Ligand Hyperfine Interaction in the Complex [Mn(H2O)6] ++ in La2(Mg,Mn)3(NO3)12·24H2O

1969 ◽  
Vol 24 (11) ◽  
pp. 1746-1751 ◽  
Author(s):  
D. van Ormondt ◽  
R. de Beer ◽  
M. Brouha ◽  
F. de Groot

Abstract The elements of the hyperfine interaction (h.f.i.) between the manganese ion and the protons in the complex [Mn(H2O)6]++ in one of the two possible sites in La2(Mg, Mn)3(NO3)12 · 24 H2O have been measured with ENDOR at 15 to 20 K. The six water molecules in the complex at the chosen site are equivalent for reasons of symmetry.One principal direction of the h.f.i. tensor of each proton is found to be perpendicular to the Mn, O line. With the assumption that each proton is located in the plane of the other two principal directions of its interaction tensor the positions of the protons are evaluated from the anisotropic parts of the h.f.i. tensors. In this calculation the effect of covalency on the anisotropic h.f.i. is ac-counted for with the aid of a simple model.The isotropic h.f.i.'s with the two protons of a water molecule appear to be very nearly equal (+ 0.890 MHz for both). This latter result is remarkable in view of the fact that one proton is distinctly nearer to the manganese ion than the other.

1979 ◽  
Vol 32 (2) ◽  
pp. 301 ◽  
Author(s):  
V Diakiw ◽  
TW Hambley ◽  
DL Kepert ◽  
CL Raston ◽  
AH White

The crystal structure of the title compound, Ca(C6H2N307)2,5H2O, has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.049 for 1513 'observed' reflections. Crystals are orthorhombic, Pmab, a 24.169(6), b l0.292(7), c 8.554(2) �, Z 4. The stereochemistry about the calcium has not been observed previously for the system [M(bidentate)2- (unidentate)4]; in the present structure, the calcium is coordinated by a pair of bidentate picrate ligands and the four water molecules in an array in which three of the water molecules occupy a triangular face of a square antiprism, the overall array having m symmetry. The remaining water molecule occupies a lattice site with no close interaction with the other species.


1971 ◽  
Vol 49 (9) ◽  
pp. 1413-1424 ◽  
Author(s):  
Michaela Holzbecher ◽  
Osvald Knop ◽  
Michael Falk

Infrared spectra of polycrystalline Na2[Fe(CN)5NO] 2H2O at different degrees of deuteration were studied as a function of temperature. The single peaks observed for the bending fundamentals of isotopically dilute H2O and D2O show that all the water molecules are equivalent, as required by Manoharan and Hamilton's structure determination; the doublets observed for the three fundamentals of isotopically dilute HDO show that the water molecules are asymmetric. Doublet separation decreases gradually with increasing temperature, indicating decreasing asymmetry. The water molecule appears to orient itself so as to maximize the strength of one [Formula: see text] bond, while the other OH group interacts only very weakly with another CN group. The hitherto unknown extent to which the nitroprusside ion deviates from the ideal C4v symmetry has been estimated from the 13C14N stretching spectrum. The 15N16O and 14N18O stretching spectrum was used to confirm that only one type of NO group is present in the crystal, and hence that all nitroprusside ions are equivalent.


2014 ◽  
Vol 70 (5) ◽  
pp. m170-m171
Author(s):  
Fei-Lin Yang ◽  
Dan Yang

The asymmetric unit of the title compound, {[Mn3{W(CN)8}2(C16H16N2)3(C3H7NO)3(CH3OH)3]·2H2O}n, consists of three [Mn(N,N-dimethylformamide)(methanol)(3,4,7,8-tetramethyl-1,10-phenanthroline)]2+cations, two [W(CN)8]3−anions and two water molecules. Each water molecule is disordered over three sets of sites, with a refined occupancy ratio of 0.310 (9):0.275 (9):0.415 (9) for one molecule and 0.335 (9):0.288 (9):0.377 (9) for the other molecule. The MnIIatoms exhibit a distorted octahedral geometry, while the WVatoms adopt a distorted square-antiprismatic geometry. The MnIIand WVatoms are linked alternatively through cyanide groups, forming a tetranuclear 12-atom rhombic metallacycle. Adjacent metallacycles are further connected by μ2-bridging cyanide anions, generating a 3,2-chain structure running parallel to [101]. Interchain π–π interactions are observed [centroid–centroid distances = 3.763 (3) and 3.620 (2) Å].


