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Inorganic Chemistry

Hiroshi Suzuki, Kanako Inabe, Yoshinori Shirakawa, Naoki Umezawa, Nobuki Kato, Tsunehiko Higuchi
The catalytic cycle of cytochrome P450 involves a change from the resting-state, water-bound, six-coordinated form (1, low-spin state) to a five-coordinated form (2, high-spin state) upon binding of a hydrophobic substrate. Here, we used a heme-thiolate model complex (SR complex) with THF as a model of nonionic H2O to address the question of whether or not coordination of nonionic water is sufficient to induce the low-spin state. Measurements of electronic absorption spectra and magnetic properties confirmed that five-coordinated SR complex has a high-spin state, and THF-bound, six-coordinated SR has a low-spin state in dichloromethane at ambient temperature...
March 28, 2017: Inorganic Chemistry
Rodolphe Pollet, Célia S Bonnet, Pascal Retailleau, Philippe Durand, Éva Tóth
The proton-exchange process between water and a carbamate has been studied experimentally and theoretically in a lanthanide-based paramagnetic chemical exchange saturation transfer agent endowed with potential multimodality detection capabilities (optical imaging, or T1 MRI for the Gd(III) analogue). In addition to an in-depth structural analysis by a combined approach (using X-ray crystallography, NMR, and molecular dynamics), our ab initio simulation in aqueous solution sheds light on the reaction mechanism for this proton exchange, which involves structural Grotthuss diffusion...
March 27, 2017: Inorganic Chemistry
A Paulina Gómora-Figueroa, Jarad A Mason, Miguel I Gonzalez, Eric D Bloch, Katie R Meihaus
The reaction of ZrCl4 with 2',3',5',6'-tetramethylamino-p-terphenyl-4,4″-dicarboxylic acid (H2tpdc-4CH2NH2·3HCl) in the presence of NaF affords Zr6O4(OH)2.1F1.9(tpdc-4CH2NH2·3HCl)6 (1), which is a new member of the Zr6O4(OH)4(dicarboxylate linker)12 or UiO-68 family, and exhibits high porosity with BET and Langmuir surface areas of 1910 m(2)/g and 2220 m(2)/g, respectively. Remarkably, fluoride ion incorporation in the zirconium clusters results in increased thermal stability, marking the first example of enhancement in the stability of a UiO framework by this defect-restoration approach...
March 27, 2017: Inorganic Chemistry
Zhiwen Zhao, Jie Qin, Chen Zhang, Yaorong Wang, Dan Yuan, Yingming Yao
Ionic rare-earth metal complexes 1-4 bearing an imidazolium cation were synthesized, which, as single-component catalysts, showed good activity in catalyzing cyclic carbonate synthesis from epoxides and CO2. In the presence of 0.2 mol % catalyst, monosubstituted epoxides bearing different functional groups were converted into cyclic carbonates in 60-97% yields under atmospheric pressure. In addition, bulky/internal epoxides with low reactivity yielded cyclic carbonates in 40-95% yields. More importantly, the readily available samarium complex 2 was reused for six successive cycles without any significant loss in its catalytic activity...
March 27, 2017: Inorganic Chemistry
Stefano Todisco, Lapo Luconi, Giuliano Giambastiani, Andrea Rossin, Maurizio Peruzzini, Igor E Golub, Oleg A Filippov, Natalia V Belkova, Elena S Shubina
Two Co(I) hydrides containing the tripodal polyphosphine ligand EP3, (κ(4)-EP3)Co(H) [E(CH2CH2PPh2)3; E = N (1), P (2)], have been exploited as ammonia borane (NH3BH3, AB) dehydrogenation catalysts in THF solution at T = 55 °C. The reaction has been analyzed experimentally through multinuclear ((11)B, (31)P{(1)H}, (1)H) NMR and IR spectroscopy, kinetic rate measurements, and kinetic isotope effect (KIE) determination with deuterated AB isotopologues. Both complexes are active in AB dehydrogenation, albeit with different rates and efficiency...
