TCTMB

Powder and single-crystal 2H NMR experiments were also carried out to study the phase transitions of l,2,3-trichloro-4,5,6-trimethylbenzene TCTMB d3203 and o -dich 1 o rotelramethylbenzene DCTMB <712.204 which show considerable dynamical disorder in their room temperature phase. 

Fig. 16. Schematic of the occupation probabilities in phase II of TCTMB and DCTMB. From left to right molecules under study, three well potential, averaged quadrupolar interaction and asymmetry parameters measured from powders spectra, occupations probabilities calculated from single-crystal experiments.

The monomer tri-isocyanto-trimethyl-borazine (TITMB) was synthesized from trichloro-trimethyl-borazine (TCTMB) according to the method reported in the literature [12]. The Intermediate TCTMB was synthesized via a modification of the procedure of Brown and Laubengayer [13]. Methyl-amine hydrochloride and excess of BCI3 were refluxed in chlorobenzene for 6h and then maintained for 16h at 80°C. The reaction mixture was filtered warm, vacuum dried and subsequently sublimed under reduced pressure. A slight increase in yield (12%) of pure TCTMB was achieved. 

The pure TCTMB was then reacted with silver cyanate to obtain TITMB. 

A pioneer effort to the account for electrostatic interaction effects in dipole reorientations and correlation functions was made by Brot and Darmon (39) in their Monte Carlo simulations for the partially ordered solid phase of 1 2 3 trichloro 4 5 6 trimethyl benzene (TCTMB) using the point charge model already mentioned in 2.4. Calculations of transition rates between 6 fold rotational wells of fluctuating depth as a result of changing neighbor orientations resulted in essentially Debye relaxation at 300 Kt but a second simulation at 186 K for which considerable rotational ordering is present produced very nearly a circular arc with od = 0.28 as compared to the experimental Ad = 0.39. 

The Brot-Darmon calculation is for solid rather than liquid like behavior on the plastic crystal phase of TCTMB as shown by the positive value of corresponding to an... 

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