Synthesis and Structure of [η 5 -1,2,4-(Me 3 Si) 3 C 5 H 2 ] 2 Th(bipy) and Its Reactivity toward Small Molecules.

Halide exchange of (Cp3tms )2 ThCl2 ( 1 ; Cp3tms = η5 -1,2,4-(Me3 Si)3 C5 H2 ) with Me3 SiI furnishes (Cp3tms )2 ThI2 ( 2 ), which is then reduced with potassium graphite (KC8 ) in the presence of 2,2'-bipyridine to give the thorium bipyridyl metallocene (Cp3tms )2 Th(bipy) ( 3 ) in good yield. Complex 3 was fully characterized and readily reacted with various small molecules. For example, 3 may serve as a synthetic equivalent for the (Cp3tms )2 Th(II) fragment when exposed to CuI, Ph2 S2 , organic azides, and CS2 . Moreover, upon the addition of thiobenzophenone Ph2 CS, p -methylbenzaldehyde ( p -MeC6 H4 )CHO, benzophenone Ph2 CO, amidate PhCONH( p -tolyl), seleno-ketone ( p , p '-dimethoxy), selenobenzophenone ( p -MeOPh)2 CSe, di( p -tolyl)methanimine ( p -tolyl)2 C═NH, 1,2-di(benzylidene)hydrazine (PhCH═N)2 , and nitriles PhCN, PhCH2 CN, and Ph2 CHCN C-C coupling results to give (Cp3tms )2 Th[(bipy)(Ph2 CS)] ( 8 ), (Cp3tms )2 Th[(bipy)( p -MePhCHO)] ( 9 ), (Cp3tms )2 Th[(bipy)(Ph2 CO)] ( 10 ), (Cp3tms )2 Th[(bipy){( p -tolylNH)(Ph)CO}] ( 11 ), (Cp3tms )2 Th[(bipy){( p -MeOPh)2 CSe}] ( 12 ), (Cp3tms )2 Th[(bipy){( p -tolyl)2 CNH}] ( 13 ), (Cp3tms )2 Th[(bipy)(PhCHNN═CHPh)] ( 14 ), (Cp3tms )2 Th[(bipy)(PhCN)] ( 16 ), (Cp3tms )2 Th[(bipy)(PhCH2 CN)] ( 17 ), and (Cp3tms )2 Th[(bipy)(Ph2 CHCN)] ( 18 ), respectively. However, when thiazole is added to 3 , the dimeric sulfido complex [(Cp3tms )2 Th]2 [μ-(bipy)CH2 NCHCHS]2 ( 15 ) can be isolated. Moreover, the addition of isonitriles such as Me3 CNC and PhCH2 NC to 3 results in C-N bond cleavage and C-C coupling processes to form the thorium isocyanido amido complexes (Cp3tms )2 Th[4-(Me3 C)bipy](NC) ( 19 ) and (Cp3tms )2 Th[4-(PhCH2 )bipy](NC) ( 20 ), respectively. Nevertheless, upon exposure of 3 to (trimethylsilyl)diazomethane Me3 SiCHN2 , the bis-amido complex (Cp3tms )2 Th[5,6-(Me3 SiCH)bipy] ( 21 ), concomitant with N2 release, is isolated.