Six guanidinium salts of arylarsenic po1ytungstates have been prepared by the 'degradation method' using sodium metatungstate as a starting material instead of sodium tungstate, They belong to three types of c...Six guanidinium salts of arylarsenic po1ytungstates have been prepared by the 'degradation method' using sodium metatungstate as a starting material instead of sodium tungstate, They belong to three types of complexes: [(RAs)_2W_6O_(25)H]^(5-) where R=C_6H_5(1),o-NO_2C_6H_4(2),m-NO_2C_6H_4(3), p-NO_2C_6H_4(4),[(RAs)_2W_6O_(25)]^(4-) where R=p-NH_2C_6H_4(5), and[(RAs)_2W_6O(25)]^(6-)where R=3,4,-C_6H_3 (NO_2)(OH)(6). Complex 1 is a known compound, prepared by the acidification building up method, i.e. conversion of sodium tungstate to polytungstate. Complex 1 and 6 prepared by the degradation method, i.e. from sodium metatungstate to lower polytungstate, are briefly reported in our previous re- port of this investigation. Complexes 2-5 are new compounds. Molecular structures of complexes 5 and 6 have been determined by means of single-crystal X-ray diffraction studies. It is especially em- phasized that the degradation method starting with metatungstate has the advantage in the simplification of reaction products. thus leading to their higher yields.展开更多
文摘Six guanidinium salts of arylarsenic po1ytungstates have been prepared by the 'degradation method' using sodium metatungstate as a starting material instead of sodium tungstate, They belong to three types of complexes: [(RAs)_2W_6O_(25)H]^(5-) where R=C_6H_5(1),o-NO_2C_6H_4(2),m-NO_2C_6H_4(3), p-NO_2C_6H_4(4),[(RAs)_2W_6O_(25)]^(4-) where R=p-NH_2C_6H_4(5), and[(RAs)_2W_6O(25)]^(6-)where R=3,4,-C_6H_3 (NO_2)(OH)(6). Complex 1 is a known compound, prepared by the acidification building up method, i.e. conversion of sodium tungstate to polytungstate. Complex 1 and 6 prepared by the degradation method, i.e. from sodium metatungstate to lower polytungstate, are briefly reported in our previous re- port of this investigation. Complexes 2-5 are new compounds. Molecular structures of complexes 5 and 6 have been determined by means of single-crystal X-ray diffraction studies. It is especially em- phasized that the degradation method starting with metatungstate has the advantage in the simplification of reaction products. thus leading to their higher yields.
