scholarly journals Tetrakis[μ3-2-(piperidin-1-yl)ethanolato]tetrakis[chloridocopper(II)]

2014 ◽  
Vol 70 (5) ◽  
pp. m194-m194
Author(s):  
Mei Luo ◽  
Yong-Hua Huang ◽  
Jing-Cheng Zhang
Keyword(s):  
Intermolecular Interactions ◽  
Minor Component ◽  
Chair Conformation ◽  
Hydroxyl Groups ◽  
Tetranuclear Complex ◽  
Pyramidal Geometry ◽  
A Minor ◽  
Square Pyramidal Geometry

In the title tetranuclear compound, [Cu4(C7H14NO)4Cl4], each CuIIcation isN,O-chelated by a piperidineethanolate anion and coordinated by a Cl−anion and two O atoms from neighboring piperidineethanolate anions in a distorted NO3Cl square-pyramidal geometry. The deprotonated hydroxyl groups of the piperidineethanolate anions bridge CuIIcations, forming the tetranuclear complex. All piperidine rings display a chair conformation. In the crystal, there are no significant intermolecular interactions present. The crystal studied was an inversion twin refined with a minor component of 0.18 (5).

Synthesis and crystal structure analyses of tri-substituted guanidine-based copper(II) complexes

2021 ◽  
Vol 76 (3-4) ◽  
pp. 193-199
Author(s):  
Muhammad Said ◽  
Sadia Rehman ◽  
Muhammad Ikram ◽  
Hizbullah Khan ◽  
Carola Schulzke
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Molecular Structures ◽  
Hydroxyl Groups ◽  
Synthesis And Crystal Structure ◽  
Pyramidal Geometry ◽  
Tautomeric Forms ◽  
Square Planar ◽  
Nitrogen Donor ◽  
Square Pyramidal Geometry

Abstract Three guanidine-derived tri-substituted ligands viz. N-pivaloyl-N′,N″-bis-(2-methoxyphenyl)guanidine (L1), N-pivaloyl-N′-(2-methoxyphenyl)-N″-phenylguanidine (L2) and N-pivaloyl-N′-(2-methoxyphenyl)-N″-(2-tolyl)guanidine (L3) were reacted with Cu(II) acetate to produce the corresponding complexes. The significance of the substituent on N″ for the resulting molecular structures and their packing in the solid state has been studied with respect to the structural specifics of the corresponding Cu(II) complexes. The key characteristic of the guanidine-based metal complexation with Cu(II) is the formation of an essentially square planar core with an N2O2 donor set. As an exception, in the complex of L1, the substituent’s methoxy moiety also interacts with the Cu(II) center to generate a square-pyramidal geometry. The hydroxyl groups of the imidic acid tautomeric forms of L1–L3, in addition to N″, are also bonded to Cu(II) in all three complexes rather than the nitrogen donor of the guanidine motif.

Dependence of the Distortion of the Square Pyramids in N, N-Dimethylethylenediammonium Pentachloroantimonate(III) on the Geometry of Hydrogen Bonds

2001 ◽  
Vol 56 (6) ◽  
pp. 521-525 ◽  
Author(s):  
Maciej Bujak ◽  
Jacek Zaleski
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Intermolecular Interactions ◽  
Mean Value ◽  
The Other ◽  
Monoclinic System ◽  
Bond Lengths ◽  
Pyramidal Geometry ◽  
The Mean ◽  
Square Pyramidal Geometry

AbstractN ,N-Dimethylethylenediammonium pentachloroantimonate(III) crystallizes in the monoclinic system, in space group P21/c (a = 12.460(2), b = 10.252(2), c = 10.330(2) Å, β = 97.75(3)°, V = 1307.5(4) Å3, Z = 4, dc = 1.997, dm = 1.99(2) g/cm3). The crystal structure of [(CH3)2NH(CH2)2NH3][SbCl5] consists of isolated [SbCl5]2- anions and [(CH3)2NH(CH2)2NH3]2+ cations. The [SbCl5]2- anion has a distorted square pyramidal geometry, presenting one short axial and four long equatorial Sb-Cl bonds. The square pyramids are characteristically stacked one close to the other, parallel to the c axis. The voids between the anionic sublattice are filled by [(CH3)2NH(CH2)2NH3]2+ cations. The five non-equivalent Sb-Cl bond distances within the [SbCl5]2- square pyramid are significantly different. The equatorial Sb-Cl bonds are in the range 2.427(2)-2.968(2) Å, whereas the axial one is 2.384(1) Å long. The study reveals that N-H...C1 hydrogen bonds are responsible for the deformation of equatorial Sb-Cl bonds from the mean value of 2.654(7) Å. Analysis of intermolecular interactions between the [SbCl5]2- pyramids in the structure, reflected in changes of Sb-Cl bond lengths from the values characteristic of non-interacting pyramids, leads to the conclusion that the van der Waals radius of Sb is significantly smaller than that estimated by Pauling.

