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1.
Mod Rheumatol ; 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38430527

RESUMO

OBJECTIVES: Foot and ankle impairments are major issues in patients with rheumatoid arthritis (RA). Foot deformities often lead to skin disorders, such as callosities, ingrown toenails, and interdigital tinea pedis. This study was aimed at investigating the efficacy and limitations of foot care by experts in patients with RA. METHODS: Thirty-one patients with RA who began receiving foot care from nurses at our institution between September 2020 and February 2023 were included. Responses to a survey using the self-administered foot evaluation questionnaire (SAFE-Q) for patient-reported outcome measures were compared at baseline, the second visit (1.3 ± 0.5 months after baseline), and the third visit (3.6 ± 1.6 months after baseline). RESULTS: Scores for 'Pain and pain-related' and 'General health and well-being' components of SAFE-Q markedly improved after foot care. On the other hand, there were no significant differences in the scores for 'Physical functioning and daily living', 'Social functioning', and 'Shoe-related' components during observation periods. CONCLUSIONS: Foot care for rheumatoid feet is effective in providing pain relief and improving general health and well-being. However, physical and social functioning and footwear issues did not improve. Clinicians must understand the effects and limitations of foot care in patients with RA.

2.
Dalton Trans ; 49(27): 9438-9443, 2020 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-32597427

RESUMO

Methods relying on the use of solid solutions can be used to produce solid materials having finely controlled physical properties. In the current investigation, we utilized this protocol to prepare solid solutions derived from two different Werner complexes in order to assess the effects of component ratios on acetone vapor adsorption properties. For this purpose, microcrystalline solid solutions with the basic elemental composition α-[Cu(PF6)2(py)4]x[Cu(CF3SO3)2(py)4]1-x (x = 0.75 and 0.5) (α-PAC-2-PF6/CF3SO3(x = 0.75 and 0.5), py = pyridine) were prepared by hexane induced precipitation of acetone solutions of [Cu(PF6)2(py)4] (PAC-2-PF6) and [Cu(CF3SO3)2(py)4] (PAC-2-CF3SO3). The results of acetone sorption isotherm measurements show that gate opening and closing pressures of the solid solutions are dependent on the composition ratios of PAC-2-CF3SO3 and PAC-2-PF6. Specifically, an increase in CF3SO3- anion content induces weakening of the interactions with acetone as a consequence of expansion of lattice constants and also strengthening host-host interactions. These effects cause an increase in gate opening and closing pressures.

3.
Dalton Trans ; 48(19): 6314-6318, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30816370

RESUMO

We report the synthesis, structural characterisation, and adsorption properties of a three-dimensional metal-organic framework [Zn(pydcao)(DMF)] (H2-pydcao = 3,5-pyridinedicarboxylic acid N-oxide) that has an unprecedented [Zn2(N-oxide)2] secondary building unit.

