Two new zinc(II) and mercury(II) complexes based on N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide): synthesis, crystal structures and antibacterial activities.

Reaction of N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide), C20H18F2N4O2, (LF), with zinc chloride and mercury(II) chloride produced different types and shapes of neutral coordination complexes, namely, dichlorido[N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide)-κ2N,O]zinc(II), [ZnCl2(C20H18F2N4O2)], (1), and dichlorido[N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide)-κ4O,N,N',O']mercury(II), [HgCl2(C20H18F2N4O2)], (2). The organic ligand and its metal complexes are characterized using various techniques: IR, UV-Vis and nuclear magnetic resonance (NMR) spectroscopies, in addition to powder X-ray diffraction (PXRD), single-crystal X-ray crystallography and microelemental analysis. Depending upon the data from these analyses and measurements, a typical tetrahedral geometry was confirmed for zinc complex (1), in which the ZnII atom is located outside the bis(benzhydrazone) core. The HgII atom in (2) is found within the core and has a common octahedral structure. The in vitro antibacterial activities of the prepared compounds were evaluated against two different bacterial strains, i.e. gram positive Bacillus subtilis and gram negative Pseudomonas aeruginosa bacteria. The prepared compounds exhibited differentiated growth-inhibitory activities against these two bacterial strains based on the difference in their lipophilic nature and structural features.

Reinventing the political role of health professionals in conflict prevention & reconciliation: the Sudanese model.

Given the persistent recurrence of armed conflict, influential actors owe it to the affected communities to take action. The legitimacy of health professionals to mitigate the effects of conflict relates to their ability to save lives and address the physical and mental consequences of armed conflict during which thousands of lives may be lost. Medical professionals have unique and potentially far-reaching skills. These become crucial during wartime and disasters in terms of providing medical services and humanitarian aid. However, they are insufficiently used in one area: involvement in politics as a tool to foster peace. Despite this, Sudanese individuals from medical backgrounds have participated actively in conflict resolution and peace-building processes. In fact, their political actions throughout the last six decades have aimed to prevent conflict at four different levels, which are described by Yusuf et al. in their article on the political involvement of health professionals in prevention. Their stand against President Nimeiri's Sharia laws was primordial prevention of religious conflict at the national level. Their leading role in the second Sudanese Intifada uprising was a key factor in saving the country from civil war, and another example of primary prevention. Sudanese physicians were also involved in secondary prevention by being influentially involved in almost all national peace agreements. Avoiding disputes at the tertiary level represents the weakest link in their repeated efforts. This paper outlines the different roles Sudanese medical personnel have taken in peacemaking. It also critically evaluates them in order to consider new methods of political involvement that suit future challenges.

Water repellency in hydrophobic nanocapsules--molecular view on dewetting.

The hydrophobic effect plays a major role in a variety of important phenomena in chemistry, materials science and biology, for instance in protein folding and protein-ligand interactions. Studies--performed within cavities of the unique metal oxide based porous capsules of the type {(pentagon)12(linker)30}≡{(W)W5}12{Mo2(ligand)}30 with different acetate/water ligand ratios--have provided unprecedented results revealing segregation/repellency of the encapsulated "water" from the internal hydrophobic ligand walls of the capsules, while the disordered water molecules, interacting strongly with each other via hydrogen bonding, form in all investigated cases the same type of spherical shell. The present results can be (formally) compared--but only regarding the repellency effect--with the amazing "action" of the (super)hydrophobic Lotus (Nelumbo) leaves, which are self-cleaning based on water repellency resulting in the formation of water droplets picking up dirt. The present results were obtained by constructing deliberately suitable hydrophobic interiors within the mentioned capsules.

Chemical adaptability: the integration of different kinds of matter into giant molecular metal oxides.

Unique properties of the two giant wheel-shaped molybdenum-oxides of the type {Mo(154)}≡[{Mo(2)}{Mo(8)}{Mo(1)}](14) (1) and {Mo(176)}≡[{Mo(2)}{Mo(8)}{Mo(1)}](16) (2) that have the same building blocks either 14 or 16 times, respectively, are considered and show a "chemical adaptability" as a new phenomenon regarding the integration of a large number of appropriate cations and anions, for example, in form of the large "salt-like" {M(SO(4))}(16) rings (M = K(+), NH(4)(+)), while the two resulting {Mo(146)(K(SO(4)))(16)} (3) and {Mo(146)(NH(4)(SO(4)))(16)} (4) type hybrid compounds have the same shape as the parent ring structures. The chemical adaptability, which also allows the integration of anions and cations even at the same positions in the {Mo(4)O(6)}-type units of 1 and 2, is caused by easy changes in constitution by reorganisation and simultaneous release of (some) building blocks (one example: two opposite orientations of the same functional groups, that is, of H(2)O{Mo=O} (I) and O={Mo(H(2)O)} (II) are possible). Whereas Cu(2+) in [(H(4)Cu(II)(5))Mo(V)(28)Mo(VI)(114)O(432)(H(2)O)(58)](26-) (5 a) is simply coordinated to two parent O(2-) ions of {Mo(4)O(6)} and to two fragments of type II, the SO(4)(2-) integration in 3 and 4 occurs through the substitution of two oxo ligands of {Mo(4)O(6)} as well as two H(2)O ligands of fragment I. Complexes 3 and now 4 were characterised by different physical methods, for example, solutions of 4 in DMSO with sophisticated NMR spectroscopy (EXSY, DOSY and HSQC). The NH(4)(+) ions integrated in the cluster anion of 4 "communicate" with those in solution in the sense that the related H(+) ion exchange is in equilibrium. The important message: the reported "chemical adaptability" has its formal counterpart in solutions of "molybdates", which can form unique dynamic libraries containing constituents/building blocks that may form and break reversibly and can lead to the isolation of a variety of giant clusters with unusual properties.

Synthetic, structural and kinetic studies on the binding of cyclohexane-1,2-bis(4-methyl-3-thiosemicarbazone) to divalent metal ions (Co, Ni, Cu, Zn or Cd).

The reactions of cyclohexane-1,2-bis(4-methyl-3-thiosemicarbazone) (CHMTSC) with MCl2 (M = Co, Ni, Cu or Zn) and Cd(NO3)2 have been shown to produce complexes in which the thiosemicarbazone has been doubly deprotonated [[M(CHMTSC - 2H+)] (M = Co, Ni or Ni)], analogous to those reported earlier with other Schiff base thiosemicarbazones. However, with ZnCl2 and Cd(NO3)2, the complexes isolated are [ZnCl(CHMTSC)]Cl and [Cd(NO3)(CHMTSC)]NO3, containing the protonated forms of the ligand, which have been characterised by X-ray crystallography, as has free CHMTSC. The kinetics of the reactions between CHMTSC and all the various metal salts have been determined by stopped-flow spectrophotometry. In all cases, the reactions are complete on the seconds timescale. The reactions exhibit a first-order dependence on the concentration of metal salt and a first-order dependence on the concentration of CHMTSC. The thermodynamic and kinetic factors influencing the protonation state of the coordinated thiosemicarbazone are discussed.