p=.34). The position of the mucosal margin did not differ between groups GBR and non-GBR (-1.57±2.04 and -1.75±2.08mm, respectively; p=.84), nor did the width of the keratinized mucosa (1.20±1.03 and 0.99±0.66mm, p=.91) or its thickness (1.28±0.44 and 1.40±0.78mm, p=.87). Apically positioned flap combined with a collagen matrix results in a more apical position of the MGJ at sites with or without GBR. Following a coronal shift during the first month after the apical positioning of the flap, the level of the MGJ remained stable.

Coordination behavior of succinylsulfathiazole – Crystal structure of [Cu(SST).(Pyridine)3.H2O]n, DNA interaction and cytotoxic studies

Mononuclear copper complex of succinylsulfathiazole has been synthesized and characterized using relevant spectroscopic and X-ray diffraction techniques. EPR data and X-ray structural analysis confirmed that Cu(II) ion exhibits an intermediate geometry between trigonal and square bipyramid. Succinylsulfathiazole (SST) ligand behaves as a head-to-tail bridging moiety linking two metal (Cu) cations via carbonyl oxygen and thiazolate nitrogen atom, resulting one dimensional polymeric chain running along [010] direction. In the mononuclear copper complex formulated as [Cu(SST).(Pyridine)3.H2O]n, three nitrogen atoms of three secondary ligand pyridines coordinated to copper at the equatorial plane, the fourth coordination of distorted pentadentate copper is due to thiazolate nitrogen (N3) occupying the apical position and carbonyl oxygen (O1) of SST ligand at -x + 1/2, y-1/2, -z-1/2 remaining at fifth coordination site completes the coordination sphere of copper. The inversely related Cu-SST molecular complexes are held together by pair of NH…O dimer forming R22(14) graph set motif which are further connected by water oxygen (O6) via OH…O interactions. Quantitative contributions of intermolecular interactions are worked out using Hirshfeld surface (HS) and 2D fingerprint plots. Lipophilicity index (Log P), correlates well with the% contribution of CH…π interaction. To evaluate the binding capabilities and binding mode of molecular complex with CT-DNA, absorption study and viscosity measurement are carried out, confirming the intercalation mode of binding which is further supported by molecular docking studies. In vitro cytotoxicity screening of the complex have been performed on zoological species Artemia cyst.

Buccal bone thickness of maxillary anterior teeth: A systematic review and meta-analysis.

To systematically review buccal bone thickness (BBT) in the anterior maxilla in different teeth, age groups and genders. PubMed, EMBASE and Cochrane databases were searched up to April 2020. Clinical and radiographic studies reporting on BBT of maxillary anterior teeth, with at least 10 patients, were included. A meta-analysis was performed using random effect models to report differences of BBT. 50 studies were included. Using bone crest (BC) as a reference point, no significant differences were found in BBT between different tooth types, except for 0.16mm (95%-CI: 0.02-0.30) increased mid-root thickness of premolars compared to canines. Using the CEJ as a reference point, canines presented with a significantly increased thickness of 0.32mm (95%-CI: 0.11-0.54) coronally compared to laterals. When BC was used as reference, males demonstrated a significantly increased thickness of 0.21mm (95%-CI: 0.15-0.27) apically, while middle-aged adults showed a 0.06mm (95%-CI: -0.12, -0.01) statistically significant increase in the coronal level compared to older adults. Few maxillary anterior teeth have BBT greater than 1mm. Buccal bone tends to get thicker from a coronal to apical position along the root surface and from an anterior to posterior position in the arch.

Effect of head position on cochlear implant MRI artifact.

A new generation of cochlear implant (CI) magnets and specific surgical techniques (e.g., implant positioning) has changed the relationship between a CI and magnet resonance imaging (MRI). MRI allows a pain free in vivo evaluation of the inner ear fluid state and internal auditory canal after the insertion of an electrode. The aim of this study is to evaluate how the patient's head position in the MRI scanner influences the CI magnet-related artefact. We performed in vivo measurement of MRI artefacts at 3T with a CI system containing a bipolar diametrical magnet. The implant magnet was positioned with a head bandage at different positions from the nasion and external auditory canal in three volunteers. We used a turbo spin echo (TSE) T2w sequence on the axial and coronal planes and observed three positions: (1) regular position, (2) chin to chest (anteflexion), and (3) hyperextension (retroflexion). By comparing the positions, anteflexion of the cervical spine in a chin-to-chest position allowed us to place the artefact in a more apical position from the IAC in the coronal plane. The hyperextension of the cervical spine position shifts the artefact father towards the cochlea's direction. The head's position can influence the location of MRI artefacts. In cases where the artefact diminished the IAC or cochlea, anteflexion of the cervical spine in the chin-to-chest position of the head in the MRI scanner should be attempted to allow a visualization of the IAC.

