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Inorganic Chemistry

Sergio A Loza-Rosas, Alexandra M Vázquez-Salgado, Kennett I Rivero, Lenny J Negrón, Yamixa Delgado, Josué A Benjamín-Rivera, Angel L Vázquez-Maldonado, Timothy B Parks, Charlene Munet-Colón, Arthur D Tinoco
The recent X-ray structure of titanium(IV)-bound human serum transferrin (STf) exhibiting citrate as a synergistic anion reveals a difference in Ti(IV) coordination versus iron(III), the metal endogenously delivered by the protein to cells. This finding enriches our bioinspired drug design strategy for Ti(IV)-based anticancer therapeutics, which applies a family of Fe(III) chelators termed chemical transferrin mimetic (cTfm) ligands to inhibit Fe bioavailability in cancer cells. Deferasirox, a drug used for iron overload disease, is a cTfm ligand that models STf coordination to Fe(III), favoring Fe(III) binding versus Ti(IV)...
June 23, 2017: Inorganic Chemistry
Lei Mei, Cong-Zhi Wang, Liu-Zheng Zhu, Zeng-Qiang Gao, Zhi-Fang Chai, John K Gibson, Wei-Qun Shi
The reaction of uranyl nitrate with terephthalic acid (H2TP) under hydrothermal conditions in the presence of an organic base, 1,3-(4,4'-bispyridyl)propane (BPP) or 4,4'-bipyridine (BPY), provided four uranyl terephthalate compounds with different entangled structures by a pH-tuning method. [UO2(TP)1.5](H2BPP)0.5·2H2O (1) obtained in a relatively acidic solution (final aqueous pH, 4.28) crystallizes in the form of a noninterpenetrated honeycomb-like two-dimensional network structure. An elevation of the solution pH (final pH, 5...
June 23, 2017: Inorganic Chemistry
Seiji Yamazoe, Shota Matsuo, Satoru Muramatsu, Shinjiro Takano, Kiyofumi Nitta, Tatsuya Tsukuda
The fluxional nature of small gold clusters has been exemplified by reversible isomerization between [Au9(PPh3)8](3+) with a crown motif (Au9(C)) and that with a butterfly motif (Au9(B)) induced by association and dissociation with compact counteranions (NO3(-), Cl(-)). However, structural isomerization was suppressed by substitution of the central Au atom of the Au9 core in [Au9(PPh3)8](3+) with a Pd atom: [PdAu8(PPh3)8](2+) with a crown motif (PdAu8(C)) did not isomerize to that with a butterfly motif (PdAu8(B)) upon association with the counteranions...
June 23, 2017: Inorganic Chemistry
Molin Zhou, Xingxing Jiang, Yangwu Guo, Zheshuai Lin, Jiyong Yao, Yicheng Wu
By combining different nonlinear optical-active structural chromophores with transition metal Mn into a crystal structure, two novel quaternary metal chalcogenides Pb0.65Mn2.85Ga3S8 (1) and Pb0.72Mn2.84Ga2.95Se8 (2) were successfully synthesized. Compounds 1 and 2 are isostructural, and they represent a new structure type that crystallizes in the space group P6̅ (No. 174) in the hexagonal system. Their structures feature an interesting three-dimensional open-tunnel framework composed of bridged infinite chains with Pb(2+) cations filling in the biggest tunnels...
June 23, 2017: Inorganic Chemistry
Nevenka Cakić, Ben Tickner, Moritz Zaiss, David Esteban-Gómez, Carlos Platas-Iglesias, Goran Angelovski
We report a detailed study of the solution structure and water exchange rate of a Eu(III) complex with the cyclen-based ligand L(1), containing (S)-2-(2-acetamido)-3-(4-(trifluoromethyl)phenyl)propanoate pendant arms at positions 1 and 7 of the cyclen ring and acetylglycinate pendants at positions 4 and 10. The EuL(1) complex was characterized by a combination of NMR and luminescence spectroscopy and density functional theory (DFT) calculations. The chemical exchange saturation transfer (CEST) spectra obtained at different temperatures and saturation powers present a CEST signal attributed to the coordinated water molecule...
