Syntheses and Structural Characterizations of Sheet- and Column-like Lanthanide−Transition Metal Arrays:  The Effect of Hydrogen Bonding on the Structure When K+Is Replaced by [NH4]+

2001 ◽  
Vol 40 (17) ◽  
pp. 4353-4360 ◽  
Author(s):  
Bin Du ◽  
Edward A. Meyers ◽  
Sheldon G. Shore
2002 ◽  
Vol 124 (18) ◽  
pp. 5197-5205 ◽  
Author(s):  
Cédric Desplanches ◽  
Eliseo Ruiz ◽  
Antonio Rodríguez-Fortea ◽  
Santiago Alvarez

Polyhedron ◽  
2009 ◽  
Vol 28 (14) ◽  
pp. 2813-2820 ◽  
Author(s):  
Aminou Mohamadou ◽  
Gerard A. van Albada ◽  
Ilpo Mutikainen ◽  
Urho Turpeinen ◽  
Jérôme Marrot ◽  
...  

1981 ◽  
Vol 34 (10) ◽  
pp. 2095 ◽  
Author(s):  
AJ Finney ◽  
MA Hitchman ◽  
CL Raston ◽  
GL Rowbottom ◽  
BW Skelton ◽  
...  

The crystal and molecular structures of the compounds [Ni(py)4(ONO)2],2py, [Ni(γmpy),(ONO)2] and [Ni(prz)4(ONO)2] are reported.�All three are trans nitrito complexes, the pyridine (py) compound containing two pyridine molecules of solvation. The aromatic rings in the first two complexes adopt 'paddle wheel' conformations with pitch angles varying between 40 and 70�. The nitrite ions are positioned so as to minimize repulsive interactions with the amines, and it seems likely that these groups bond through oxygen rather than nitrogen because this allows a lesser degree of interligand steric interference. The amine rings in [Ni(prz)4(ONO)2] are orthogonal to the plane containing the nickel and coordinated pyrazole nitrogen atoms; the nitrito groups are disordered between two inequivalent positions, each of which involves hydrogen bonding with the pyrazole NH groups. The nitrite infrared frequencies are similar to those observed for other nickel(II) nitrito complexes except that the antisymmetric NO stretching mode of one of the groups in the pyrazole complex is much lower in energy than expected, being in the range normally associated with a nitrogen-bonded or chelated nitrite group. It is suggested that this deviation may be caused by the hydrogen bonding in the complex. The electronic spectra of the compounds yield 10Dq values of 9100 and 8500 cm-1 for the nitrite ligands in [Ni(py)4(ONO)2] and Ni(prz)4(ONO)2], respectively, placing the nitrito group towards the weaker end of the spectro-chemical series.


2019 ◽  
Vol 8 (2S11) ◽  
pp. 3182-3190

Chemical speciation of ternary complexes of L-arginine and L-aspartic acid with essential transition metal ions was studied pH metrically. The following MLX, MLXH and ML2X ternary species are detected and reported in this paper. The existence of different ternary species is established from modeling studies using the computer program MINIQUAD75. The relative concentrations (M: L: X=1:2:2, 1:2:4, 1:4:2) and stabilities of the ternary species are compared with those of binary species. The extra stability associated with the ternary complexes is attributed to factors such as charge neutralization, chelate effect, stacking interactions and hydrogen bonding. Trend in variation of stability constants with the change in the mole fraction of the surfactant in various micellar media is explained on the basis of electrostatic and non-electrostatic forces. Distribution diagrams in relation to pH and plausible structures were presented.


2021 ◽  
Vol 50 (35) ◽  
pp. 12088-12092
Author(s):  
Clare A. Leahy ◽  
Michael J. Drummond ◽  
Josh Vura-Weis ◽  
Alison R. Fout

Hydrogen bonding networks are vital for metallo-enzymes to function; however, modeling these systems is non-trivial. The development of 1st-row transition metal chloride complexes with intramolecular hydrogen-bonding interactions are detailed herein.


2003 ◽  
Vol 58 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Christian Näther ◽  
Jan Greve ◽  
Inke Jeß

Abstract Three new coordination polymers have been prepared by hydrothermal reaction of squaric acid, pyrazine and the metal halides FeCl2 · 4H2O, CoBr2 and NiBr2. In their crystal structures the metal atoms are coordinated by four water molecules and two pyrazine ligands within slightly distorted octahedra. The pyrazine ligands connect the metal atoms via μ-N,N’-coordination to linear chains which are connected via hydrogen bonding. The squarate dianions are not coordinated to the metal atoms and are located between the chains. The thermal behaviour of all compounds was investigated using TG-DTA-MS measurements. A complex behaviour for all compounds is found and the decomposition temperatures increase from Fe to Ni. From these investigations there are no hints for the occurrence of stoichiometric intermediate compounds.


1986 ◽  
Vol 41 (11) ◽  
pp. 1329-1332 ◽  
Author(s):  
Armin Weiss ◽  
Eugen Riegler ◽  
Christian Robl

Abstract The isotypic compounds (MC4O4·2 H2O)3·CH3COOH·H2O(M=Zn2+,Ni2+) crystallize in the cubic space group Pn3n. The 3-dimensional framework structure contains cavities, which may be filled with CH3COOH · H2O . The metal ions are coordinated almost octahedrally by two water molecules and four oxygen atoms of four C4O42- dianions. Thus the squarate dianions act as fourfold monodentate ligands. Strong hydrogen bonding between H2O and C4O42- has to be assumed.


Author(s):  
Casseday P. Richers ◽  
Jeffery A. Bertke ◽  
Thomas B. Rauchfuss

The dinuclear title complex, [Co2(C5H7O2)4(μ-OH)2] or [Co(acac)2(μ-OH)]2, where acac is acetylacetonate, is centrosymmetric with half of the molecule per asymmetric unit. The molecular structure is a dimer of octahedrally coordinated CoIIIatoms with four O atoms from two chelating acac ligands and two O atoms from bridging hydroxide ligands. The crystal packing features weak C—H...O interactions between neighboring molecules, leading to the formation of chains normal to theacplane. The hydroxide H atoms are not involved in hydrogen bonding because of the bulky acac ligands. This is the first crystal structure reported of a dimeric transition metal bis-acac complex with OH−as the bridging group.


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