Cu(II)-Ln(III) (Ln = Gd, Tb and Dy) complexes of an unsymmetrical N2O3 donor ligand: field induced SMM behaviour of Cu(II)-Tb(III) complexes.

Three new hetero-metallic CuII-LnIII complexes [(CuL)Gd(NO3)3(CH3OH)]n (1), [(CuL)Tb(NO3)3(H2O)]·[CuL] (2) and [(CuL)Dy(NO3)3(H2O)]·[CuL] (3) have been synthesized using a mono-nuclear Cu(II) complex, [CuL], of an unsymmetrically di-condensed N2O3 donor Schiff base ligand, N-(3-methoxysalicylidene)-N-(salicylidene)-1,2-ethylenediamine (H2L). Single crystal X-ray crystallography revealed that complex 1 is a nitrate bridged 1D chain of dinuclear Cu(II)-Gd(III) units whereas in 2 and 3, the dinuclear Cu(II)-Ln(III) units are co-crystallized with a [CuL] unit. The Ln(III) centers are nine coordinated with the geometry of a spherical capped square antiprism for Gd and spherical tricapped trigonal prism for Tb and Dy. The geometry of the Cu(II) center is distorted octahedral for complex 1 and distorted square planar for complexes 2 and 3. Temperature-dependent molar magnetic susceptibility measurements in 1-3 revealed the presence of overall ferromagnetic coupling between the Cu(II) and Ln(III) centers. Notably, field induced single-molecule magnet behavior was witnessed in the Tb(III) derivative (2). The ab initio calculations indicated that upon application of an external magnetic field, the tunneling in the ground state of complex 2 gets reduced and thereby field-induced SMM behaviour is observed. Besides, in the case of complex 1, BS-DFT calculations were carried out to gain further insights into the magnetic exchange coupling interactions between the Cu(II) and Gd(III) centers.

Role of Redox-Inactive Metal Ions in Modulating the Reduction Potential of Uranyl Schiff Base Complexes: Detailed Experimental and Theoretical Studies.

A mononuclear uranyl complex, [UO2L] (1), has been synthesized with the ligand N,N'-bis(3-methoxy-2-hydroxybenzylidene)-1,6-diamino-3-azahexane (H2L). The complex showed a reversible U(VI)/U(V) redox couple in cyclic voltammetric measurements. The reduction potential of this couple showed a positive shift upon the addition of redox-inactive alkali- and alkaline-earth Lewis acidic metal ions (Li+, Na+, K+, Ca2+, Sr2+, and Ba2+) to an acetonitrile solution of complex 1. The positive shift of the reduction potential has been explained on the basis of the Lewis acidity and internal electric-field effect of the respective metal ions. The bimetallic complexes [UO2LLi(NO3)] (2), [UO2LNa(BF4)]2 (3), [UO2LK(PF6)]2 (4), [(UO2L)2Ca]·(ClO4)2·CH3CN (5), [(UO2L)2Sr(H2O)2]·(ClO4)2·CH3CN (6), and [(UO2L)2Ba(ClO4)]·(ClO4) (7) have also been isolated in the solid state by reacting complex 1 with the corresponding metal ions and characterized by single-crystal X-ray diffraction. Density functional theory calculations of the optimized [UO2LM]n+ complexes have been used to rationalize the experimental reduction and electric-field potentials imposed by the non-redox-active cations.

Patterns and Management of Unprovoked Bull Attack Injuries: A Retrospective Case Series.

Introduction Animal attacks cause a considerable number of injuries and lead to morbidity and mortality among children and adults. Bull gore injuries following bullfighting and other provoked attacks have been frequently described in literature. Our study describes the pattern of injuries and the unique mechanisms and management of blunt and penetrating trauma associated with unprovoked bull attacks. Methods In this retrospective study, we collected the data of 36 patients presenting to our emergency department with a history of bullhorn injury. The data comprised age, sex, location of injury, type and description of the injury, surgical procedure performed if any, requirement of postoperative intensive care unit (ICU) admission, and mortality. The data were then compiled and analyzed with MS Excel. Results Among the 36 patients, blunt injuries constituted 58.3% of cases, whereas penetrating injuries were seen in 41.7%. Men were commonly injured with a mean age of 39.1 years. Thorax (36%) and abdomen (33%) were the common sites of injury followed by perineum (17%), head (5%), spine (6%), and extremity (2%). Fall following the impact of bull led to indirect injuries, such as intracranial hemorrhage, parietal bone fracture, cervical spine injuries, and tibial fracture. More than half of the patients (n=19, 52.8%) required some form of surgery under local or general anesthesia. Among the operated patients, seven required postoperative ICU care and two expired. Conclusion Animal attack injuries represent a less explored niche of surgical conditions. Management in the emergency department includes prompt resuscitation to achieve hemodynamic stability, thorough wound wash to remove the contaminants, and appropriate imaging, if indicated. Wound exploration is recommended for penetrating injuries and on a case-to-case basis for blunt injuries. The complications of these wounds are due to multiple wound paths, muscle tearing, evisceration of internal organs, and high risk of wound infection.

