Never a dull moment with praseodymium metal.

Unexpectedly, a mixture of bismuth N , N '-bis(2,6-diisopropylphenyl)formamidinates in three different oxidation states namely, [BiI2(DippForm) 2 ] (1), [BiII2(DippForm) 2 (C 6 F 5 ) 2 ] (2) and [Bi III (DippForm) 2 (C 6 F 5 )] (3), together with [Pr(DippForm) 2 F(thf)]·PhMe (4), [ p -HC 6 F 4 DippForm]·0.5thf (5), and a ring-opened tetrahydrofuran [ o -HC 6 F 4 O(CH 2 ) 4 DippForm] (6) was obtained by the reaction of an excess of praseodymium metal with tris(pentafluorophenyl)bismuth, [Bi(C 6 F 5 ) 3 ]·0.5dioxane, and bulky N , N '-bis(2,6-diisopropylphenyl)formamidine (DippFormH) in tetrahydrofuran. Similar reactions between praseodymium metal, [Bi(C 6 F 5 ) 3 ]·0.5dioxane and 3,5-diphenylpyrazole (Ph 2 pzH), or 3,5-di- tert -butylpyrazole ( t Bu 2 pzH), yielded the paddlewheel dibismuthanes [BiII2(Ph 2 pz) 4 ]·dioxane (7) and [BiII2( t Bu 2 pz) 4 ] (8) respectively.