Synthesis and Structural Characterization of Highly Chlorinated, Brominated, Iodinated, and Methylated Carborane Anions, 1-H-CB₉X₉^-, 1-NH₂-CB₉X₉^- (X = Cl, Br, I), and 1-H-CB₉(CH₃)₉^-

Abstract

The highly chlorinated, brominated, and iodinated carborane anions 1-R-CB9X9- (R = H, NH2; X = Cl, Br, I) were prepared in high yields by treatment of [Me3NH][1-R-CB9H9] with excess ICl, Br2/triflic acid, and I2/triflic acid, respectively, in sealed tubes at 180-240 degrees C. With the aid of a Pd catalyst, B-I bonds could be converted into the B-Me bonds by treatment with excess MeMgBr, which led to the preparation of the permethylated species 1-H-CB9Me9- in good yield. These new anions were fully characterized by 1H, 13C, and 11B NMR, IR, and negative-ion MALDI MS spectroscopy. Some were further characterized by single-crystal X-ray analyses. The weakly coordinating nature of these new anions was probed by 29Si chemical shifts.

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

“…The bidentate binding is characterized by Ag-Br bond lengths of ~2.78 Å, whereas the monodentate interaction is weaker at 2.842(6) Å. Secondly, in the bidentate interaction, the Ag-Br(10) and Ag-Br(6) bond lengths are practically indistinguishable (2.783(6) and 2.775(6) Å, respectively) ( Figure 46) [73]. The silver salts of C-substituted perchloro and perbromo derivatives of 1-carba-closo-decaborate anion, Ag[1-Bn-1-CB9Cl9] and Ag[1-H2N-1-CB9Br9], were prepared by treatment of the corresponding sodium salts with AgNO3 in aqueous solution [74]. The silver salt of the perbromo derivative of 1-carba-closo-decaborate anion, Ag[1-HCB9Br9], was prepared by the metathesis of Cs[1-HCB9Br9] with AgNO3 from aqueous solution and crystallized from benzene/THF solution to give {Ag(η 2 -benzene)[1-HCB9Br9]}n [74].…”

“…The average Ag-Br distance of 2.778 Å is close to those found in {Ag(η 2 -toluene)[1-CB9H5-6,7,8,9,10-Br5]}n. The asymmetric η 2 benzene coordination has Ag-C distances of 2.629 (8) The silver salts of C-substituted perchloro and perbromo derivatives of 1-carba-closo-decaborate anion, Ag[1-Bn-1-CB 9 Cl 9 ] and Ag[1-H 2 N-1-CB 9 Br 9 ], were prepared by treatment of the corresponding sodium salts with AgNO 3 in aqueous solution [74]. The silver salt of the perbromo derivative of 1-carba-closo-decaborate anion, Ag[1-HCB 9 Br 9 ], was prepared by the metathesis of Cs[1-HCB 9 Br 9 ] with AgNO 3 from aqueous solution and crystallized from benzene/THF solution to give {Ag(η 2 -benzene)[1-HCB 9 Br 9 ]} n [74]. The [1-HCB 9 Br 9 ]´anions act as bridging ligands in a one-dimensional coordination polymer chain, an increasingly familiar motif in silver carborane structures.…”

“…Ag(3) is in a highly distorted square-pyramidal arrangement having one η 1 -benzene, one bidentate [1-HCB 9 Br 9 ]´anion, and one bidentate NO 3´a nion. It is noteworthy that a bromine atom from the upper tetragonal belt can also coordinate to an Ag + ion ( Figure 48) [74]. While the relatively labile chloride ligand in complexes MCl(CO)(PPh3)2 (M = Ir, Rh) can be readily abstracted with silver perchlorate or triflate, the reactions with Ag[1-CB9H5-6,7,8,9,10-Br5] result in M→Ag donor-acceptor metal-metal bonded adducts (PPh3)2(CO)ClM·Ag[1-CB9H5-6,7,8,9,10-Br5] that were isolated in the solid state [73].…”

Synthesis and structure of fluorophenyl derivatives of the 10-vertex monocarbaborane anions [1-CB9H10]− and [2-CB9H10]−

“…The research interest was focused mainly on 12-vertex carboranes whereas their 10-vertex analogues received some less attention [4][5][6][7]. Described recently direct synthesis of C-aryl derivatives of 1-carba-closo-decaborate from decaborane B 10 H 14 and aryl aldehydes [8][9][10] gives possibility to increase total size of carborane anion due to introduction of aryl group.…”

The synthesis of functional derivatives of the [1-CB9H10]− anion by Brellochs reaction

“…More recently, two new methods based on the deamination of [1-Me 3 Ncloso-1-CB 9 H 9 ] [9] and [1-H 3 N-closo-1-CB 9 H 9 ] [10] were proposed. These findings have made the 1-carba-closodecaborate anion more available and by now a number of its halogen derivatives were prepared [10][11][12].…”