Gerald Oates

Trifluoromethyliodine(V) tetrafluoride and related compounds

Trifluoromethyl iodide is oxidised by chlorine trifluoride in C6F14 at –78 °C to give trifluoromethyliodine(V) tetrafluoride. Evidence for the formation of trifluoromethyliodine(III) difluoride has also been obtained. CF3IF4 Decomposes readily at 20 °C but is more stable in this respect than CF3IF2. Other RFIF4[RF= C2F5, (CF3)2CF, or n-C4F9] compounds are more stable with respect to decomposition than had been supposed. CF3IF4 Reacts with methylmethoxosilanes at 20 °C to give CF3IF4–n(OMe)n(n= 1–4).

Reactions of chlorine trifluoride with pentafluoroiodobenzene and related compounds. Preparation of pentafluorophenyliodine(V) tetrafluoride

Pentafluoroiodobenzene is oxidised by chlorine trifluoride below room temperature to pentafluorophenyliodine(V) tetrafluoride and C6F4(IF4)2 is one of the products from the oxidation of 1,4-I2C6F4 under similar conditions. Bromopentafluorobenzene is not oxidised by ClF3 but addition of chlorine and fluorine to the ring occurs. Similar behaviour is observed with C6F5IF4 and ClF3.

Formation of silylcarbaboranes from 1,2-bis(trimethylsilyl)pentaborane(9)

By way of an apparent carbon-insertion process, 1,2-bis(trimethylsilyl)pentaborane(9) gives, on flash thermolysis, a number of C-silyl derivatives of the smallest known carbaborane, 1-H3Si-1,5-C2B3H3, 1-MeH2Si-1,5-C2B3H4, 2-Me-1-(H3Si)-1,5-C2B3H3, as well as an equilibrium mixture of 2- and 4-methyl derivatives of CB5H7. A total carbaborane yield of ca. 40 mol % has been obtained. Temperature-dependent n.m.r. studies on the B-methyl isomers of CB5H7 show a fast bridge-hydrogen tautomerism at ca. 100 °C. A substituent chemical-shift effect has been calculated for Me3Si and H3Si groups on all positions of the pentaborane(9) cage.

Substitution reactions of iodine pentafluoride: preparation and properties of methoxoiodine(V) fluorides

Methoxoiodine(V) fluorides, IF5 –n(OMe)n(n=1–4), and fluoro(methyl)silanes are formed from reactions of iodine pentafluoride with methoxomethylsilanes at 20 °C. The IF5 derivatives are labile and readily decompose with reduction of iodine(V). Although Me3SiF is formed from reactions of IF5 with other Me3SiX [X = Cl, SMe, OC(O)R, or Me] compounds, substituted derivatives of IF5 are not isolated because reduction occurs.

Organosilyl- and silylorgano-pentaboranes: monocarbahexaboranes from 2-[(chlorodimethylsilyl)methyl]pentaborane(9)

Bridge and terminally substituted pentaborane(9) derivatives of the type [(ClCH2)Me2Si] B5H8, have been prepared. Rearrangement of both the 1- and 2-terminally substituted pentaboranecompounds to the carbon-attached isomers, 1- and 2-[(ClMe2Si)CH2] B5H8, is accomplished with the use of AlCl3 as catalyst. Flash thermolysis of 2-[(ClMe2Si)-CH2] B5H8 yields SiMe2ClH (48%), B5CH9(4.2%), and B5CH7(9.4%) as the major volatile products. Alkylation of B5H9 with SiMe3(CH2Cl) in the presence of AlCl3, gives 1 -MeB5H8 and SiMe3Cl in quantitative amounts, whereas use of Si(CH2Cl)Cl3 as the alkylating agent gives only 1-[(Cl3Si)CH2]Br5H8.