4.
Dalton Trans ; 47(39): 14001-14007, 2018 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-30230484

RESUMO

We report the synthesis of five novel crystals [(4-BrAni+)(DB[18]crown-6)]2[SMo12O402-]·2CH3CN (1), [(4-BrAni+)(B[18]crown-6)]2[SMo12O402-]·CH3CN (2), [(4-BrAni+)(B[18]crown-6)]3[PMo12O402-]·2CH3CN (3), [(3-AP+)3(B[18]crown-6)2][PMo12O403-] (4) and [NBu4+][(3-AP2+)(DB[30]crown-10)][PMo12O403-]·CH3CN (5) (4-BrAni+ = 4-bromoanilinium; B[18]crown-6 = benzo[18]-crown-6; DB[18]crown-6 = dibenzo[18]-crown-6; DB[30]crown-10 = dibenzo[30]-crown-10; 3-AP+ = 3-aminopyridinium; 3-AP2+ = 3-ammoniumpyridinium; NBu4+ = tetrabutylammonium). In order to construct non-centrosymmetric crystals, the five crystals were designed using a method to gradually introduce asymmetry into the building units. Crystal 1 was constructed with a symmetric supramolecular cation (SPC) [(4-BrAni+)(DB[18]crown-6)], resulting in a P21/n space group. The asymmetric SPC [(4-BrAni+)(B[18]crown-6)] was introduced into [SMo12O402-] to obtain crystal 2, which belongs to the symmetric P1[combining macron] space group. Introducing trivalent [PMo12O403-], [(4-BrAni+)(B[18]crown-6)] produced crystal 3 with a non-centrosymmetric Pc space group. The asymmetric sandwich SPC [(3-AP+)3(B[18]crown-6)2] was designed with multiple hydrogen bonding sites on the 3-AP+ cation, and crystal 4 was obtained with trivalent [PMo12O403-]. Crystal 4 has the properties of the chiral P1 space group. The distorted SPC (3-AP2+)(DB[30]crown-10) was constructed using flexible DB[30]crown-10, resulting in crystal 5 which matched the chiral P21 space group with trivalent [PMo12O403-]. This work focuses on strategies for the rational design of novel non-centrosymmetric crystals without a chiral synthon.

5.
Sci Adv ; 3(8): e1601594, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28819640

RESUMO

The Mott transition-a metal-insulator transition caused by repulsive Coulomb interactions between electrons-is a central issue in condensed matter physics because it is the mother earth of various attractive phenomena. Outstanding examples are high-Tc (critical temperature) cuprates and manganites exhibiting colossal magnetoresistance. Furthermore, spin liquid states, which are quantum-fluctuation-driven disordered ground states in antiferromagnets, have recently been found in magnetic systems very near the Mott transition. To date, intensive studies on the Mott transition have been conducted and appear to have established a nearly complete framework for understanding the Mott transition. We found an unknown type of Mott transition in an organic spin liquid material with a slightly disordered lattice. Around the Mott transition region of this material under pressure, nuclear magnetic resonance experiments capture the emergence of slow electronic fluctuations of the order of kilohertz or lower, which is not expected in the conventional Mott transition that appears as a clear first-order transition at low temperatures. We suggest that they are due to the unconventional metal-insulator fluctuations emerging around the disordered Mott transition in analogy to the slowly fluctuating spin phase, or Griffiths phase, realized in Ising spin systems with disordered lattices.

6.
Chemistry ; 22(31): 11042-7, 2016 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-27373696

RESUMO

A two-dimensional (2D) layered Mg(II) coordination polymer (CP) with a high tolerance for H2 O was designed, synthesised, and crystallographically characterised. The synthesis was achieved by the introduction of a flexible 2D layered structure composed of Mg(II) ions and isonicotinate N-oxide ligands. Owing to its high H2 O tolerance, the obtained 2D layered structure has the flexibility to repeatedly adsorb a large amount of H2 O associated with interlayer expansion and enable the removal of H2 O from a H2 O/2-propanol mixed vapour. These results indicate that the CP could be an excellent dehydrating agent.

7.
Nat Commun ; 6: 5851, 2015 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-25592677

RESUMO

The design of inexpensive and less toxic porous coordination polymers (PCPs) that show selective adsorption or high adsorption capacity is a critical issue in research on applicable porous materials. Although use of Group II magnesium(II) and calcium(II) ions as building blocks could provide cheaper materials and lead to enhanced biocompatibility, examples of magnesium(II) and calcium(II) PCPs are extremely limited compared with commonly used transition metal ones, because neutral bridging ligands have not been available for magnesium(II) and calcium(II) ions. Here we report a rationally designed neutral and charge-polarized bridging ligand as a new partner for magnesium(II) and calcium(II) ions. The three-dimensional magnesium(II) and calcium(II) PCPs synthesized using such a neutral ligand are stable and show selective adsorption and separation of carbon dioxide over methane at ambient temperature. This synthetic approach allows the structural diversification of Group II magnesium(II) and calcium(II) PCPs.