2010 ◽  
Vol 66 (2) ◽  
pp. 213-221 ◽  
Author(s):  
Maxime A. Siegler ◽  
Jacob H. Prewitt ◽  
Steven P. Kelley ◽  
Sean Parkin ◽  
John P. Selegue ◽  
...  

Five structures of co-crystals grown from aqueous solutions equimolar in 15-crown-5 (or 15C5) and [M(H2O)6](NO3) n , M = Al3+, Cr3+ and Pd2+, are reported. The hydrogen-bonding patterns in all are similar: metal complexes including the fragment trans-H2O—M—OH2 alternate with 15C5 molecules, to which they are hydrogen bonded, to form stacks. A literature survey shows that this hydrogen-bonding pattern is very common. In each of the two polymorphs of the compound [Al(H2O)6](NO3)3·15C5·4H2O there are two independent cations; one forms hydrogen bonds directly to the 15C5 molecules adjacent in the stack, while the other cation is hydrogen-bonded to two water molecules that act as spacers in the stack. These stacks are then crosslinked by hydrogen bonds formed by the three nitrate counterions and the three lattice water molecules. The hydrogen-bonded stacks in [Cr(H2O)5(NO3)](NO3)2·1.5(15C5)·H2O are discrete rather than infinite; each unit contains two Cr3+ complex cations and three 15C5 molecules. These units are again crosslinked by the uncoordinated nitrate ions and a lattice water molecule. In [Pd(H2O)2(NO3)2]·15C5 the infinite stacks are electrically neutral and are not crosslinked. In [Pd(H2O)2(NO3)2]·2(15C5)·2H2O·2HNO3 a discrete, uncharged unit containing one Pd complex and two 15C5 molecules is `capped off' at either end by a lattice water molecule and an included nitric acid molecule. In all five structures the infinite stacks or discrete units form an array that is at least approximately hexagonal.


1979 ◽  
Vol 177 (1) ◽  
pp. 289-302 ◽  
Author(s):  
R Barker ◽  
N Boden ◽  
G Cayley ◽  
S C Charlton ◽  
R Henson ◽  
...  

Benzylamine oxidase from pig plasma has been studied by a variety of chemical and physical techniques. 1. Analytical ultracentrifugation, gel electrophoresis and isoelectric-focusing studies suggest that the enzyme is composed of two subunits with closely similar primary structures. 2. E.s.r. and n.m.r. measurements show that the enzyme contains two well-separated (greater than 0.6 nm) Cu2+ ions at chemically distinct sites. Each Cu2+ ion is coordinated by two water molecules, one ‘axial’ and the other ‘equatorial’. Both water molecules undergo fast exchange (10(5)–10(8) s-1) with solvent and are deprotonated in the pH r!ange 8–9, but only the equatorial water molecule is displaced by the inhibitors N3- and CN-. 3. Kinetic and e.s.r. measurements show that azide and cyanide compete against O2 binding and also make the two Cu2+ sites identical. It is concluded that Cu2+ must participate in the re-oxidation of reduced enzyme by molecular O2.


2007 ◽  
Vol 63 (11) ◽  
pp. m2682-m2683 ◽  
Author(s):  
Xianfu Zheng ◽  
Caoyuan Niu ◽  
Xinsheng Wan ◽  
Chunhong Kou

The title mononuclear MnII complex, [Mn(C13H14N2)4(H2O)2](PF6)2·H2O, is isostructural with the previously reported ZnII complex. The metal center is coordinated by four monodentate 1,3-di-4-pyridylpropane (L1) ligands and two water molecules. One L1 ligand is affected by disorder of two propane C atoms, which are distributed over two positions, with occupancies 0.771 (8)/0.229 (8). The asymmetric unit is completed by one solvent water molecule and two PF6 − anions, both disordered over two positions, with occupancies for F atoms of 0.621 (10)/0.379 (10) for one anion and 0.69 (2)/0.31 (2) for the other. Uncoordinated N atoms of pyridyl groups belonging to L1 and water molecules are involved in hydrogen bonds, with D...A separations ranging from 1.85 (4) to 2.07 (4) Å and D—H...A angles from 169 (3) to 174 (4)°.


