Amidinato-supported bis-silylenes I (1, R1-R3 = alkyl, aryl, alkenyl, cycloalkyl, heterocycle; L = O, benzenediolate, pyridinediaminate, ferrocenediyl, preferably, L = 1,1'-ferrocenediyl), useful as ligands for transition metal complexes, active as catalysts in alkene hydroformylation and prodn. of aldehydes, were prepd. by metalation of linker precursors H2L and reaction with amidinato-supported chlorosilylenes R2CNR1NR3SiCl; subsequent complexation of I with transition metal precursors, preferably, with HRh(CO)(PPh3)3 produced active and stable hydroformylation catalysts. In an example, lithiation of 3.23 mmol of ferrocene with BuLi/TMEDA gave the dilithioferrocene intermediate, which was reacted with 6.45 mmol of (N,N'-di-tert-butylbenzamidinato)chlorosilicon in 30 mL of toluene for 12 h at 20°, giving the invented ligand, 1,1'-[PhC(NtBu)2Si]2(C5H4)2Fe (1a). Complexation of 1a with HRh(CO)(PPh3)3, taken in equimol. amts. in C6D6 gave the rhodium complex [[1,1'-[PhC(NtBu)2Si]2(C5H4)2Fe]RhH(CO)(PPh3)] (2a). Hydroformylation of styrene at 100° and CO/H2 pressure of 30 atm, catalyzed by HRh(CO)(PPh3)3/1a (1:3), exhibited TOF of 9075 h-1, compared to 3007 in the same conditions catalyzed by HRh(CO)(PPh3)3/Xantphos (1:3) combination.
|IPC||PCT Int. Appl. (2017), WO 2017178536 A1 20171019.|
|Publication status||Published - Oct 2017|