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1.
Artículo en Inglés | MEDLINE | ID: mdl-38928975

RESUMEN

Double-Duty Carers (DDCs) refer to people who work in the healthcare industry while also providing unpaid care to relatives, friends, or neighbours. The expectations placed on DDCs is expected to grow, and these employees already experience a high caring burden. As such it is important to understand how best to support their health and wellbeing. This paper explores DDCs' wellbeing during the COVID-19 pandemic, focusing an understudied factor: their mobility constraints. Following the Mobility of the Care Economy framework and a qualitative research design, it does so through a thematic analysis of 16 semi-structured interviews with female DDCs in Southern Ontario, Canada. Once data saturation was reached, three mobility pathways during the pandemic were identified, all of which negatively affected DDCs wellbeing. First, some COVID-19 policies (e.g., testing requirements) resulted in increased mobility demands and increased spatiotemporal constraints. Second, the closure of institutions that care for dependents (schools, daycares, day centres) resulted in forced reduced mobility, which increased financial stress. Finally, indirect mobility effects were identified: the reduced mobility of other informal carers increased the workload and emotional strain on DDCs. The paper concludes with a discussion of mobility-related policies that could improve DDC wellbeing.


Asunto(s)
COVID-19 , Cuidadores , Humanos , COVID-19/psicología , Ontario , Cuidadores/psicología , Femenino , Adulto , Persona de Mediana Edad , SARS-CoV-2 , Carga de Trabajo/psicología , Pandemias/economía
2.
Inorg Chem ; 63(17): 7604-7612, 2024 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-38556753

RESUMEN

A new iron(II) molecular complex {[W(CN)8][Fe(bik*)3]2}BF4·7H2O·1.5CH3OH (1.7H2O·1.5CH3OH) was synthesized using a versatile octacyanotungstate(V) building block and N-donor bidentate ligand (bik* = bis(1-ethyl-1H-imidazol-2-yl)ketone) and detailed characterizations were carried out. The crystal structure of 1.7H2O·1.5CH3OH is composed of an ionic salt from one anionic [W(CN)8]3- unit, two isolated cationic [Fe(bik*)3]2+ units, and one BF4- counteranion in the asymmetric unit. Magnetic studies of 1.7H2O·1.5CH3OH display interesting two-step reversible thermo-induced spin-state switching and the partially desolvated form 1.7H2O shows a photomagnetic effect at low temperatures. Additionally, the physical properties of 1.7H2O·1.5CH3OH were compared with the monomeric unit of {[Fe(bik*)3]2}·4ReO4·H2O (2.H2O) and detailed photophysical investigations were also performed to study the effect of a structural matrix {[W(CN)8]3- and ReO4- unit} on the spin-state switching properties of the [Fe(bik*)3]2+ unit in both systems (1.7H2O·1.5CH3OH and 2.H2O).

3.
Environ Sci Pollut Res Int ; 31(15): 22199-22242, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38411907

RESUMEN

Bacteriophages infect and replicate within bacteria and play a key role in the environment, particularly in microbial ecosystems and bacterial population dynamics. The increasing recognition of their significance stems from their wide array of environmental and biotechnological uses, which encompass the mounting issue of antimicrobial resistance (AMR). Beyond their therapeutic potential in combating antibiotic-resistant infections, bacteriophages also find vast applications such as water quality monitoring, bioremediation, and nutrient cycling within environmental sciences. Researchers are actively involved in isolating and characterizing bacteriophages from different natural sources to explore their applications. Gaining insights into key aspects such as the life cycle of bacteriophages, their host range, immune interactions, and physical stability is vital to enhance their application potential. The establishment of diverse phage libraries has become indispensable to facilitate their wide-ranging uses. Consequently, numerous protocols, ranging from traditional to cutting-edge techniques, have been developed for the isolation, detection, purification, and characterization of bacteriophages from diverse environmental sources. This review offers an exploration of tools, delves into the methods of isolation, characterization, and the extensive environmental applications of bacteriophages, particularly in areas like water quality assessment, the food sector, therapeutic interventions, and the phage therapy in various infections and diseases.


Asunto(s)
Bacteriófagos , Terapia de Fagos , Ecosistema , Bacterias , Biotecnología , Terapia de Fagos/métodos , Antibacterianos
4.
Chem Commun (Camb) ; 60(13): 1739-1742, 2024 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-38240479

RESUMEN

Crystalline polymeric structures of trans-1,4-cyclohexylene bridged N-tethered bis-CAACs in the form of their LiOTf adducts were synthesized and isolated. These were further used as building blocks for the synthesis of crystalline (amino)(carboxy)-based diradicals. The triplet diradical character of these compounds was unambiguously confirmed by the presence of a half-field signal in their EPR spectra. Theoretical calculations show that the singlet state is marginally more stable than the triplet state.