Assessing the role of women in tourism related sectors in the Caribbean

AbstractThis study contributes to the rapidly growing literature on women in tourism. It focuses on a group of 13 Caribbean countries. The study analyses the impact of women in apical positions within firms (top manager or owner) on firm performance—productivity, profitability and female employment. For this both a decomposition model and the inverse probability weighted regression adjustment estimator are used. The analysis finds that opportunities for women in these positions in the Caribbean are constrained to less productive and profitable firms, as elsewhere. However, those firms with females at the top employ more women, particularly in management roles.

Pentanuclear Scaffold: A Molecular Platform for Small-Molecule Conversions.

Small-molecule conversions involving multielectron transfer processes enable the conversion of earth-abundant materials into valuable chemicals and are regarded as a solution for environmental and energy shortage problems. In this context, the development of artificial catalysts that promote these reactions is an important research target. In nature, metalloenzymes that contain multinuclear metal complexes as active sites are known to efficiently catalyze reactions under mild conditions. Therefore, using multinuclear metal complexes as artificial catalysts can be an attractive strategy for small-molecule conversions involving multielectron transfer processes. However, multinuclear-metal-complex-based catalysts for these reactions have not been well established. In this Account, we describe our recent advances in the development of multinuclear metal complexes as catalysts for small-molecule conversion, mainly focusing on water oxidation. As small-molecule conversions involving multielectron transfer processes consists of two essential processes, (1) the transfer of multiple electrons and (2) the formation/cleavage of covalent bond(s), catalysts for these reactions should facilitate both steps. Therefore, we assumed that the assembly of redox-active metal ions and the cooperative effect of neighboring coordinatively unsaturated metal ions can promote these processes. On the basis of this assumption, we employed a pentanuclear metal complex as a molecular scaffold for the catalyst. The scaffold has a pentanuclear structure with quasi-D3 symmetry and consists of a [M3(μ3-X)] core (X = O2- or OH-) wrapped by two [M(μ-bpp)3] units (Hbpp = 3,5-bis(2-pyridyl)pyrazole). The metal ions in the triangular core are coordinatively unsaturated, whereas the metal ions at the apical positions are coordinatively saturated. In other words, the pentanuclear scaffold possesses multiple redox-active centers and coordinatively unsaturated sites. It should also be noted that the electron transfer ability of the complex changes dramatically depending on the identity of the constituent metal ions. The iron derivative of the pentanuclear scaffold was found to serve as an electrocatalyst for water oxidation (2H2O → O2 + 4e- + 4H+) with a high reaction rate and excellent robustness. The substitution of metal ions in the pentanuclear scaffold to cobalt ions resulted in the development of a catalyst for CO2 reduction. Furthermore, we investigated the effect of substituents on the ligands of the pentanuclear iron complex and succeeded in precisely manipulating the electron transfer possess. These results clearly demonstrate that the pentanuclear scaffold is an attractive platform for catalysts for small-molecule conversions. Additionally, the intrinsic features of the multinuclear catalytic system, which are totally different from those of conventional mononuclear-metal-complex-based catalysts, are disclosed. In reactions mediated by multinuclear complexes, the multinuclear core can initially accumulate the charge required for catalysis to reach the catalytically active state. Subsequently, the catalyst in the active state reacts with the substrate, initiating electron transfer to the substrate and rearrangement of covalent bonds in the substrate to afford the product. In such a mechanism, the desired number of electrons can be transferred to the substrates in an on-demand fashion, and the formation of undesired chemical species in the targeted catalysis may be prevented. This feature of multinuclear-metal-complex-based catalysts will achieve demanding small-molecule conversions with a high reaction rate, selectivity, and durability.

