Monocarbollide Complexes of Rhodium

Abstract

The rhodium sandwich complexes [Rh(η6-arene)(η5-7-NHBut-7-CB10H10)] (arene = C6H5Me (2b), C6H3Me3-1,3,5 (3), MeC6H4C6H4Me-4,4‘ (4), [22](1,4)-C16H16 (5)) have been prepared from reactions between 1:1 mol mixtures of the arenes and [RhCl(PPh3)(η5-7-NH2But-7-CB10H10)] (1a) in CH2Cl2 in the presence of AgBF4. The crystal structures of 3 and 5 have been determined by X-ray diffraction confirming that in these species the rhodium is pentahapto coordinated on one side by the formally three-electron-donor 7-NHBut-7-CB10H10 and on the other in the hexahapto manner by a mesitylene molecule and one C6H4 ring of the cyclophane, respectively. The reaction between 4 and [Mo(CO)3(NCMe)3] in THF gave the dirhodium complex [Rh2(CO)2(η5-7-NH2But-7-CB10H10)2] (6), the structure of which has been established by X-ray diffraction. In the molecule two Rh(CO)(η5-7-NH2But-7-CB10H10) fragments are held together by a Rh−Rh bond which is spanned by two B−H⇀Rh two-electron three-center bonds employing in each CBBBB ring ligating a rhodium center a boron atom in one of the β-sites with respect to the carbon vertex. Reactions between 1a and tris(pyrazolyl)methane in the presence of TlPF6 and between 1a and K[HB(pzMe2-3,5)3] (HB(pzMe2-3,5)3 = hydrotris(3,5-dimethylpyrazolyl)borate) afforded respectively [Rh{HC(pz)3}(η5-7-NH2But-7-CB10H10)][PF2O2] (7) and [Rh{HB(pzMe2-3,5)3}(η5-7-NH2But-7-CB10H10)] (8). An X-ray diffraction study on 7 confirmed the pentahapto bonding of the charge-compensated 7-NH2But-7-CB10H10 ligand and the tridentate character of the tris(pyrazolyl)methane group and also established the anion as [PF2O2]- formed by hydrolysis of [PF6]-. The NMR data for the new compounds are reported and discussed.

Iridium Halide Complexes [1,1‐X2‐8‐SMe2‐1,2,8‐IrC2B9H10]2 (X = Cl, Br, I): Synthesis, Reactivity and Catalytic Activity

“…In all compounds, the pentagonal CB 4 face is folded along the B3⋯B6 line by ca 9.7° for 2 , 8.1° for 3 , 6.8° for 5 , and 3.3° for 6 , so that the M–C2 bond is longer than the M–B bonds. A similar pattern was observed earlier by Stone and co‐workers for the monocarbollide complexes . In contrast, in the transition‐metal complexes of the [7,8‐C 2 B 9 H 11 ] 2– and [9‐SMe 2 ‐7,8‐C 2 B 9 H 10 ] – anions, in which the metal atom is bonded with the C 2 B 3 face, the M–C bonds are usually shorter than the M–B bonds, in accordance with the larger covalent radius of boron vs. carbon…”

Five-Coordinate [RuCl(P−P*)2]+Complexes Containing Chiral Diphosphines: Application in the Asymmetric Cyclopropanation and Epoxidation of Olefins

“…The unit cell contains two crystallographically independent [RuCl(bnpe) 2 ] + cations, one [PF 2 O 2 ] - anion, one (μ-H)-bridged [PF 2 O 2 H···O 2 F 2 P] - unit, one (μ-H) 2 -bridged [PF 2 O 2 H] 2 dimer, and two CH 2 Cl 2 molecules. The presence of the [PF 2 O 2 ] - anion, possibly formed by hydrolysis of [PF 6 ] - , is confirmed by 31 P NMR. As the two cations are very similar, only one will be discussed here.…”

Coordination, organometallic and related chemistry of tris(pyrazolyl)methane ligands

“…99 More recently, Stone and coworkers have prepared the first mixed sandwich complex of Rh with an arene and monocarbon carborane ligand. 100 The reaction between [RhCl(PPh 3 )(g 5 -7-NH 2 t Bu-7-CB 10 H 10 )] and tris (3,5-dimethylpyrazolyl) C in CD 2 Cl 2 a rearrangement to a hydrido-crotyl species occurs, with the exo isomer being favoured (Scheme 8). 103 Elguero and co-workers have reported a number of iridium and rhodium complexes of tris(pyrazolyl)methane incorporating cyclic diolefins.…”