Single crystal Raman spectroscopy of brandholzite Mg[Sb(OH)6]2���6H2O and bottinoite Ni[Sb(OH)6]2���6H2O and the polycrystalline Raman spectrum of mopungite Na[Sb(OH)6]

The single crystal Raman spectra of minerals brandholzite and bottinoite, formula M[Sb(OH)6]2���6H2O, where M is Mg+2 and Ni+2 respectively, and the non-aligned Raman spectrum of mopungite, formula Na[Sb(OH)6], are presented for the first time. The mixed metal minerals comprise of alternating layers of [Sb(OH)6]-1 octahedra and mixed [M(H2O)6]+2 / [Sb(OH)6]-1 octahedra. Mopungite comprises hydrogen bonded layers of [Sb(OH)6]-1 octahedra linked within the layer by Na+ ions. The spectra of the three minerals were dominated by the Sb-O symmetric stretch of the [Sb(OH)6]-1 octahedron, which occurs at approximately 620 cm-1. The Raman spectrum of mopungite showed many similarities to spectra of the di-octahedral minerals informing the view that the Sb octahedra gave rise to most of the Raman bands observed, particularly below 1200 cm-1. Assignments have been proposed based on the spectral comparison between the minerals, prior literature and density field theory calculations of the vibrational spectra of the free [Sb(OH)6]-1 and [M(H2O)6]+2 octahedra by a model chemistry of B3LYP/6-31G(d) and lanl2dz for the Sb atom. The single crystal data spectra showed good mode separation, allowing the majority of the bands to be assigned a symmetry species of A or E.

Homo- and heteronuclear meso,meso-(E)-Ethene-1,2-diyl-Linked Diporphyrins : preparation, X-ray crystal structure, electronic absorption and emission spectra and density functional theory calculations

Homo-and heteronuclear meso,meso-(E)-ethene-1,2-diyl-linked diporphyrins have been prepared by the Suzuki coupling of porphyrinylboronates and iodovinylporphyrins. Combinations comprising 5,10,15-triphenylporphyrin (TriPP) on both ends of the ethene-1,2-diyl bridge M 210 (M 2=H 2/Ni, Ni 2, Ni/Zn, H 4, H 2Zn, Zn 2) and 5,15-bis(3,5-di-tert-butylphenyl)porphyrinato-nickel(II) on one end and H 2, Ni, and ZnTriPP on the other (M 211), enable the first studies of this class of compounds possessing intrinsic polarity. The compounds were characterized by electronic absorption and steady state emission spectra, 1H NMR spectra, and for the Ni 2 bis(TriPP) complex Ni 210, single crystal X-ray structure determination. The crystal structure shows ruffled distortions of the porphyrin rings, typical of Ni II porphyrins, and the (E)-C 2H 2 bridge makes a dihedral angle of 50�� with the mean planes of the macrocycles. The result is a stepped parallel arrangement of the porphyrin rings. The dihedral angles in the solid state reflect the interplay of steric and electronic effects of the bridge on interporphyrin communication. The emission spectra in particular, suggest energy transfer across the bridge is fast in conformations in which the bridge is nearly coplanar with the rings. Comparisons of the fluorescence behaviour of H 410 and H 2Ni10 show strong quenching of the free base fluorescence when the complex is excited at the lower energy component of the Soret band, a feature associated in the literature with more planar conformations. TDDFT calculations on the gas-phase optimized geometry of Ni 210 reproduce the features of the experimental electronic absorption spectrum within 0.1 eV. �� 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecular complexes of metallo tetraphenyl porphyrins with 2,4,5,7-tetranitro fluorenone

The interactions of mesotetraphenyl porphyrin and its metallo derivatives with 2,4,5,7-tetra nitrofluorenone have been studied using spectroscopic methods. The association constants (K) for 1:1 complexes in Ch2Cl2Cl2 follow the order Pd+2>Co+2> Cu+2>VO+2>Ni+2>Zn+2. The values of K are accounted in terms of stereochemistry of MTPPs and the electronic configuration of the metal ions. The magnitude and direction of the proton NMR shifts of the acceptor and donor in the complexes and their ESR parameter furnish information as to the possible structures of these complexes in solution.