June 23, 2017: Inorganic Chemistry
Ryan J Roberts, Debbie Le, Daniel B Leznoff
The new lanthanide-dicyanoaurate coordination polymers [(n)Bu4N]2[Ln(NO3)4Au(CN)2] (Ln = Sm, Dy) and Sm[Au(CN)2]3·3H2O were prepared and structurally characterized and their luminescence spectra described. The emissions of solid-solutions of [(n)Bu4N]2[Ln(NO3)4Au(CN)2] (Ln = Ce, Sm, Eu, Tb, and Dy) were explored with an emphasis on their capacity for luminescent color tuning and white-light emission via the selection of composition, excitation wavelength, and temperature. Specifically, the binary solid-solutions [(n)Bu4N]2[Ce0...
June 23, 2017: Inorganic Chemistry
Ruihan Dai, Fei Peng, Pengfei Ji, Kuangda Lu, Cheng Wang, Junliang Sun, Wenbin Lin
Nanoscale metal-organic frameworks (nMOFs) have shown tremendous potential in cancer therapy and biomedical imaging. However, their small dimensions present a significant challenge in structure determination by single-crystal X-ray crystallography. We report here the structural determination of nMOFs by rotation electron diffraction (RED). Two isostructural Zr- and Hf-based nMOFs with linear biphenyldicarboxylate (BPDC) or bipyridinedicarboxylate (BPYDC) linkers are stable under intense electron beams to allow the collection of high-quality RED data, which reveal a MOF structure with M12(μ3-O)8(μ3-OH)8(μ2-OH)6 (M = Zr, Hf) secondary building units (SBUs)...
June 22, 2017: Inorganic Chemistry
Richard A Mole, Stephen Greene, Paul F Henry, Simon M Humphrey, Kirrily C Rule, Tobias Unruh, Gerald F Weldon, Dehong Yu, John A Stride, Paul T Wood
Kagomé lattice types have been of intense interest as idealized examples of extended frustrated spin systems. Here we demonstrate how the use of neutron diffraction and inelastic neutron scattering coupled with spin wave theory calculations can be used to elucidate the complex magnetic interactions of extended spin networks. We show that the magnetic properties of the coordination polymer Mn3(1,2,4-(O2C)3C6H3)2, a highly distorted kagomé lattice, have been erroneously characterized as a canted antiferromagnet in previous works...
June 22, 2017: Inorganic Chemistry
Yan Li, Jinguang Cheng, José Antonio Alonso, John B Goodenough, Jianshi Zhou
A SrRhO3 polytype with six-layered (6M) structure was synthesized under high pressure and high temperature. The crystal structure was obtained by refining X-ray powder diffraction with the monoclinic space group C2/c with lattice parameters a = 5.5650(1) Å, b = 9.5967(2) Å, c = 14.0224(4) Å, and β = 92.846(2)°. It is isostructural with SrIrO3 synthesized under ambient pressure and consists of dimers of the face-shared Rh(2)O6 octahedra connected by their vertices to the corner-shared Rh(1)O6 octahedra along the c axis with a stacking of SrO3 layers in the sequence of CCHCCH, where C and H denote cubic and hexagonal closed packing, respectively...
June 22, 2017: Inorganic Chemistry
Srinivasan Ramakrishnan, Christopher E D Chidsey
The one-electron reduction of [CpRu(bpy)NCCH3]PF6 (Cp = cyclopentadienyl; bpy = 2,2'-bipyridine), abbreviated as [Ru-S](+), where S = CH3CN, in CO2-saturated acetonitrile initiates a cascade of rapid electrochemical and chemical steps (ECEC) at an electrode potential of ca. 100 mV positive of the first reduction of the ruthenium complex. The overall two-electron process leads to the generation of a CO-bound ruthenium complex, [Ru-CO](+), and carbonate, as independently confirmed by NMR spectroscopy. Simulations of the cyclic voltammograms using DigiElch together with density functional theory based calculations reveal that the singly reduced ruthenium complex [Ru-S](0) binds CO2 at a rate of ca...
