Strongly Bound Noncovalent (SO3)n:H2CO Complexes (n = 1, 2)

The potential energy surfaces (PES) for the SO3:H2CO and (SO3)2:H2CO complexes were thoroughly examined at the MP2/aug-cc-pVDZ computational level. Heterodimers and trimers are held together primarily by SO chalcogen bonds, supplemented by weaker CHO and/or OC bonds. The nature of the interactions is probed by a variety of means, including electrostatic potentials, AIM, NBO, energy decomposition, and electron density redistribution maps. The most stable dimer is strongly bound, with an interaction energy exceeding 10 kcal mol(-1). Trimers adopt the geometry of the most stable dimer, with an added SO3 molecule situated so as to interact with both of the original molecules. The trimers are strongly bound, with total interaction energies of more than 20 kcal mol(-1). Most such trimers show positive cooperativity, with shorter SO distances, and three-body interaction energies of nearly 3 kcal mol(-1)

A theoretical study of the mechanism of rearrangement of dihydropyrimidines into pyrroles

Pyrimidines, pyrroles, cycloreversion,CO extrusion, Two possible mechanisms for the transformation of a 1,4-dihydropyrrolo[3,2-b]pyrrole derivative into a tetrasubstituted pyrrole have been studied theoretically and one of them has been found in reasonable accord with the experimental data. This mechanismis part of the very rare example of rearrangement of dihydropyrimidines into pyrroles

How Aromatic Fluorination Exchanges the Interaction Role of Pyridine with Carbonyl Compounds: The Formaldehyde Adduct

The rotational spectrum of the weakly bound complex pentafluoropyridine⋅⋅⋅formaldehyde has been investigated using Fourier transform microwave spectroscopy. From the analysis of the rotational parameters of the parent species and of the 13C and 15N isotopologues, the structural arrangement of the adduct has been unambiguously established. The full ring fluorination of pyridine has a dramatic effect on its binding properties: It alters the electron density distribution at the π-cloud of pyridine creating a π-hole and changing its electron donor-acceptor capabilities. In the complex, formaldehyde lies above the aromatic ring with one of the oxygen lone pairs, as conventionally envisaged, pointing toward its centre. This lone pair⋅⋅⋅π-hole interaction, reinforced by a weak C−H⋅⋅⋅N interaction, indicates an exchange of the electron-acceptor roles of both molecules when compared to the pyridine⋅⋅⋅formaldehyde adduct. Tunnelling doublets due to the internal rotation of formaldehyde have also been observed and analysed leading to a discussion on the competition between lone pair⋅⋅⋅π-hole and π⋅⋅⋅π stacking interactions

Large stabilization effects by intramolecular Beryllium bonds in Ortho-Benzene derivatives

Intramolecular interactions are shown to be key for favoring a given structure in systems with a variety of conformers. In ortho-substituted benzene derivatives including a beryllium moiety, beryllium bonds provide very large stabilizations with respect to non-bound conformers and enthalpy differences above one hundred kJ·mol(−1) are found in the most favorable cases, especially if the newly formed rings are five or six-membered heterocycles. These values are in general significantly larger than hydrogen bonds in 1,2-dihidroxybenzene. Conformers stabilized by a beryllium bond exhibit the typical features of this non-covalent interaction, such as the presence of a bond critical point according to the topology of the electron density, positive Laplacian values, significant geometrical distortions and strong interaction energies between the donor and acceptor quantified by using the Natural Bond Orbital approach. An isodesmic reaction scheme is used as a tool to measure the strength of the beryllium bond in these systems in terms of isodesmic energies (analogous to binding energies), interaction energies and deformation energies. This approach shows that a huge amount of energy is spent on deforming the donor–acceptor pairs to form the new rings

An ab initio investigation of alkali-metal non-covalent bonds BLiR and BNaR (R = F, H or CH3) formed with simple Lewis bases B : the relative inductive effects of F, H and CH3

The alkali-metal bonds formed by simple molecules LiR and NaR (R = F, H or CH3) with each of the six Lewis bases B = OC, HCN, H2O, H3N, H2S and H3P were investigated by ab initio calculations at the CCSD(T)/AVTZ and CCSD(T)/awCVTZ levels of theory with the aim of characterising this type of non-covalent interaction. In some complexes, two minima were discovered, especially for those involving the NaR. The higher-energy minimum (referred to as Type I) for a given B was found to have geometry that is isomorphous with that of the corresponding hydrogen-bonded analogue BHF. The lower-energy minimum (when two were present) showed evidence of a significant secondary interaction of R with the main electrophilic region of B (Type II complexes). Energies D_e^"CBS" for dissociation of the complexes into separate components were found to be directly proportional to the intermolecular stretching force constant kσ The value of D_e^"CBS" could be partitioned into a nucleophilicity of B and an electrophilicity of LiR or NaR, with the order ELiH ≳ ELiF = ELiCH3 for the LiR and ENaF > ENaH ≈ ENaCH3 for the NaR. For a given B, the order of the electrophilicities is ELiR > ENaR , which presumably reflects the fact that Li+ is smaller than Na+ and can approach the Lewis base more closely. A SAPT analysis revealed that the complexes BLiR and BNaR have larger electrostatic contributions to De than do the hydrogen- and halogen-bonded counterparts BHCl and BClF