Molecular-complexes of metallo tetraphenyl porphyrins with 2,4,5,7-tetranitro fluorenone

The interactions of mesotetraphenyl porphyrin and its metallo derivatives with 2,4,5,7-tetra nitrofluorenone have been studied using spectroscopic methods. The association constants (K) for 1:1 complexes in Ch2Cl2Cl2 follow the order Pd+2>Co+2> Cu+2>VO+2>Ni+2>Zn+2. The values of K are accounted in terms of stereochemistry of MTPPs and the electronic configuration of the metal ions. The magnitude and direction of the proton NMR shifts of the acceptor and donor in the complexes and their ESR parameter furnish information as to the possible structures of these complexes in solution.

Metal-spinel-corundum three phase equilibria in the system Ni-Cr-Al-O at 1373 K

The tie-lines representing the inter-crystalline ion exchange equilibria between the NiCr2O4-NiAl2O4 spinet solid solution and Cr2O3-Al2O3 corundum solid solution are determined by electron microprobe andEDAX pointcountanalysis of the oxide phases equilibrated with metallic Ni at 1373 K. The component activities in the spinet solid solution are derived from the tie-lines and thermodynamic data for Cr2O3-Al2O3 solid solution available in the literature. The Gibbs energy of mixing of the spinet solid solution calculated from the experimental data is discussed in relation to the values derived from the cation distribution models which assume random mixing of cations on both tetrahedral and octahedral sites. Positive deviation from the models is observed indicating significant positive enthalpy contribution arising form the size mismatch between Al+3 and Ni+2 ions on the tetrahedral site and Al+3, Ni+2 and Cr+3 on the octahedral site. Variation of the oxygen potential for threephase equilibrium involving metallic nickel, spinet solid solution and corundum solid solution is computed as a function of composition of the solid solutions at 1373 K. The oxygen potential exhibits a minimum at aluminum cationic fraction eta(Al)/(eta(Al) + eta(Cr)) = 0.524 in the oxide solid solutions.

Synthesis, spectral characterization and in vitro microbiological evaluation of novel glyoxal, biacetyl and benzil bis-hydrazone macrocyclic Schiff bases and their Co(II), Ni(II) and Cu(II) complexes

A series of binuclear Co(II), Ni(II) and Cu(II) complexes were synthesized by the template condensation of glyoxal, biacetyl or benzil bis-hydrazide, 2,6-diformyl-4-methylphenol and Co(11), Ni(II) or Cu(II) chloride in a 2:2:2 M ratio in ethanol. These 22-membered macrocyclic complexes were characterized by elemental analyses, magnetic, molar conductance, spectral, thermal and fluorescence studies. Elemental analyses suggest the complexes have a 2:1 stoichiometry of the type (M2LX2]center dot nH(2)O and Ni(2)LX(2)2H(2)O]center dot nH(2)O (where M = Co(II) and Cu(II); L = H2L1, H2L2 and H2L3; X = Cl; n = 2). From the spectroscopic and magnetic studies, it has been concluded that the Co(11) and Cu(11) complexes display a five coordinated square pyramidal geometry and the Ni(II) complexes have a six coordinated octahedral geometry. The Schiff bases and their metal complexes have also been screened for their antibacterial and antifungal activities by the MIC method. (C) 2011 Elsevier Ltd. All rights reserved.

DNA and protein targeting 1,2,4-triazole based water soluble dinickel(II) complexes enhances antiproliferation and lactate dehydrogenase inhibition

Water soluble dinickel(II) complexes Ni-2(L)(2)(1-2)](NO3)(4) (1-2), where L1-2 are triazole based dinucleating ligands, were synthesized and characterized. The DNA binding, protein binding, DNA hydrolysis and anticancer properties were investigated. The interactions of complexes 1 and 2 with calf thymus DNA were studied by spectroscopic techniques, including absorption and fluorescence spectroscopy. The DNA binding constant values of the complexes 1 and 2 were found to be 2.36 x 10(5) and 4.87 x 10(5) M-1 and the binding affinities are in the following order: 2 > 1. Both the dinickel(II) complexes 1 and 2, promoted the hydrolytic cleavage of plasmid pBR322 DNA under both anaerobic and aerobic conditions. Kinetic data for DNA hydrolysis promoted by 1 and 2 under physiological conditions give the observed rate constants (k(obs)) of 5.05 +/- 0.2 and 5.65 +/- 0.1 h(-1), respectively, which shows 10(8)-fold rate acceleration over the uncatalyzed reaction of ds-DNA. Meanwhile, the interactions of the complex with BSA have also been studied by spectroscopy. Both the complexes 1 and 2 display strong binding propensity and the binding constant (K-b), number of binding sites (n) were obtained are 0.71 x 10(6) 1.47] and 5.62 x 10(6) 1.98] M-1, respectively. The complexes 1 and 2 also promoted the apoptosis against human carcinoma (HeLa, and BeWo) cancer cells. Cytotoxicity of the complexes was further confirmed by lactate dehydrogenase enzyme level in cancer cell lysate and content media. (c) 2013 Elsevier Ltd. All rights reserved.

