scholarly journals Σύμπλοκα του Cu(II) και Mn(II) με φαινοξυαλκανοϊκά οξέα και μεταλλοκορονοειδείς ενώσεις του Ni(II)

2000 ◽  
Author(s):  
Γεώργιος Ψωμάς
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Hydrogen ◽  
General Type ◽  
Magnetic Measurements ◽  
Carboxylate Group ◽  
Antimicrobial Studies ◽  
Mononuclear Complexes ◽  
Salicyl Hydroxamic

Complexes of Mn(II) and Cu(II) with phenoxyalkanoic herbicides as ligands as wellas metallacrowns of Ni(II) hosting herbicides were prepared and characterized. The herbicidesligands L 2,4-DP, MCPA, 2,4,5-T, 2,4-D and 2,3-D have the characteristic existence of thecarboxylato group. All complexes were characterized spectroscopically (IR, UV-Vis, EPR),analytically and magnetically.Mn(II) complexes have the general type [Mn(L)2(H2O)2]n. In these complexes, thecarboxylate group of the ligands is coordinated in a bidentate bridging mode. The crystalstructure of the 2-dimensioned complex [Mn(MCPA)2(H2O)2]n was determined with X-Ray.This complex shows weak antiferromagnetic behavior.Cu(II) complexes have the general types Cu(L)2(MeOH)2 or Cu2(L)4(MeOH)2,Cu(L)2(L')(H2O), [Cu(L)(L')2]Cl and Cu2(L)4(bipyam)2, where L': a heterocyclic N-donorligand (bipy, phen, bipyam). In complex Cu2(2,3-D)4(MeOH)2, the carboxylate group of theligand 2,3-D is coordinated in a bidentate bridging mode, in complexes of the general typeCu(L)2(L')(H2O) and [Cu(L)(L')2]Cl the carboxylate group is in a monodentate mode, while indinuclear complexes of the type Cu2(L)4(bipyam)2 both monodentate mode and bidentatebridging mode for the carboxylate group were found. In all complexes Cu+2 ion is five coordinatedand could be described as having highly distorted square pyramidal to trigonalbipyramidal geometry. The neutral mononuclear complexes of the type Cu(L)2(L’)(H2O)exhibit magnetochemical properties which are characteristic of a di- or multi-nuclear structureand are due to intra- and inter-molecular hydrogen bonds. Antimicrobial studies of thecomplexes showed that the best inhibition is provided by the cationic mononuclear complexesof the type [Cu(L)(L')2]Cl.Ni(II) metallacrowns hosting herbicides are of the general type NiII2(L)2(CH3OH)3(H2O)[12-MCNi(II)N(shi)2(pko)2-4][12-MCNi(II)N(shi)3(pko)-4], where H3shi=salicyl-hydroxamic acidand Hpko=di-(2-pyridyl)-ketonoxim, and are consisted of two metallacrown rings with +1 and-1 charges. Both metallacrown rings have an encapsulated Ni(II) ion and are held togetherthrough Ni-O bonds. Magnetic measurements for complex NiII2(MCPA)2[12-MCNi(II)N(shi)2(pko)2-4][12-MCNi(II)N(shi)3(pko)-4](CH3OH)3(H2O) showed weak antiferromagneticbehavior.

scholarly journals Molecular Hydrogen as a Lewis Base in Hydrogen Bonds and Other Interactions

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3294 ◽  
Author(s):  
Sławomir J. Grabowski
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Hydrogen ◽  
Spectroscopic Properties ◽  
Lewis Base ◽  
Basis Set ◽  
Orbital Method ◽  
Topological Parameters ◽  
Theoretical Approaches ◽  
Strength Of Interaction ◽  
Moller Plesset

The second-order Møller–Plesset perturbation theory calculations with the aug-cc-pVTZ basis set were performed for complexes of molecular hydrogen. These complexes are connected by various types of interactions, the hydrogen bonds and halogen bonds are most often represented in the sample of species analysed; most interactions can be classified as σ-hole and π-hole bonds. Different theoretical approaches were applied to describe these interactions: Quantum Theory of ‘Atoms in Molecules’, Natural Bond Orbital method, or the decomposition of the energy of interaction. The energetic, geometrical, and topological parameters are analysed and spectroscopic properties are discussed. The stretching frequency of the H-H bond of molecular hydrogen involved in intermolecular interactions is considered as a parameter expressing the strength of interaction.

scholarly journals Crystal structure ofcatena-poly[[diaquabis(4-formylbenzoato-κO1)cobalt(II)]-μ-pyrazine-κ2N:N′]

2015 ◽  
Vol 71 (4) ◽  
pp. 339-341 ◽  
Author(s):  
Gülçin Şefiye Aşkın ◽  
Fatih Çelik ◽  
Nefise Dilek ◽  
Hacali Necefoğlu ◽  
Tuncer Hökelek
Keyword(s):  
Hydrogen Bonds ◽  
Rotation Axis ◽  
Three Dimensional ◽  
Water Molecules ◽  
Carboxylate Group ◽  
Polymeric Compound ◽  
Distorted Octahedral Coordination ◽  
Linear Chains ◽  
Dimensional Network ◽  
Distorted Octahedral

In the title polymeric compound, [Co(C8H5O3)2(C4H4N2)(H2O)2]n, the CoIIatom is located on a twofold rotation axis and has a slightly distorted octahedral coordination sphere. In the equatorial plane, it is coordinated by two carboxylate O atoms of two symmetry-related monodentate formylbenzoate anions and by two N atoms of two bridging pyrazine ligands. The latter are bisected by the twofold rotation axis. The axial positions are occupied by two O atoms of the coordinating water molecules. In the formylbenzoate anion, the carboxylate group is twisted away from the attached benzene ring by 7.50 (8)°, while the benzene and pyrazine rings are oriented at a dihedral angle of 64.90 (4)°. The pyrazine ligands bridge the CoIIcations, forming linear chains running along theb-axis direction. Strong intramolecular O—H...O hydrogen bonds link the water molecules to the carboxylate O atoms. In the crystal, weak O—Hwater...Owaterhydrogen bonds link adjacent chains into layers parallel to thebcplane. The layers are linkedviaC—Hpyrazine...Oformylhydrogen bonds, forming a three-dimensional network. There are also weak C—H...π interactions present.

