Crystal structure of (E)-3-(1-iodoethylidene)-2,3-dihydro-[1,4]thiazino- [2,3,4-ij]quinolin-4-ium triiodide, C13H11I4NS

Abstract

Source of material 8-(But-2-yn-1-ylthio)quinoline was prepared by method described in [3] from sodium 8-quinolinethiolate with 1-bromobut-2-yne as alkylating agent. The title compound was synthesized by the reaction of 8-(but-2-yn-1-ylthio)quinoline with iodine. The solutions of iodine( 0.381g ,1 .5 mmol) and 8-(but-2-yn-1-ylthio)-quinoline (0.107 g, 0.5mmol) in dichloromethane (10 ml) were mixed. Single crystals for the X-ray diffraction study were obtained after keeping the resulting mixture at room temperature in closed flask for 48 hours, yield: 0.447 g(55 %). Experimental detailsPosition of theHatoms were calculated basedongeometric criteria (C-H =0.96 Åand 0.93 Åfor methyl and aromatic atoms, respectively) than have been placed in their calculated position and refined isotropically using ar iding modelw ith U iso (H) =1 .5 U eq (C) for methyl and U iso (H) =1.2 U eq (C) forall others. DiscussionTricyclic quinoline based systems, including sulfur-containing derivatives, are known as effective antibiotics [1-2]. Anumber of syntheses for 8-thioquinoline compounds with fused N-1/C-8 centers [3][4][5] werereported. Represented crystal structure can be aconvenient model for studying cation×××triiodide anion interactions [6][7] as it illustrates I×××Inon-covalent interactions involving terminal triiodide atomsa sd onors of electrons and iodine atom in =C12-I1 group as electron acceptor. This type of interactions can be attributed to halogen bonding [8].The asymmetric unit of title structure consists of one quinolinium derivative cation [C 13 H 11 INS] + and one triiodide anion. The six-membered ring, formeda st he result of cyclization process, deviates from planarity. TheC10 atom of methylene group is significantly out of plane (16.4°). Molecular conformation is stabilized by intramolecular contacts C13-H13c×××N1' (D×××Adistance of 2.957(7) Å; '=x,y,z), C10-H10b×××I1' (D×××Ad istance of 3.362(6) Å; '= x,y,z)a nd C13-H13A×××I1' (D×××Ad istance of 3.036(7) Å; '= x,y,z). The triiodide anion is symmetric and nearly linear with I2-I3 and I3-I4 distances of 2.9130(7) Åa nd 2.9114(7) Å; the I2-I3-I4 angle of 177.97(2)°. Terminal atom of triiodide involved in the short contact with iodine of =C12-I1 group: I4×××I1' (' =-x+2,y,-z+½; distance is 3.6988(6) Å, angle is close to right angle (82.62°)). This I×××Id istance is slightly longer than those values reported for triiodide -t riiodide interactions [9]. The triiodide anion is situated near the organic cation so that central I6 atom is locatedoverthe center of the p-system with centroid×××I3 distances of 3.81 Å. The axis of triiodide anions is inclined on 25.7°in respect to the plane of quinolinium ring. This mutual orientation is aresultofcharge-transfer interactions which favor location of iodide donor orbital toward the nitrogen or adjacent carbon of quinolinium rings. Aparticularly interesting feature of crystal packing is the formation of dimeric structural motifs represented by [C 13 H 11 INS] + organic cations and triiodide anions linked via C10-H10B×××I4' (H×...

Raman spectroscopy study of new thia- and oxazinoquinolinium triodides

“…68 Crystal structures were proven by X-ray diffraction experiments and described earlier. 13,[69][70][71] Herein, we can see various types of polyiodide organization: isolated slightly asymmetric triiodide 1 and asymmetric triiodide 2, which interact with the organic cation, and symmetric triiodide 3 and triiodide 4 as a part of the polyiodide formed as a result of Z-shaped I 3 À Á Á ÁI 2 interactions. These types of triiodide anions demonstrate the different crystal packing due to specific non-covalent interactions, thus we can presume their different spectral properties.…”