March 27, 2017: Inorganic Chemistry
Abu Saleh Musha Islam, Rahul Bhowmick, Kaberi Pal, Atul Katarkar, Keya Chaudhuri, Mahammad Ali
A smart molecule, QT490, containing thiosemicarbazide moiety acts as a highly selective turn-on in vitro NO sensor through the unprecedented NO-induced transformation of thiosemicarbazide moiety to 1,3,4-oxadiazole heterocycle with the concomitant release of HSNO, thereby eliminating any interference from various endogenous biomolecules including dehydroascorbic acid, ascorbic acid, etc. The kinetic studies of the reactions between QT490 and NO provide a mechanistic insight into formation of HSNO/RSNO from the reaction between H2S/RSH and NO in the biological system...
March 27, 2017: Inorganic Chemistry
Arvind Kumar Gupta, Sunisa Akkarasamiyo, Andreas Orthaber
A series of dibenzoarsole (also known as 9-arsafluorene) derivatives have been prepared, and their coordination chemistry has been investigated. The different ligand topology and the arsenic substituents govern the reactivity of the ligands. We report various crystal structures of palladium and platinum complexes derived from this family of ligands. The biphenyl backbone of the bridged bidentate ligands allows very flexible coordination. We have also studied the application of an allylic Pd complex in nucleophilic substitution reactions, revealing that the benzoarsole substituent is susceptible to metal insertion...
March 27, 2017: Inorganic Chemistry
Ting Song, Yuan Cao, Gang Zhao, Lin Pu
Fluorescence responses of two BINOL-based diastereomeric salicylaldimines toward a variety of metal cations have been studied in methanol solution. It is revealed that both compounds show great fluorescence enhancements in the presence of Zn(2+) but not with any other metal ions. Moreover, these two diastereomers exhibit dramatically different responses toward Zn(2+) under the same conditions. That is, one can produce much stronger fluorescence enhancement also at a longer wavelength than the other. This fluorescence recognition of Zn(2+) also shows distinctive color changes under a UV lamp...
March 27, 2017: Inorganic Chemistry
Saurabh S Chitnis, Rebecca A Musgrave, Hazel A Sparkes, Natalie E Pridmore, Vincent T Annibale, Ian Manners
Heterolytic cleavage of homoatomic bonds is a challenge, as it requires separation of opposite charges. Even highly strained homoatomic rings (e.g., cyclopropane and cyclobutane) are kinetically stable and do not react with nucleophiles or electrophiles. In contrast, cycloalkanes bearing electron-donating/withdrawing substituents on adjacent carbons have polarized C-C bonds and undergo numerous heterolytic ring-opening and expansion reactions. Here we show that upon electrophile activation phosphorus homocycles exhibit analogous reactivity, which is modulated by the amount of ring strain and extent of bond polarization...
March 27, 2017: Inorganic Chemistry
Nicole Harmgarth, Phil Liebing, Florian Zörner, Mindaugas Silinskas, Edmund P Burte, Frank T Edelmann
The first antimony(III) aziridinyl derivatives are reported. Treatment of anhydrous SbCl3 with N-lithioaziridine Li(Azn) (Azn = NC2H4) afforded the structurally unique heterobimetallic lithium/antimony(III) amide complex [Li3Sb(μ3-Cl)2(μ-Azn)4(THF)2]∞ (1). Homoleptic Sb2(Azn)6 (2) has become available for the first time through an amide group exchange reaction between Sb(NMe2)3 and 3 equiv of aziridine. The low-melting Sb2(Azn)6 exhibits a "weak dimer" structure in the crystal.
March 27, 2017: Inorganic Chemistry
Fang Xu, Yulong Liao, Dainan Zhang, Tingchuan Zhou, Jie Li, Gongwen Gan, Huaiwu Zhang
LiZn ferrite ceramics with high saturation magnetization (4πMs) and low ferromagnetic resonance line widths (ΔH) represent a very critical class of material for microwave ferrite devices. Many existing approaches emphasize promotion of the grain growth (average size is 10-50 μm) of ferrite ceramics to improve the gyromagnetic properties at relatively low sintering temperatures. This paper describes a new strategy for obtaining uniform and compact LiZn ferrite ceramics (average grains size is ∼2 μm) with enhanced magnetic performance by suppressing grain growth in great detail...
