Highly Chlorinated, Brominated, and Iodinated Icosahedral Carborane Anions:  1-H-CB₁₁X₁₁^-, 1-CH₃-CB₁₁X₁₁^- (X = Cl, Br, I); 1-Br-CB₁₁Br₁₁^-

Abstract

Direct chlorination of 1-CH(3)-CB(11)H(11)(-) in glacial acetic acid gave the highly chlorinated carborane anion 1-CH(3)-CB(11)Cl(11)(-), and treatment of 1-CH(3)-CB(11)H(11)(-) with ICl in triflic acid afforded the highly iodinated carborane anion 1-CH(3)-CB(11)I(11)(-). Under similar or more vigorous reaction conditions, however, the reaction of 1-CH(3)-CB(11)H(11)(-) with Br(2) in triflic acid did not proceed to completion. The highly brominated carborane anion 1-CH(3)-CB(11)Br(11)(-) was achieved via a sealed-tube reaction. This new method has led to the isolation of 1-H-CB(11)X(11)(-) (X = Cl, Br, I) and 1-Br-CB(11)Br(11)(-) in high yield. The lithiation of 1-H-CB(11)X(11)(-) resembles that of its parent anion CB(11)H(12)(-). Treatment of these lithio species with methyl iodide gave the methylated carborane anions 1-CH(3)-CB(11)X(11)(-). These new weakly coordinating anions were fully characterized by (1)H, (13)C, and (11)B NMR, IR, and negative-ion MALDI MS spectroscopy. Some were further confirmed by single-crystal X-ray analysis.

Silver and Copper Complexes with closo-Polyhedral Borane, Carborane and Metallacarborane Anions: Synthesis and X-ray Structure

“…It is noteworthy that no interaction between Ag + and any one of the bromine atoms from the upper belt of the cage is observed, although Ag + usually prefers to bind to a bromine atom rather than a chlorine atom according to the hard-soft acid-base principle. The silver salts of the perchloro and perbromo derivatives of 1-carba-closo-dodecaborate anion, Ag[1-HCB 11 Cl 11 ] and Ag[1-HCB 11 Br 11 ], were prepared by treatment of the corresponding sodium salt with AgNO 3 in aqueous solution [98]. Single crystals of {(η 2 -p-xylene) 2 Ag[1-HCB 11 Cl 11 ]}¨1/2(p-xylene) were grown from p-xylene.…”

“…These results may suggest that the charge distribution on the icosahedral cage plays a predominant role in the coordination chemistry of carborane anions. aqueous solution [98]. Single crystals of {Ag[1-Me-1-CB 11 Cl 11 ]} n were grown from benzene solution.…”

“…The silver salts of C-methyl perhalogen derivatives of the carba-closo-dodecaborate anion Ag[1-Me-1-CB11X11] (X = Cl, Br) were prepared by treatment of the sodium salts with AgNO3 in aqueous solution [98]. Single crystals of {Ag[1-Me-1-CB11Cl11]}n were grown from benzene solution.…”

“…. Br distance of 2.848(5) Å) ( Figure 76) [98]. The methyl group is completely mixed with eleven bromine atoms of the cage anion.…”

“…Therefore, it is not possible to distinguish the BBr vertex antipodal to carbon from other vertexes. Unlike in the solid state structure of {Ag[1-HCB 11 H 5 -7,8,9,10,11,12-Br 6 ]} n , where the most basic bromine atom attached to B (12) antipodal to carbon is shared by two silver ions, there is no bromine atom shared by the silver ion in {Ag[1-Me-1-CB 11 Br 11 ]} n , perhaps reflecting the steric effect and/or the fact that there is no significantly electron-rich bromine atom on the cage due to donor effect of the methyl group The silver salts of C-methyl perhalogen derivatives of the carba-closo-dodecaborate anion Ag[1-Me-1-CB11X11] (X = Cl, Br) were prepared by treatment of the sodium salts with AgNO3 in aqueous solution [98]. Single crystals of {Ag[1-Me-1-CB11Cl11]}n were grown from benzene solution.…”