scholarly journals Crystal structure of di-μ-hydroxido-bis{aqua[ethyl (1,10-phenanthrolin-3-yl)phosphonato-κ2N,N′]copper(II)} heptahydrate

2018 ◽  
Vol 74 (12) ◽  
pp. 1751-1754
Author(s):  
Alexander Yu. Mitrofanov ◽  
Yoann Rousselin
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Title Compound ◽  
Binuclear Complex ◽  
Three Dimensional ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Pyramidal Geometry ◽  
Square Pyramidal Geometry

In the title compound, [Cu2(OH)2{C12H7N2(PO3C2H5)}2(H2O)2]·7H2O, two Cu2+cations are bridged by two hydroxide groups, forming a centrosymmetric binuclear complex. Each Cu2+cation is further coordinated by the N atoms of a bidentate ethyl (1,10-phenanthrolin-3-yl)phosphonate anion and a water molecule in a square-pyramidal geometry. In the crystal, a network of O—H...O hydrogen bonds involving the P(O)(O−)(OEt) groups, bridging hydroxyl groups, coordinated and uncoordinated water molecules generates a three-dimensional supramolecular structure. The ethyl group exhibits disorder and was modelled over three sites with occupancies of 0.455, 0.384 and 0.161.

A Molecular Orbital Study of the Stereochemistry of Pentacoordinated Aluminium

1979 ◽  
Vol 32 (2) ◽  
pp. 231 ◽  
Author(s):  
RJ Hill ◽  
GV Gibbs ◽  
RC Peterson
Keyword(s):  
Total Energy ◽  
Molecular Orbital ◽  
Minimum Energy ◽  
Edge Length ◽  
Hydroxyl Groups ◽  
Bond Lengths ◽  
Pyramidal Geometry ◽  
Trigonal Bipyramidal ◽  
Square Pyramidal Geometry ◽  
Shared Edge

An attempt has been made to characterize the stereochemical requirements of an aluminium atom coordinated by five hydroxyl groups (AlO5H52-) within the framework of CNDO/2 molecular orbital formalism. Total energy surfaces calculated for this system as the valence angles are varied within the constraints of C2v symmetry clearly show the 'reaction coordinate' for the so-called Berry pseudo- rotation mechanism. With all Al-O and O-H bond lengths fixed at 1.84 and 1.00 Ǻ respectively, the activation energy for trigonal-bipyramidal/square-pyramidal interconversion is 7.1 kJ mol-1. In addition, the minimum energy O(axial)-Al-O(basal) angle for the square-pyramidal group is estimated to be c. 103.5°. When one bond is lengthened relative to the other four the trigonal-bipyramidal configuration is further stabilized, but approaches tetrahedral geometry. When one bond is shortened square-pyramidal geometry is stabilized and the minimum energy O(ax)-Al-O(bs) angle increases. With two bonds lengthened (or shortened) the favoured trigonal-bipyramidal configuration is the one with long bonds directed towards the axial positions and at no stage is there a stabilization of square-pyramidal geometry. These results agree with trends in calculated Mulliken bond overlap populations and with observed ratios of axial-to-basal bond lengths in suggesting that for trigonal- bipyramidal stereochemistry the axial bonds are weaker, whereas for square-pyramidal geometry the axial bond is stronger. Moreover, consideration of the total energy for various isomers of Al(OH)4F2- indicates that more electronegative substituents prefer to enter the apical and basal positions in a trigonal bipyramid and a square pyramld respectively. For a cluster Al2(OH)82-, consisting of two aluminium trigonal-bipyramidal groups sharing a common edge of variable length, an energy minimum (62.2 kJ mol-1 lower than the undistorted case) is found at a shared edge length of 2.246 A, 13 % shorter than for the undistorted polyhedron. The corresponding observed distance for a similar dimer in the mineral andalusite, Al2SiO5, is 2.247(7) Ǻ. Plots of minimum energy shared edge length against mean bond length for various clusters M2(OH)8n-, where M = Al or Mg, clearly demonstrate an essentially linear relationship between the two parameters consistent wlth trends observed for natural systems in which M = Co, Cu, Mn and Zn.

scholarly journals Chlorido(2,2′-{[2-(1-methyl-1H-imidazol-2-yl-κN 3)imidazolidine-1,3-diyl-κN]bis(methylene)}bis(1-methyl-1H-imidazole-κN 3))copper(II) perchlorate

2019 ◽  
Vol 75 (5) ◽  
pp. 547-551
Author(s):  
Diego da Silva Padilha ◽  
Marciela Scarpellini
Keyword(s):  
Crystal Structure ◽  
Intermolecular Interactions ◽  
Title Complex ◽  
Stacking Interactions ◽  
Metal Centre ◽  
Pyramidal Geometry ◽  
Π Stacking ◽  
Methyl Imidazole ◽  
Square Pyramidal Geometry

In the crystal structure of the title complex, [CuCl(C17H24N8)]ClO4, the copper(II) metal exhibits an N4Cl pentacoordinate environment in a distorted square-pyramidal geometry. Coordination to the metal centre occurs through the three 1-methylimidazole N atoms from the pendant groups, one amine N atom from the imidazolidine moiety and one chlorido anion. Intermolecular interactions take place at two of the 1-methyl-imidazole rings in the form of parallel-displaced π–π stacking interactions forming chains parallel to the a axis. Three O atoms of the perchlorate anion are rotationally disordered between two orientations with occupancies of 0.5.

