An automatic system for crystal growth studies at constant supersaturation

An automatic system for growing crystals from seeded supersaturated solutions at constant supersaturation is described. Control of burettes and data acquisition are controlled by computer. The system was tested with a study of the calcium oxalate kinetics of crystal growth

Metal-Dependent Cytotoxic and Kinesin Spindle Protein Inhibitory Activity of Ru, Os, Rh, and Ir Half-Sandwich Complexes of Ispinesib-Derived Ligands

Ispinesib is a potent inhibitor of kinesin spindle protein (KSP), which has been identified as a promising target for antimitotic anticancer drugs. Herein, we report the synthesis of half-sandwich complexes of Ru, Os, Rh, and Ir bearing the ispinesib-derived N,N-bidentate ligands (R)- and (S)-2-(1-amino-2-methylpropyl)-3-benzyl-7-chloroquinazolin-4(3H)-one and studies on their chemical and biological properties. Using the enantiomerically pure (R)- and (S)-forms of the ligand, depending on the organometallic moiety, either the SM,R or RM,S diastereomers, respectively, were observed in the molecular structures of the Ru- and Os(cym) (cym = η6-p-cymene) compounds, whereas the RM,R or SM,S diastereomers were found for the Rh- and Ir(Cp*) (Cp* = η5-pentamethylcyclopentadienyl) derivatives. However, density functional theory (DFT) calculations suggest that the energy difference between the diastereomers is very small, and therefore a mixture of both will be present in solution. The organometallics exhibited varying antiproliferative activity in a series of human cancer cell lines, with the complexes featuring the (R)-enantiomer of the ligand being more potent than the (S)-configured counterparts. Notably, the Rh and Ir complexes demonstrated high KSP inhibitory activity, even at 1 nM concentration, which was independent of the chirality of the ligand, whereas the Ru and especially the Os derivatives were much less active

3,12-Diaza-6,9-diazo­nia-2,13-dioxotetra­decane bis­(perchlorate)

The crystal structure of the title diprotonated diacetyl­triethyl­ene­tetra­mine (DAT) perchorate salt, C10H24N4O2 2+·2ClO4 −, can be described as a three-dimensional assembly of alternating layers consisting of diprotonated diacetyl­triethyl­ene­tetra­mine (H2DAT)2+ strands along [100] and the anionic species ClO4 −. The (H2DAT)2+ cations in the strands are connected via N—H⋯O hydrogen bonding between the acetyl groups and the amine groups of neighbouring (H2DAT)2+ cations. Layers of (H2DAT)2+ strands and perchlorate anions are connected by a network of hydrogen bonds between the NH and NH2 groups and the O atoms of the perchlorate anion. The asymmetric unit consits of one perchlorate anion in a general position, as well as of one cation that is located on a center of inversion