Asymmetric and Symmetric Dicopper(II) Paddle-Wheel Units with Modified Nucleobases

2015 ◽  
Vol 15 (11) ◽  
pp. 5485-5494 ◽  
Author(s):  
Khaled Hassanein ◽  
Oscar Castillo ◽  
Carlos J. Gómez-García ◽  
Félix Zamora ◽  
Pilar Amo-Ochoa
Keyword(s):  
Paddle Wheel ◽  
Modified Nucleobases

scholarly journals Thermochemical and Structural Analysis of Tautomers of Sulfur and Selenium Modified RNA Nucleobases

2019 ◽  
Vol 2 (2) ◽  
pp. 47-48
Author(s):  
Megan Joy ◽  
Alex Brown ◽  
Arturo Mora Gomez ◽  
Maria Rossano-Tapia ◽  
Shyam Parshotam
Keyword(s):  
Ir Spectra ◽  
Structural Changes ◽  
Chemical Properties ◽  
Hydrogen Atoms ◽  
Relative Population ◽  
Geometry Analysis ◽  
Physical And Chemical ◽  
Modified Nucleobases ◽  
Relative Gibbs Free Energy ◽  
And Chemical Properties

Nucleobases (adenine, cytosine, guanine, and uracil), the four molecules that forms RNA, have been found to be useful in probing in the human body when modified because they can emit light. Non-modified nucleobases do not exhibit emissive properties and cannot be used as probes. Some of the modifications include the substitution of nitrogen atoms with sulfur and selenium, and the resulting modified nucleobases give place to the so-called tz- and ts- RNA alphabets, respectively. Therefore, the aim of this project was to provide insights about the viability, from a computational perspective, of using the modified nucleobases as probes, evaluating the differences in thermochemical, structural and emissive properties of the modified nucleobases with respect to the non-modified ones. Nucleobases can coexist with other modified nucleobases or tautomers, molecules that differ due to the change in position of hydrogen atoms in a molecule’s structure and as a result have different physical and chemical properties. The thermochemical properties evaluation mainly consisted in the computation of the relative Gibbs Free Energy (G), which is related to the fraction F, an index of the relative population among tautomers. This was done using Gaussian 09 software by performing geometry analysis and frequency computations on each one of the tautomers. By comparing the equilibrium fractions, it was determined that in both cases, tz- and ts- guanine and cytosine exist principally in the form of one of their tautomers (Cytosine 2 and Guanine 2) as in the case of the non-modified cases. After confirming which tz- and ts- tautomers were the ones with the largest probable population, infrared (IR) and ultraviolet-visible (UV-vis) spectra were obtained. The IR spectra of selenium and sulfur tautomers of guanine and cytosine indicated that the tautomers had peaks at similar frequencies with respect to each other, however, the intensities varied, implying slight structural changes between the tautomers. On the other hand, the UV-vis spectra showed a change in peak positions between the tautomers with sulfur and selenium, suggesting that the change between sulfur and selenium has an effect on the spectra by shifting the peaks from the original molecules’ λmax values. Their relative population fractions show that only the canonical forms of the modified nucleobases exist in a larger extent than the rest of their tautomer forms. In addition, the features in their UV-vis and IR spectra allow these tautomers to be differentiated from each other.

Synthesis, structure, and magnetic properties of two dimer paddle-wheel CuII toluate complexes with nitronyl nitroxide radicals

2013 ◽  
Vol 66 (12) ◽  
pp. 2166-2177 ◽  
Author(s):  
Jie Zhou ◽  
Lin Du ◽  
Zongze Li ◽  
Yongfeng Qiao ◽  
Jing Liu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Nitronyl Nitroxide ◽  
Nitroxide Radicals ◽  
Paddle Wheel

Metal–organic aerogels based on dinuclear rhodium paddle-wheel units: design, synthesis and catalysis

