Orthotellurated derivatives of N,N-dimethylbenzylamine: crystal and molecular structures of [2-(dimethylaminomethyl)phenyl]tellurium(IV) tribromide and [2-(butyldichlorotelluro)benzyl]dimethylammonium chloride

Abstract

The reaction of o-lithiobenzylamine with elemental tellurium followed by air oxidation furnished an ill defined 'tellurinic anhydride'. Halogenolysis reactions of this with bromine and sulphonyl chloride afforded the corresponding [2-(dimethylaminomethyl)phenyl]trihalogenotellurium(IV) derivatives. Reduction of the trihalides with excess of hydrazine hydrate gave novel [2-(dimethylaminomethyl)phenyl]halogenotellurium(II) derivatives. Metathesis of the chlorotellurium-(IV) and -(II) derivatives with sodium diethyldithiocarbamate resulted in the formation of dithiocarbamato derivatives. The crystal structure of [2-(dimethylaminomethyl)phenyl]tellurium(IV) tribromide is monoclinic, space group P2₁/n with a=9.226(6), b=15.439(8), c=9.618(5)Å. β=94.94(5)°, Z=4, and R=0.0419 for 938 observed reflections. The co-ordination about Te approximates to octahedral with a vacant equatorial site: two Br atoms axial, the third Br and the organic ligand equatorial [Te-Br_(ax) 2.758(2) and 2.633(3), Te-Br_(eq) 2.632(2), Te-C 2.12(1), and Te-N 2.42(1)Å]. The compound is essentially monomeric, with a weak association between Te and a neighbouring bromine atom [3.896(2)Å]. [2-(Butyldichlorotelluro)benzyl]dimethylammonium chloride is monoclinic, space group P2₁/n with a=14.278(12), b=8.349(5), c= 14.480(8)Å. β= 93.59(5)°, Z=4, and R=0.0288, for 2 245 observed reflections. The co-ordination about Te can also be considered as octahedral with a vacant equatorial site: two chlorines apical, and the chloride ion and two carbon atoms equatorial [Te-Cl 2.527(1) and 2.487(1), Te···Cl 3.337(2), Te-C 2.134(4) and 2.154(4)Å]. The quaternary nitrogen atom is twisted away from the tellurium atom, Te···N 4.380(4)Å, forming a hydrogen bond with a chloride ion.