The synthesis and structural characterisation of a novel C3-symmetric tris-bidentate ligand, L, featuring a triphenylamine core appended by pyridylimine coordination sites is reported: 1H NMR compleximetric titration studies with Ag(I) and ESMS indicate the presence of [Ag3L2]3+ species in solution, consistent with the formation of a trinuclear double helicate complex: the Trinity helix.

We show how serum magnesium can be determined with a centrifugal analyzer. The method is based upon a manual procedure involving magnesium/calmagite complex formation in an alkaline reagent mixture. The assay, performed at 30 degrees C, requires 5 mul of serum in a final reaction volume of 405 mul, including 350 mul of reagent mixture. The stable color produced at 1 min is measured at 520 nm. L...

Titrimetric estimation of calcium with disodium ethylene diamine tetra-acetate (E.D.T.A., sodium edetate), as performed on serum (Baron and Bell, 1957), cannot be applied directly to most other biological specimens because of their high concentration of phosphate. A high ratio of phosphate to calcium in the material titrated causes a drawnout and inaccurate endpoint. A rapid procedure for calci...