Structure of a diorganotelluroxonium(IV) cation, {[2,6-(CH2NMe2)2C6H3Te(μ-O)]2}2+, with the tri-chlorido-(dimethyl sulfoxide)-platinum(II) anion.

In the title salt, di-μ-oxido-bis-{2,6-bis-[(di-methyl-amino)-meth-yl]phenyl-κC 1}tellurium(-IV) bis[tri-chlorido-(dimethyl sulfoxide-κS)platinate(II)], (C24H38N4O2Te2)[PdCl3(C2H6OS)]2, which crystallizes in the triclinic space group P , each Te atom is in a distorted five-coordinated TeO2N2C square-pyramidal geometry (τ values of 0.026 and 0.001) with the C atoms of the phenyl rings occupying the apical positions. The phenyl rings in the [C24H38N4O2Te2]2+ cation are in a cis arrangement to enable this species to participate in Te⋯Cl cation-anion inter-actions. There are also C-H⋯O inter-actions involving the dimethyl sulfoxide ligands and numerous cation-anion and anion-anion C-H⋯Cl inter-actions, which link the ions into a complex three-dimensional array.

Photoreceptor progenitor dynamics in the zebrafish embryo retina and its modulation by primary cilia and N-cadherin.

Photoreceptor cells of the vertebrate neural retina originate in the neuroepithelium, and like other neurons, must undergo cell body translocation and polarity transitions to acquire their final functional morphology, which includes features of neuronal and epithelial cells. We analyzed this process in detail in zebrafish embryos using in vivo confocal microscopy and electron microscopy. Photoreceptor progenitors were labeled by the transgenic expression of enhanced green fluorescent protein under the regulation of the photoreceptor-specific promoter crx, and structures of interest were disrupted using morpholino oligomers to knock-down specific genes. Photoreceptor progenitors detached from the basal retina at pre-mitotic stages, rapidly retracting a short basal process as the cell body translocated apically. They remained at an apical position indefinitely to form the outer nuclear layer (ONL), initially extending and retracting highly dynamic neurite-like processes, tangential to the apical surface. Many photoreceptor progenitors presented a short apical primary cilium. The number and length of these cilia was gradually reduced until nearly disappearing around 60 hpf. Their disruption by knocking-down ift88 and elipsa caused a notorious defect on basal process retraction. To assess the role of cell adhesion in the organization of photoreceptor progenitors, we knocked-down cdh2/N-cadherin and observed the cell behavior by time-lapse microscopy. The ectopic photoreceptor progenitors initially migrated in an apparent random manner, profusely extending cell processes, until they encountered other cells to establish cell rosettes in which they stayed, acquiring photoreceptor-like polarity. Altogether, our observations indicate a complex regulation of photoreceptor progenitor dynamics to form the retinal ONL, previous to the post-mitotic maturation stages.

Formation of a nona-nuclear copper(II) cluster with 3,5-di-methyl-pyrazolate starting from an NHC complex of copper(I) chloride.

The complete nona-nuclear cluster in bis-[1,3-bis-(2,6-di-methyl-phen-yl)imid-azol-ium] di-μ-chlorido-tetra-chlorido-octa-kis-(μ-3,5-di-methyl-pyrazolato)hexa-μ3-hydroxido-nona-copper(II) chloro-form disolvate, [HIXy]2[Cu9(μ-pz*)8(μ3-OH)6(μ2-Cl)2Cl4]·2CHCl3 or (C19H21N2)2[Cu9(C5H7N2)8Cl6(OH)6]·2CHCl3, where pz* is the 3,5-di-methyl-pyrazolyl anion, C5H7N2 -, and HIXy is the 1,3-bis-(2,6-di-methyl-phen-yl)imidazolium cation, C19H21N2 +, is generated by a crystallographic centre of symmetry with a square-planar CuII ion bound to four μ3-OH ions lying on the inversion centre. Of the four remaining unique CuII atoms, three adopt CuN2O2Cl square-pyramidal coordination geometries with the chloride ion in the apical position and one has a distorted CuN2OCl tetra-hedral geometry. The dianionic nona-nuclear core can be described as a 24-membered [CuNN]8 ring that contains a Cu9O6Cl6 core. The cluster features three intra-molecular O-H⋯Cl hydrogen bonds. In the crystal, weak C-H⋯N and C-H⋯Cl inter-actions link the components. Polynuclear paramagnetic clusters of this type are of considerable inter-est due to their relevance to both the bioinorganic and single-mol-ecule magnets research fields.

