Synthesis and Molecular Structure of trans‐[IrCl(NO)(PtBu₂H)₂]BF₄

Abstract

The synthesis and structural characterization of trans-[IrCl(NO)(PtBu 2 H) 2 ]BF 4 (1) is reported. The title compound was prepared in good yield in the reaction of in situ-prepared trans-[IrCl(coe)(PtBu 2 H) 2 ] (coe = cis-cyclooctene) with an appropriate Recently we reported the synthesis and molecular structure in the crystal of the nitrosyl compound trans-[RhCl(NO) (PtBu 2 H) 2 ]BF 4 . [1] The latter was obtained in good yield by a kind of "bridge-splitting" reaction of [{Rh(μ-Cl)(PtBu 2 H) 2 } 2 ] with a corresponding amount of nitrosonium tetrafluoridoborate in dichloromethane at room temperature. Complexes of the type trans-[IrX(NO)(PPh 3 ) 2 ] + (X = Cl, OH, OR) were described in the literature long ago, [2] but no crystal structure reports for these species have been published till now. Moreover the synthesis of 15 N enriched compounds with the formula trans-[RhCl( 15 NO)(PiPr 3 ) 2 ]X (X = ClO 4 or BF 4 ) were described, [3] however, even in the case of rhodium no reports on crystal structures have hitherto been reported for such species. Because no hints at the existence of complexes [{Ir(μ-Cl)(PR 3 ) 2 } 2 ] serving as possible starting compounds in the above mentioned "bridge-splitting" reaction exist in the literature, we searched for other suitable precursor compounds to prepare complexes of the general formula [IrX(NO)(PR 3 ) 2 ] + .In this light we proofed the usefulness of complex trans-[IrCl(coe)(PtBu 2 H) 2 ] [4] (coe = cis-cycclooctene) as a possible precursor for the preparation of the envisaged nitrosyl compounds. Indeed, during this study we could obtain the new compound trans-[IrCl(NO)(PtBu 2 H) 2 ]BF 4 (1) in good yield and were able to confirm its molecular structure by a singlecrystal X-ray diffraction study.

Spontaneous Reductive Elimination at Iridium(III) Induced by the Strong π‐Acceptor Ligand Trifluorophosphane

“…We confirmed such observations e.g. also for trans ‐[IrCl(NO)(P( t Bu) 2 H) 2 ] + and related complexes …”

“…The molecular structure is comparable to the cationic complex trans ‐[IrCl(NO)(P( t Bu) 2 Ph) 2 ] + , for the latter the following selected bonding parameters were found: Ir1–Cl1, 2.2652(7); Ir1–P1, 2.429(6); Ir1–P2, 2.429(6) Å and P1–Ir1–P2, 178.31(2); P1–Ir1–N1, 89.71(6)° (for 2 compare the data in caption of Figure ). Furthermore, the found data of 2 are comparable with the observed ones of trans ‐[IrCl(NO)(P( t Bu) 2 H) 2 ] + in its corresponding tetrafluoridoborate salt …”

“…also for trans-[IrCl(NO)(P(tBu) 2 H) 2 ] + and related complexes. [3] In this light, we expected similar phenomena for compound 2. To study the DNMR behavior at higher temperatures, the solvent was changed to [D 8 ]toluene exhibiting for 2 similar signals as observed in CD 2 Cl 2 at room temperature.…”

“…Furthermore, the found data of 2 are comparable with the observed ones of trans-[IrCl(NO)(P(tBu) 2 H) 2 ] + in its corresponding tetrafluoridoborate salt. [3] In the literature, iridium complexes bearing the PF 3 ligand are structurally not explored to date. Only one example containing the unusual PF 4…”

Conformational Rigidity in Complexes [MCl(tBu2PH)3] (M = Rh, Ir)

“…In this light, we explain similar effects for the interpretation of the NMR spectra of complexes 1 and 2 . Recently we observed closely related stereodynamic behavior during 31 P{ 1 H} NMR studies on compounds trans ‐[ M Cl(NO)( t Bu 2 PH) 2 ]BF 4 ( M = Rh, Ir) . In this paper we report results on reaction studies of [{ M (μ‐Cl)(coe) 2 } 2 ] ( M = Rh, Ir; coe = cis ‐cyclooctene) with t Bu 2 PH, whereas some related findings in this field were already published by us elsewhere .…”