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���������Li-Ni-La-O���������������������������������������������������������������������������������������.���780������CH_4:O_2:N_2=2:1:7���������15000h~(-1)���,C_2���������������25.8���.XRD���IR���XPS���SEM������������������������,���LiLa_(1-x)Ni_xO_2������������,���0.1���x���0.9���,���������������LiNiO_2���LaNi_(1-y)Li_yO_(4-��)������������,x<0.3������������LiLaO_2���,La_2Ni_(1-y)Li_yO_(4-��)���������������������������������������,���������Li~+-O~--Ni~(2+)���������������������������������������������.LiNiO_2���LiLaO_2������������������,���������La_2Ni_(1-y)Li_yO_4���������������������������������������������������������.

Pharmacological profiling of store-operated Ca(2+) entry in retinal arteriolar smooth muscle

Objective: Pharmacological profiling of store-operated Ca(2+) entry (SOCE) and molecular profiling of ORAI and TRPC expression in arterioles.��<br/>Methods: Fura-2 based microfluorimetry was used to assess CPA-induced SOCE in rat retinal arteriolar myocytes. Arteriolar ORAI and TRP transcript expression were screened using RT-PCR.��<br/>Results: SKF96365 and LOE908 blocked SOCE (IC(50) s of 1.2��M and 1.4��M, respectively). Gd(3+) and La(3+) potently inhibited SOCE (IC(50) s of 21nM and 42nM, respectively), but Ni(2+) showed lower potency (IC(50) = 11.6��M). 2-aminoethyldiphenyl borate (2APB) inhibited SOCE (IC(50) = 3.7��M) but enhanced basal influx (&gt;100��M). Verapamil and nifedipine had no effect at concentrations that inhibit L-type Ca(2+) channels, but diltiazem inhibited SOCE by approximately 40% (=0.1��M). RT-PCR demonstrated transcript expression for ORAI 1, 2 and 3, and TRPC1, 3, 4 and 7. Transcripts for TRPV1 and 2, which are activated by 2APB, were also expressed.��<br/>Conclusion: The pharmacological profile of SOCE in retinal arteriolar smooth muscle appears unique when compared to other vascular tissues. This suggests that the molecular mechanisms underlying SOCE can differ, even in closely related tissues. Taken together, the pharmacological and molecular data are most consistent with involvement of TRPC1 in SOCE, although involvement of ORAI or other TRPC channels cannot be excluded. �� 2012 John Wiley &amp; Sons Ltd.

Nouveaux complexes pinces POCOP, NHCCOP, PIMCOP et PIMIOCOP, et complexes cyclom��tall��s de Ni(II) : synth��se, caract��risation et r��activit��.

