138380-52-6Relevant academic research and scientific papers
A STUDY ON THE DONATING PROPERTIES OF 4,5,6,7-TETRATHIOCINODIIMIDAZOLYL-1,3,8,10-TETRAPHENYL-2,9-DITHIONE (Ph4todit) TOWARDS I2. CRYSTAL AND MOLECULAR STRUCTURE OF Ph4todit*CHCl3
Bigoli, Francesco,Deplano, Paola,Mercuri, Maria Laura,Pellinghelli, Maria Angela,Trogu, Emanuele F.,Vacca, Alberto
, p. 53 - 64 (2007/10/02)
The X-ray structure of Ph4todit*CHCl3 (the title molecule) has shown that the crystals are monoclinic, space group P21/n, a = 13.393(5), b = 20.764(6), c = 12.286(5) Angstroem, β = 97.88(2) deg, V = 3384(2) Angstroem3, Z = 4.Solution and refinement of intensity data gave final residuals of R = 0.0551 and Rw = 0.0680, using 2958 observed reflections 2?(I)>.A comparison with the previously reported structural data of the corresponding tetraethyl substituted compound (Et4todit) shows that the only significant differences are observed for the N-C-C-N torsion angle (63.5(7) deg, -70(1) deg in the Et derivative), and for the values of the torsion angles indicating the orientation of the substituents with respect to the imidazoline ring plane.A spectrophotometric study on the reaction between diiodine and Ph4todit in CHCl3 has shown the formation of a 1:1 charge-transfer complex.A computer program has been used to refine the formation constant at six different temperatures and the extinction coefficients in the 260-520 nm range.The enthalpy of formation (ΔH0 = -3.9(2) Kcal mol-1) falls in usual thione-diiodine complexes range.In the solid state a microcrystalline solid characterized as Ph4todit*2I2*2CHCl3 has been isolated.FT-Raman spectra on this solid compound show a very strong band attributed to ν(I-I) at 172 cm-1.A comparison with the donor behaviour of Et4todit shows that the very small differences detected by means of u.v. visible measurements, suggesting the sequence order Et4todit > Ph4todit, are supported by FT-Raman results, which indicate that the donation of Et4todit produces a lengthening of the I-I distance (ν(I-I) at 147 cm-1) larger than in Ph4todit.Key words: Charge-transfer; diiodine; formation constants; X-ray; imidazolyl-thiones.
