Electronic structure and NH-tautomerism of a novel metal-free phenanthroline-annelated phthalocyanine

A novel low-symmetry A3B-type phthalocyanine annelated with a pyrazino[2,3-f]phenanthroline ring system and substituted with six solubilizing diisopropylphenoxy-groups (1) was synthesized by metalfree DBU-promoted cross-condensation of diiminoisoindolines derived from 4,5- bis(diisopropylphenoxy)phthalonitrile and pyrazino[2,3-f][1,10]phenanthroline-2,3-dicarbonitrile. The use of these particular precursors affords A3B phthalocyanine in 15% yield, while cross-condensation of the corresponding dinitriles yields only trace amounts of the target compound. Comparative studies of the A3B-type phthalocyanine and its symmetrical octa(diisopropylphenoxy)-substituted counterpart 2 reveal striking differences in the Q band regions of their UVevisible absorption (UVeVis) spectra, which could be readily rationalized through a comparison with calculated TD-DFT spectra. Since 1 can have two NH-tautomers with equivalent and non-equivalent NH-groups, and DFT calculations predict that the former tautomer is only 2.3 kcal/mol more stable than the latter one, a comprehensive analysis of 13C NMR spectra was carried out through the application of 1 He13C HMBC and HSQC techniques. It demonstrated that only the tautomer with equivalent NH-groups is present in solution

Methodological Survey of Simplified TD-DFT Methods for Fast and Accurate Interpretation of UV−Vis−NIR Spectra of Phthalocyanines

A methodological survey of density functional theory (DFT) methods for the prediction of UV−visible (vis)−near-infrared (NIR) spectra of phthalocyanines is reported. Four methods, namely, full time-dependent (TD)-DFT and its Tamm−Dancoff approximation (TDA), together with their simplified modifications (sTD-DFT and sTDA, respectively), were tested by using the examples of unsubstituted and alkoxy-substituted metal-free ligands and zinc complexes. The theoretical results were compared with experimental data derived from UV−visible absorption and magnetic circular dichroism spectroscopy. Seven popular exchange-correlation functionals (BP86, B3LYP, TPSSh, M06, CAM-B3LYP, LC-BLYP, and ωB97X) were tested within these four approaches starting at a relatively modest level using 6-31G(d) basis sets and gas-phase BP86/def2-SVP optimized geometries. A gradual augmentation of the computational levels was used to identify the influence of starting geometry, solvation effects, and basis sets on the results of TD-DFT and sTD-DFT calculations. It was found that although these factors do influence the predicted energies of the vertical excitations, they do not affect the trends predicted in the spectral properties across series of structurally related substituted free bases and metallophthalocyanines. The best accuracy for the gas-phase vertical excitations was observed in the lower-energy Q-band region for calculations that made use of range-separated hybrids for both full and simplified TD-DFT approaches. The CAMB3LYP functional provided particularly accurate results in the context of the sTD-DFT approach. The description of the higherenergy B-band region is considerably less accurate, and this demonstrates the need for further advances in the accuracy of theoretical calculations. Together with a general increase in accuracy, the application of simplified TD-DFT methods affords a 2−3 orders of magnitude speedup of the calculations in comparison to the full TD-DFT approach. It is anticipated that this approach will be widely used on desktop computers during the interpretation of UV−vis−NIR spectra of phthalocyanines and related macrocycles in the years ahead

MCD spectroscopy and TD-DFT calculations of magnesium tetra-(15-crown-5-oxanthreno)-phthalocyanine

An analysis of the MCD spectroscopy and TD-DFT calculations of magnesium tetra-(15-crown-5-oxanthreno)-phthalocyanine is reported. This study provides a reassessment of an earlier study on the nature of the bands in UV-visible absorption spectra of magnesium and zinc tetra-(15-crown-5-oxanthreno)-phthalocyanine that was based on an analysis of TD-DFT calculations for a series of model complexes with the B3LYP functional. A detailed analysis of MCD spectral data and TD-DFT calculations with the CAM-B3LYP functional for the complete Mg(II) complex provides an additional insight into the optical properties and electronic structures of tetra-(15-crown-5-oxanthreno)-phthalocyanines. Thus, the bands in the Q-band region are reassigned as being due exclusively to the Q transition of Gouterman’s 4-orbital model, since intense pseudo-A11 terms are observed in the MCD spectrum in a spectral region that had previously been assigned as charge transfer bands

Optical limiters with improved performance based on nanoconjugates of thiol substituted phthalocyanine with CdSe quantum dots and Ag nanoparticles

