Distibine ditelluride

Ditellurides, also in the fifth period, seem quite analogous to distibines. Like tetraphenyldistibine (1) the red diphenylditelluride (56) does not associate in the solid state. The closest intermolecular Te---Te contact is 4.255 A, near the van der Waals separation of 4.40 A 61). On the other hand, di(p-methoxyphenyl)ditelluride (57), which has a brown-green metallic luster in the solid, has close intermolecular Te---Te contacts of 3.57 and 3.98 A (62). The ratio Te---Te/Te—Te is 1.32. Just as in the distibines the intermolecular bonding in ditellurides is sensitive to substitution. It is also interesting to note that the intermolecular interaction in ditellurides and dihalogens occurs normal to the metal-metal axis, as well as colinear as in distibines (63). Thus, it is clear that the intermolecular association shown by distibines is a general property of many of the diatomic like compounds of the heavier main group elements. 

Distibines and dibismuthines (R2MMR2 M = Sb, Bi) react with disulfides, diselenides and ditellurides (R EER E = S, Se, Te) to form R2MER (equation 103"°). The experimental procedure for the preparation of Me2SbTe(Tol-p)" has been described in detail. 

Diheteroatom compounds, such as dimethyl ditelluride, diphenyl ditelluride, tetramethyl distibine, tetraphenyl distibine, and 2,6-dimesitylphenylthiodiphenylbismuthine 2 (Scheme 5), were used as cocatalysts to increase the MWD control. As these cocatalysts do not generate initiating radical species for the polymerization, a binary system consisting of an... 

Addition of ditellurides and distibines in TERP and SBRP, respectively, is effective for increasing MWD control in styrene and especially in methacrylate polymerization, as mentioned in the previous section. Thiobisumthine 2 is also effective for the controlled s)mthesis of ultrahigh molecular weight polymers. 

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