Synthesis, Structure and Reactivity of Iridium Hydrido Fluorido Complexes

Abstract

The oxidative addition of HF at trans‐[Ir(ArF)(η2‐C2H4)(PiPr3)2] (1a: ArF = 4‐C5NF4; 1b: ArF = 2‐C6H3F2) affords the fluorido complexes trans‐[Ir(ArF)(F)(H)(PiPr3)2] (2a: ArF = 4‐C5NF4; 2b: ArF = 2‐C6H3F2). The hydrido fluorido complex 2a is also accessible by means of the reaction of the hydroxido complex trans‐[Ir(4‐C5NF4)(H)(OH)(PiPr3)2] (3a) with Et3N·3HF. Both compounds 2a and 2b react with CO to give the carbonyl complexes trans‐[Ir(4‐C5NF4)(F)(H)(CO)(PiPr3)2] (4a: ArF = 4‐C5NF4; 4b: ArF = 2‐C6H3F2). In the presence of traces of water, a slow reaction of 2a with CO2 yields the hydrogencarbonato complex trans‐[Ir(4‐C5NF4)(H)(κ2‐(O,O)‐O2COH)(PiPr3)2] (5a). Upon using 2a or 2b as fluorinating agent, Ph3SiH could be converted into Ph3SiF and CH3C(O)Cl into CH3C(O)F.

Insertion of CS2 into Iridium–Fluorine Bonds

“…[8b,d, 21] Note that it was reported before that the reaction of 1 a with CO 2 results in the formation of the hydrogencarbonato complex trans-[Ir (7) in the presence of traces of water. [13] An insertion of CO 2 into the Ir À F bond of 1 a was not observed. We also computed the formation of the putative insertion product trans-[Ir …”

“…[18] The complex trans{Ir(4-C 5 NF 4 )(FH)(PiPr 3 ) 2 } (A1) is formed as a shallow intermediate, which then releases HF to yield trans-{Ir ( (4) was observed before. [13] The computed reaction profile for pathway B, which involves the concerted insertion of CS 2 into the metalfluorine bond, proceeds via a four-membered transition state (TS2) at + 71.1 kJ mol À1 (Figure 3 [19] Note that an interaction of CS 2 with the Ir center requires a vacant coordination site at the metal. The LUMO of 1 a has santibonding character in the IrÀH bond, but is essentially metal-centered with one lobe Figure 1.…”

“…[13,14] the singlet at d = 96.8 ppm can be assigned to the fluorine atom of the fluorodithiocarbonato ligand. For the isotopologue […”

“…To get more insight into that reaction, 2 a was treated with Ph 3 SnCl at 50 8C. This reaction led to the generation of the chlorido complex trans-[Ir(4-C 5 NF 4 )(Cl)(H)(PiPr 3 ) 2 ] (6) [13,24] and a colorless solid, which was identified as Ph 3 SnF [25] by elemental analysis and IR spectroscopy (Scheme 4). CS 2 was detected in the reaction mixture by GC/MS and 13 C NMR experiments.…”

“…[12] Herein we report on the synthesis of iridium(III) fluorodithiocarbonato complexes by insertion of CS 2 into the IrÀF bond of the iridium(III) fluorides trans-[Ir(Ar F )(F)(H)-(PiPr 3 ) 2 ] (1 a: Ar F = 4-C 5 NF 4 ; 1 b: Ar F = 2-C 6 H 3 F 2 ; Scheme 1). [13] The insertion mechanism is supported by density-functional theory (DFT) calculations.…”