Improved Enzymatic Depolymerization of Chitosan by Ionic Liquid Pretreatment and the Effect of Oligo-Chitosan on Intestinal Flora In Vitro

2011 ◽  
Vol 391-392 ◽  
pp. 1319-1323
Author(s):  
Cui Zheng ◽  
Lin Li ◽  
Hao Pang ◽  
Zhao Mei Wang ◽  
Na Li
Keyword(s):  
Ionic Liquid ◽  
Hydrogen Bonds ◽  
Molecular Hydrogen ◽  
Intestinal Flora ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrolysis Of ◽  
Positive Effect ◽  
Enzymatic Depolymerization

It still remains challenging for effective hydrolysis of chitosan into chitosan oligomers. In this work, a pretreatment was conducted on chitosan by an ionic liquid 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), aiming at improving enzymatic depolymerization of chitosan. X-ray diffraction analysis indicated that the inter- and intra-molecular hydrogen bonds within chitosan molecules were broken by [C4mim]Cl and the crystalline was destroyed. The oligo-chitosan hydrolyzed from IL-pretreated chitosan, coded as COS-IL, showed a DP of 3~5, in contrast to DP 5~8 with oligo-chitosan obtained from untreated chitosan(coded as COS-UN). COS-IL was more effective than COS-UN in inhibiting intestinal spoilage bacterials growth and it has positive effect on the growth of intestinal probiotic bacterials.

scholarly journals Synthesis, Characterization and Antimicrobial Studies of N1-[(1E)-1-(2-Hydroxyphenyl) ethylidene]-2-oxo-2H-chromene-3-carbohydrazide and its Metal Complexes

2009 ◽  
Vol 6 (3) ◽  
pp. 615-624 ◽  
Author(s):  
K. Siddappa ◽  
K. Mallikarjun ◽  
Tukaram Reddy ◽  
M. Mallikarjun ◽  
C. V. Reddy ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Magnetic Susceptibility ◽  
Schiff Base ◽  
Metal Complexes ◽  
Molar Conductance ◽  
Tetrahedral Geometry ◽  
H Nmr ◽  
Antimicrobial Studies ◽  
Mononuclear Complexes ◽  
Uv Visible

A new complexes of the type ML, MʹL and M″L [where M=Cu(II), Co(II), Ni(II) and Mn(II), Mʹ=Fe(III) and M″=Zn(II), Cd(II) and Hg(II) and L=N1-[(1E)-1-(2-hydroxyphenyl)ethylidene]-2-oxo-2H-chromene- 3-carbohydrazide (HL)] Schiff base have been synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance, IR,1H NMR, UV-Visible and ESR data. The studies indicate the HL acts as doubly monodentate bridge for metal ions and form mononuclear complexes. The complexes Ni(II), Co(II), Cu(II) Mn(II) and Fe(III) complexes are found to be octahedral, where as Zn(II), Cd(II) and Hg(II) complexes are four coordinated with tetrahedral geometry. The synthesized ligand and its metal complexes were screened for their antimicrobial activity.

scholarly journals Different Molecular Interaction between Collagen and α- or β-Chitin in Mechanically Improved Electrospun Composite

Marine Drugs ◽  
2019 ◽  
Vol 17 (6) ◽  
pp. 318 ◽  
Author(s):  
Hyunwoo Moon ◽  
Seunghwan Choy ◽  
Yeonju Park ◽  
Young Mee Jung ◽  
Jun Mo Koo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Tensile Strength ◽  
Regenerative Medicine ◽  
Hydrogen Bonds ◽  
Molecular Interactions ◽  
Molecular Interaction ◽  
Molecular Hydrogen ◽  
Correlation Spectroscopy ◽  
Two Dimensional ◽  
Secondary Interaction

Although collagens from vertebrates are mainly used in regenerative medicine, the most elusive issue in the collagen-based biomedical scaffolds is its insufficient mechanical strength. To solve this problem, electrospun collagen composites with chitins were prepared and molecular interactions which are the cause of the mechanical improvement in the composites were investigated by two-dimensional correlation spectroscopy (2DCOS). The electrospun collagen is composed of two kinds of polymorphs, α- and β-chitin, showing different mechanical enhancement and molecular interactions due to different inherent configurations in the crystal structure, resulting in solvent and polymer susceptibility. The collagen/α-chitin has two distinctive phases in the composite, but β-chitin composite has a relatively homogeneous phase. The β-chitin composite showed better tensile strength with ~41% and ~14% higher strength compared to collagen and α-chitin composites, respectively, due to a favorable secondary interaction, i.e., inter- rather than intra-molecular hydrogen bonds. The revealed molecular interaction indicates that β-chitin prefers to form inter-molecular hydrogen bonds with collagen by rearranging their uncrumpled crystalline regions, unlike α-chitin.

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