5.
Chem Commun (Camb) ; 59(88): 13107-13124, 2023 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-37846652

RESUMEN

Addressing molecular bistability as a function of external stimuli, especially in spin-crossover (SCO) and metal-to-metal electron transfer (MMET) systems, has seen a surge of interest in the field of molecule-based magnetic materials due to their enormous potential in various technological applications such as molecular spintronics, memory and electronic devices, switches, sensors, and many more. The fine-tuning of molecular components allow the design and synthesis of materials with tailored properties for these vast applications. In this Feature Article, we discuss a part of our research work into this broad topic, pertaining to the recent discoveries in the field of switchable molecular magnetic materials based on SCO and MMET systems, along with some historical background of the area and related accomplishments made in recent years.

6.
Dalton Trans ; 52(32): 11335-11348, 2023 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-37530419

RESUMEN

A series of mononuclear manganese(III) complexes [Mn(X-sal2-323)](ReO4) (X = 5 Cl, 1; X = 5 Br, 2; X = 3,5 Cl, 3; X = 3,5 Br, 4; and X = 5 NO2, 5), containing hexadentate ligands prepared using the condensation of N,N'-bis(3-aminopropyl)ethylenediamine and 5- or 3,5-substituted salicylaldehyde, has been synthesized. Variable temperature single-crystal X-ray diffraction, magnetic, spectroscopic, electrochemical, and spectroelectrochemical analyses, and theoretical calculations have been used to explore the role of various ligand substituents in the spin-state switching behavior of the prepared manganese(III) complexes. All five complexes consist of an analogous distorted octahedral monocationic MnN4O2 surrounding offered by the flexible hexadentate ligand and ReO4- as the counter anion. However, a disordered water molecule was detected in complex 4. Complexes 1 (X = 5 Cl) and 5 (X = 5 NO2) show gradual and complete spin-state switching between the high-spin (HS) (S = 2) and the low-spin (LS) (S = 1) state with T1/2 values of 146 and 115 K respectively, while an abrupt and complete transition at 95 K was observed for complex 2 (X = 5 Br). Alternatively, complex 3 (X = 3, 5 Cl) exhibits an incomplete and sharp transition between the HS and LS states at 104 K, while complex 4 (X = 3, 5 Br) (desolvated) remains almost LS up to 300 K and then displays gradual and incomplete SCO at a higher temperature. The nature of the spin-state switch and transition temperature suggest that the structural effect (cooperativity) plays a more significant role in comparison with the electronic effect coming from various substituents (Cl, Br, and NO2), which is further supported by the detailed structural, electrochemical, and theoretical studies.

8.
J Am Chem Soc ; 145(29): 15896-15905, 2023 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-37440690

RESUMEN

Finding stable analogues of three-dimensional (3D) lead halide perovskites has motivated the exploration of an ever-expanding repertoire of two-dimensional (2D) counterparts. However, the bandgap and exciton binding energy in these 2D systems are generally considerably higher than those in 3D analogues due to size and dielectric confinement. Such quantum confinements are most prominently manifested in the extreme 2D realization in (A)mPbI4 (m = 1 or 2) series of compounds with a single inorganic layer repeat unit. Here, we explore a new A-site cation, 4,4'-azopyridine (APD), whose size and hydrogen bonding properties endow the corresponding (APD)PbI4 2D compound with the lowest bandgap and exciton binding energy of all such compounds, 2.19 eV and 48 meV, respectively. (APD)PbI4 presents the first example of the ideal Pb-I-Pb bond angle of 180°, maximizing the valence and conduction bandwidths and minimizing the electron and hole effective masses. These effects coupled with a significant increase in the dielectric constant provide an explanation for the unique bandgap and exciton binding energies in this system. Our theoretical results further reveal that the requirement of optimizing the hydrogen bonding interactions between the organic and the inorganic units provides the driving force for achieving the structural uniqueness and the associated optoelectronic properties in this system. Our preliminary investigations in characterizing photovoltaic solar cells in the presence of APD show encouraging improvements in performances and stability.