Assuntos
Materiais Biocompatíveis/química , Metais/química , Polímeros/química , Adsorção , Cálcio/química , Magnésio/química , Estrutura Molecular , Porosidade
8.
Chempluschem ; 80(10): 1490, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31973386

RESUMO

Invited for this month's cover is the group of Prof. Shin-ichiro Noro from Hokkaido University, Japan. The cover picture shows a copper(II) porous coordination polymer that can adsorb CO2 over CH4 at high selectivity under CO2 /CH4 mixed gas conditions, even with the coexistence of water. Read the full text of the article at 10.1002/cplu.201500278.

9.
Chempluschem ; 80(10): 1517-1524, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31973388

RESUMO

The development of highly efficient CO2 separation materials is very important for environmental preservation and energy conservation. Crystalline porous coordination polymers (PCPs)/metal-organic frameworks are one of a number of promising types of porous materials for CO2 separation because of their controllable pore size, shape and surface function. Simultaneously, the unique structural flexibility of PCPs affords both high CO2 selectivity and inexpensive regeneration. However, this family of materials suffers from the coexistence of water that destroys the framework of PCPs and its adsorption in the pores is greater than that of CO2 , which results in a deterioration in CO2 -separation performance. Herein, a flexible and hydrophobic CuII PCP that is stable towards water has been designed and synthesised. This PCP has extremely high adsorption selectivity for CO2 over CH4 , derived from its structural flexibility. Furthermore, the obtained water-tolerant flexible PCP, under CO2 /CH4 mixed-gas conditions, exhibits highly selective CO2 adsorption over CH4 , even in the presence of water.

10.
Ther Apher Dial ; 18(6): 612-7, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24674153

RESUMO

We evaluated the skeletal muscle loss in hemodialysis (HD) patients by bioelectrical impedance analysis (BIA) and handgrip strength test. Thirty-four HD patients and 16 healthy subjects (control group) were measured for skeletal muscle mass normalized as the skeletal muscle mass index (SMI), calculated as skeletal muscle mass (kg)/height (m)(2) using a tetrapolar bioelectrical impedance plethysmograph. Handgrip strength test was also performed using a hand dynamometer in both groups. In HD patients, the associations of SMI and handgrip strength with age, sex, HD conditions, and HD parameters such as body mass index (BMI), single-pool Kt/V (spKt/V), normalized protein catabolic rate (nPCR), creatinine generation rate (CGR) and serum albumin level (Alb) were investigated. SMI of HD patients (4.58 ± 0.95 kg/m(2) ) was significantly lower than that of the control group (5.55 ± 0.80 kg/m(2) , P<0.01). The handgrip strength of HD patients (19.9 ± 7.74 kg) was also significantly lower than that of the control group (33.0 ± 8.94 kg, P<0.01). In HD patients, HD duration was associated with both SMI and handgrip strength. Among HD parameters, spKt/V was negatively associated with both SMI and handgrip strength, BMI and Alb were positively associated with SMI, while nPCR and CGR were associated with neither SMI nor handgrip strength. HD duration independently contributed to skeletal muscle loss and the value of spKt/V may be affected by skeletal muscle loss in HD patients.


Assuntos
Força da Mão/fisiologia , Músculo Esquelético/patologia , Diálise Renal/métodos , Insuficiência Renal Crônica/terapia , Adulto , Idoso , Índice de Massa Corporal , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dinamômetro de Força Muscular , Pletismografia de Impedância , Diálise Renal/efeitos adversos , Fatores de Tempo
11.
Int Urol Nephrol ; 46(3): 633-9, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24526334