Risk factors for maxillary impacted canine–linked severe lateral incisor root resorption: A cone-beam computed tomography study

Impacted maxillary canine-linked severe lateral incisor root resorption (SIRRc) is rare, but it greatly influences the survival of the affected teeth. Our study was designed to investigate the risk factors for SIRRc. Eighty-two patients with SIRRc and 81 patients with impacted maxillary canines but without SIRRc were included and evaluated by cone-beam computed tomography in software programs by 1 examiner (H.W.). Age, sex, positions, and dental follicles and angular inclinations of impacted canines were measured in this study. Binary logistic regression was used to analyze the risk factors for SIRRc. SIRRc was highly related to sex, vertical and mesiodistal position, dental follicles sizes of canines, and intersection angles in 3dimensions.The regression analysis showed female sex, dental follicles between 1mm and 3mm, mesial third and apical third position, vertical angle smaller than 30°, and the relative angle between 30° and 60° were significant risk factors for SIRRc. Early diagnosis and treatment for SIRRc are imperative, especially in Asian patients that are female with apically and mesially positioned canines as well as wider dental follicles. Vertical angles and relative angles of impacted canines should also be noticed.

Effect of alkyl substituent on molecular configuration in a Cu(II) complex: Synthesis of Cu and CuO nanoparticles using a single, solid-source precursor

A new hydrazone-type ligand, methyl 4-(pyridine-4yl-methylene) hydrazinecarboxylate (C8H9N3O2; 4-pymc) and its Cu(II) complex [Cu(4-pymc)2(CH3COO)2(H2O)] (1) were prepared and characterized. The structure of 1 comprises monomers in which Cu is five-coordinated with a distorted square pyramidal structure. Oxygen atoms of two monodentate acetate anions and a pair of nitrogen atoms from pyridine rings form the basal plane. The apical position is filled by a water molecule. Further, the TEM images demonstrated successful preparation of both Cu (~35 nm) and CuO (~95 nm) nanoparticles (NPs) using the single source as-prepared Cu(II) complex via a thermal decomposition approach simply by changing the atmospheric conditions (i.e., vacuum and air atmospheres) under which the Cu(II) complex was calcined for 1 h at 400 °C. Furthermore, the TG-DTA studies indicate that 1 underwent endo- followed by exo-thermic decomposition to form CuO as the end residue in an air atmosphere. The production of Cu and CuO NPs was corroborated by powder x-ray diffraction (PXRD) analysis. The sharp and high intensity PXRD peaks of the calcined samples corroborated that the formed NPs had no impurity and high crystallinity. Furthermore, both ligand and Cu(II) complex showed photoluminescence properties. Also, we demonstrated that the prepared 1 can act as a single, solid-source precursor to form both Cu and CuO NPs.

Structural characterization of the derivatives of bis{[2,6-(dimethylamino)methyl]phenyl} selenide with palladium(II) and mercury(II).

The intramolecularly coordinated homoleptic diorgano selenide bis{2,6-bis[(dimethylamino)methyl]phenyl} selenide, C24H38N4Se or R2Se, where R is 2,6-(Me2NCH2)2C6H3, 14, was synthesized and its ligation reactions with PdII and HgII precursors were explored. The reaction of 14 with SO2Cl2 and K2PdCl4 resulted in the formation of the meta C-H-activated dipalladated complex {μ-2,2'-bis[(dimethylamino)methyl]-4,4'-bis[(dimethylazaniumyl)methyl]-3,3'-selanediyldiphenyl-κ4C1,N2:C1',N2'}bis[dichloridopalladium(II)], [Pd2Cl4(C24H38N4Se)] or [{R(H)PdCl2}2Se], 15. On the other hand, when ligand 14 was reacted with HgCl2, the reaction afforded a dimercurated selenolate complex, {μ-bis{2,6-bis[(dimethylamino)methyl]benzeneselanolato-κ4N2,Se:Se,N6}-μ-chlorido-bis[chloridomercury(II)], [Hg2(C12H19N2Se)Cl3] or RSeHg2Cl3, 16, where two HgII ions are bridged by selenolate and chloride ligands. In palladium complex 15, there are two molecules located on crystallographic twofold axes and within each molecule the Pd moieties are related by symmetry, but there are still two independent Pd centers. Mercury complex 16 results from the cleavage of one of the Se-C bonds to form a bifurcated SeHg2 moiety with the formal charge on the Se atom being -1. In addition, one of the Cl ligands bridges the two Hg atoms and there are two terminal Hg-Cl bonds. Each Hg atom is in a distorted environment which can be best described as a T-shaped base with the bridging Cl atom in an apical position, with several angles close to 90° and with one angle much larger and closer to 180°.

