Tellurium—nitrogen bonds

Dimeric self-assembly via tellurium-nitrogen secondary bonding has been reported in (2-phenylazophenyl-C,A )tellurium(II) thiocyanate (Te- N 3.535 A), 231 [531]. The NCS group is linear (N-C-S 179.3°) and is oriented approximately perpendicular to the tellurium-organic ligand plane (Te-S-C 98.4°). In the bis-(thiocyanato) diphenyltelluriumoxide, (NCSTePh2)20, however, the chain-like... 

Tellurium(VI)-nitrogen bonds can be generated by the reaction of hexamethyldisilazane with tellurium hexafluoride (Eq. 2.12). The product (Mc3SiNH)TeE5 is a useful precursor for a variety of NTeEs compounds. By contrast, SEe is inert towards Si-N reagents. 

In general, it was found that this process is strongly endothermic for sulfur diimides, approximately thermoneutral for selenium diimides and strongly exothermic for tellurium diimides, consistent with experimental observations. These differences can be attributed to the expected trend to lower r-bond energies for chalcogen-nitrogen (np-2p) r-bonds along the series S (n = 3), Se (n = 4) and Te (n = 5). 

The polar tellurium(II)-nitrogen bond is readily susceptible to protolysis by weakly acidic reagents. Eor example, the reaction of [Te(NMe2)2]oo with two equivalents of Ph3CSH produces the monomeric thiolato derivative Te(SCPh3)2. Alkynyl tellurides may be prepared by the reaction of terminal acetylenes with arenetellurenamides (Eq. 10.13). ... 

The method (i) can be applied to the synthesis of almost all heavy ketones (Tables 3-5). Silanethiones and a silaneselone stabilized by the coordination of a nitrogen group have been synthesized by the method (ii) (Table 4). The method (iii) is effective to the synthesis of kinetically stabilized tricoordinate heavy ketones, although it cannot be applied to the synthesis of double-bond compounds between heavier group 14 elements and tellurium due to the instability of polytellurides (Table 3). The method (iv) can be used only when the unique dilithiometallanes can be generated (Table 3). The synthesis of heavy ketones by the method (v) demands the isolation of the corresponding heavy acyl chlorides as stable compounds (Table 5). 

Eleterostannenes can also be stabilized by intramolecular coordination by a nitrogen substituent. The four-coordinate stannylene shown in Equation (191) reacts with sulfur to give the dimeric thione, but with selenium or tellurium to give the five-coordinate monomeric yellow-orange selenone or red tellurone. The Sn=Se and Se=Te bonds, at 239.8 and... 

From what has just been said with regard to carbon, it is evident that the atomicity of an element is, apparently at least, not a fixed and invariable quantity thus nitrogen is sometimes equivalent to five atoms of hydrogen, as in ammonic chloride, (i H Cl), sometimes to three atoms, as in ammonia (N" H,), mid sometimes to only one atom, as in nitrous oxide (N,0). But it is found that this variation in atomicity always takes place by the disappearance or development of an even number of bonds thus nitrogen is either a pentad, a triad, or a monad phosphorus and arsenic, either pentads or triads carbon and tin, either tetrads or dyads and sulphur, selenium, and tellurium, either hexads, tetrads, or dyads. 

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