Two alternative synthetic approaches affording a low-symmetry A3B-type phthalocyanine 1 bearing two [2′-(2′′-mercaptoethoxy)ethoxy] anchoring substituents were developed. Due to the presence of thiol groups, this phthalocyanine could be conjugated with TOPO-capped (TOPO - trioctylphosphine)-capped CdSe quantum dots (CdSe-QDs) or oleylamine capped silver nanoparticles (Ag-NPs). The nonlinear optical behaviour of starting phthalocyanine, quantum dots, nanoparticles and their conjugates was studied by using an open aperture Z-scan technique, revealing that the grafting of 1 onto the nanomaterials resulted in a significant enhancement of the optical limiting of 1-Ag and 1-CdSe in comparison with the individual components. The conjugate 1-CdSe, being the first example of Pc-based thiol conjugated with quantum dots, revealed superior limiting characteristics with a limiting threshold below 0.18 J cm−2

Dark energy problem: from phantom theory to modified Gauss-Bonnet gravity

The solution of dark energy problem in the models without scalars is presented. It is shown that late-time accelerating cosmology may be generated by the ideal fluid with some implicit equation of state. The universe evolution within modified Gauss-Bonnet gravity is considered. It is demonstrated that such gravitational approach may predict the (quintessential, cosmological constant or transient phantom) acceleration of the late-time universe with natural transiton from deceleration to acceleration (or from non-phantom to phantom era in the last case).Comment: LaTeX 8 pages, prepared for the Proceedings of QFEXT'05, minor correctons, references adde

Blood preparations of humans and animals in terms of their quality, efficacy and safety

The problems of quality and safety products derived from human blood plasma and hyperimmune animal sera as well as recombinant blood products resolved strict government regulation of their production processes. The risk of implications is minimized by plasma fractionation and purification of a specific drugs from various impurities (immunoglobulin aggregates, protease, plasmin, plasminogen, prekallikrein activator, IgA and IgM etc.). Viral safety is achieved by multi-step manufacturing process that includes at least two independent methods (treatment with solvent/detergent + incubation at low pH or pasteurization, combined with polyethylene glycol processing). It was justified that for today the technological process of the development of plasma preparations and hyperimmune animal sera has reached its limit. Their further development is the most likely to refer to specific improvements. The improvements will relate to increasing the efficiency of manufacturing technologies and methods of clinical use (preparations for subcutaneous administration, combinations of different immunoglobulin preparations, etc.), viral safety, ways to eliminate component, that were previously not considered to be able to influence the outcome of clinical use (soluble molecules CD4, CD8, HLA, thrombin, trace amounts of blood clotting factors VIII, IX, X, XI, XII etc.). At the same time new genetic engineered preparations with well-characterized molecular composition and a high selectivity for target impact are expected to appear on the market because of these unsolved issues. These are recombinant blood factors with altered properties; cocktails of recombinant antibodies and Fab-fragments of IgG, highly affine for toxin epitopes, etc. Therefore, in the upcoming years it is necessary to create in Russia a new system for assessing the quality, efficacy and safety of blood products, taking into account the future course of their development

Modeling of the Magnetic Susceptibilities of the Ambient- and High-Pressure Phases of (VO)_{2}P_{2}O_{7}

The magnetic susceptibilities chi versus temperature T of powders and single crystals of the ambient-pressure (AP) and high-pressure (HP) phases of (VO)_{2}P_{2}O_{7} are analyzed using an accurate theoretical prediction of chi(T, J1, J2) for the spin-1/2 antiferromagnetic alternating-exchange (J1, J2) Heisenberg chain. The results are consistent with recent models with two distinct types of alternating-exchange chains in the AP phase and a single type in the HP phase. The spin gap for each type of chain is derived from the respective set of two fitted alternating exchange constants and the one-magnon dispersion relation for each of the two types of chains in the AP phase is predicted. The influences of interchain coupling on the derived intrachain exchange constants, spin gaps, and dispersion relations are estimated using a mean-field approximation for the interchain coupling. The accuracies of the spin gaps obtained using fits to the low-T chi(T) data by theoretical low-T approximations are determined. The results of these studies are compared with previously reported estimates of the exchange couplings and spin gaps in the AP and HP phases and with the magnon dispersion relations in the AP phase measured previously using inelastic neutron scattering.Comment: 25 two-column REVTeX pages, 16 embedded figures, 6 tables. Figures 9 and 10 and Sec. IIIC revised due to errors in Eq. (1) of Ref. 24 which gives the theoretical one-magnon dispersion relation for coupled alternating-exchange chains. Minor revisions also made in other section