Prescripción inducida en atención primaria de la Comarca Bilbao

ObjetivosPrincipales: conocer la proporción de prescripción inducida (PI) en Comarca Bilbao y su procedencia, la proporción de gasto correspondiente a la PI, la proporción de PI en los principales grupos terapéuticos, la actitud del médico de atención primaria ante la prescripción solicitada y su influencia en el gasto, la proporción de desacuerdo con dicha prescripción y los motivos de desacuerdo, y la proporción con informe del especialista. Secundarios: conocer la proporción de PI en los demás grupos terapéuticos, en fármacos VINE, EFG y en los de nula o baja mejora terapéutica.Diseño.Estudio transversal, descriptivoEmplazamientoAtención primariaParticipantesFármacos financiables prescritos por y/o solicitados a los médicos de familia de EAP.Resultados principalesSe estudiaron 7.922 fármacos. Tipo de prescripción: PI, 48,3% (IC del 95%, 47,2–49,4); del médico de atención primaria (PRO), 50,6% (IC del 95%, 49,5–51,7); desconocida, 1,1% (IC del 95%, 0,9–1,3). Procedencia principal: especialista público (72,2%), especialista privado (16,6%). Un 62,5% del gasto correspondió a la PI. En el grupo terapéutico más prescrito, sistema nervioso central (24,2%), PI, 39,8%; PRO, 58,9%; en aparato cardiovascular (19,1%), PI, 56,2%, PRO, 43,1%. Se prescribió el fármaco solicitado en un 98,4% de los casos, se cambio en el 1,2% y se suprimió en un 0,4%. Proporción de desacuerdo, 11%; motivos de desacuerdo, no hay necesidad de tratar (23,9%), grupo terapéutico (34,4%), principio activo (13,2%), marca comercial (28,5%). Hubo informe de especialista en un 62,4% de los casos.ConclusionesSe detecta una proporción considerable de prescripción no atribuible a atención primaria y una proporción importante de fármacos que el médico de primaria prescribe sin estar de acuerdo. Sería necesario un sistema que permitiera separar el gasto por niveles, así como mejorar la comunicación entre éstos.ObjectivesMain objetives: to know the proportion of induced prescription (IP) in Area Bilbao and its source, the proportion of cost IP accounts for, the proportion of IP in the main therapeutic groups, the attitude of GP when requested for prescription and its influence on cost, the proportion of disagreement with requested prescription, the reasons for disagreement, and the proportion with letter from specialist. Secondary objectives: to know the proportion of IP in the remaining therapeutic groups, in drugs of low clinical value, in generic drugs and in new drugs with low or no therapeutic improvement.DesignA descriptive cross-sectional study.SettingPrimary health care.ParticipantsDrugs prescribable under National Health Service prescribed by and/or requested to GPs.Main results7.922 drugs were analysed. Type of prescription: IP, 48.3% (95% CI, 47.2–49.4); GP prescription (GPP), 50.6% (95% CI, 49.5–51.7); unknown source, 1,1% (95% CI, 0.9–1.3). Main source, public specialist (72.2%), private specialist (16.6%). IP accounted for 62.5% of cost. In the most prescribed therapeutic group, central nervous system (24.2%), IP, 39.8%; GPP, 58.9%; in cardiovascular system (19.1%), IP, 56.2%; GPP, 43.1%. 98.4% of requested prescription was actually prescribed, 1.2% was changed and 0.4%, suppressed. Proportion of disagreement, 11%; reasons for disagreement, no need for medical treatment (23.9%), therapeutic group (34.4%), active ingredient (13.2%), brand name (28.5%). There was a 62.4% with letter from specialist.ConclusionsPrimary care is not accountable for a substantial proportion of prescription. GP prescribes a considerable proportion of drugs without agreement. It would be necessary a system that allows to separate the cost by care levels and also improve their communication

Characterization of PFGR-derived fibrin scaffold interactome by 2DE and LC-MS/MS

Comunicaciones a congreso