Quality of Life of Patients With Major Amputations in the Tertiary Care Center of Western Rajasthan: A Prospective Observational Study in 2019-2020.

Introduction Amputation of a limb is a loss of physical integrity that has disastrous consequences for a person's mental, physical, and social well-being. Aim We aim to analyze the quality of life (QoL) after major amputations and long-term outcomes. Method and materials A prospective, observational study has been conducted in a health care institute in western Rajasthan from January 2019 to July 2020. This study included 64 patients who had major upper or lower limb amputations. We analyzed the sociodemographic factors of the patients, the type of procedure, postoperative hospital stay, complications, and follow-up status with both the SF-12 and the World Health Organization Quality of Life (WHOQOL)-BREF questionnaires. Mean, median, range, standard deviation, percentages, univariable, and multivariable logistic regression were analyzed with SPSS version 23.0 software (IBM Corp., Armonk, NY). Results The mean age of the study patients was 53.6 years (SD 2.6) and they were mostly male (71.9%). Atherosclerotic peripheral vascular disease (PVD) was the most common indication (37.5%) of amputation, and below-the-knee amputation (46.88%) was the most commonly performed procedure. There was a significant increment in both PCS (p-value= 0.001), MCS scores (p-value=0.0001) of SF-12 and physical (p-value=0.0001) and psychological domains (p-value=0.001) of the WHOQOL-BREF questionnaire in the postoperative period. A total of 83.9% of patients have used prostheses, and 15.6% had mortality. Conclusions Major amputations can significantly affect the quality of life of patients, and all efforts should be made to avoid factors that adversely affect their quality of life.

COVID-19 associated rhino-orbital-cerebral mucormycosis: An observational study from Eastern India, with special emphasis on neurological spectrum.

AIMS: 1: Describe the epidemiology and determine risk factors for COVID-19 associated mucormycosis. 2: Elaborate the clinical spectrum of Rhino-Orbital-Cerebral Mucormycosis (ROCM), pattern of neuroaxis involvement and it's radiological correlates. METHODS: Observational study. Consecutive, confirmed cases of mucormycosis (N = 55) were included. A case of mucormycosis was defined as one who had clinical and radiological features consistent with mucormycosis along with demonstration of the fungus in tissue via KOH mount/culture/histopathological examination (HPE). Data pertaining to epidemiology, risk factors, clinico-radiological features were analysed using percentage of total cases. RESULTS: Middle aged, diabetic males with recent COVID-19 infection were most affected. New onset upper jaw toothache was a striking observation in several cases. Among neurological manifestations headache, proptosis, vision loss, extraocular movement restriction; cavernous sinus, meningeal and parenchymal involvement were common. Stroke in ROCM followed a definitive pattern with watershed infarction. CONCLUSIONS: New onset upper jaw toothache and loosening of teeth should prompt an immediate search for mucormycosis in backdrop of diabetic patients with recent COVID-19 disease, aiding earlier diagnosis and treatment initiation. Neuroaxis involvement was characterized by a multitude of features pertaining to involvement of optic nerve, extraocular muscles, meninges, brain parenchyma and internal carotid artery.

Synthesis of Ni(ii)-Mn(ii) complexes using a new mononuclear Ni(ii) complex of an unsymmetrical N2O3 donor ligand: structures, magnetic properties and catalytic oxidase activity.