RESUMO

PURPOSE: To determine whether vigorous and moderate physical activity volumes are associated with skeletal muscle loss and chronic kidney disease-mineral and bone disorder (CKD-MBD) in hemodialysis (HD) patients. METHODS: Skeletal muscle index (SMI) was measured using a bioelectrical impedance plethysmograph, and grip strength using a hand dynamometer, in 32 HD patients and 16 healthy controls. In HD patients, bone density was measured using digital image processing, and serum bone metabolism markers were measured as surrogate markers for CKD-MBD. Vigorous and moderate physical activity volumes of HD patients were measured using an activity monitor for 1 week, and associations between vigorous and moderate physical activity volumes and SMI, grip strength, and surrogate markers for CKD-MBD were investigated. RESULTS: SMI of HD patients (4.60 ± 0.98 kg/m(2)) was significantly lower than that of controls (5.55 ± 0.80 kg/m(2), p < 0.01). Grip strength of HD patients (19.9 ± 7.74 kg) was also significantly lower than that of controls (33.0 ± 8.94 kg, p < 0.01). In HD patients, vigorous and moderate physical activity volumes were significantly positively associated with SMI (ß = 0.309, p = 0.023) but not grip strength (ß = 0.231, p = 0131) after adjustment for age, sex, and HD duration. They were not associated with bone density (ß = 0.106, p = 0.470) or any markers of bone metabolism. CONCLUSIONS: Vigorous and moderate physical activity volumes were positively associated with skeletal muscle mass but not skeletal muscle strength or surrogate markers for CKD-MBD.


Assuntos
Densidade Óssea , Doenças Ósseas/metabolismo , Exercício Físico , Falência Renal Crônica/metabolismo , Falência Renal Crônica/terapia , Atividade Motora , Músculo Esquelético/anatomia & histologia , Diálise Renal , Adulto , Idoso , Biomarcadores/sangue , Doenças Ósseas/etiologia , Feminino , Humanos , Falência Renal Crônica/complicações , Masculino
12.
Sci Rep ; 3: 2249, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23873392

RESUMO

Ferroelectricity is essential to many forms of current technology, ranging from sensors and actuators to optical or memory devices. In this circumstance, organic ferroelectrics are of particular importance because of their potential application in tomorrow's organic devices, and several pure organic ferroelectrics have been recently developed. However, some problems, such as current leakage and/or low working frequencies, make their application prospects especially for ferroelectric memory (FeRAM) not clear. Here, we describe the molecule-displacive ferroelectricity of supramolecular adducts of tartaric acid and 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide. The adducts show large spontaneous polarization, high rectangularity of the ferroelectric hysteresis loops even at high operation frequency (10 kHz), and high performance in polarization switching up to 1 × 106 times without showing fatigue. It opens great perspectives in terms of applications, especially in organic FeRAM.

13.
Dalton Trans ; 42(31): 11100-10, 2013 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-23801351

RESUMO

We report the syntheses and crystal structures of novel porous assemblies of coordination complexes (PACs) with/without guest molecules, α-[Cu(A)2(py)4] (α-PAC-2-A (A = PF6, BF4, CF3SO3, and CH3SO3); py = pyridine), γ-{[Cu(PF6)2(py)4]·2guest} (γ-PAC-2-PF6 ⊃ 2guest (guest = acetone and py)), γ-{[Cu(BF4)2(py)4]·2acetone} (γ-PAC-2-BF4 ⊃ 2acetone), and ß-{[Cu(CH3SO3)2(py)4]·2.67H2O} (ß-PAC-2-CH3SO3 ⊃ 2.67H2O). The single-crystal X-ray diffraction analyses of α-PAC-2-A show that α-PAC-2-A have dense packing structures, in which anions of the discrete coordination complexes form weak hydrogen-bonding and anion-π interactions. In contrast, γ-PAC-2-PF6 ⊃ 2guest, γ-PAC-2-BF4 ⊃ 2acetone, and ß-PAC-2-CH3SO3 ⊃ 2.67H2O form guest-including structures with coordination environments around the Cu(II) atoms similar to the α-forms. The vapour adsorption measurements for MeCN and acetone in α-PAC-2-A suggest that the adsorption associated with structural transformations is induced by weak Lewis-base PF6⁻ and BF4⁻ anions covered only with fluorine atoms, which weaken the host-host interactions.

