Diarylhalotelluronium(IV) cations [(8-Me2NC10H6)(2)TeX](+) (X = Cl, Br, I) stabilized by intramolecularly coordinating N-donor substituents

作者：Beckmann Jens^*; Bolsinger Jens; Duthie Andrew; Finke Pamela

来源：Dalton Transactions, 2013, 42(34): 12193-12202.

DOI：10.1039/c3dt51011e

The stoichiometrically controlled halogenation of the intramolecularly coordinated diaryltelluride (8-Me2NC10H6)(2)Te using SO2Cl2, Br-2 and I-2 was studied. At an equimolar ratio, the diarylhalotelluronium cations [(8-Me2NC10H6)(2)TeX](+) (1, X = Cl; 2, X = Br; 3, X = I) formed and were isolated as 1 center dot Cl-center dot H2O center dot 1/2THF, 2 center dot Br-, and 3 center dot I-, respectively. When the same reactions were carried out in the presence of KPF6, 1 center dot PF6 and 2(2)center dot Br-center dot PF6- were obtained. The chlorination of (8-Me2NC10H6)(2)Te with an excess of SO2Cl2 occurred with a double electrophilic substitution at the 8-dimethylaminonaphthyl residues (in the ortho- and para-positions) and afforded the diaryltellurium dichloride (5,7-Cl-2-8-Me2NC10H4)(2)TeCl2 (4). The bromination of (8-Me2NC10H6)(2)Te with three equivalents of Br-2 took place with a single electrophilic substitution at the 8-dimethylaminonaphthyl residues (in the para-positions) and provided the diaryltellurium dibromide (5-Br-8-Me2NC10H5)(2)TeBr2 (5), while an excess of Br-2 produced the diarylbromotelluronium cation [(5-Br-8-Me2NC10H5)(2)TeBr](+) (6) that was isolated as 6 center dot Br-3(-). The reaction of (8-Me2NC10H6)(2)Te with two or three equivalents of iodine provided 3 center dot I-3(-) and 3 center dot I-3(-)center dot I-2, respectively. In the presence of water, 1 center dot Cl-center dot H2O center dot 1/2THF, 2 center dot Br-, 3 center dot I- and 3 center dot I-3(-) hydrolyzed to give the previously known diarylhydroxytelluronium cation [(8-Me2NC10H6)(2)TeOH](+) (7) that was isolated as 7 center dot Cl-, 7 center dot Br-center dot H2O center dot THF, 7 center dot I- and 7 center dot I-3(-)center dot H2O, respectively. The molecular structures of 1-7 were investigated in the solid-state by Te-125 MAS NMR spectroscopy and X-ray crystallography and in solution by multinuclear NMR spectroscopy (H-1, C-13, Te-125), electrospray mass spectrometry and conductivity measurements. The stabilization of cations 1-3 by the intramolecular coordination was estimated by DFT calculations at the B3PW91/TZ level of theory.

• 出版日期2013