Vanadium chemistry of ascidians

Abstract

1. 1. Addition of exogenous ligands, 2,2′-bipyridine and 1,10-phenanthroline, to a variety of aplousobranch and phlebobranch ascidians, oproduced deep purple oxo-bridged binuclear complexes of bis(chelate)vanadium(III) within compartment (including signet ring) and some unpigmented morula cells confirming the presence of vanadium(III) in these cells. 2. 2. Treatment with acetylacetone formed [VO(acac)] and [V(acac)]. 3. 3. Electron paramagnetic resonance studies confirmed the presence of vanadium(IV) in all vanadium-containing Aplousobranchs, and little or no vanadium(IV) in the Phlebobranchs, and identified two types of vanadium(IV) binding to organic ligands with the 'oxidized' Phlebobranchs generally of Type I and the Aplousobranchs generally of Type II with e.p.r. parameters: Type I-g 1.992, g 1.987, g 1.967, A 53.01, A 51.95, A 155.47 × 10 cm; Type II-g 1.980, g 1.985, g 1.951, A 59.08, A 55.72, A 166.68 × 10 cm. 4. 4. Electron microscopic investigation of the morula cells of the phlebobranch, Ecteinascidia nexa, showed that the intracellular globules were rich in vanadium