SYNTHESIS AND CHARACTERIZATION OF PSEUDOCLOSO IRIDIUM AND RUTHENIUM DIPHENYL CARBABORANES - MOLECULAR-STRUCTURES OF 1,2-PH(2)-3-(ETA-C6H6)-3,1,2-PSEUDOCLOSO-RUC2B9H9 AND 1,2-PH(2)-3-(CYM)-3,1,2-PSEUDOCLOSO-RUC2B9H9 (CYM EQUALS P-CYMENE) AND INDIVIDUAL GAUGE FOR LOCALIZED ORBITALS CALCULATIONS ON CARBAMETALLABORANES
Pt. Brain et al., SYNTHESIS AND CHARACTERIZATION OF PSEUDOCLOSO IRIDIUM AND RUTHENIUM DIPHENYL CARBABORANES - MOLECULAR-STRUCTURES OF 1,2-PH(2)-3-(ETA-C6H6)-3,1,2-PSEUDOCLOSO-RUC2B9H9 AND 1,2-PH(2)-3-(CYM)-3,1,2-PSEUDOCLOSO-RUC2B9H9 (CYM EQUALS P-CYMENE) AND INDIVIDUAL GAUGE FOR LOCALIZED ORBITALS CALCULATIONS ON CARBAMETALLABORANES, Journal of the Chemical Society. Dalton transactions, (2), 1996, pp. 231-237
The syntheses and characterisations of Ph(2)-3-(eta-C(5)Me(5))-3,1,2-p
seudocloso-IrC2B9H9 1, 1,2-Ph(2)-3-(eta-C6H6)-3,1,2-pseudocloso-RuC2B9
H9 2, 1,2,-Ph(2)-3-(cym)-3,1,2-pseudocloso-RuC2B9H9 (cym = p-cymene) 3
and Ph(2)-3-(eta-C(6)Me(6))-3,1,2-pseudocloso-RuC2B9H9 4 are reported
from the reactions between Tl-2[7,8-Ph(2)-nido-7,8-C2B9H9] and either
[{IrCl2(C(5)Me(5))}(2)] or the appropiate [{RuCl2(arene)}(2)] species
. By B-11 NMR spectroscopy all these compounds have pseudocloso geomet
ries, in which the C(1)... C(2) connectivity is broken and an approxim
ately square M(3)C(1)B(6)C(2) face is generated. Crystallographic stud
ies on 2 and 3 confirm this suggestion. It is suggested that distortio
n in these species arises from steric crowding between the C-phenyl su
bstituents, forced to adopt conformations with high theta values by th
e presence of the eta-bonded substituent at M(3). Individual gauge for
localised orbitals calculations, reported for the first time on trans
ition-metal heteroboranes, reasonably reproduce the (previously assign
ed) B-11 NMR chemical shifts of 3-(eta-C(5)Me(5))-3,1,2-closo-RhC2B9H1
1, and allow a tentative assignment of those of h(2)-3-(eta-C(5)Me(5))
-3,1,2-pseudocloso-RhC2B9H9.