June 22, 2017: Inorganic Chemistry
Alessandra Curci, Valentina Gandin, Cristina Marzano, James D Hoeschele, Giovanni Natile, Nicola Margiotta
Two new Pt(II) derivatives of kiteplatin ([PtCl2(cis-1,4-DACH)]) with pyrophosphate as carrier ligand, one mononuclear (1) and one dinuclear (2), were synthesized with the aim of potentiating the efficacy of kiteplatin. Complex 1 resulted to be remarkably stable at physiological pH, but it undergoes a fast hydrolysis reaction at acidic pH releasing free pyrophosphate and (aquated) kiteplatin. The dinuclear compound 2 resulted to be less stable than 1 at both neutral and acidic pH forming 1 and (aquated) kiteplatin as first step...
June 21, 2017: Inorganic Chemistry
Fengrui Qu, Seungjo Park, Kristina Martinez, Jessica L Gray, Fathima Shazna Thowfeik, John A Lundeen, Ashley E Kuhn, David J Charboneau, Deidra L Gerlach, Molly M Lockart, James A Law, Katherine L Jernigan, Nicole Chambers, Matthias Zeller, Nicholas A Piro, W Scott Kassel, Russell H Schmehl, Jared J Paul, Edward J Merino, Yonghyun Kim, Elizabeth T Papish
Metallo prodrugs that take advantage of the inherent acidity surrounding cancer cells have yet to be developed. We report a new class of pH-activated metallo prodrugs (pHAMPs) that are activated by light- and pH-triggered ligand dissociation. These ruthenium complexes take advantage of a key characteristic of cancer cells and hypoxic solid tumors (acidity) that can be exploited to lessen the side effects of chemotherapy. Five ruthenium complexes of the type [(N,N)2Ru(PL)](2+) were synthesized, fully characterized, and tested for cytotoxicity in cell culture (1A: N,N = 2,2'-bipyridine (bipy) and PL, the photolabile ligand, = 6,6'-dihydroxybipyridine (6,6'-dhbp); 2A: N,N = 1,10-phenanthroline (phen) and PL = 6,6'-dhbp; 3A: N,N = 2,3-dihydro-[1,4]dioxino[2,3-f][1,10]phenanthroline (dop) and PL = 6,6'-dhbp; 4A: N,N = bipy and PL = 4,4'-dimethyl-6,6'-dihydroxybipyridine (dmdhbp); 5A: N,N = 1,10-phenanthroline (phen) and PL = 4,4'-dihydroxybipyridine (4,4'-dhbp)...
June 21, 2017: Inorganic Chemistry
Shan-Shan Liu, Yin-Shan Meng, Yi-Quan Zhang, Zhao-Sha Meng, Ke Lang, Zhen-Liang Zhu, Chang-Fang Shang, Bing-Wu Wang, Song Gao
A mononuclar six-coordinate dysprosium complex was synthesized and structurally and magnetically characterized. X-ray structural analyses show trigonal-prismatic coordination geometry of the Dy(III) center. Slow relaxation of magnetization in the absence of a direct-current field and magnetic hysteresis up to 3.0 K could be observed, indicating its single-ion-magnet behavior. Arrhenius fitting and ab initio calculations suggest that the magnetic relaxation process may not occur through the Orbach process at high temperatures under the experimental conditions...
June 21, 2017: Inorganic Chemistry
Lu Chen, Suman Mallick, Ying Ning Tan, Miao Meng, Chun Y Liu
Three quadruply bonded dimolybdenum complexes equipped with a triarylamine pendant, [(DAniF)3Mo2(μ-O2CC6H4N(C6H4CH3)2] (DAniF = N,N'-di(p-anisyl)formamidinate; [OO-ph-N]), [(DAniF)3Mo2(μ-OSCC6H4N(C6H4CH3)2] ([OS-ph-N]), and [(DAniF)3Mo2(μ-S2CC6H4N(C6H4CH3)2] ([SS-ph-N]), have been synthesized and characterized by single crystal X-ray diffraction. In electrochemical measurements, the redox couple for the organic amine group becomes irreversible, reflecting the substantially strong electronic interaction between the dimetal center and organic redox site...
June 21, 2017: Inorganic Chemistry
Seung-Tae Hong
Quasicrystals (QCs) are well-ordered but aperiodic crystals with classically forbidden symmetries (such as 5-fold). High-dimensional (HD) crystallography is a standard method to locate atom positions explicitly. However, in practice, it is still challenging because of its complexity. Here, we report a new simple approach to three-dimensional (3D) atomic modeling derived from X-ray diffraction data, and apply it to the icosahedral QC Al0.63Cu0.25Fe0.12. Electron density maps were calculated directly from 3D diffraction data indexed with noninteger (fractional) numbers as measured, with proper phases; each of 2(5) = 32 possible phase assignments for the five strongest reflections was used for Fourier synthesis...