14.
Inorg Chem ; 52(10): 5630-2, 2013 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-23659188

RESUMO

The use of divalent Cu(II) ions and an anion-mixing method led to the rational construction of a porous coordination polymer bridged by weak Lewis-base inorganic CF3SO3(-) monoanions.


Assuntos
Cobre/química , Compostos Organometálicos/síntese química , Polímeros/química , Ânions/química , Modelos Moleculares , Compostos Organometálicos/química , Porosidade , Propriedades de Superfície
15.
Inorg Chem ; 52(8): 4229-37, 2013 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-23527798

RESUMO

Porous coordination polymer (PCP) polymorphs with the formula [Cu(CF3SO3)2(bpp)2]n [1 and 2, where bpp = 1,3-bis(4-pyridyl)propane] have been synthesized and crystallographically characterized, and their distinguishable porous properties have been investigated. 1 was obtained by the removal of guest acetone molecules from one-dimensional PCP {[Cu(CF3SO3)(bpp)2]·CF3SO3·2acetone}n (1⊃2acetone), while 2 was derived from two-dimensional PCP {[Cu(CF3SO3)2(bpp)2]·H2O}n (2⊃H2O) by the loss of guest H2O molecules. The desolvated PCPs 1 and 2 with the same formula [Cu(CF3SO3)2(bpp)2] showed distinguishable structures, suggesting PCP polymorphs. In addition, their adsorption behaviors were completely different: 1 showed adsorption with the structural transformation from closed to open forms, while 2 appeared to expand its framework for only as long as was required for the passage of guest molecules. To the best of our knowledge, PCP polymorphs showing either of two different types of flexible pores are very rare.

16.
Inorg Chem ; 52(1): 423-30, 2013 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-23244518

RESUMO

Two new isostructural molecular metals-(BDH-TTP)(6)[M(III)(C(5)O(5))(3)]·CH(2)Cl(2) (BDH-TTP = 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene, where M = Fe (1) and Ga (2))-have been prepared and fully characterized. Compound 1 is a molecular conductor showing paramagnetic behavior, which is due to the presence of isolated [Fe(C(5)O(5))(3)](3-) complexes with high-spin S = (5)/(2) Fe(III) metal ions. The conductivity originates from the BDH-TTP organic donors arranged in a κ-type molecular packing. At 4 kbar, compound 1 behaves as a metal down to ∼100 K, showing high conductivity (∼10 S cm(-1)) at room temperature. When applying a pressure higher than 7 kbar, the metal-insulator (M-I) transition is suppressed and the compound retains the metallic state down to low temperatures (2 K). For 1, ESR signals have been interpreted as being caused by the fine structure splitting of the high-spin (S = 5/2) state of Fe(III) in the distorted octahedral crystal field from the ligands. At 4 kbar, the isostructural compound 2 behaves as a metal down to ∼100 K, although it is noteworthy that the M-I transition is not suppressed, even at pressures of 15 kbar. For 2, only the signal assigned to delocalized π-electrons has been observed in the ESR measurements.


Assuntos
Gálio/química , Ferro/química , Compostos Organometálicos/química , Ligantes , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/síntese química , Estereoisomerismo
17.
Dalton Trans ; 42(8): 2930-9, 2013 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-23247574

