Synthesis and characterization of a dimeric hydridorhodacarbaborane anion derived from the nido-monocarbaborane, B10H12CNH3

Abstract

The reaction of RhCI(PPh3)3 with nido-B,,H,,CNH, in the presence of Bun4NOH produced [Bun4N] [clos0-2,2-(Ph~P)~-2-H-I -(NH2)-2,l -RhCB,oH,o]f which upon heating in methanol produced a new orange compound confirmed by an X-ray diffraction study to be the [Bun,N] + salt of an -NH,-bridged Rh-H-Rh dimer anion.

Electronic Requirements for Macropolyhedral Boranes

“…[(PPh 3 )Rh(NH 2 )CB 10 H 10 ] 2 - ( 131 ). This compound consists of two polyhedra bridged through two NH 2 moieties and a hydrogen atom . The rule indicates 26 skeletal electron pairs ( m = 2, n = 24).…”

“…This compound consists of two polyhedra bridged through two NH 2 moieties and a hydrogen atom. 269 The rule indicates 26 skeletal electron pairs (m ) 2, n ) 24). However, the number of electron pairs contributed from 20 BH groups (20), 2 CH groups (3) (the terminal hydrogen is replaced by a NH 2 moiety, which forms a dative bond with the carbon atom), 2 dative bonds (1), 2 d 9 -ML fragments (1), and a negative charge sum to 25.5 electron pairs.…”

Metal complexes of monocarbon carboranes bearing C-amine or -amino substituents

“…Some years ago, in related chemistry, it was shown that the carborane 7-NH 3 -nido-7-CB 10 H 12 reacted with [RhCl(PPh 3 ) 3 ] in methanolic solution to give [1-NH 2 -2,2-(PPh 3 ) 2 -2-H-closo-2,1-RhCB 10 H 10 ] À , which in refluxing methanol was converted to the dimeric anionic [2,2 0 -l-H-{1,2 0 -l-NH 2 -2-PPh 3 -closo-2,1-RhCB 10 H 10 } 2 ] À [18]. In contrast, the carborane 7-NMe 3 -nido-7-CB 10 H 12 in refluxing methanol with the same rhodium reagent yields primarily 18-electron [1-NMe 3 -2-H-2-Cl-2,7-(PPh 3 ) 2 -closo-2,1-RhCB 10 H 9 ], together with the 16-electron complex [1-NMe 3 -2-Cl-2-PPh 3 -closo-2,1-RhCB 10 H 10 ] [19].…”

Amine–nitrile coupling in amino-monocarbollide complexes of molybdenum

“…9 This contrasts with the earlier work of Hawthorne et al, in which the non-N-substituted carbaborane 7-NH 3 -nido-7-CB 10 H 12 was found to react with the same rhodium reagent in methanolic KOH solution to give the anion [1-NH 2 -2,2-(PPh 3 ) 2 -2-H-closo-2,1-RhCB 10 H 10 ] Ϫ . 10 Significantly, the latter rhodium-carbaborane complex, upon mild thermolysis, forms dimeric [2,2Ј-µ-H-{1,2Ј-µ-NH 2 -2-PPh 3closo-2,1-RhCB 10 H 10 } 2 ] Ϫ , in which each of the µ-NH 2 units forms a bridge between the cage-carbon atom of one {RhCB 10 } cluster and the rhodium centre of the other. 10 In earlier work, 11 we found that interaction of the carbaborane anion [7-NHBu t -nido-7-CB 10 H 12 ] Ϫ with [Mo(CO) 6 ] in refluxing NCMe results in dihydrogen elimination and formation of the novel molybdenacarbaborane [1,2-µ-NHBu t -2,2,2-(CO) 3 -closo-2,1-MoCB 10 H 10 ] Ϫ , isolated as the [N(PPh 3 ) 2 ] ϩ salt 1a, which contains an intramolecular NHBu t bridging moiety.…”

“…10 Significantly, the latter rhodium-carbaborane complex, upon mild thermolysis, forms dimeric [2,2Ј-µ-H-{1,2Ј-µ-NH 2 -2-PPh 3closo-2,1-RhCB 10 H 10 } 2 ] Ϫ , in which each of the µ-NH 2 units forms a bridge between the cage-carbon atom of one {RhCB 10 } cluster and the rhodium centre of the other. 10 In earlier work, 11 we found that interaction of the carbaborane anion [7-NHBu t -nido-7-CB 10 H 12 ] Ϫ with [Mo(CO) 6 ] in refluxing NCMe results in dihydrogen elimination and formation of the novel molybdenacarbaborane [1,2-µ-NHBu t -2,2,2-(CO) 3 -closo-2,1-MoCB 10 H 10 ] Ϫ , isolated as the [N(PPh 3 ) 2 ] ϩ salt 1a, which contains an intramolecular NHBu t bridging moiety. Analogous tungsten (1b) and chromium (1c) species were prepared similarly.…”