March 27, 2017: Inorganic Chemistry
Kwing To Lai, Alexander Christoph Komarek, Maria Teresa Fernández-Díaz, Pi-Shan Chang, Sungjoon Huh, Helge Rosner, Chang-Yang Kuo, Zhiwei Hu, Tun-Wen Pi, Peter Adler, Vadim Ksenofontov, Liu Hao Tjeng, Martin Valldor
From stoichiometric amounts of CaO, Fe, and Se, pure powders and single crystals of quaternary [Formula: see text] can be obtained by solid-state reaction and self-flux growth, respectively. The as-synthesized compound exhibits a polymorphic crystal structure, where the two modifications have different stacking sequences of [Formula: see text] layers. The two polymorphs have similar unit cells but different crystal symmetries (Cmc21 and Pnma), of which the former is non-centrosymmetric. Fe is divalent (d(6)) and high-spin, as proven by X-ray spectroscopy, Mössbauer spectroscopy, and powder neutron diffraction data...
March 27, 2017: Inorganic Chemistry
Li-Dan Lin, Xin-Xiong Li, Yan-Jie Qi, Xiang Ma, Shou-Tian Zheng
The two novel cluster organic frameworks based on heterometallic supertetrahedral cluster secondary building units (SBUs) [Cd4Cu6(L)4(Ac)7(H2O)4](Ac)·7H2O (1) and [Mn4Cu6(L)4(Ac)4.5(H2O)9]CuCN(Ac)3.5·H2O (2), where H3L = 2-(hydroxymethyl)-2-(pyridin-4-yl)-1,3-propanediol and Ac = CH3COO(-), have been prepared under solvothermal conditions. 1 and 2 are the first cases of cluster organic frameworks containing Cd-Cu/Mn-Cu heterometallic supertetrahedral cluster SBUs. Furthermore, 1 and 2 show an integration of magnetic properties and adsorption properties from both the heterometallic cluster secondary building units and the framework in a porous material...
March 27, 2017: Inorganic Chemistry
Tian-Yi Gu, Ming Dai, David James Young, Zhi-Gang Ren, Jian-Ping Lang
Three photoluminescent zinc coordination polymers (CPs), {[Zn2(tpeb)2(2,5-tdc)(2,5-Htdc)2]·2H2O}n (1), {[Zn2(tpeb)2(1,4-ndc)(1,4-Hndc)2]·2.6H2O}n (2), and {[Zn2(tpeb)2(2,3-ndc)2]·H2O}n (3) (tpeb = 1,3,5-tri-4-pyridyl-1,2-ethenylbenzene, 2,5-tdc = 2,5-thiophenedicarboxylic acid, 1,4-ndc = 1,4-naphthalenedicarboxylic acid, and 2,3-ndc = 2,3-naphthalenedicarboxylic acid) were prepared from reactions of Zn(NO3)2·6H2O with tpeb and 2,5-H2tdc, 1,4-H2ndc, or 2,3-H2ndc under solvothermal conditions. Compound 1 has a two-dimensional (2D) grid-like network formed from bridging 1D [Zn(tpeb)]n chains via 2,5-tdc dianions...
March 24, 2017: Inorganic Chemistry
Sk Imran Ali, Reinhard K Kremer, Mats Johnsson
The new oxofluoride compound FeSbO2F2 was synthesized by hydrothermal techniques at 230 °C. Its crystal structure was determined from single-crystal X-ray diffraction data. The compound crystallizes in the monoclinic space group C2/c with one crystallographic site for Fe(3+) and Sb(3+), respectively. The crystal structure is made of [FeO2F4] octahedra and seesaw [SbO4] building blocks. These are connected to form [FeO2F2]n layers and [SbO2]n chains that bond together via the oxygen atoms to form the three-dimensional framework structure...