Cette th��se traite de la chimie des complexes pinces de Ni(II) ainsi que des complexes cyclom��tall��s de Ni(II) comportant au moins un motif phosphinite. Elle se divise en trois parties. La premi��re concerne la synth��se, la caract��risation, le m��canisme de formation et la r��activit�� des complexes pinces de Ni(II) �� base de ligand de type POCOP 1,3-(i-Pr2PO)2C6H4. De nouveaux ligands de type R-(POCOP) = ��P,��C,��P-{Rn-2,6-( R'2PO)2C6H4-n}; Rn = 4-OMe, 4-Me, 4-CO2Me, 3-OMe, 3- CO2Me, 3,5-t-Bu2 ; R' = i-Pr, t-Bu ont ��t�� synth��tis��s suite �� l'addition de chlorophosphine ClPR'2 �� une solution de r��sorcinol ou d��riv��s en pr��sence de base. La synth��se des complexes R-(POCOP)Ni(Br) s'effectue �� partir du ligand correspondant en pr��sence de base, et de {NiBr2(NCiPr)}n. Ce nouveau pr��curseur de nickel est synth��tis�� �� partir de brome de nickel m��tallique dans l'isobutyronitrile. Il est stable sous atmosph��re inerte et sa solubilit�� dans les solvants polaires permet d'��tudier les synth��ses des complexes en milieu homog��ne. Le m��canisme de formation des complexes portant des ligand pinces (PCsp3P) 1,3-(i- Pr2PCH2CH2)2CH2, (POCsp3OP) 1,3-(i-Pr2POCH2)2CH2, (PCsp2P) 1,3-(i- Pr2PCH2)2C6H4, Rn-(POCsp2OP) 1,3-(i-Pr2PO)2C6H4-n via nickellation du lien C-H a ��t�� investigu�� avec une m��thode de r��action de comp��tition. Cette ��tape a ��t�� d��termin��e comme ��tant de nature ��lectrophile. Les complexes r��sultants ont ��t�� compl��tement caract��ris��s. Une corr��lation a notamment ��t�� effectu��e entre le d��placement chimique du Cipso en spectroscopie RMN 13C et le potentiel d'oxydation Eox en voltam��trie cyclique. Une nouvelle m��thode de synth��se directe verte "one pot" a ��t�� mise en place. En faisant r��agir �� 75 ��C un m��lange h��t��rog��ne de II r��sorcinol, de chlorodiisopropylphosphine et de nickel m��tallique en poudre, on obtient le complexes pince (POCOP)Ni(Cl) avec des rendements allant jusqu'�� 93%. La r��activit�� de ces complexes POCOP a ��t�� investigu��e pour des r��actions de fluorination et trifluorom��thylation des halog��nures d'alkyle. La synth��se du (POCOP)Ni(F) a lieu �� partir de pr��curseur (POCOP)Ni(X) (X=Br, Cl), en pr��sence d'un large exc��s de fluorure d'argent AgF. Ce complexe catalyse la fluorination du bromure de benzyle et peut ��tre converti en (POCOP)Ni(CF3) en pr��sence de r��actif du Ruppert, Me3SiCF3. La r��action entre (POCOP)Ni(CF3) et le bromure de benzyle dans les solvants aromatiques m��ne �� la conversion totale du complexe en (POCOP)Ni(Br) et �� l'inattendue benzylation du solvant aromatique utilis��. La seconde partie concerne la synth��se des nouveaux complexes non sym��triques �� base de ligands comportant un motif imidazolo-phosphine (PIMCOP) 3-[2-(R2P)-C3H2N2]-(R2PO)-C6H3, imidazoliophosphine (PIMIOCOP) 3-[2-(R2P)-3- (CH3)-C3H2N2]-(R2PO)-C6H3] et carb��ne N-h��t��rocyclique (NHCCOP). La double d��protonation du 3-hydroxyphenyl-imidazole suivi de l'addition de deux ��quivalents de chlorodiphenylphosphine m��ne �� l'obtention du ligand PIMCOP 3-[3-(CH3)- C3H2N2]-(R2PO)-C6H3. L'��tape de nickellation a lieu comme dans le cas des compos��s (POCOP)Ni. La m��thylation du motif imidazole du (PIMCOP)Ni(Br) par le triflate de m��thyle MeOTf, donne le d��riv�� (PIMIOCOP)Ni(Br). Ce dernier est converti en (NHCCOP)Ni(Br) apr��s l'addition de chlorure de t��tra��thylamonium NEt4Cl. Les analogues i-Pr2P de ces complexes sont synth��tis��s en rempla��ant ClPPh2 par ClPiPr2. On obtient les esp��ces cationiques [(PIMCOP)Ni(NCCH3)][OTf], [(PIMIOCOP)Ni(NCCH3)][OTf]2 et III [(NHCCOP)Ni(NCCH3)][OTf] suite �� l'addition en solution dans l'ac��tonitrile de triflate d'argent AgOTf. Ces esp��ces ont ��t�� utilis��s comme catalyseurs pour la synth��se d'amidine �� partir de benzonitrile et de diverse amines aliphatiques. Enfin des complexes orthonickell��s trans-Ni[(��2-P,C-P(OC6H4)-(iPr2)( iPr2P(OC6H5))]Br �� base de phosphinite ont ��t�� synth��tis��s et caract��ris��s. Les ligands sont synth��tis��s par r��action d'un ph��nol et de chlorodiisopropylphosphine en pr��sence de base. L'ajout de {NiBr2(NCiPr)}n et de tri��thylamine permet l'orthom��tallation via une ��tape de nickellation C-H. Un interm��diaire trans- [NiBr2{PiPr2(OC6H5)}2] de cette r��action a ��t�� isol��. Le complexe dim��re peut r��agir avec des esp��ces ��lectrophiles mener �� l'ortho-fonctionnalisation de la phosphinite.

