Opening the B10H102-cage to produce B10H12(Et2S)2

Abstract

Work on recovery of the (NH4)2B10H~0 from the double salt by use of other solvents is in progress. With large excesses of HC1 the reaction gives some free NH4C1 and correspondingly higher quantities of B10H12-(Et2S)2. Several samples have been allowed to react with propargyl bromide, and the expected bromomethylcarborane derivative was ~b t a i n e d .~Muetterties has reported obtaining a bridge-hydrogen structure from the BloHlo2-i o n 6 Dehydration of an aqueous solution of (H30)2B10H10 gave a white solid from which a material could be sublimed. The sublimate showed evidence for bridge hydrogens in its infrared pattern. The unknown had the approximate composition of BloH120H2. He concluded that the solid belonged to the BloH12(base) or B10H13-structural class. A referee has pointed out that the formation of Bl8H22 from B20H18'-plus acid involves opening BloHlo cages. However, degradation with loss of boron also obviously occurred.'Mechanistically the synthesis of BloH12(Et2S)2 from (NH4)2B10H10 can be pictured as just the reverse of the BloHlz(base)z conversion to BloHlo2-derivatives. Hawthorne suggests that this latter conversion occurs by the removal of protons from the bridge positions in the BloH12(base)2 structure, and that the resulting filled two-center orbitals undergo a nucleophilic displacement of the coordinated bases. In our reaction, protons which are presumably supplied via the ethylsulfonium ion, Et2SH+, probably attack in the apex region of the BloHlo2-cage. Nmr studies with deuterium chloride have established that hydrogen exchange occurs at the apex borons.6,8*9 Single crystal X-ray space group is Pbca, with a = 16.9, b = 18.9, c = 14.7 A. The formula weight from these data and the observed density is 61 1 (f 1 %) (calcd for [PtCl(CO)-(P(C2H6)3)2]SiF5: 618; calcd for O.S[PtCl(CO)(P-(C~H&)ZIZS~FB : 566).Although the previous conclusions are now known to be incorrect, the reactions described above are remarkable in several ways. (a) The formation of a platinum carbonyl and BF4-under such mild conditions, presumably by interaction of GF4 with the glass surface in contact with the hydride, is remarkable. It can be related to, but is more extreme than, the ability of the isoelectronic Ir(1) and Rh(1) systems to abstract carbon monoxide from oxygen-containing organic solvents.2t6 (b) The cation is isoelectronic with Vaska's compound2 and may show similar properties. These are being investigated. (c) This is the first reported isolation of the SiF5-ion. Further detailed studies of this species are currently in progress.Acknowledgment.The preparations of BloH12(base)2 derivatives have been reported from reactions of decaborane with soft bases.1v2 These have been converted further to the BloHlo2-structure by action of more or harder base.a We wish to report the synthesis of B10H12(Et2S)2 from (NH4)2B10H10, which is the first time, to our knowledge, that the BloHlo2-cage has been opened to clearly reestablish the decaborane skeleton.This reaction takes on further significance with the recent preparation...

closo‐[B21H18]−: A Face‐Fused Diicosahedral Borate Ion

“…[9] Now we have found that trans-M 2 [B 20 H 18 H 19 ] À ion, which is designated as fac-[B 20 H 19 ] À in the following discussion. It is known that under acidic conditions the closo-[B 10 H 10 ] 2À ion reacts to form nido-B 10 H 13 X, [25,26] nido-B 10 H 12 X 2 , [27,28] or BF 3 /[BF 4 ] À . [29][30][31] In view of these reactions, the rearrangement of trans-[B 20 H 18 ] 2À (Figure 1) might be initiated by protonation of one of its two {B 10 (Figure 1).…”

A Convenient Approach To Synthesize o‐Carborane‐Functionalized Phosphorescent Iridium(III) Complexes for Endocellular Hypoxia Imaging

“…An alternative method is to start from commercially available B 10 H 10 (Et 4 N) 2 , which is cheap, stable, and nontoxic. It can be readily converted to the precursor B 10 H 12 (Et 2 S) 2 , which is reactive, but easy to handle and suitable for synthesis of o ‐carborane–pyridine derivatives by reaction with pyridine‐bearing alkynes (Scheme ) –. On the basis of this modified synthetic approach, three new o ‐carborane‐functionalized H ligands ( a – c in Figure and Scheme ) were prepared in high yields and with low costs.…”

New method of synthesis of 6-hydroxy-nido-decaborane 6-(OH)B10H13 by cage opening of closo-[B10H10]2−

“…The reverse conversion requires the opening of the very stable [B 10 H 10 ] 2À cage. In strong acidic medium and in the presence of chelating and not highly polar solvent L, the cage [B 10 H 10 ] 2À is opened and 6,9-L 2 B 10 H 12 is produced [11][12][13]. When the solvent L is non polar and not chelating as C 6 H 6 and in presence of the very strong acid CF 3 SO 3 H, the conversion products are 6-(C 6 H 5 )B 10 H 13 and 6-(OSO 3 H)B 10 H 13 [13].…”

“…The mechanism of the reaction between [B 10 H 10 ] 2À and concentrated acids would be very similar to that between strong acid and a [B 10 H 10 ] 2À anion salt in diethylsulphide suspension, from which (Et 2 S) 2 B 10 H 12 is obtained [12,13]; the first step is the fixation of one proton on each of the apical positions. Cage opening occurs when hydrogen-bridge bonds form between (B-5 and B-6), (B-8 and B-9) and boron-boron bonds are destroyed (Fig.…”