June 21, 2017: Inorganic Chemistry
Meng-Na Peng, Zhi-Yuan Zhu, Li-Feng Tan
The first investigation of chiral ruthenium(II) complexes Δ- and Λ-[Ru(bpy)2dppz](2+) and triplex RNA poly(U)·poly(A)*poly(U) was carried out, which showed that Δ enantiomer displayed significant ability in stabilizing model triplex RNA.
June 21, 2017: Inorganic Chemistry
Zhao-Feng Wu, Liao-Kuo Gong, Xiao-Ying Huang
Here we report a fluorescent magnesium coordination polymer (Mg-CP), namely, [CH3-dpb]2[Mg3(1,4-NDC)4(μ-H2O)2(CH3OH)(H2O)]·1.5H2O (1, 1,4-H2NDC = 1,4-naphthalene dicarboxylic acid, dpb = 1,4-bis(pyrid-4-yl)benzene). Compound 1 possesses a three-dimensional (3D) host-guest structure constructed by the 1,4-NDC linkers bridging the linear trinuclear secondary building units of [Mg3(COO)8(μ-H2O)2]. The dpb molecules were in situ reacted with CH3OH resulting in photochromic cations of [CH3-dpb](+) that acted as guests located in the channels parallel to the b-axis...
June 21, 2017: Inorganic Chemistry
Xudong Yu, Zengyao Wang, Yajuan Li, Lijun Geng, Jujie Ren, Guoliang Feng
Herein, ditopic ligand DTA comprised of terpyridine and acetylene segments with only one aromatic π-conjugated building block was designed and synthesized. Driven by metal-ligand coordination interactions, we presented that the use of metal salts can direct the self-assembly of DTA in the generation of fluorescent and electrochemical polymers that entrapped water to form ambidextrous hydrogels. These were characterized by several approaches including fluorescent titrations, UV-vis, circular dichroism, and X-ray diffraction spectra as well as scanning electron microscopy and transmission electron microscopy experiments...
June 20, 2017: Inorganic Chemistry
Amandine Boulmier, Xinxin Feng, Olivier Oms, Pierre Mialane, Eric Rivière, Christopher J Shin, Jiaqi Yao, Tadahiko Kubo, Taisuke Furuta, Eric Oldfield, Anne Dolbecq
We synthesized a series of polyoxometalate-bisphosphonate complexes containing Mo(VI)O6 octahedra, zoledronate, or an N-alkyl (n-C6 or n-C8) zoledronate analogue, and in two cases, Mn as a heterometal. Mo6L2 (L = Zol, ZolC6, ZolC8) and Mo4L2Mn (L = Zol, ZolC8) were characterized by using single-crystal X-ray crystallography and/or IR spectroscopy, elemental and energy dispersive X-ray analysis and (31)P NMR. We found promising activity against human nonsmall cell lung cancer (NCI-H460) cells with IC50 values for growth inhibition of ∼5 μM per bisphosphonate ligand...
June 20, 2017: Inorganic Chemistry
Majeda Al Hareri, Zineb Ras Ali, Jeffery Regier, Emma L Gavey, Luis D Carlos, Rute A S Ferreira, Melanie Pilkington
Two complexes comprising 9-coordinate capped square antiprismatic [Ln(NO3)3(OH2)2(MeOH)] units [Ln(III) = Dy 6; Tb 7] are reported in which the metal complexes are hydrogen-bonded to 15C5 (15-crown-5) macrocycles to form supramolecular chains, {[Ln(NO3)3(OH2)2(MeOH)]·(15C5)}n. Alternating current magnetic susceptibility measurements supported by ab initio studies show field-induced SMM (single-molecule magnet) behavior for 6, but rapid relaxation of the magnetization for 7 because of the presence of dominant quantum tunneling processes as evidenced by the presence of a significant calculated tunnel splitting within the ground-state multiplet...
June 20, 2017: Inorganic Chemistry
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