Reported are multi-component one-pot syntheses of chiral complexes [M(L(R) OR')Cl2 ] or [M(L(R) SR')Cl2 ] from the mixture of an N-substituted ethylenediamine, pyridine-2-carboxaldehyde, a primary alcohol or thiol and MCl2 utilizing in-situ formed cyclized Schiff bases where a C-O bond, two stereocenters, and three C-N bonds are formed (M=Zn, Cu, Ni, Cd; R=Et, Ph; R'=Me, Et, nPr, nBu). Tridentate ligands L(R) OR' and L(R) SR' comprise two chiral centers and a hemiaminal ether or hemiaminal thioether moiety on the dipicolylamine skeleton. Syn-[Zn(L(Ph) OMe)Cl2 ] precipitates out readily from the reaction mixture as a major product whereas anti-[Zn(L(Ph) OMe)Cl2 ] stays in solution as minor product. Both syn-[Zn(L(Ph) OMe)Cl2 ] and anti-[Zn(L(Ph) OMe)Cl2 ] were characterized using NMR spectroscopy and mass spectrometry. Solid-state structures revealed that syn-[Zn(L(Ph) OMe)Cl2 ] adopted a square pyramidal geometry while anti-[Zn(L(Ph) OMe)Cl2 ] possesses a trigonal bipyramidal geometry around the Zn centers. The scope of this method was shown to be wide by varying the components of the dynamic coordination assembly, and the structures of the complexes isolated were confirmed by NMR spectroscopy, mass spectrometry, and X-ray crystallography. Syn complexes were isolated as major products with Zn(II) and Cu(II) , and anti complexes were found to be major products with Ni(II) and Cd(II) . Hemiaminals and hemiaminal ethers are known to be unstable and are seldom observed as part of cyclic organic compounds or as coordinated ligands assembled around metals. It is now shown, with the support of experimental results, that linear hemiaminal ethers or thioethers can be assembled without the assistance of Lewis acidic metals in the multi-component assembly, and a possible pathway of the formation of hemiaminal ethers has been proposed.

A series of eight tris-arylthiotriazines were synthesized to study the lone pair-π interaction between the triazine ring centroid of these molecules and halogenated solvents. All the eight compounds were characterized using 1 H and 13 C NMR spectroscopy and single crystal X-ray diffraction techniques. All these compounds show interesting structural properties in the solid state. Unprecedented Janus head type lp⋯π⋯lp and S⋯F⋯S interactions were observed between one of the tris-arylthiotriazines and hexafluorobenzene.4438 | CrystEngComm, 2016, 18, 4438-4444 This journal isChart 1 Piedfort units of tris-aryloxotriazines (TArOTz) with 3-fold symmetry (C 3IJg) , C 3i , and D 3 ) 17-21,23-25 and the motif anticipated and observed in the present work for tris-arylthiotriazines (TArTTz).Scheme 1 Tris-1,3,5-arylthiotriazines (TArTTz) synthesised for the present study and the schematic diagram of the observed synergism of fluorine bonding and lone pair-π interactions. CrystEngCommPaper

By a new sustainable strategy, sulfur dioxide (SO2) was converted at room temperature into sulfuric acid by taking advantage of the spontaneous aerial oxidation of benzothiazoline into benzothiazole. 2-(4-Methoxy­phenyl)­benzo­thiazoline (HL) was reacted with SO2 at room temperature, and the adduct upon reaction with aerial oxygen produced 2-(4-methoxy­phenyl)­benzo­thiazolium bisulfate. The same strategy was applied on [CdL2] and [ZnL2] and found to work better than neat benzothiazoline. Bunte salt, S-(2-((pyridin-1-ium-2-ylmethyl)­amino)­phenyl) thiosulfate, was obtained upon reacting SO2 with 2-(pyridin-2-yl)-2,3-dihydro­benzo­thiazole which is an important clue for the intermediates involved in the S-oxygenation of SO2 bound on electron rich centers. This sustainable route offers a new avenue of utilizing the suicidal reaction of benzothiazoline into benzothiazole in the activation of SO2 with the help of aerial oxygen.

A group of symmetrically‐trisubstituted‐1,3,5‐triazine‐based molecules have been studied extensively in order to create Piedfort pairs that are intended to be employed in sequestration of small molecules. Extensive inter and intramolecular interactions observed in the solid‐state of the studied triazine molecules lead to the formation of one‐dimensional ribbon and two‐dimensional sheet motifs. Koneramine formation was applied as a new strategy to increase the bulkiness of the substituents on 1,3,5‐triazine ring that prevented the formation of ribbons and sheets yet yielded hydrogen‐bonded dimer. The protonated forms of one of the triazine compound showed that the triazine ring nitrogens are more basic than amine nitrogens on the periphery; protonated N2,N4,N6‐triphenyl‐1,3,5‐triazine‐2,4,6‐triamine resulted in eccentric Piedfort pairs that displayed aesthetic structural patterns possessing variety of inter and intramolecular interactions including stacking between electron deficient triazine ring of one member and electron rich aryl ring of another member.

By employing a simple strategy of reacting SO2 gas with easily attainable hydride donors such as 2-substituted-1,3-dimethyl-2,3-dihydro-1H-benzo­[d]­imidazole, benzimidazoline and SO2 were converted into benzimidazolium bisulfate at room temperature and atmospheric pressure. Bisulfate originated from SO2 and hydride from benzimidazoline and aerial oxygen. Metastable dimers of bisulfate anions were observed in the solid state and in solution where the anions are not stabilized by encapsulation in cages but through hydrogen bonding from benzimidazolium cations. All three benzimidazolines and resulted benzimidazolium bisulfates have been characterized using 1H and 13C NMR spectroscopy, high-resolution electrospray ionization mass spectrometry, and single crystal X-ray diffraction techniques.