新規有機ヒ素化合物の合成と金属錯体

抄録

Trivalent arsenic compounds have lone pairs, which can coordinate with many kinds of transition metals. Several studies of organoarsine-transition metal complexes have been reported to show attractive properties. However, most synthesis of the organoarsenic compounds used for complexations are prepared from arsenic chlorides or arsenic hydrides. Ultimate care should be given for handling of these arsenic intermediates due to their volatility. To stimulate the field of organoarsenic chemistry, practical synthetic methods should be discovered. We have synthesized cis-1,4-dihydro-1,4-diarsinines, 1,4-diarsa-1,4-cyclohexadienes, as cyclic organoarsenic compounds by radical reaction of pentamethylcyclopentaarsine and acetylene derivatives. The cis-1,4-dihydro-1,4-diarsinines have unique structures, two arsenic atoms are connected with two rigid ethylene bridges and have divergent syn conformations of the two lone pairs on the arsenic atoms. Their stability toward air and moisture was great enough to allow their handling in air. The present report describes unique reactivity and coordination behaviors of the cis-1,4-dihydro-1,4-diarsinines. The experimental results suggest that the flexibility of the bond angles around the arsenic center is an inherent property in the present organiarsenic compounds, and the flexibility might be a main reason for the stabilization of the strained conformations, enable synthesis of unusual complexes, and showing unique properties.