Homoleptic Metal Carbonyl Cations

CATIONS OF GROUP 6-12 ELEMENTS 4.5.1. Homoleptic Metal Carbonyl Cations 

The first homoleptic carbonyl cations of Group 7 metals with the general formula [M (CO)6]+ (M = Mn, Tc, Re) were generated by Fischer and co-workers992 993 and Hieber and co-workers994 995 in the 1960s 6,997 applying halide abstraction by Lewis acids [Eq. (4.236)]. 

Versatile synthetic routes are available to prepare metal carbonyl cations in superacidic media. The most successful methods include reductive carbonylation of metal fluorosulfates or fluorides [Eqs. (4.237)1003 and (4.238)1004]-1002 1005 This 

2lrF6 + 15CO + 6SbF5 + 8HF —HF SbFs [lr(CO)6]3 (SbF6 )3 4 HF + 3COF2 

Oxidative reactions are the method of choice in the generation of cations of Group 6, 8, and 9 metals [Eq. (4.241)].1007 The /ac-Rh(C0)3(FS03)3 complex used in the synthesis of the Rh(I) salt 361 [Eq. (4.242)] was prepared from the solvated [Rh (CO)4]+ cation generated from [Rh(CO)2Cl]2 1008 All procedures are performed under a CO atmosphere (1-2 atm).1002 

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H. Willner, and F. Aubke, Homoleptic Metal Carbonyl Cations of the Electron-rich Metals Their Generation in Superacidic Media Together with Their Spectroscopic and Structural Characterization, Angew. Chem. Int. Ed. Engl. 36, 2402-2425 (1997). 

B. von Ahsen, M. Berkei, G. Henkel, H. Willner, and F. Aubke, The Synthesis, Vibrational Spectra, and Molecular Structure of [Ir(CO)6][SbF6]3-4HF - The First Structurally Characterized Salt with a Tripositive, Homoleptic Metal Carbonyl Cation and the First Example of a Tetrahedral Hydrogen-Bonded (HF)4 Cluster, J. Am. Chem. Soc. 124, 8371-8379 (2002). 

H. WUlner, F. Aubke, Homoleptic metal carbonyl cations of the electron-rich metals their generation in superacid media together with their spectroscopic and structural characterization. Angewandte Chemie-Int Ed. Engl. 36(22), 2403-2425 (1997). doi 10.1002/anie.l99724021... 

Lupinetti, A.J., Jonas, V., Thiel, W., Strauss, S.H. and Frenking, G. (1999) Trends in Molecular Geometries and Bond Strengths of the Homoleptic d Metal Carbonyl Cations [M(CO)J ... 

The reaction of the transition-metal fragments with main group 15 elements directly has proven a very fruitful field for exploration. The methodology has been successful for a wide range of metal complexes. These fall generally into three basic types (1) reactions with cyclopentadienyl metal carbonyls, (2) reactions with homoleptic metal carbonyls and substituted derivatives, and (3) reactions with metal cations in the presence of a multi-dentate chelating ligand. 

Pathways to a variety of homoleptic transition metal carbonyl cations have now been developed., 1,1 B10UOT (... 

Figure 4.4. Metals with known homoleptic carbonyl cations (shading indicates structural characterization).

Figure 3.4 Homoleptic carbonyl cations of the late transition metals...

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