9.
Dalton Trans ; 52(31): 10700-10707, 2023 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-37489028

RESUMEN

A two-step thermo-induced spin-state switching was observed in a cyanide-bridged [Fe2Fe2] molecular square complex, {[Fe(pzTp)(CN)3]2[Fe(L)2]2}[Fe(pzTp)(CN)3]2·4CH3OH·2H2O [1·4MeOH·2H2O; pzTp = tetrakis(pyrazol-1-yl)borate and L = bis(1-ethylimidazol-2-yl)ketone (bik*)], which was characterized fully by single-crystal X-ray diffraction, (photo)magnetic measurements, and spectroscopic techniques. 1·4MeOH·2H2O exhibited a two-step thermo-induced spin transition with T1/2 (1) ↑ = 306 K and T1/2 (2) ↑ = 370 K converting the low-temperature ground state, {[(FeIIILS)2(FeIILS)2](FeIIILS)2} into the high-temperature state, {[(FeIIILS)2(FeIIHS)2](FeIIILS)2} via a stable intermediate phase. The desolvated phase, 1 also exhibited a gradual but reversible thermo-induced spin state change with a T1/2 value of 190 K, significantly shifted to a lower temperature. It also exhibited photo-induced spin-state switching at 20 K with the TLIESST value of 60 K.

10.
Rev Port Cardiol ; 42(11): 917-924, 2023 11.
Artículo en Inglés, Portugués | MEDLINE | ID: mdl-37414337

RESUMEN

Peripartum cardiomyopathy is a rare type of heart failure manifesting towards the end of pregnancy or in the months following delivery, in the absence of any other cause of heart failure. There is a wide range of incidence across countries reflecting different population demographics, uncertainty over definitions and under-reporting. Race, ethnicity, multiparity and advanced maternal age are considered important risk factors for the disease. Its etiopathogenesis is incompletely understood and is likely multifactorial, including hemodynamic stresses of pregnancy, vasculo-hormonal factors, inflammation, immunology and genetics. Affected women present with heart failure secondary to reduced left ventricular systolic function (LVEF <45%) and often with associated phenotypes such as LV dilatation, biatrial dilatation, reduced systolic function, impaired diastolic function, and increased pulmonary pressure. Electrocardiography, echocardiography, magnetic resonance imaging, endomyocardial biopsy, and certain blood biomarkers aid in diagnosis and management. Treatment for peripartum cardiomyopathy depends on the stage of pregnancy or postpartum, disease severity and whether the woman is breastfeeding. It includes standard pharmacological therapies for heart failure, within the safety restrictions for pregnancy and lactation. Targeted therapies such as bromocriptine have shown promise in early, small studies, with large definitive trials currently underway. Failure of medical interventions may require mechanical support and transplantation in severe cases. Peripartum cardiomyopathy carries a high mortality rate of up to 10% and a high risk of relapse in subsequent pregnancies, but over half of women present normalization of LV function within a year of diagnosis.


Asunto(s)
Cardiomiopatías , Insuficiencia Cardíaca , Complicaciones Cardiovasculares del Embarazo , Trastornos Puerperales , Embarazo , Femenino , Humanos , Periodo Periparto , Cardiomiopatías/diagnóstico , Cardiomiopatías/etiología , Cardiomiopatías/terapia , Insuficiencia Cardíaca/diagnóstico , Insuficiencia Cardíaca/etiología , Insuficiencia Cardíaca/terapia , Pronóstico , Ecocardiografía , Trastornos Puerperales/diagnóstico , Trastornos Puerperales/etiología , Trastornos Puerperales/terapia , Complicaciones Cardiovasculares del Embarazo/terapia , Complicaciones Cardiovasculares del Embarazo/tratamiento farmacológico
11.
Inorg Chem ; 62(23): 8794-8802, 2023 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-36867089

RESUMEN

A mixed-valence Fe(II)Fe(III) molecular system, {[Fe(pzTp)(CN)3]2[Fe(bik)2]2}·[Fe(pzTp)(CN)3]2·4MeOH (1·4MeOH) (bik = bis-(1-methylimidazolyl)-2-methanone, pzTp = tetrakis(pyrazolyl)borate), exhibits single-crystal-to-single-crystal (SC-SC) transformation while increasing the temperature and is converted into {[Fe(pzTp)(CN)3]2[Fe(bik)2]2}·[Fe(pzTp)(CN)3]2 (1). Both complexes exhibit thermo-induced spin-state switching behavior along with reversible SC-SC transformation, where the low-temperature [FeIIILSFeIILS]2 phase transforms into a high-temperature [FeIIILSFeIIHS]2 phase. 1·4MeOH exhibits an abrupt spin-state switching with T1/2 at 355 K, whereas 1 undergoes a gradual and reversible spin-state switching with a lower T1/2 at 338 K. Astonishingly, 1 exhibits ON/OFF photo-induced spin-state switching with TLIESST = 67 K, whereas 1·4MeOH does not show such an effect.