RESUMO

Supramolecular cations formed by monoprotonated pyridazinium cations and cis-anti-cis-dicyclohexano[18]-crown-6 (DCH[18]-crown-6) or dibenzo[18]-crown-6 (DB[18]-crown-6) were introduced into [Ni(dmit)2]− salts (where dmit2− = 2-thione-1,3-dithiole-4,5-dithiolate). X-ray crystal structure analysis of (pyridazinium+)(DCH[18]-crown-6)[Ni(dmit)2]− (1) revealed a chair-type conformation of the DCH[18]-crown-6 moiety. A V-shaped conformation of the DB[18]-crown-6 moiety was observed in (pyridazinium+)(DB[18]-crown-6)2[Ni(dmit)2]−(H2O)2 (2). Nitrogen atoms in the pyridazinium cations interacted with the oxygen atoms of the DCH[18]-crown-6 and DB[18]-crown-6 through N­H+O hydrogen bonds, forming 1:1 and 1:2 supramolecular structures, respectively. Sufficient space for molecular motions of the pyridazinium cations, namely flip-flop and in-plane rotations, exists in salt 1. Disorder in nitrogen atoms was observed by X-ray analysis, indicating dynamic motion of the pyridazinium cation, namely flip-flop motion and in-plane motion. A potential energy calculation further supported the possibility of dynamic motion of cations in the crystal. By contrast, the flip-flop motion of the pyridazinium group in salt 2 is restricted by the two nearest-neighbouring DB[18]-crown-6 molecules. Weak antiferromagnetic intermolecular interactions between the [Ni(dmit)2]− anions in the two-dimensional layers of salt 1 were observed, resulting in alternating antiferromagnetic Heisenberg chain-type magnetic susceptibility. Quasi-one-dimensional intermolecular interactions between the [Ni(dmit)2]− anions were observed in salt 2, whose magnetic behaviour followed the Bonner­Fisher model.


Assuntos
Éteres de Coroa/química , Níquel/química , Compostos Organometálicos/química , Piridazinas/química , Compostos de Sulfidrila/química , Cátions/química , Ligação de Hidrogênio , Substâncias Macromoleculares/síntese química , Substâncias Macromoleculares/química , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/síntese química , Sais/química
18.
Inorg Chem ; 51(23): 12968-75, 2012 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-23167663

RESUMO

Supramolecular assemblies of anilinium (Ani(+)) and fluoroanilinium derivatives (FAni(+)) with [18]crown-6 were introduced into electrically conducting [Ni(dmit)(2)] crystals (dmit(2-) is 2-thioxo-1,3-dithiole-4,5-dithiolate). The crystal structures, electrical conductivities, and magnetic susceptibilities of four new crystals of (Ani(+))([18]crown-6)[Ni(dmit)(2)](3) (1), (o-FAni(+))([18]crown-6)[Ni(dmit)(2)](3) (2), (m-FAni(+))([18]crown-6)[Ni(dmit)(2)](3) (3), and (p-FAni(+))([18]crown-6)[Ni(dmit)(2)](3) (4) were examined from the viewpoint of dynamic supramolecular rotator structures within the crystals. The crystal structures, electrical conduction, and magnetic properties were classified into group-I (crystals 1 and 4) and group-II (crystals 2 and 3). The hydrogen-bonding interaction between -NH(3)(+) and the oxygen atoms of [18]crown-6 formed the stand-up configuration of rotator-stator structures of (Ani(+))([18]crown-6) and (FAni(+))([18]crown-6) supramolecules. The potential energy barriers for the 2-fold flip-flop motion of phenyl- and p-fluorophenyl-rings in crystals 1 and 4 had a relatively small magnitude of ∼150 kJ mol(-1), suggesting that rotations of Ani(+) and p-FAni(+) cations around the C-NH(3)(+) axis occurred in the crystals. In contrast, a large magnitude of the potential energy barriers for the rotations of o-FAni(+) and m-FAni(+) cations in crystals 2 and 3 (>600 kJ mol(-1)) resulted in static supramolecular cationic structures. The cation:anion ratio of 1:3 in these crystals yielded a trimer π-stack of [Ni(dmit)(2)] with a semiconductor-like temperature dependence. The magnetic susceptibilities of the static crystals 2 and 3 were reproduced by the one-dimensional antiferromagnetic linear Heisenberg chain through the one-dimensional linear trimer arrangement. The magnetic susceptibilities of dynamic crystals 1 and 4 enhanced electron delocalization through the intratrimer and intertrimer interactions within the trimer stack, where the molecular rotations of Ani(+) and p-FAni(+) cations played an important role.


