Tomáš Jelínek

A simple route to essential tricarbollides. A high-yield synthesis of 7-amine-nido-7,8,9-tricarbaundecaboranes(10), 7-L-nido-7,8,9-C3B8H10 (where L=H3N, Me2NH, Me3N, and ButH2N)

Abstract Reported is an improved synthesis of essential starting compounds for the development of tricarbollide and metallatricarbollide chemistry. Evaporation of a solution of Na + [5,6-C 2 B 8 H 11 ] − ( 1 − ) in neat Bu t NC, followed by acidification, led to the isolation of 7-(Bu t H 2 N)- nido -7,8,9-C 3 B 8 H 10 ( 2a ) in a 90% yield. This was converted into the 7-(H 3 N)- nido -7,8,9-C 3 B 8 H 10 ( 2b ) derivative via reaction with AlCl 3 in refluxing benzene (yield 77%). Methylation of 2b with Me 2 SO 4 in an alkaline solution gave the 7-(Me 3 N)- nido -7,8,9-C 3 B 8 H 10 ( 2c ) derivative in essentially quantitative yield. The reaction of 2c with sodium in liquid ammonia resulted in the formation of highly pure compounds 7-(Me 2 HN)- nido -7,8,9-C 3 B 8 H 10 ( 2d ) (yield 71%) and nido -7,8,9-C 3 B 8 H 12 ( 3 ) (yield 19%).

Metallaborane reaction chemistry. Macropolyhedral metallaheteroborane synthesis by direct heteroatom insertion. Formation of the twenty-vertex [(η5-C5Me5)IrB18H19S]− anion from nineteen-vertex syn-[(η5-C5Me5)IrB18H20]

Abstract Syn-[(η5-C5Me5)IrB18H20] (1), from [{IrCl2(η5-C5Me5)}2] and syn-B18H22 with base, consists of nido-type twelve-vertex {IrB11} and ten-vertex {B10} subclusters fused with a common {B3} triangular face. Reaction of 1 with excess elemental sulfur and base results in the generation of the iridathiaborane anion [(η5-C5Me5)IrB18H19S]− (2), which consists of a nido-type twelve-vertex {IrB11} subcluster and an arachno-type ten-vertex {SB9} subcluster fused with a {B2} edge in common. The reductive addition of electron-rich sulfur results in a loss in the degree of intimacy of the intercluster fusion together with a nido→arachno conversion of the non-metalla subcluster character.

The Parent Hexacarbaboranearachno-C6B6H12 and a Methylated Pentacarbaboranearachno-CH3C5B7H12: Domains of Incipient Hydrocarbon Behavior within Borane Clusters

Increasingly pronounced hydrocarbon character is exhibited by C6 H6 B12 , the first unsubstituted hexacarbaborane, and CH3 C5 B7 H12 , the first cluster pentacarbaborane. These compounds shed light on the structural dichotomy between open hydrocarbon skeletons and polyhedral borane frameworks for high-carbon carboranes.

Macropolyhedral boron-containing cluster chemistry. Isolation and structure of the twenty-one-vertex globular cluster compound [(η5-C5Me5)3Ir3B18H15(OH)]

Abstract Reaction of syn-B18H20 with [(η5-C5Me5)IrCl2]2 and base results in multiple metal-centre addition, allied with oxidative cluster closure by multiple dihydrogen loss, giving the twenty-one-vertex globular cluster compound [(η5-C5Me5)3Ir3B18H15(OH)] based on twelve-vertex closo {IrB11} and isonido {Ir2B10} clusters fused with a common five-atom {IrB4} unit that contains a central tetrahedral {IrB3} core.