12.
Chem Sci ; 13(42): 12533-12539, 2022 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-36382295

RESUMEN

The isolation of carbon-centered diradicals is always challenging due to synthetic difficulties and their limited stability. Herein we report the synthesis of a trans-1,4-cyclohexylene bridged bis-NHC-CAAC dimer derived thermally stable dicationic diradical. The diradical character of this compound was confirmed by EPR spectroscopy. The variable temperature EPR study suggests the singlet state to be marginally more stable than the triplet state (2J = -5.5 cm-1 (ΔE ST = 0.065 kJ mol-1)). The presence of the trans-1,4-cyclohexylene bridge is instrumental for the successful isolation of this dicationic diradical. Notably, in the case of ethylene or propylene bridged bis-NHC-CAAC dimers, the corresponding dicationic diradicals are transient and rearrange to hydrogen abstracted products.

13.
ACS Omega ; 7(43): 39268-39279, 2022 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-36340084

RESUMEN

We have explored the impact of electron-donating (methoxy) and electron-withdrawing (nitro) substituents on SalEen ligand based spin crossover (SCO) behavior of Fe(III) complexes. Thus, 3-X-substituted SalEen ligands were employed to prepare [Fe(3-X-SalEen)2]·NCSe, where X = OMe (1), H (2), and NO2 (3) (3-X-SalEen is the condensation product of 3-substituted salicylaldehyde and N-ethylethylenediamine). The characteristic spin transition temperature (T 1/2) is shown to shift to a lower temperature when an electron-donating substituent (OMe) is used and to a higher temperature when an electron-withdrawing substituent (NO2) is used. We used experimental and theoretical methods to determine the reasons for this behavior. The solid-state magnetic data revealed the transition temperatures for complexes 1, 2, and 3 to be 219, 251, and 366 K, respectively. The solution-state magnetic data also support this trend in T 1/2 values. UV-vis spectra analysis indicates that there is greater delocalization in the π-manifold of the ligand when the nitro group is the substituent. Theoretical studies through density functional theory methods suggest the methoxy substituent decreases the energy gap between the t2g and eg orbitals (explaining the lower T 1/2 value), while the nitro substituent increases the energy gap between the t2g and eg orbitals and thus increases the T 1/2 value.

14.
Inorg Chem ; 61(43): 17080-17088, 2022 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-36264687

RESUMEN

The self-assembly of a redox-active ethylenedioxythiophene (EDOT)-terpyridine-based tridentate ligand and cobalt(II) unit with different counteranions has led to a series of new cobalt(II) complexes [Co(L)2](X)2 (X = BF4 (1), ClO4 (2), and BPh4 (3)) (L = 4'-(3,4-ethylenedioxythiophene)-2,2':6',2″-terpyridine). The impact of various counteranions on stabilization and spin-state switching of the cobalt(II) center was explored through detailed magneto-structural investigation using variable temperature single-crystal X-ray diffraction, magnetic, spectroscopic, electrochemical, and spectroelectrochemical studies. All three complexes 1-3 consisted of an isostructural dicationic distorted octahedral CoN6 coordination environment offered by the two L ligands in a bis-meridional fashion and BF4-, ClO4-, and BPh4- as a counteranion, respectively. Complex 2 with ClO4- counteranion showed a reversible, gradual, and nearly complete spin-state switching between low-spin (LS) (S = 1/2) and high-spin (HS) (S = 3/2) states, while an incomplete spin-state switching behavior was observed for complexes 1 (BF4-) and 3 (BPh4-) in the measured temperature range of 350-2 K. The non-covalent cation-anion interactions played a significant role in stabilizing the spin-state in 1-3. Additionally, complexes 1-3 also exhibited interesting redox-stimuli-based reversible paramagnetic HS cobalt(II) (S = 3/2) to diamagnetic LS cobalt(III) (S = 0) conversion, offering an alternate way to switch the magnetic properties.

