Trennung der einkernigen kationischen Rutheniumnitrosylnitratokomplexe mittels tr?gerfreier Capillarisotachophorese

Zusammenfassung Mit der trägerfreien Capillarisotachophorese gelingt die Isolierung von neun Rutheniumnitrosylnitratokomplexen, darunter drei Paare von cis-trans-Isomeren. Die besten Trennungen erhält man mit einem Neun-Komponenten-Spacer, bestehend aus anorganischen und einfachen organischen Kationen. Aufgrund der Ergebnisse bietet sich die trägerfreie Durchflußisotachophorese zur präparativen Gewinnung dieser Rutheniumkomplexe an.

---

Separation of the mononuclear cationic ruthenium nitrosyl nitrato complexes by carrier-free capillary isotachophoresis

Summary By carrier-free capillary isotachophoresis it is possible to isolate nine ruthenium nitrosyl nitrato complexes, among which are three pairs of cis-trans-isomers. The best separations are achieved by using a spacer containing nine components and consisting of inorganic and simple organic cations. Based on these results, carrier-free through-flow isotachophoresis is suggested for the preparative isolation of these complexes.

---

---

Herrn Prof. Dr. H. Weisz zum 60. Geburtstag gewidmet     

Darstellung,lsolierung und Charakterisierung gemischter Cyanoselenocyanatochromate(III)

Preparation, Isolation, and Characterization of Mixed Cyanoselenocyanatochromates(III) The potassiumcyanoselenocyanatochromates(III) are isolated in pure state, as previously described for a similar system of complexes. The tetrabutylammonium salts are used for the characterization.     

Ermittlung des Vernetzungsgrades und Beladungszustandes von Ionenaustauschern auf Kunstharzbasis durch Pyrolyse-Gas-Chromatographie

A special introduction device with switching of carrier gas for improving the reproducibility of pyrolysate composition in pyrolysis gas-chromatography has been described. Its influence on the formation of pyrolysis products and on retention times has been studied on a model substance. The peak area ratios for determining the degree of cross-linking in ion exchangers on styrene-DVB basis can be estimated considerably more accurately with the help of carrier gas switching. Since anion exchangers yield lessα-methylstyrene on pyrolysis than do cation exchangers, their peak area ratios are appreciably larger. Increasing the degree of cross-linking lowers the ratios with the anion exchangers and raises them with the cation exchangers. At 400° C the thermal attack on anion exchangers with styrene-DVB matrix occurs mainly at the active group. The methyl esters or their decomposition products formed from the counter ions are characteristic pyrolysis products. A feature of Dowex 1 is the formation of trimethylamine; of Dowex 2, acetaldehyde. In this way, pyrolysis gas-chromatography enables information about the degree of cross linking and the nature of the anion of ion exchangers, as well as about the matrix, type and structure of the functional group and position of substitution of the anchor group in the matrix to be obtained.     

Darstellung,Isolierung und Charakterisierung gemischter Thiocyanato(1,3-diaminopropan)chrom(III)-Komplexe

Preparation, Isolation, and Characterization of Mixed Thiocyanato(1.3-diaminopropane) -chromium(III) Complexes The complexes [Cr(NCS)₄dap]^? and trans-[Cr(NCS)₂(dap)₂]⁺ (dap = 1.3-diaminopropane) are prepared for the first time, isolated as salts and characterized by CHN analysis, chromium contents, the electrophoretic behaviour in dimethylformamide, and by UV, VIS, and IR spectra.     

Cage Structure Formation of Singly Doped Aluminum Cluster Cations Al<Subscript><Emphasis Type="BoldItalic">n</Emphasis></Subscript><Emphasis Type="BoldItalic">TM</Emphasis><Superscript>+</Superscript> (<Emphasis Type="BoldItalic">TM</Emphasis> = Ti,V, Cr)

Structural information on free transition metal doped aluminum clusters, Al _n TM ⁺ (TM = Ti, V, Cr), was obtained by studying their ability for argon physisorption. Systematic size (n = 5 – 35) and temperature (T = 145 – 300 K) dependent investigations reveal that bare Al _n ⁺ clusters are inert toward argon, while Al _n TM ⁺ clusters attach one argon atom up to a critical cluster size. This size is interpreted as the geometrical transition from surface-located dopant atoms to endohedrally doped aluminum clusters with the transition metal atom residing in an aluminum cage. The critical size, n _crit , is found to be surprisingly large, namely n _crit = 16 and n _crit = 19 – 21 for TM = V, Cr, and TM = Ti, respectively. Experimental cluster–argon bond dissociation energies have been derived as function of cluster size from equilibrium mass spectra and are in the 0.1–0.3 eV range.     

Complexity in human transportation networks: a comparative analysis of worldwide air transportation and global cargo-ship movements

We present a comparative network-theoretic analysis of the two largest global transportation networks: the worldwide air-transportation network (WAN) and the global cargo-ship network (GCSN). We show that both networks exhibit surprising statistical similarities despite significant differences in topology and connectivity. Both networks exhibit a discontinuity in node and link betweenness distributions which implies that these networks naturally segregate into two different classes of nodes and links. We introduce a technique based on effective distances, shortest paths and shortest path trees for strongly weighted symmetric networks and show that in a shortest path tree representation the most significant features of both networks can be readily seen. We show that effective shortest path distance, unlike conventional geographic distance measures, strongly correlates with node centrality measures. Using the new technique we show that network resilience can be investigated more precisely than with contemporary techniques that are based on percolation theory. We extract a functional relationship between node characteristics and resilience to network disruption. Finally we discuss the results, their implications and conclude that dynamic processes that evolve on both networks are expected to share universal dynamic characteristics.