Study of Spacer Arm Length Influence on Drug Vectorization by Fullerene C 60

This work studies theoretically the effect of spacer arm lengths on the characteristics of a fullerene C 60 -based nanovector. The spacer arm is constituted of a carbon chain including a variable number of methylene groups (n = 2-11). To improve the ability of the fullerene carriage, two arms are presented simultaneously through a malonyl bridge. Then the evolution of selected physicochemical parameters is monitored as a function of the spacer arm length and the angle between the two arms. We show here that while the studied characteristics are almost independent of the spacer arm length or vary monotonically with it, the dipole moment and its orientation vary periodically with the parity of the number of carbon atoms. This periodicity is related to both modules and orientations of dipole moments of the spacer arms. In the field of chemical synthesis, these results highlight the importance of theoretical calculations for the optimization of operating conditions. In the field of drug discovery, they show that theoretical calculations of the chemical properties of a drug candidate can help predict its in vivo behaviour, notably its bioavailability and biodistribution, which are known to be tightly dependent of its polarity

Fluorine and chlorine gas storage by confinement inside Boron Nitrogen Nanotubes.

DFT calculations using the WB97XD and CAM-B3LYP functional and the basis set 6-31G(d,p) were performed to study the interaction between the X2(X=F or Cl) molecule and boron nitrogen nanotubes (BNNTs). Each molecule was confined within BNNTs with different dimensions in either parallel or perpendicular positions along the nanotube axis. The interaction between X2 molecule and the BNNT nanotube differed according to the extension of the confinement space and the molecular orientation. Unlike Cl2, F2 forms a very stable complex with the (4,4) and (5,5) BNNTs. The van der Waals interactions of the X2 molecule with the BNNT leads to charge transfer and a change in the charge distribution in the X2 molecule, producing a new detectable infrared signal of the X-X bond stretch that is nanotube’s diameter dependent

Fluorine and chlorine gas storage by confinement inside boron nitrogen nanotubes

1192-1200DFT calculations using the WB97XD and CAM-B3LYP functional and the basis set 6-31G(d,p) have been performed to study the interaction between the X2(X=F or Cl) molecule and boron nitrogen nanotubes (BNNTs). Each molecule is confined within BNNTs with different dimensions in either parallel or perpendicular positions along the nanotube axis. The interaction between X2 molecule and BNNT nanotube differed according to the extension of the confinement space and the molecular orientation. Unlike Cl2, F2 forms a very stable complex with (4,4) and (5,5) BNNTs. The van der Waals interactions of the X2 molecule with the BNNT leads to charge transfer and a change in the charge distribution in the X2 molecule, producing a new detectable infrared signal of the X-X bond stretch which is dependent on nanotube diameter

Beyond the Madelung-Klechkowski Rule of aufbau Orbital Filling Principle

Abstract We propose a more general wording for Madelung rule using a new descriptor based on the four quantum numbers n, ℓ, m ℓ , m s of the most recently added electron notes K( Z X). By this formulation, K( Z X) will increment as the atomic number Z increases. No exceptions will remain. It can be connected to the first ionization energy

A DFT Study of the Hexene Hydrogenation Catalysed by the Complex RuH(CO)(Cl)(PCy3): Monophosphine vs Diphosphine Paths

A DFT study of hexene hydrogenation catalysed by the RuH(CO)(Cl)(PCy3)2 complex is presented. The investigation explores the feasibility of two different mechanisms: the first exploits a single phosphine complex and the second uses a two phosphines complex. The energy barriers involving a hydrogen transfer have a ten kcal.mol-1 higher than the one obtained through the single-phosphine mechanism. These results confirm the experimental hypothesis claiming that the departure of a phosphine is favourable at the beginning of the reaction which is the substitution of the catalyst model RuHCl(CO)(PMe3)2 by the real catalyst RuHCl(CO)(PCy3)2 shows no significant influence on the energetic barriers of hexene hydrogenation mechanism. The most important step of the mechanism is the kinetically determining step. The heterolytic cleavage of ruthenium-complexed H2 molecule leads to the generation of two Ru-H bonds and the oxidation of the ruthenium from Ru(II) to Ru(IV). The energy profile of this step is not relative to an elementary reaction because a shouldering is observed after the transition state. This results in an unusual gradient norm profile with five extrema. This is a direct consequence of the asynchronous nature of the different processes taking place during this step. In the case of the model complex RuHCl(CO)(IMes)(PMe3) with IMes = ( N , N \u27-bis( mesityl)imidazol-2-ylidene), an increase of the free enthalpy of activation is observed during the kinetically determining step, which is in agreement with the experimental work

In Silico Study of Spacer Arm Length Influence on Drug Vectorization by Fullerene C60

This work studies theoretically the effect of spacer arm lengths on the characteristics of a fullerene C60-based nanovector. The spacer arm is constituted of a carbon chain including a variable number of methylene groups (n = 2–11). To improve the ability of the fullerene carriage, two arms are presented simultaneously through a malonyl bridge. Then the evolution of selected physicochemical parameters is monitored as a function of the spacer arm length and the angle between the two arms. We show here that while the studied characteristics are almost independent of the spacer arm length or vary monotonically with it, the dipole moment and its orientation vary periodically with the parity of the number of carbon atoms. This periodicity is related to both modules and orientations of dipole moments of the spacer arms. In the field of chemical synthesis, these results highlight the importance of theoretical calculations for the optimization of operating conditions. In the field of drug discovery, they show that theoretical calculations of the chemical properties of a drug candidate can help predict its in vivo behaviour, notably its bioavailability and biodistribution, which are known to be tightly dependent of its polarity

Etude théorique des complexes mono et dinucléaires du ruthénium à liaisons (sigma)-silane

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Confinement of the antitumoral drug cisplatin inside edge-functionalized carbon nanotubes and its release near lipid membrane

Platinum complexes are active antitumor agents. They are widely used in chemotherapy medication for the treatment of several cancer types. Unfortunately, these drugs present poor stability when administered and have several side effects, damaging healthy cells around the tumor. One way to remedy the damage is to confine drug molecules in carbon cages such as carbon nanotubes (CNTs) before delivering them near their target cells. In order to open their ends, the CNTs must be functionalized by oxidation. This leads to the saturation of the carbon dangling bonds with an alcohol functional group, for instance. In this study, molecular dynamics simulations are carried out to assess the influence of CNT’s chemical functional groups (–H, –OH, –COOH) on the retention time and release processes of cisplatin molecules throughout the process of vectorization to a cell membrane