A simple and high-yield route to iridium, rhodium, osmium and ruthenium nido -6-metalladecaborane compounds

• Published in: Dalton transactions : an international journal of inorganic chemistry 2021-11, Vol.50 (45), p.16751-16764
• Main Authors: Bould, Jonathan, Londesborough, Michael G. S., Passarelli, Vincenzo, Clegg, William, Waddell, Paul G., Cvačka, Josef, Macías, Ramón
• Format: Article
• Language: English
• Subjects: Bimetals; Carbon monoxide; Clusters; Crystal structure; Infrared spectroscopy; Liquid phases; Mass spectrometry; Molecular structure; NMR spectroscopy; Osmium; Potential energy; Reagents; Rhodium; Ruthenium; Single crystals
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d1dt02971a

We report a high-yield heterogeneous solid/liquid phase synthetic method to a series of nido -6-metalladecaboranes. The hydridoirida– and hydridorhoda–decaboranes, [6,6,6-H(PPh 3 ) 2 - nido -6-MB 9 H 13 ] [M = Ir (1), Rh (2)] are isolatable in 98% yields from the reaction of the square-planar M( i ) complexes, [MCl(PPh 3 ) 3 ] (M = Rh, Ir), with K[B 9 H 14 ]. The same synthetic procedure, but using [MCl(CO)H(PPh 3 ) 3 ] (M = Ru, Os) as metal starting reagents produces the CO-ligated clusters, [6,6,6-(CO)(PPh 3 ) 2 - nido -6-MB 9 H 13 ] [M = Ru (3), Os (4)], in yields of 83% and 95%, respectively. These highly convenient syntheses permit the investigation of the reaction chemistry of the new nido -6-metalladecaboranes. Thus, the CO-ligated compounds, 3 and 4, react with the square-planar platinum( ii ) complex, [PtCl 2 (PMe 2 Ph) 2 ], in the presence of potassium triethylborohydride, to give the bimetallic clusters, [1,1,1-(CO)H(PPh 3 )- isocloso -1-RuB 9 H 8 -μ-(1,2)-{Pt(PMe 2 Ph) 2 }] (5) and [7,7-(PMe 2 Ph) 2 -9,9,9-(CO)(PPh 3 ) 2 - nido -7,9-PtOsB 9 H 11 ] (6), and the monometallic nido -5-osamadecaborane, [5,5,5-(PPh 3 ) 2 (CO)- nido -5-OsB 9 H 13 ] (7). This reactivity illustrates the potential of polyhedral boron-based clusters as molecular scaffolds (“B-frames”) for the construction of multimetallic species. Single-crystal X-ray diffraction analyses have revealed the molecular structures of 3, 5, 6 and 7; the compounds are also studied by multielement NMR spectroscopy, mass spectrometry, IR spectroscopy, and in some cases computationally. Futhermore, the rotation of the {M(X)(PR 3 ) 2 } moiety (X = H, CO), as PH 3 -ligated models, is studied by means of DFT-calculated relaxed potential energy surface scans, giving some insight into the lability of the metal-to-borane fragment interaction and of the exo -polyhedral ligands.