A new Ni(ii) complex [NiL] (complex 1) of an asymmetrically di-condensed N2O3 donor Schiff base ligand, N-salicylidene-N'-3-methoxysalicylidene-1,3-propanediamine (H2L), has been synthesized and utilized for the synthesis of three heterometallic complexes, [(NiL)2Mn(NCS)2(CH3OH)2]·CH3OH (2) [(NiL)2Mn(N(CN)2)2(CH3OH)2]·CH3OH (3) and [(NiL)2Mn2(N3)2(µ1,1-N3)2(CH3OH)2] (4). Single crystal X-ray diffraction analyses show that complexes 2 and 3 have linear trinuclear structures where two tridentate O3 donor (NiL) units are coordinated to the central octahedral Mn(ii) centre, whereas complex 4 has a centrosymmetric tetranuclear structure where two binuclear (NiL)Mn units are linked via two phenoxido and two µ1,1-N3 bridges. Among the heterometallic complexes (2-4), only 4 is active towards the catalytic oxidation of 3,5-di-tert-butylcatechol to the corresponding quinone. The turnover number for the aerobic oxidation of 3,5-DTBC is 935 h-1. ESI-mass spectra have been recorded to scrutinize the mechanistic pathway of this catalytic reaction. Variable temperature magnetic susceptibility measurements suggest that complexes 2-4 are antiferromagnetically coupled with coupling constants (J) of -4.84 and -5.23 cm-1 for complexes 2 and 3, respectively and J1 = -2.20 cm-1, J2 = 1.13 cm-1 and J3 = -1.12 cm-1 for complex 4. DFT calculations have been used to rationalize the magnetic super-exchange in complexes 2-4, by computing the theoretical coupling constants and analyzing the spin density plots.

Family of Isomeric CuII-LnIII (Ln = Gd, Tb, and Dy) Complexes Presenting Field-Induced Slow Relaxation of Magnetization Only for the Members Containing GdIII.

The strategic design and synthesis of two isomeric CuII complexes, [CuLA] and [CuLB], of asymmetrically dicondensed N2O3-donor Schiff-base ligands (where H2LA and H2LB are N-salicylidene-N'-3-methoxysalicylidenepropane-1,2-diamine and N-3-methoxysalicylidene-N'-salicylidenepropane-1,2-diamine, respectively) have been accomplished via a convenient CuII template method. These two complexes have been used as metalloligands for the synthesis of three pairs of Cu-Ln isomeric complexes [CuL(µ-NO3)Ln(NO3)2(H2O)]·CH3CN (for complexes 1A-3A, L = LA, and for complexes 1B-3B, L = LB and Ln = Gd, Tb, and Dy, respectively), all of which have been characterized structurally. In all six isomorphous and isostructural complexes, the decacoordinated LnIII centers and pentacoordinated CuII centers possess sphenocorona and square-pyramidal geometries, respectively. The isomeric pair of Cu-Gd compounds shows field-induced slow relaxation of magnetization, although they present the typical isotropic behavior of GdIII complexes, indicating that slow relaxation is not due to the usual energy barrier originating from the magnetic anisotropy. The isostructural derivatives with the ion-anisotropic lanthanides TbIII and DyIII do not show slow magnetic relaxation with or without a direct-current bias field, demonstrating that the magnetic response of the isotropic system CuII-GdIII occurs through different mechanisms than the rest of the Ln cations.

The role of 3d-4f exchange interaction in SMM behaviour and magnetic refrigeration of carbonato bridged CuLn (Ln = Dy, Tb and Gd) complexes of an unsymmetrical N2O4 donor ligand.

The strategic design and synthesis of a new Cu(ii) complex, [CuL] (1) of an asymmetrically dicondensed N2O4 donor ligand (where H2L = N-3-ethoxysalicylidene-N'-3-methoxysalicylidene-1,3-propanediamine) and its utilization as a metalloligand towards the synthesis of three new tetra-nuclear carbonato bridged Cu-Ln complexes [(µ4-CO3)2{(CuL)(MeOH)Ln(NO3)}2] (where Ln = Dy, Tb and Gd for complexes 2, 3 and 4 respectively) have been achieved. Each tetranuclear CuII2LnIII2 structure can be described as two µ2-phenoxo bridged CuIILnIII dinuclear units connected via two µ4-κ2:η1:η1CO32-. Single crystal X-ray diffraction studies show that complexes 2, 3 and 4 are isostructural and isomorphic. The LnIII centres are nona-coordinated with spherical capped-square antiprism geometry and the geometry around the CuII centre is distorted octahedral. The DC magnetic susceptibility and field dependent magnetization measurements reveal the ferromagnetic interactions between the CuII and LnIII centres in all three complexes. The ac susceptibility measurements under an applied bias field reveal the SMM behaviour of complexes 2 and 3 with Ueff 6.5 and 4.5 K, respectively. Complex 4 shows a notable magnetocaloric effect (MCE) with -ΔSm 23.5 J kg-1 K-1 for ΔH = 7 T at 3 K. The ab initio CASSCF/RASSI-SO/SINGLE_ANISO calculations predict that the observed SMM behaviour under an external dc field in 2 and 3 does not arise solely from the single ion anisotropy of the lanthanide ions. The exchange interactions (CuII-LnIII and LnIII-LnIII) lower the energy of the exchange coupled states as well as enhance QTM or tunnel splitting and play an important role in the overall magnetic properties of the complexes. Furthermore, to obtain more insight into the exchange interaction, BS-DFT calculations have been performed for complexes 2-4.