ПОВЫШЕНИЕ ЭФФЕКТИВНОСТИ И БЕЗОПАСНОСТИ АНТИКОАГУЛЯНТНОЙ ТЕРАПИИ У ПАЦИЕНТОВ С ПРОТЕЗАМИ КЛАПАНОВ СЕРДЦА

Purpose. To improve efficiency and safety of anticoagulant therapy in patients with prosthetic heart valves by developing and implementing original approaches: 1) sinus rhythm restoration after simultaneous mitral valve replacement with maze procedure, 2) pharmacogenetics approach for individual choice of anticoagulants, and 3) the implementation of patient education program.Materials and methods. 525 patients with prosthetic heart valves were included in the study using cluster sampling in the period from 2008–2013. Group 1 (n=118) patients underwent the study aimed at assessing the restoration of sinus rhythm using original approaches, Group 2 (n=249) patients were included in the study aimed at assessing the efficiency of education program, and Group 3 (n=216) patients were included in the study aimed at assessing the efficiency of pharmacogenetics-based warfarin therapy. All patients underwent on-pump heart valve replacement. Genomic methods as well as non-invasive ultrasound monitoring of intracardiac hemodynamic parameters were used in the study.Results. Simultaneous mitral valve replacement with maze procedure resulted in the restoration of sinus rhythm in 61,8 % of cases; scheduled cardioversion 1,5 months after cardiac surgery ensured sinus rhythm restoration in 84,8 % of patients, and radiofrequency catheter ablation in patients with biological prosthetic heart valves 6 months after cardiac surgery allowed both sinus rthym restoration and warfarin withdrawal. The introduction of pharmacogenetic approach to warfarin dosing in the early postoperative period resulted in a 2-fold reduction in the time of warfarin dose adjustment and a 25,2 % increase of the therapeutic range of anticoagulation level. The implementation of training program based on the continuity of inpatient and outpatient care allowed decreasing 1,8-fold the risk of thrombotic complications and 2,6-fold hemorrhagic complications 2 years after heart valve replacement. The introduction of the strategy aimed at the improvement of efficiency and safety of warfarin therapy demonstrated the benefits of biological heart valve replacement and the feasibility of an integrated approach.Conclusion. The introduction of the integrated approach composed of the strategies for sinus rhythm restoration, information and motivational approach, and pharmacogenetic approach, ensures a reduction in hemorrhagic and thrombotic complications, improving quality control for warfarin therapy, awareness, and treatment adherence.Цель. Повысить эффективность и безопасность антикоагулянтной терапии у пациентов с протезированными клапанами сердца путем разработки и внедрения комплекса, основанного на последовательности восстановления синусового ритма после одномоментного протезирования митрального клапана и процедуры «Лабиринт», фармакогенетическом подходе к выбора антикоагулянтов и внедрении обучающей программы.Материалы и методы. За 2008–2013 гг. обследовано 525 больных с протезами клапанов сердца. Первая группа (n=118) пациентов приняла участие в разделе работы, посвященном стратегии восстановления синусового ритма, вторая группа (n=249) участвовала при оценке эффективности обучающей программы, третья (n=216) – в разделе исследования по применению фармакогенетической чувствительности к варфарину. Больным проведены операции в условиях ИК по коррекции клапанной патологии, использовали геномные методы исследования, оценку данных ультразвукового исследования внутрисердечной гемодинамики.Результаты. Применение одномоментной коррекции порока митрального клапана и процедура «Лабиринт» в 61,8 % случаев обеспечивало восстановление синусового ритма; плановая электроимпульсная терапия, проводимая через 1,5 месяца после операции на сердце, увеличивала возможность восстановления синусового ритма у 84,8 % больных; применение катетерной радиочастотной аблации через 6 месяцев после операции на сердце в 100 % случаях способствовало восстановлению синусового ритма у пациентов с биологическими протезами и обеспечивало отмену варфарина. Применение фармакогенетического подхода в раннем послеоперационном периоде привело к уменьшению в 2 раза сроков подбора терапевтической дозы варфарина и увеличению на 25,2 % времени терапевтического диапазона гипокоагуляции. Использование обучающей программы, основанной на преемственности стационарного и амбулаторного этапов, позволило через 2 года после протезирования клапанов сердца в 1,8 раза снизить риск тромботических и в 2,6 раза – геморрагических осложнений.Заключение. Применение комплексного подхода, включающего последовательное восстановление синусового ритма, информационно-мотивационный и фармакогенетический подходы, способствуя улучшению качества контроля терапии варфарином, повышению информированности, приверженности к лечению, обеспечивает уменьшение геморрагических и тромботических осложнений