Diastereoisomerically Pure, (S)-O-1,2-O-isopropyli dene-(5-O-α-d-glucofuranosyl) t-butanesulfinate: Synthesis, Crystal Structure, Absolute Configuration and Reactivity

The reaction of t-butylmagnesium chlorides with diastereomerically pure (R)-1,2-O-isopropylidene-3,5-O-sulfinyl-α-d-glucofuranose (R)-4 was found to be stopped at the stage of the corresponding, diastereoisomerically pure 1,2-O-isopropylidene-(5-O-α-d-glucofuranosyl) t-butanesulfinate (S)-10 for which the crystal structure and the (S)-absolute configuration was determined by X-ray crystallography. Comparison of the absolute configurations of the starting sulfite (R)-4, and t-butanesulfinate (S)-10 (which crystallizes in the orthorhombic system, space group P212121, with the single compound molecule present in the asymmetric unit), clearly indicates that the reaction of nucleophilic substitution at the stereogenic sulfur atom in the sulfite (R)-4 occurs with the full inversion of configuration via the trigonal bipyramidal sulfurane intermediate 4c in which both the entering and leaving groups are located in apical positions.

Di-aqua-bis-{μ-1,5-bis-[(pyridin-2-yl)methyl-idene]carbonohydrazide(1-)}di-μ-chlorido-tetra-chlorido-tetra-zinc(II).

A tetra-nuclear ZnII complex, [Zn4(C13H11N6O)2Cl6(H2O)2] or {[Zn2(HL)(H2O)(Cl2)](μCl)2[Zn2(HL)(H2O)(Cl)]}2, was synthesized by mixing an equimolar amount of a methanol solution containing ZnCl2 and a methanol solution containing the ligand H2 L [1,5-bis-(pyridin-2-yl-methyl-ene)carbono-hydrazide]. In the tetra-nuclear complex, each of the two ligand mol-ecules forms a dinuclear unit that is connected to another dinuclear unit by two bridging chloride anions. In each dinuclear unit, one ZnII cation is penta-coordinated in a N2OCl2 in a distorted square-pyramidal geometry, while the other ZnII cation is hexa-coordinated in a N3OCl2 environment with a distorted octa-hedral geometry. The basal plane around the penta-coordinated ZnII cation is formed by one chloride anion, one oxygen atom, one imino nitro-gen atom and one pyridine nitro-gen atom with the apical position occupied by a chloride anion. The basal plane of the hexa-coordinated ZnII cation is formed by one chloride anion, one hydrazinyl nitro-gen atom, one imino nitro-gen atom and one pyridine nitro-gen atom with the apical positions occupied by a water oxygen atom and a bridged chloro anion from another dinuclear unit, leading to a tetra-nuclear complex. A series of intra-molecular C-H⋯Cl hydrogen bonds is observed in each tetra-nuclear unit. In the crystal, the tetra-nuclear units are connected by inter-molecular C-H⋯Cl, C-H⋯O and N-H⋯O hydrogen bonds, forming a planar two-dimensional structure in the ac plane.

