Unusual cage rearrangements in 10-vertex nido-5,6-dicarbaborane derivatives : An interplay between theory and experiment

The reaction between selected X-nido-5,6-C2B8H11 compounds (where X = Cl, Br, I) and "Proton Sponge" [PS; 1,8-bis(dimethylamino)naphthalene], followed by acidification, results in extensive rearrangement of all cage vertices. Specifically, deprotonation of 7-X-5,6-C2B8H11 compounds with one equivalent of PS in hexane or CH2Cl2 at ambient temperature led to a 7 → 10 halogen rearrangement, forming a series of PSH+[10-X-5,6-C2B8H10]- salts. Reprotonation using concentrated H2SO4 in CH2Cl2 generates a series of neutral carbaboranes 10-X-5,6-C2B8H11, with the overall 7 → 10 conversion being 75%, 95%, and 100% for X = Cl, Br, and I, respectively. Under similar conditions, 4-Cl-5,6-C2B8H11 gave ∼66% conversion to 3- Cl-5,6-C2B8H11. Since these rearrangements could not be rationalized using the Bvertex swing mechanism, new cage rearrangement mechanisms, which are substantiated using DFT calculations, have been proposed. Experimental 11B NMR chemical shifts are well reproduced by the computations; as expected δ(11B) for B(10) atoms in derivatives with X = Br and I are heavily affected by spin-orbit coupling

Periodic trends and easy estimation of relative stabilities in 11-vertex nido-p-block-heteroboranes and -borates

Density functional theory computations were carried out for 11-vertex nido-p-block-hetero(carba)boranes and -borates containing silicon, germanium, tin, arsenic, antimony, sulfur, selenium and tellurium heteroatoms. A set of quantitative values called “estimated energy penalties” was derived by comparing the energies of two reference structures that differ with respect to one structural feature only. These energy penalties behave additively, i.e., they allow us to reproduce the DFT-computed relative stabilities of 11-vertex nido-heteroboranes in general with good accuracy and to predict the thermodynamic stabilities of unknown structures easily. Energy penalties for neighboring heteroatoms (HetHet and HetHet′) decrease down the group and increase along the period (indirectly proportional to covalent radii). Energy penalties for a five- rather than four-coordinate heteroatom, [Het5k(1) and Het5k(2)], generally, increase down group 14 but decrease down group 16, while there are mixed trends for group 15 heteroatoms. The sum of HetHet′ energy penalties results in different but easily predictable open-face heteroatom positions in the thermodynamically most stable mixed heterocarbaboranes and -borates with more than two heteroatoms

The Prospects and Future Potential of the IPO in the Czech Republic

Department of National EconomyKatedra národního hospodářstvíFaculty of LawPrávnická fakult

Information System of Customs Administration of the Czech Republic

Import 02/11/2016Tato práce se zabývá analýzou Informačního systému Celní správy České republiky s cílem zmapovat proces integrace dílčích aplikací do jednoho celistvého informačního systému tak, jak se jeví koncovému uživateli. Zvláštní kapitola je věnována Microsoft Active Directory, na jejímž základě je postavena bezpečnost celého informačního systému, který je složen z mnoha navzájem mezi sebou spolupracujících různorodých systémů zpracovávajících a uchovávajících obrovské množství dat pořizovaných v rámci činnosti a kompetencí Celní správy. Práce se rovněž věnuje oblastem řízení informačního systému, které se bezprostředně dotýkají koncových uživatelů, a současným novým trendům v jeho vývoji.This thesis deals with the analysis Information System of Customs Administration of the Czech Republic. With the aim of mapping the process of integration of individual applications into a single coherent information system as it appears to the end user. A special chapter is devoted to Microsoft Active Directory, based on which is built the security of the entire information system, which is composed of many cooperating with each other disparate systems processing and storing vast amounts of disparate data acquired in the work and competences of the Customs Administration. Work is also dedicated to the field of management information system that directly affect end users, and present new trends in its development.Prezenční545 - Institut ekonomiky a systémů řízenívelmi dobř