Structural motifs of diiodine complexes with amides and thioamides

Abstract

The reaction of 2-pyrimidone hydrochloride ([C(4)H(5)N(2)O](+)[Cl](-) or [PMOH(2)](+)[Cl](-)) with diiodine in a dichloromethane-methanol solution resulted in the formation of ([C(4)H(5)N(2)O](+))(2)[I(2)Cl(2)](2-) (1) complex. The compound was characterized by elemental analysis, FT-IR, DTA-TG and conductivity titrations. The crystal structure of 1 was also determined by X-ray diffraction at 294(1) K. Compound 1 is monoclinic, space group P2(1)/n, consisting of two cationic [PMOH(2)](+) species and a [I(2)Cl(2)](2-) counter dianion. The cation is in its keto form. Direct reaction of thiazolidine-2-thione (tzdtH), with diiodine in dichloromethane solution, on the other hand, led to the formation of a crystalline solid which contained two complexes of formulae [(tzdtH)(2)I](+)[I(3)](-).2I(2) (2) and [(tzdtH)I(2)](2).I(2) (2a) in a ratio of 90 to 10%. Complex 2a was characterized by X-ray analysis at 180(2) K. Compound is monoclinic, space group C2/c and contains two units of [(tzdtH)I(2)] "spoke" structures. Compound 1, as well as the known species iodonium salt [(tzdtH)(2)I](+)[I(3)](-).2I(2) (2) and the charge transfer (CT) iodine complexes of formulae [(bztzdtH)I(2)] (3) and [(bztzdtH)I(2)].I(2) (4) (bztzdtH = 2-mercaptobenzothiazole) with "spoke" and extended "spoke" structures respectively, were tested for their oxidizing activity towards 3,5-di-tert-butylcatechol to 3,5-di-tert-butyl-o-benzoquinone.

Inhibition of peroxidase-catalyzed iodination by thioamides: experimental and theoretical study of the antithyroid activity of thioamides

“…(d) The ability of some of the thioamides to inhibit iodothyronine deiodinase (ID-1), an enzyme responsible for the monodeiodination of the T4 prohormone to the active hormone T3, as proposed by du Mont et al 21 The kinetic study of the thioamide action performed here on LPO showed that the degree of inhibition ranges from 3.62 mM as highest value (DTUC) to 1155.25 mM for the lowest (THP) ( Table 3). [1][2][3][4][5][6][7][8][9] NMBZT shows also a relatively high percent of inhibition (20.2%). 3,[21][22][23] The study of the inhibition of the catalytic effect of FeTPPCl (model for the active site of TPO), confirmed the kinetic study results of LPO above.…”

“…3,[21][22][23] The study of the inhibition of the catalytic effect of FeTPPCl (model for the active site of TPO), confirmed the kinetic study results of LPO above. [1][2][3][4][5][6][7][8][9] DFT calculations of the geometric and energetic profiles of the inhibition process revealed that the thermodynamically and kinetically favored reaction pathway for both the quartet and sextet states involves as a first step the coordination of H 2 O 2 to FeTPPCl complex followed by the elimination of H 2 O to yield [FeCl(TPP)(OI)] À complex, which upon elimination of Cl À affords the intermediate FeTPP(OI) complex. [1][2][3][4][5][6][7][8][9] NMBZT shows also a relatively high percent of inhibition (20.2%).…”

“…5 9 The compounds that show very low inhibition are PyOH, PTU, PyTU, THP, CMBZT and MPmCl. The crystal structure of NMBZT occurs in two forms the spoke structure [LI 2 ] and the iodonium salt 1.…”

Recent Discoveries of Polyhalogen Anions – from Bromine to Fluorine

“…The only known non‐classical interhalide dianion is [Cl–I–I–Cl] 2– , which is formed in the reaction of 2‐pyrimidone hydrochloride with elemental iodine 95. Like the other tetrahalide dianions [Cl–I–I–Cl] 2– is linear.…”

Solvent mediated reaction of 1-methyl-1H-tetrazoline-5-thione with iodine

“…The adiabatic ionization potentials of heteroaromatic thiones are rather low due to which they are readily oxidized to form radical cations or thiyl radicals as a result of the loss of the hydrogen atom from thione [11]. Ability of heteroaromatic thioamides to interact with iodine, stoichiometry and stability of charge transfer complexes, molecular and crystal structures have been studied by several authors [12][13][14][15][16][17][18][19].…”