15.
Sci Rep ; 12(1): 12029, 2022 07 14.
Artículo en Inglés | MEDLINE | ID: mdl-35835800

RESUMEN

The Axin family of scaffolding proteins control diverse processes, such as facilitating the interactions between cellular components and providing specificity to signaling pathways. While several Axin family members have been discovered in metazoans and shown to play crucial roles, their mechanism of action are not well understood. The Caenorhabditis elegans Axin homolog, pry-1, is a powerful tool for identifying interacting genes and downstream effectors that function in a conserved manner to regulate Axin-mediated signaling. Our lab and others have established pry-1's essential role in developmental processes that affect the reproductive system, seam cells, and a posterior P lineage cell, P11.p. Additionally, pry-1 is crucial for lipid metabolism, stress responses, and aging. In this study, we expanded on our previous work on pry-1 by reporting a novel interacting gene named picd-1 (pry-1-interacting and Cabin1 domain-containing). PICD-1 protein shares sequence conservation with CABIN1, a component of the HUCA complex. Our findings have revealed that PICD-1 is involved in several pry-1-mediated processes, including stress response and lifespan maintenance. picd-1's expression overlapped with that of pry-1 in multiple tissues throughout the lifespan. Furthermore, PRY-1 and PICD-1 inhibited CREB-regulated transcriptional coactivator homolog CRTC-1, which promotes longevity in a calcineurin-dependent manner. Overall, our study has demonstrated that picd-1 is necessary for mediating pry-1 function and provides the basis to investigate whether Cabin-1 domain-containing protein plays a similar role in Axin signaling in other systems.


Asunto(s)
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animales , Proteína Axina/genética , Proteína Axina/metabolismo , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Longevidad/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
16.
Front Aging ; 3: 866861, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35821842

RESUMEN

Fibroblast growth factor receptors (FGFRs) regulate diverse biological processes in eukaryotes. The nematode Caenorhabditis elegans is a good animal model for studying the roles of FGFR signaling and its mechanism of regulation. In this study, we report that KIN-9 is an FGFR homolog in C. elegans that plays essential roles in aging and stress response maintenance. kin-9 was discovered as a target of miR-246, a microRNA that is positively regulated by the Axin family member pry-1. We found that animals lacking kin-9 function were long-lived and resistant to chemically induced stress. Furthermore, they showed a reduced expression of endoplasmic reticulum unfolded protein response (ER-UPR) pathway genes, suggesting that kin-9 is required to maintain a normal ER-UPR. The analysis of GFP reporter-based expression in transgenic animals revealed that KIN-9 is localized in the intestine. Overall, our findings demonstrate that kin-9 is regulated by miR-246 and may function downstream of pry-1. This study prompts future investigations to understand the mechanism of miRNA-mediated FGFR function in maintaining aging and stress response processes.

17.
Dalton Trans ; 51(25): 9642-9652, 2022 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-35698930

RESUMEN

The three mononuclear cobalt(II) complexes, [Co(L)(NCX)2] (L = N,N'-di-tert-butyl-2,11-diaza[3,3](2,6)pyridinophane, and X = S (1), Se (2), and [C(CN)2] (3)), have been synthesized and characterized using variable temperature single-crystal X-ray crystallography, and spectroscopic, magnetic, and electrochemical studies. All three complexes have a similar distorted octahedral CoN6 coordination geometry produced by the macrocyclic tetradentate ligand L and two NCX- co-ligands in the cis position. Complexes 1 and 2 crystallized in the monoclinic P21/n (Z = 4) space group, while complex 3 was isolated in the monoclinic P21/c (Z = 4) space group. Interestingly, complexes 1 and 2 exhibit a reversible and gradual spin-crossover behavior between the high-spin (S = 3/2) and low-spin (S = 1/2) states at ca. 168 K and 255 K, respectively. However, for complex 3, a low-spin configuration persists up to 260 K and it exhibits an incomplete and reversible spin crossover even at 400 K. In addition, complex 1 displays a reversible redox behavior indicating the paramagnetic cobalt(II) to diamagnetic cobalt(III) conversion.