Protonation effects on dynamic flux properties of aqueous metal complexes

2009 ◽  
Vol 74 (10) ◽  
pp. 1543-1557 ◽  
Author(s):  
Herman P. Van Leeuwen ◽  
Raewyn M. Town
Keyword(s):  
Complex Formation ◽  
Metal Ion ◽  
Good Description ◽  
Minor Component ◽  
Outer Sphere ◽  
Metal Species ◽  
Central Metal ◽  
Inner Sphere ◽  
A Minor ◽  
Protonated Ligand

The degree of (de)protonation of aqueous metal species has significant consequences for the kinetics of complex formation/dissociation. All protonated forms of both the ligand and the hydrated central metal ion contribute to the rate of complex formation to an extent weighted by the pertaining outer-sphere stabilities. Likewise, the lifetime of the uncomplexed metal is determined by all the various protonated ligand species. Therefore, the interfacial reaction layer thickness, μ, and the ensuing kinetic flux, Jkin, are more involved than in the conventional case. All inner-sphere complexes contribute to the overall rate of dissociation, as weighted by their respective rate constants for dissociation, kd. The presence of inner-sphere deprotonated H2O, or of outer-sphere protonated ligand, generally has a great impact on kd of the inner-sphere complex. Consequently, the overall flux can be dominated by a species that is a minor component of the bulk speciation. The concepts are shown to provide a good description of experimental stripping chronopotentiometric data for several protonated metal–ligand systems.

scholarly journals Synthesis and spectral characterizations of vanadyl(ii) and chromium(iii) mixed ligand complexes containing metformin drug and glycine amino acid

2021 ◽  
Vol 19 (1) ◽  
pp. 735-744
Author(s):  
Samar O. Aljazzar
Keyword(s):  
Amino Acid ◽  
Type Ii Diabetes ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Spectroscopic Techniques ◽  
Nanoscale Structures ◽  
Pyramidal Geometry ◽  
Effective Drugs ◽  
Square Pyramidal Geometry ◽  
Spectral Characterizations

Abstract Metformin is one of the most effective drugs for the treatment of type II diabetes. Two new mixed ligand complexes of vanadyl(ii) and chromium(iii) ions with the general formula [VOL1L2]SO4 and [CrL1L2(Cl)2]Cl, respectively, where L1 is the metformin and L2 is the glycine amino acid, have been synthesized in MeOH solvent with 1:1:1 stoichiometry and characterized by several spectroscopic techniques. The spectroscopic data suggested that the [VOL1L2]SO4 complex possesses a square pyramidal geometry, where the [CrL1L2(Cl)2]Cl complex possesses an octahedral geometry. The L1 ligand coordinated to the VO(ii) and Cr(iii) ions via the N atoms of the imino (‒C═NH) groups, where the L2 ligand coordinated via the O atom of the carboxylate group (COO) and the N atom of the amino group (NH2). The interaction of ligands L1 and L2 with the metal ions leads to complexes that have organized nanoscale structures with a main diameter of ∼14 nm for the [CrL1L2(Cl)2]Cl complex and ∼40 nm for the [VOL1L2]SO4 complex.

Petrography and provenance of the Marambio Group, Vega Island, Antarctica

1994 ◽  
Vol 6 (4) ◽  
pp. 517-527 ◽  
Author(s):  
Duncan Pirrie
Keyword(s):  
Late Cretaceous ◽  
Sedimentary Rocks ◽  
Clay Mineralogy ◽  
Minor Component ◽  
Source Area ◽  
Low Grade ◽  
Western Margin ◽  
Sediment Input ◽  
A Minor ◽  
Sandstone Petrography

Late Cretaceous sedimentary rocks assigned to the Santa Marta (Herbert Sound Member) and López de Bertodano (Cape Lamb and Sandwich Bluff members) formations of the Marambio Group, crop out on Cape Lamb, Vega Island. Although previous studies have recognized that these sedimentary rocks were derived from the northern Antarctic Peninsula region, the work presented here allows the provenance and palaeogeographical evolution of the region to be described in detail. On the basis of both sandstone petrography and clay mineralogy, the Herbert Sound and Cape Lamb members reflect sediment input from a low relief source area, with sand grade sediment sourced from low grade metasediments, and clay grade sediment ultimately derived from the weathering of an andesitic source area. In contrast, the Sandwich Bluff Member reflects a switch to a predominantly andesitic volcaniclastic source. However, this sediment was largely derived from older volcanic suites due to renewed source area uplift, with only a minor component from coeval volcanism. Regional uplift of both the arc terrane and the western margin of the James Ross Basin was likely during the Maastrichtian.

Sign in / Sign up

Export Citation Format

Share Document