Elucidating the secondary effect in the Lewis acid mediated anodic shift of electrochemical oxidation of a Cu(ii) complex with a N2O2 donor unsymmetrical ligand.

A metalloligand [CuL] (H2L = N-α-methylsalicylidene-N'-salicylidene-1,3-propanediamine) was reacted with a series (Li+, Na+, K+, Mg2+, Ca2+, Zn2+, Cd2+, Pr3+, Nd3+ and Sm3+) of redox-inactive metal ions (in excess) with different Lewis acidities in acetonitrile to form heterometallic complexes in situ. In the cases of K+ and Zn2+, single crystals were isolated from their respective solutions and solved. The complexes were found to be trinuclear with the phenoxido bridge between the redox-inactive metals and the copper center having closest equilibrium distance. In solution, some metal ions (Na+, K+, Mg2+ and Ca2+) formed predominantly 1 : 1 [CuL] : Mn+ adducts whereas others did not. Spectroscopic studies revealed that both the energy and intensity of the LMCT band of [CuL] at 363 nm were influenced by the Lewis acidity of the guest metal ions. The blue shift and the hypochromic shift of this band showed a linear dependence on the Lewis acidity of the corresponding redox-inactive metal ions only for 1 : 1 adducts. A combined EPR and d-d transition spectral analysis of these 1 : 1 adducts in acetonitrile at 298 K indicates that there is a change in the coordination geometry around Cu(ii) on proximal cation binding of free [CuL]. The correlation of the half wave potential (E1/2) of the first oxidation of [CuL] with pKa of the corresponding metal(aqua)n+ ion as a measure of its Lewis acidity revealed that the potentials were linearly dependent for 1 : 1 adducts whereas in the case of the other metal ions an unexpected deviation from linearity was observed. An incremental addition of water to some of these mixtures revealed a decrease in the corresponding oxidation peak potential with a concomitant increase in the molar absorptivity. The molar absorptivities of different mixtures with their corresponding E1/2 values show a linear dependence with better correlation suggesting that the modulation of electron density around Cu(ii) regulates the electrochemical oxidation of the metalloligand.

The catalytic activities and magnetic behaviours of rare µ3-chlorido and µ1,1,1-azido bridged defective dicubane tetranuclear Mn(ii) complexes.

Reaction of Mn(ii) salts with a flexidentate Mannich base ligand, N,N'-dimethyl-N,N'-bis(2-hydroxy-3-methoxy-5-methylbenzyl)ethylenediamine (H2L) in the presence of chloride or azide ions yielded two new tetranuclear complexes, [Mn4L2(µ3-Cl)2Cl2] (1) and [Mn4L2(µ1,1,1-N3)2(N3)2] (2). Single crystal X-ray structural analyses reveal that these two discrete tetranuclear Mn(ii) complexes possess defective dicubane cores with two µ3-Cl (for 1) or two µ1,1,1-N3 bridges (for 2). One of the triply bridging groups is situated above and the other one below the plane of the four Mn(ii) ions. In both complexes, all Mn(ii) ions are in a hexa-coordinated distorted octahedral environment. Both complexes 1 and 2 exhibit catecholase like activity and phenoxazinone synthase-like activity under ambient conditions. The turnover numbers (kcat) for the aerobic oxidation of 3,5-di-tert-butylcatechol are 1492.4 and 1431.2 h-1 and those of o-aminophenol are 2265.5 and 2132.2 h-1 for complexes 1 and 2, respectively. Mass spectral analyses were performed to get an idea about the probable mechanistic pathway for these catalytic reactions. Variable temperature magnetic susceptibility measurements of a solid sample reveal that both the complexes are antiferromagnetically coupled. The coupling constants are calculated to be J1 = -0.19 cm-1, J2 = -6.87 cm-1 and J3 = -0.70 cm-1 for 1 and J1 = 0.11 cm-1, J2 = -0.64 cm-1 and J3 = 0.11 cm-1 for 2 and these values are rationalized by DFT calculations.