Synthesis and characterization of N,N′,C-bound organotellurium(IV) and organomercury(II) derivatives

Abstract

We report the synthesis and characterization of the first examples of organotellurium (IV)/organomercury(II) derivatives of N,N′,C-chelating aryldiamine ligand, 2-{Me2NCH2CH2N(Me)CH2}C6H4Br (20). The dichalcogenides, [2-{Me2NCH2CH2N(Me)CH2}C6H4Se]2 (24) and [2-{Me2NCH2CH2N(Me)CH2}C6H4Te]2 (25), were prepared by treatment of the corresponding Grignard reagent (21)/organolithium reagent (22) in THF with selenium or tellurium, respectively. Compounds [2-{Me2NCH2CH2N(Me)CH2}C6H4]2Se (26) and [2-{Me2NCH2CH2N(Me)CH2}C6H4]Te(S2CN(CH2CH3)2 (27) were synthesized by the reaction of 21/22 with Se(dtc)2 in 2:1 or Te(dtc)2 (dtc = diethyldithiacarbamate) in 1:1 ratio at room temperature. In contrast, the reaction of 21 with TeI2 afforded an unexpected protonated derivative, [2-{(Me2NH)CH2CH2N(Me)CH2}C6H4TeI]+(I)− (28a). Similarly, the halogenation reactions of 25 with chlorine gas or a solution of bromine in THF afforded protonated derivatives, [2-{(Me2NH)CH2CH2N(Me)CH2}C6H4TeCl3]+(Cl)− (29a) and [2-{(Me2NH)CH2CH2N(Me)CH2}C6H4TeBr3]+(Br) − (30a), respectively. The organomercury precursors; 2-{Me2NCH2CH2N(Me)CH2}C6H4HgCl0.54/Br0.46 (31) and 2-{Me2NCH2CH2N(Me)CH2}C6H4HgBr (32), were obtained by the reaction of 21 with HgCl2 and HgBr2 in dry THF, respectively. The metathetical reaction of 31with silver azide afforded air- and moisture-stable organomercury azide, 2-{Me2NCH2CH2N(Me)CH2}C6H4HgN3 (33) in 87% yield. The transmetallation reaction of 31 with TeBr4 led to isolation of known o-formylphenyltellurenyl bromide. All the derivatives were characterized by various spectroscopic techniques such as 1H, 13C, 77Se, 125Te, 199Hg NMR spectroscopy, elemental analysis, ES-MS and HRMS studies.