18.
Dalton Trans ; 51(19): 7681-7694, 2022 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-35521740

RESUMEN

Four mononuclear manganese(III) complexes coordinated with photo-active hexadentate azobenzene ligands, [Mn(5azo-sal2-323)](X) (X = Cl, 1; X = BF4, 2; X = ClO4, 3; X = PF6, 4), were prepared. The impact of various counter anions on the stabilization and switching of the spin state of the manganese(III) center was explored through detailed magneto-structural investigation using variable temperature single-crystal X-ray diffraction, magnetic, spectroscopic, and spectroelectrochemical studies, along with theoretical calculations. All four complexes consisted of an isostructural monocationic distorted octahedral MnN4O2 coordination environment offered by the hexadentate ligand and Cl-, BF4-, ClO4-, and PF6- as counter anions respectively. Complex 1 with a spherical Cl- counter anion showed a reversible and gradual spin-state switching between low-spin (LS) (S = 1) and high-spin (HS) (S = 2) states above 400 K, where non-covalent cation-anion interactions played a significant role in stabilizing the LS state. While, irrespective of the shape of the counter anion, complexes 2-4 remained in the HS state throughout the measured temperature range of 300-2 K, where strong π-π interaction between the azobenzene motifs among cationic units played a substantial role in stabilizing the HS state. Furthermore, magnetic data analyses revealed significantly large zero-field splitting in the S = 1 state for 1 (D = 19.4 cm-1, E/D = 0.008) in comparison with that in the S = 2 state for 2-4 (D = 3.99-4.97 cm-1, E/D = 0.002-0.195). Spectroelectrochemical investigations revealed the quasi-reversible reduction and oxidation of the manganese(III) center to manganese(II) and manganese(IV), respectively. A detailed theoretical calculation at the DFT and CASSCF level of theory was carried out to better understand the magneto-structural correlation.

19.
Chem Asian J ; 17(16): e202200404, 2022 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-35617522

RESUMEN

Four cobalt(II) complexes, [Co(L1)2 (NCX)2 (MeOH)2 ] (X=S (1), Se (2)) and {[Co(L2)2 (NCX)2 ]}n (X=S (3), Se (4)) (L1=2,5-dipyridyl-3,4,-ethylenedioxylthiophene and L2=2,5-diethynylpyridinyl-3,4-ethylenedioxythiophene), were synthesized by incorporating ethylenedioxythiophene based redox-active luminescence ligands. All these complexes have been well characterized using single-crystal X-ray diffraction analyses, spectroscopic and magnetic investigations. Magneto-structural studies showed that 1 and 2 adopt a mononuclear structure with CoN4 O2 octahedral coordination geometry while 3 and 4 have a 2D [4×4] rhombic grid coordination networks (CNs) where each cobalt(II) center is in a CoN6 octahedral coordination environment. Static magnetic measurements reveal that all four complexes displayed a high spin (HS) (S=3/2) state between 2 and 280 K which was further confirmed by X-band and Q-band EPR studies. Remarkably, along with the molecular dimensionality (0D and 2D) the modification in the axial coligands lead to a significant difference in the dynamic magnetic properties of the monomers and CNs at low temperatures. All complexes display slow magnetic relaxation behavior under an external dc magnetic field. For the complexes with NCS- as coligand observed higher energy barrier for spin reversal in comparison to the complexes with NCSe- as coligand, while mononuclear complex 1 exhibited a higher energy barrier than that of CN 3. Theoretical calculations at the DFT and CASSCF level of theory have been performed to get more insight into the electronic structure and magnetic properties of all four complexes.

20.
Dalton Trans ; 51(18): 7255-7267, 2022 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-35475451

RESUMEN

A new coordination polymer based on the sulphate-capped pentamolybdate unit has been synthesized from the reaction of {Mo3S7Br6}2- with copper(II) bromide and pyridine, in DMF. The as-synthesized compound, formulated as [CuII(C5H5N)4]3[{MoVI5O15(SO4)2}{CuII(C5H5N)3(DMF)(H2O)}][MoVI5O15(SO4)2]·2DMF (1), crystallizes in the monoclinic space group of P21/c. This compound has a one-dimensional double-chain coordination polymeric structure, composed of the pentameric {MoVI5O15(SO4)2} and the {CuII(C5H5N)4} units, and has been characterized in the solid-state with single-crystal and powder X-ray diffraction, infrared and optical spectroscopy, as well as thermal and magnetic studies. Due to its unique arrangement, the compound is observed to be nanoporous in nature, occupied by a co-crystallized DMF molecule. Surface area measurements confirm the presence of nano-sized pores within the compound. Variable temperature P-XRD studies show the framework to be stable up to a temperature of at least 100 °C. Due to its rigid framework and the presence of nano-sized pores, the compound was extensively studied as a catalyst for oxidative desulphurization of model oil and commercial diesel. The compound not only shows excellent performance for the removal of recalcitrant sulphur components, such as dibenzothiophene (DBT) in fuel oil (∼100% removal), but is also observed to show excellent turn-over-numbers, regeneration, and reproducibility during the catalytic process.

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