Dinuclear complexes of M-II thiocyanate (M = Ni and Cu) containing a tridentate Schiff-base ligand: synthesis, structural diversity and magnetic properties

A dinuclear Ni-II complex, [Ni-2(L)(2)(H2O)(NCS)(2)]center dot 3H(2)O (1) in which the metal atoms are bridged by one water molecule and two mu(2)-phenolate ions, and a thiocyanato-bridged dimeric Cull complex, [Cu(L)NCS](2) (2) [L = tridentate Schiff-base ligand, N-(3-aminopropyl)salicylaldimine, derived from 1:1 condensation of salicylaldehyde and 1,3-diaminopropane], have been synthesized and characterized by IR and UV/Vis spectroscopy, cyclic voltammetry and single-crystal X-ray diffraction studies. The structure of 1 consists of dinuclear units with crystallographic C-2 symmetry in which each Ni-II atom is in a distorted octahedral environment. The Ni-O distance and the Ni-O-Ni angle, through the bridged water molecule, are 2.240(11) angstrom and 82.5(5)degrees, respectively. The structure of 2 consists of dinuclear units bridged asymmetrically by di-mu(1,3)-NCS ions; each Cull ion is in a square-pyramidal environment with tau = 0.25. Variable-temperature magnetic susceptibility studies indicate the presence of dominant ferromagnetic exchange coupling in complex 1 with J = 3.1 cm(-1), whereas complex 2 exhibits weak antiferromagnetic coupling between the Cu-II centers with J = -1.7 cm(-1). ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Two new Ni-II complexes with mu(1.5)-dicyanamide as bridging ligand

One 3D and one 2D mu(1,5)-dicyanamide bridged Ni-II complexes having molecular formula [Ni(L1)(dca)(2)] (1) and [Ni-2(L-2)(2)(dca)(4)] (.) 0.5H(2)O (2) (L1 = 4-(2-aminoethyl)-morpholine, L2 = 1-(2-aminoethyl)-piperidine and dca = dicyanamide dianion) have been synthesized. X-ray single crystal analyses and low temperature magnetic measurements were used to characterize the complexes. Complex 1 represents a 3D structure where each metal ion is chelated by morpholine ligand (L1) and connected by four mu(1,5)-dca. Whereas complex 2 shows an undulated 2D structure with grid of (4,4) topology having two crystallographically independent Ni-II centers in similar octahedral environment where each metal center is chelated by one piperidine ligand (L2) and coordinated by four mu(1,5)-dca. Magnetic measurements of both the complexes indicate weak antiferromagnetic interactions through the mu-(1,5)-dca bridging ligands. (c) 2004 Elsevier B.V. All rights reserved.

Gap junction-mediated spontaneous Ca(2+) waves in differentiated cholinergic SN56 cells

Neuronal gap junctions are receiving increasing attention as a physiological means of intercellular communication, yet our understanding of them is poorly developed when compared to synaptic communication. Using microfluorimetry, we demonstrate that differentiation of SN56 cells (hybridoma cells derived from murine septal neurones) leads to the spontaneous generation of Ca(2+) waves. These waves were unaffected by tetrodotoxin (1microM), but blocked by removal of extracellular Ca(2+), or addition of non-specific Ca(2+) channel inhibitors (Cd(2+) (0.1mM) or Ni(2+) (1mM)). Combined application of antagonists of NMDA receptors (AP5; 100microM), AMPA/kainate receptors (NBQX; 20microM), nicotinic AChR receptors (hexamethonium; 100microM) or inotropic purinoceptors (brilliant blue; 100nM) was also without effect. However, Ca(2+) waves were fully prevented by carbenoxolone (200microM), halothane (3mM) or niflumic acid (100microM), three structurally diverse inhibitors of gap junctions, and mRNA for connexin 36 was detected by PCR. Whole-cell patch-clamp recordings revealed spontaneous inward currents in voltage-clamped cells which we inhibited by Cd(2+), Ni(2+) or niflumic acid. Our data suggest that differentiated SN56 cells generated spontaneous Ca(2+) waves which are propagated by intercellular gap junctions. We propose that this system can be exploited conveniently for the development of neuronal gap junction modulators.