Synthesis, crystal structure, and thermal behavior of a diiron toluenethiolate complex with triphenylphosphine coligand

A bis(p-toluenethiolato) dinuclear-carbonyl complex with triphenylphosphine coligand, [μ-(SC6H4CH3-p)2Fe2(CO)5(PPh3)], has been synthesized from [μ-(SC6H4CH3-p))2Fe2(CO)6] via facile CO substitution by PPh3 in 33% yield. The structure of [μ-(SC6H4CH3-p)2Fe2(CO)5(PPh3)] has been determined by X-ray crystallography and spectroscopic measurements. In the solid state, the compound adopts a butterfly conformation with anti-orientation of the p-tolyl groups and apical position of triphenylphosphine. Thermogravimetric studies reveal that [μ-(SC6H4CH3-p)2Fe2(CO)5(PPh3)] undergoes sequential decomposition eliminating all of the CO ligands at ca 197 °C, followed by cleavage of the tolyl and PPh3 groups below ca 258 °C.

The assessment of patients with situs inversus and corrected transposition of the great arteries

IntroductionCongenitally corrected transposition of the great arteries (ccTGA) is a rare congenital heart defect. There are different subgroups according to the location of the heart in the thorax, apical position and situs. ObjectivesThe purpose of this study was to assess pediatric patients with situs inversus (SI) ccTGA (SI-ccTGA), a rare subgroup of this condition, in detail. MethodsThe records of patients with SI-ccTGA followed between January 1, 2010 and January 1, 2019 in our clinic were analyzed retrospectively. Demographic features, associated cardiac defects, arrhythmias and follow-up data were recorded. ResultsTwenty-one out of 120 ccTGA patients had SI. The median age was 30 months (4 days-18 years). There were hemodynamically significant associated lesions in 85.7% (n=18) of the patients. A large ventricular septal defect was found in 16 patients (76.2%), severe pulmonary stenosis in 11 (52.4%), pulmonary atresia in six (28.5%), and severe tricuspid regurgitation in two (9.5%). Eleven out of 21 patients had biventricular physiology and eight had single-ventricle physiology. Bidirectional cavopulmonary anastomosis followed by a hemi-Mustard-Rastelli operation were planned for the remaining two patients. Twelve out of 18 patients with associated defects (66.6%) were operated and surgery was planned for three more patients (16.6%). The remaining three patients were scheduled for clinical follow-up. Arrhythmias developed in two (9.5%) patients on follow-up; ablation was performed in one of them and pacemaker implantation followed by cardiac resynchronization therapy was performed in the other. Two patients died during follow-up, one after a central shunt operation and the other preoperatively due to pneumonia and sepsis. ConclusionSI-ccTGA is not a mirror image of situs solitus ccTGA (SS-ccTGA) due to important anatomic and physiologic differences between them. SI-ccTGA patients have a lower risk of tricuspid valve regurgitation than SS-ccTGA patients. The timing of clinical presentation of these patients mainly depends on the type and severity of the associated lesions, as in all subtypes of ccTGA.

Mononuclear Antimony(V) Catecholate Complexes with Additional Pyridine Ligands

A series of triarylantimony(V) complexes with p-dimethylaminopyridine and р-cyanopyridine of the general formulas [(Cat)SbAr3(р-Me2N–Py)] (complexes I–IV) and [(Cat)SbAr3(р-CN–Py)] (complexes V–VII) has been synthesized. Their molecular structures and electrochemical properties have been studied. 3,6-Di-tert-butyl-o-benzoquinone, 4,5-piperazine-1,4-diyl-3,6-di-tert-butyl-o-benzoquinone, and 4,5-dichloro-3,6-di-tert-butyl-o-benzoquinone are used as redox-active ligands. The molecular structures of several complexes in the crystalline state are determined by X-ray diffraction analysis (CIF files CCDC nos. 1974173 (I ⋅ 0.5toluene), 1974174 (II ⋅ 2toluene), 1974175 (V), 1974176 (VI ⋅ hexane), and 1974177 (VII)). All complexes have a distorted octahedral structure, and an additional neutral pyridine ligand occupies one of the apical positions. Electrochemical transformations of the complexes are studied by cyclic voltammetry in a dichloromethane solution. The introduction of substituted pyridine into the molecule of the complex does not change the electrooxidation mechanism of the complexes. For all complexes with р-dimethylaminopyridine, both oxidation potentials are shifted to the cathodic region (0.13–0.21 V for the potential of the first oxidation process and to 0.3–0.4 V for the potential of the second oxidation process). A similar shift for the complex with p-cyanopyridine is less pronounced (0.05 V for the potential of the first oxidation process of complex V as compared to that of complex I).