Assuntos
Compostos de Anilina/química , Éteres de Coroa/química , Níquel/química , Compostos Organometálicos/química , Cristalografia por Raios X , Condutividade Elétrica , Substâncias Macromoleculares/química , Modelos Moleculares , Compostos Organometálicos/síntese química
19.
Dalton Trans ; 41(31): 9297-303, 2012 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-22692376

RESUMO

Sandwich-type hydrogen-bonded supramolecular dications (DAAz(2+))([18]crown-6)(2) and (DAAz(2+))(dicyclohexane[18]crown-6)(2) (DAAz(2+) = 4,4'-(phenylazophenyl)diammonium) were introduced into [Ni(dmit)(2)](-) anions via a diffusion method to form novel single crystals (DAAz(2+))([18]crown-6)(2)[Ni(dmit)(2)](2) (1) and (DAAz(2+))(dicyclohexane[18]crown-6)(2)[Ni(dmit)(2)](2) (2), respectively, which were characterized based on their crystal structures and magnetic susceptibilities. The molecular assembly structures and its physical properties were expanded in the use of a three component molecular network system. The two ammonium groups (-NH(3)(+)) of the DAAz(2+) dication formed N-H(+)-O hydrogen-bonding interactions with the oxygen atoms of [18]crown-6 and dicyclohexane[18]crown-6. In the case of crystal 1, an alternating π-stacking interaction was observed for the [Ni(dmit)(2)](-) anions, whereas orthogonal linear π-S interactions were detected for crystal 2. Temperature-dependent magnetic susceptibilities of crystals 1 and 2 followed the alternate Heisenberg antiferromagnetic chain (J = -15.8 K) and linear Heisenberg antiferromagnetic chain (J = -13.7 K) models, respectively.

20.
Inorg Chem ; 50(19): 9337-44, 2011 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-21888332

RESUMO

The electrochemical oxidation of an acetone solution containing [Mn(III) (5-MeOsaltmen)(H(2)O)](2)(PF(6))(2) (5-MeOsaltmen(2-) = N,N'-(1,1,2,2-tetramethylethylene)bis(5-methoxysalicylideneiminate)) and (NBu(4))[Ni(dmit)(2)] (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate) afforded a hybrid material, [Mn(5-MeOsaltmen)(acetone)](2)[Ni(dmit)(2)](6) (1), in which [Mn(2)](2+) single-molecule magnets (SMMs) with an S(T) = 4 ground state and [Ni(dmit)(2)](n-) molecules in a charge-ordered state (n = 0 or 1) are assembled in a layer-by-layer structure. Compound 1 crystallizes in the triclinic space group P1 with an inversion center at the midpoint of the Mn···Mn dimer. The [Mn(2)](2+) unit has a typical nonplanar Mn(III) dimeric core and is structurally consistent with previously reported [Mn(2)] SMMs. The six [Ni(dmit)(2)](n-) (n = 0 or 1) units have a square-planar coordination geometry, and the charge ordering among them was assigned on the basis of ν(C═C) in IR reflectance spectra (1386, 1356, 1327, and 1296 cm(-1)). The [Mn(2)](2+) SMM and [Ni(dmit)(2)](n-) units aggregate independently to form hybrid frames. Electronic conductivity measurements revealed that 1 behaved as a semiconductor (ρ(rt) = 2.1 × 10(-1) Ω·cm(-1), E(a) = 97 meV) at ambient pressure and as an insulator at 1.7 GPa (ρ(1.7GPa) = 4.5 Ω·cm(-1), E(a) = 76 meV). Magnetic measurements indicated that the [Mn(2)](2+) units in 1 behaved as S(T) = 4 SMMs at low temperatures.

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