March 24, 2017: Inorganic Chemistry
Boushra Mortada, Tamara Abou Matar, Aya Sakaya, Hala Atallah, Zeinab Kara Ali, Pierre Karam, Mohamad Hmadeh
Metal-organic frameworks (MOFs) have emerged as an important class of hybrid organic-inorganic materials. One of the reasons they have gained remarkable attention is attributed to the possibility of altering them by postsynthetic modification, thereby providing access to new and novel advanced materials. MOFs have been applied in catalysis, gas storage, gas separation, chemical sensing, and drug delivery. However, their bactericidal use has rarely been explored. Herein, we developed a two-step process for the synthesis of zirconium-based MOFs metalated with silver cations as a potent antibacterial agent...
March 24, 2017: Inorganic Chemistry
M Paz Clares, Laura Acosta-Rueda, Carmen E Castillo, Salvador Blasco, Hermas R Jiménez, Enrique García-España, Manuel G Basallote
The Fe(II) coordination chemistry of a pyridinophane tren-derived scorpiand type ligand containing a pyridine ring in the pendant arm is explored by potentiometry, X-ray, NMR, and kinetics methods. Equilibrium studies in water show the formation of a stable [FeL](2+) complex that converts to monoprotonated and monohydroxylated species when the pH is changed. A [Fe(H-2L)](2+) complex containing an hexacoordinated dehydrogenated ligand has been isolated, and its crystal structure shows the formation of an imine bond involving the aliphatic nitrogen of the pendant arm...
March 24, 2017: Inorganic Chemistry
Li Xu, László Valkai, Alena A Kuznetsova, Sergei V Makarov, Attila K Horváth
The thiourea dioxide (TDO)-iodine reaction was investigated spectrophotometrically monitoring the consumption of total amount of iodine at 468 nm, at T = 25.0 ± 0.1 °C, and at 0.5 M ionic strength in buffered slightly acidic medium. The nitrogen- and carbon-containing products were found to be ammonium ion and dissolved carbon dioxide, respectively, while from sulfur part sulfate ion was exclusively detected, when fresh TDO solution was used. The stoichiometry of the reaction was established as 2I2 + TDO + 4H2O → SO4(2-) + 2NH4(+) + 4I(-) + CO2 + 4H(+) indicating a strict 2:1 stoichiometric ratio...
March 24, 2017: Inorganic Chemistry
Maria Fumanal, Fernando Jiménez-Grávalos, Jordi Ribas-Arino, Sergi Vela
The spin transition of Fe(II) complexes is the subject of intensive synthetic and computational efforts. In this manuscript, we analyze the spin crossover (SCO) of [Fe(E-dpsp)2](2+) (1), which features a spin transition depending on the cocrystallizing solvent molecules. Whereas the use of acetone results in a hysteretic spin transition at ∼170 K, the use of propylene carbonate (PC) results in a permanent diamagnetic signal up to 300 K. By means of DFT+U+D2 calculations in the solid state of the material, we unravel the reasons for such different behavior...
March 23, 2017: Inorganic Chemistry
Dmitry V Peryshkov, Steven H Strauss
The single-crystal X-ray structures, thermogravimetric analyses, and/or FTIR spectra of a series of salts of the B12F12(2-) anion and homoleptic Ag(L)n(+) cations are reported (L = CH2Cl2, n = 2; L = PhCH3, n = 3; L = CH3CN; n = 2-4; L = CO, n = 1, 2). The superweak-anion nature of B12F12(2-) (Y(2-)) was demonstrated by the rapid reaction of microcrystalline Ag2(Y) with 1 atm of CO to form a nonclassical silver(I) carbonyl compound with an FTIR ν(CO) band at 2198 cm(-1) (and with the proposed formula [Ag(CO)n]2[Y])...
March 23, 2017: Inorganic Chemistry
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