2015 ◽  
Vol 71 (6) ◽  
pp. m127-m128
Author(s):  
Chao Wu ◽  
Peng Cao

The asymmetric unit of the polymeric title compound, [Ni(C8H4O4)(C10H14N4)(H2O)]n, contains one Ni2+cation, one coordinating water molecule, one 3,3′,5,5′-tetramethyl-4,4′-bipyrazole ligand and half each of two benzene-1,4-dicarboxylate anions, the other halves being generated by inversion symmetry. The Ni2+cation exhibits an octahedral N2O4coordination sphere defined by the O atoms of the water molecule and two different anions and the N atoms of two symmetry-relatedN-heterocycles. TheN-heterocycles and both anions bridge adjacent Ni2+cations into a three-dimensional network structure, with one of the anions in a bis-bidentate and the other in a bis-monodentate bridging mode. N—H...O and O—H...O hydrogen bonds between the N-heterocycles and water molecules as donor groups and the carboxylate O atoms as acceptor groups consolidate the crystal packing.


2014 ◽  
Vol 70 (5) ◽  
pp. 455-459 ◽  
Author(s):  
Natalija van Well ◽  
Christian Klein ◽  
Franz Ritter ◽  
Wolf Assmus ◽  
Cornelius Krellner ◽  
...  

The crystal structures of two crown-ether-coordinated caesium halogen salt hydrates, namely di-μ-bromido-bis[aqua(1,4,7,10,13,16-hexaoxacyclooctadecane)caesium(I)] dihydrate, [Cs2Br2(C12H24O6)2(H2O)2]·2H2O, (I), and poly[[diaquadi-μ-chlorido-μ-(1,4,7,10,13,16-hexaoxacyclooctadecane)dicaesium(I)] dihydrate], {[Cs2Cl2(C12H24O6)(H2O)2]·2H2O} n , (II), are reported. In (I), all atoms are located on general positions. In (II), the Cs+ cation is located on a mirror plane perpendicular to the a axis, the chloride anion is located on a mirror plane perpendicular to the c axis and the crown-ether ring is located around a special position with site symmetry 2/m, with two opposite O atoms exactly on the mirror plane perpendicular to the a axis; of one water molecule, only the O atom is located on a mirror plane perpendicular on the a axis, while the other water molecule is completely located on a mirror plane perpendicular to the c axis. Whereas in (I), hydrogen bonds between bromide ligands and water molecules lead to one-dimensional chains running along the b axis, in (II) two-dimensional sheets of water molecules and chloride ligands are formed which combine with the polymeric caesium–crown polymer to give a three-dimensional network. Although both compounds have a similar composition, i.e. a Cs+ cation with a halogen, an 18-crown-6 ether and a water ligand, the crystal structures are rather different. On the other hand, it is remarkable that (I) is isomorphous with the already published iodide compound.


2012 ◽  
Vol 68 (4) ◽  
pp. o1204-o1204 ◽  
Author(s):  
Sanaz Khorasani ◽  
Manuel A. Fernandes

In the title hydrated salt, C8H18N+·C4H5O4−·H2O, the cyclooctyl ring of the cation is disordered over two positions in a 0.833 (3):0.167 (3) ratio. The structure contains various O—H.·O and N—H...O interactions, forming a hydrogen-bonded layer of molecules perpendicular to thecaxis. In each layer, the ammonium cation hydrogen bonds to two hydrogen succinate anions and one water molecule. Each hydrogen succinate anion hydrogen bonds to neighbouring anions, forming a chain of molecules along thebaxis. In addition, each hydrogen succinate anion hydrogen bonds to two water molecules and the ammonium cation.


Sign in / Sign up

Export Citation Format

Share Document