2016 ◽  
Vol 3 (5) ◽  
pp. 702-710 ◽  
Author(s):  
Baofu Zhu ◽  
Gang Liu ◽  
Lianfen Chen ◽  
Liqin Qiu ◽  
Liuping Chen ◽  
...  
Keyword(s):  
Design Synthesis ◽  
Paddle Wheel ◽  
Metal Organic ◽  
Organic Aerogel ◽  
Organic Aerogels

A metal–organic aerogel (MOA-Rh-1d) with Rh2+–Rh2+ bonds has been obtained, which can efficiently promote CO2 conversion and C–H amination reactions.

scholarly journals Crystal structure ofcatena-poly[hemi[1,3-bis(2,6-diisopropylphenyl)imidazolium] [[μ3-acetato-κ3O:O:O′-tri-μ2-acetato-κ6O:O′-dicopper(II)(Cu—Cu)]-μ-chlorido] dichloromethane sesquisolvate]

2015 ◽  
Vol 71 (8) ◽  
pp. m148-m149
Author(s):  
Mohammad Iqbal ◽  
James Raftery ◽  
Peter Quayle
Keyword(s):  
Coordination Polymer ◽  
Rotation Axis ◽  
Metal Organic Framework ◽  
Solvent Molecule ◽  
Central Metal ◽  
Imidazolium Cation ◽  
One Dimensional ◽  
Paddle Wheel ◽  
Internuclear Axis ◽  
Solvent Molecules

The title copper(II) complex, {(C27H37N2)[Cu4(CH3COO)8Cl]·3CH2Cl2}n, is a one-dimensional coordination polymer. The asymmetric unit is composed of a copper(II) tetraacetate paddle-wheel complex, a Cl−anion situated on a twofold rotation axis, half a 1,3-bis(2,6-diisopropylphenyl)imidazolium cation (the whole molecule being generated by twofold rotation symmetry) and one and a half of a dichloromethane solvent molecule (one being located about a twofold rotation axis). The central metal-organic framework comprises of a tetranuclear copper(II) acetate `paddle-wheel' complex which arises from the dimerization of the copper(II) tetraacetate core comprising of three μ2-bidentate acetate and one μ3-tridentate acetate ligands per binuclear paddle-wheel complex. Both CuIIatoms of the binuclear component adopt a distorted square-pyramidal coordination geometry (τ = 0.04), with a Cu...Cu separation of 2.6016 (2) Å. The apical coordination site of one CuIIatom is occupied by an O atom of a neighbouring acetate bridge [Cu—O = 2.200 (2) Å], while that of the second CuIIatom is occupied by a bridging chloride ligand [Cu...Cl = 2.4364 (4) Å]. The chloride bridge is slightly bent with respect to the Cu...Cu internuclear axis [Cu—Cl—Cu = 167.06 (6)°] and the tetranuclear units are located about a twofold rotation axis, forming the one-dimensional polymer that propagates along [101]. Charge neutrality is maintained by the inclusion of the 1,3-bis(2,6-diisopropylphenyl)imidazolium cation within the crystal lattice. In the crystal, the cation and dichloromethane solvent molecules are linked to the coordination polymer by various C—H...O and C—H...Cl hydrogen bonds. There are no other significant intermolecular interactions present.

Synthesis and Structure of the Novel “Paddle-Wheel” Complex [{(η5-Cp)2Pb(μ:η5-Cp)K}·2THF]

2003 ◽  
Vol 22 (12) ◽  
pp. 2528-2530 ◽  
Author(s):  
Richard A. Layfield ◽  
Mary McPartlin ◽  
Dominic S. Wright
Keyword(s):  
The Novel ◽  
Paddle Wheel

Semiconductive and Magnetic One-Dimensional Coordination Polymers of Cu(II) with Modified Nucleobases

2013 ◽  
Vol 52 (19) ◽  
pp. 11428-11437 ◽  
Author(s):  
Pilar Amo-Ochoa ◽  
Oscar Castillo ◽  
Carlos J. Gómez-García ◽  
Khaled Hassanein ◽  
Sandeep Verma ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
One Dimensional ◽  
Modified Nucleobases
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