Rhodium(III) and iridium(III) half-sandwich complexes with tertiary arsine and stibine ligands

Abstract

The syntheses of rhodium(III) and iridium(III) half sandwich complexes containing tertiary arsine and C NMR spectroscopy, mass spectrometry and single crystal X-ray diffraction. DFT calculations show the formation of the complexes from (Cp*MCl 2 ) 2 and EPh 3 (E = P, As, Sb) to be highly exothermic, although the enthalpic driving force is decreasing in the expected sequence P > As > Sb.

Coordinatively Unsaturated [RhCp*Rf2] (Cp* = C5Me5; Rf = C6F3Cl2-3,5), General Precursor to Cp*-Diaryl and Cp*-Halo-Aryl RhIII Complexes. Observing and Testing the Effect of Cp* as Electronic Buffer

“…Plot of Rh-Cp*centroid distances in complexes reported in this paper (blue and red lines) or in the literature (green line). 6d, 40,43,44 On the other hand, we could expect that the ligands donating more overall electron density to Rh should produce also longer Rh-Cp*centroid distances, more or less following the order of trans influence series available in the literature. 47,48 In fact this is the case in the three series.…”

Synthesis and Oxidation of a Paddlewheel‐Shaped Rhodium/Antimony Complex Featuring Pyridine‐2‐Thiolate Ligands

“…Considering that the δ in the 121 Sb Mössbauer spectra of 1 and 2 provided only marginal information about the electronic situation of the Sb atoms in these complexes ( δ correlates with just the 5s occupancy), we also looked into the electronic features of 1 and 2 in more detail by calculating the 5s and 5p orbital populations (from NBO analyses) of the Sb atoms in these compounds in comparison with the electronic populations of a series of Sb III and Sb V reference compounds as well as of the triorganoantimony rhodium complexes [Rh III Cl 2 Cp*(SbPh 3 )] ( 3 ) and [Rh I Cl(Sb i Pr 3 ) 2 (CNMe)] ( 4 ) (Figure ).…”

“…This high 5s(Sb) contribution to the SbÀ Rh bond in 2 (a shiftt owardsl one pair characteristics, %5s tot = 82 %f or the lone pairs depicted in Figure 3, A) indicates a pronounced contributiono ft he Sb!Rh (L-Type) canonical form for complex 2.W eh ave then questioned whether the high coordination number (6) of the Sb atom of 2 might be responsible for this partial L-type Sb!Rh bonding. Therefore, Considering that the d in the 121 Sb Mçssbauer spectra of 1 and 2 provided only marginal information about the electronic situation of the Sb atoms in thesec omplexes (d correlates with just the 5s occupancy), we also lookedi nto the electronic features of 1 and 2 in more detail by calculating the 5s and 5p orbital populations (from NBOa nalyses) of the Sb atoms in these compounds in comparison with the electronic populations of as eries of Sb III and Sb V reference compounds as well as of the triorganoantimonyr hodiumc omplexes [Rh III Cl 2 Cp*(SbPh 3 )] (3) [29] and [Rh I Cl(SbiPr 3 ) 2 (CNMe)] (4) [30] (Figure 4).…”

Arsinocarbyne reactivity

“…Under the same conditions, there is no discernible reaction at all with the related ruthenium and rhodium dimers, [Ru 2 (µ-Cl) 2 Cl 2 ( p-cymene) 2 ] and [Rh 2 (µ-Cl) 2 Cl 2 (Cp*) 2 ], even upon stirring for 24 h at RT or on warming to 40 °C for 2 h (higher temperatures leading to decomposition of 1). This implies that the arsenic atom in 1 is an even weaker donor than AsPh 3 , which does cleave these halide-bridged dimers to coordinate to "RhCl 2 (Cp*)" under these conditions, 19 and to "RuCl 2 ( pcymene)" 20 or related ruthenium centres 21 upon mild heating. This result is perhaps not surprising given the negatively inductive (I − ) nature of the sp-carbyne fragment by analogy with alkynyl substituents.…”

“…15 kJ mol −1 stronger than the same bond in the rhodium analogue. 19 Steric encumbrance involving a clash between the bulky W(CO) 2 (Tp*) moiety and the ligands on Ru or Rh is unlikely to be a significant factor given that the phosphorus analogue of 1, [W(uCPPh 2 )(CO) 2 (Tp*)], readily coordinates to a 'RhCl 2 (Cp*)' unit under these conditions without issue. 10c 2), C4-As1-C10 102.9(2), C4-As1-Os1 121.26 (15), C10-As1-Os1 114.00 (16).…”