Synthesis of new heteroscorpionate iridium(I) and iridium(III) complexes

The reactivity of different heteroscorpionate ligands based on bis(pyrazol-1-yl) methane, with different iridium-(I) and -(III) precursors is reported. The reaction of the heteroscorpionate lithium salts "Li(bdmpza)", [bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate], "Li(bdmpzdta)" [bdmpzdta = bis(3,5-dimethylpyrazol- 1-yl) dithioacetate] and "Li(S)-mbpam" [(S)-mbpam = (S)-( )-N-alpha-methylbenzyl-2,2-bis( 3,5-dimethylpyrazol-1-yl) acetamidate] with 1 equivalent of [IrCl3(THF)(3)] in THF for 18 h affords high yields of neutral and anionic heteroscorpionate chloride iridium complexes [IrCl2(bdmpza)(THF)] (1), [Li( THF) 4][IrCl3(bdmpzdta)] (2) and [IrCl2{(S)-mbpam})(THF)] (3). Solution of complex 3 in acetonitrile at room temperature leads to complex [IrCl2{(S)-mbpam})(NCCH3)] (4). Complexes 3 and 4 were isolated as enantiopure compounds. The reaction of the lithium salt "Li(bdmpza)" with [IrCl(eta(4)-CH2=C(Me)C(Me) =CH2)](2) in THF for 18 h gave the Ir(I) complex [Ir(bdmpza)(eta(4)-CH2=C(Me)C(Me) =CH2)] (5). The reaction of complex 5 with CO (2 atm) at room temperature leads to a new complex of Ir(III), [Ir(bdmpza)(k(2)-CH2C( Me)=C(Me)CH2)(CO)] (6). Treatment of heteroscorpionate ligand precursors "Li(bdmpza)" and " Li(bdmpzdta)" with [IrCp* Cl-2](2) in THF yielded the iridium(III) complexes [Ir2Cp*Cl-2(2)(bdmpzx)] (x = a 7, x = dta 8). These complexes have helical chirality due to the demands of the fixed pyrazole rings. The stereoisomerism and the self-assembly processes of these helicates have been studied in some detail in solution by NMR spectroscopy and in the solid state by X-ray diffraction. Mixtures of M-and P-handed enantiomers were obtained. Complex 7 undergoes a decarboxylation process initiated by the HCl generated in the previous step leading to the known ionic complex [IrClCp*(bdmpm)][IrCl3Cp*] [bdmpm = bis(3,5-dimethylpyrazol-1-yl) methane] (9). The structures of the complexes were determined by spectroscopic methods and the X-ray crystal structures of 4, 6, 8 and 9 were also established.