87370-05-6Relevant articles and documents
THE FIRST OSMABORANES AND A NEW IRIDATETRABORANE
Bould, Jonathan,Greenwood, Norman N.,Kennedy, John D.
, p. 11 - 22 (1983)
The reactions of under mild conditions with the anions arachno-- and nido-- yield the first air-stable polyhedral osmaborane species arachno (65percent) and nido- (80percent) respectively.The 11B and 1H NMR properties of these osmaboranes are similar to those of their iridium analogues arachno- (also previously unreported) and nido-.Mild thermolysis of nido- yields nido- (40percent) for which there is, as yet, no iridium analogue.
Degradation and modification of metallaboranes: Part 3. Reactions of the hexaborane(10) analogue nido-(PPh3)2 (CO)OsB5H9 with bidentate phosphines containing a rigid backbone: Formation of linked cluster systems
McQuade, Paul,Winter, Rudolph E.K.,Barton, Lawrence
, p. 82 - 91 (2003)
In the reaction between the osmahexaborane nido-(PPh3) 2(CO)OsB5H9 (1) and the bidentate phosphines, [1,2-(PPh2)2(CH2) 2] and [1,3-(PPh2)2(CH2) 3] (abbreviated as dppe and dppp, respectively), two products are observed in each case. The major product, (4a), [2,2,2-(PPh3) 2(CO)- nido -2-OsB4 H7-3-(BH2·dppe)] (or 4b -BH2·dppp) is an osmapentaborane cluster with a BH2·dppp group attached to the cage at a basal B(3) position and the distal end of the pendent bidentate phosphine donor is uncoordinated. In the other (5a), [2,2-(PPh3) 2(CO)- nido -2-OsB4H7-η 2-3,2- (BH2·dppe)] (or 5b -BH2·dppp) the uncoordinated phosphine present in 4a (or 4b) has replaced a PPh3 group on the osmium center. In an effort to avoid intramolecular substitution, bidentate phosphines of the type PPh2XPPh2 {X=1,4-C6H4, (arphos), 1,4-CH2C6H4CH2 (dppx), and Fe(C5H4)2 (dppf)}were used to preclude the formation of species 5. However three products were obtained instead of just one. These were [2,2,2-(PPh3)2(CO)- nido -2-OsB4H7-3-BH2·PPh2 XPPh2] (6), a linked metallaborane system of the of the type [{2,2,2-(PPh3)2(CO)- nido -2-OsB4H 7-3-BH2·PPh2}2X] (7) and a bis-borane adduct of the type [2,2,2-(PPh3) 2(CO)- nido -2-OsB4H7 -3-BH2·PPh2XPPh2 ·BH3] (8). This chemistry, which is seen for all the rigid backbone bases studied, is similar to that observed in reactions of phosphine bases with 1 which were described previously and is explained in terms of chemistry previously observed in studies of 1.
Degradation and Modification of Metallaboranes: Reactions of the Hexaborane(10) Analogue nido-(PPh3)2(CO)OsB5H9 with Phosphines and the Crystal and Molecular Structure of [2,2,2-(PPH3)2(CO)-nido-2-OsB4H7-3-BH2.PPh2.Me]
McQuade, Paul,Hupp, Kevin,Bould, Jonathan,Fang, Hong,Rath, Nigam P.,et al.
, p. 5415 - 5424 (2008/10/08)
The reaction between the osmahexaborane [2,2,2-(PPh3)2(CO)-nido-2-OsB5H9] (1) and bases such as PPh3, PPh2Me, and PMe3 in refluxing CH2Cl2 affords unique adducts of the type [2,2,2-(PPh3)2(CO)-nido-2-OsB4H7-3-BH2.PR3] (2) for which spectroscopic data suggest the presence of a pendent boryl group. This was confirmed by a crystal structure determination for the PPh2Me adduct which shows that 2 is a nido-osmapentaborane with a terminal BH2.PPh2Me moiety on a basal boron atom adjacent to the metal. The reaction is reversible in the case of PPh3 and to a lesser extent PPh2Me, but not for PMe3. Heating the PPh3 adduct affords the osmahexaborane 1, liberating PPh3, but degradation to the osmapentaborane [2,2,2-(PPh3)2(CO)-nido-2-OsB4H8] (6) and BH3.PPh3 competes. The tendency to degrade to phosphine.borane increases markedly down the series R3 = Ph3, Ph2Me, and Me3. When the bidentate bases [1,2-(PPh2)2(CH2)2] and [1,3-(PPh2)2(CH2)3] (abbreviated as dppe and dppp, respectively) are used, two major products are observed in each case. One (3a) [2,2,2-(PPh3)2(CO)-nido-2-OsB4H7-3-(BH2.dppe)] (or 3b, BH2.dppp) is analogous to 2 with one end of the bidentate phosphine donor uncoordinated. In the other (4a) [2,2-(PPh3)(CO)-nido-2-OsB4H7-η(2)-3,2-(BH2.dppe)] (or 4b, BH2.dppp), the free end of the bidentate ligand has replaced a PPh3 group on Os. In the reaction of [(PPh2)2(CH2)] (abbreviated as dppm) with 1, only a species analogous to 3 is observed. The species 3b, the one involving dppp, has beenfurther modified at the free phosphine end of the ligand, to form [2,2, 2-(PPh3)2(CO)-nido-2-OsB4H7-3-(BH2.dppp.BH3)] (5).
