Iodinated Aluminum(III) Corroles with Long-Lived Triplet Excited States

The first reported iodination of a corrole leads to selective functionalization of the four C–H bonds on one pole of the macrocycle. An aluminum(III) complex of the tetraiodinated corrole, which exhibits red fluorescence, possesses a long-lived triplet excited state

Tetrabenzylcyclen as a receptor for fluoride

A tetraazacyclic ligand, tetrabenzylcyclen (L), was synthesized using an improved method with a higher yield by treatment of cyclen with benzylchloride in the presence of potassium carbonate. The reaction of L with an aqueous solution of fluorosilicic acid yielded a mixed-anionic salt with the composition [H3L][F][SiF6]$4H2O (1). The single crystal X-ray study revealed that the macrocyclic trication essentially changes the conformation compared to the free ligand in order to tightly accommodate the fluoride inside and to keep the hexafluorosilicate anions and water molecules outside in the solid state complex

Preparation, structure and properties of pyridinium/bipyridinium hexafluorosilicates

Pyridinium hexafluorosilicates with the compositions (LH)2[SiF6] (where L = 2,6-bis(hydroxymethyl)-pyridine (I), 4,5-bis(hydroxymethyl)-2-methylpyridine-3-ol (II)), monohydrate (LH)2[SiF6]H2O (L = 2-bromo-6-methylpyridine (III)) and (LH2)[SiF6] (L = 4,40-bipyridine (IV), 2,20-bipyridine (V)) were separated as crystalline products of interaction of fluorosilicic acid with different pyridines. All compounds were characterized by elemental analysis, IR, NMR 19F and mass-spectrometry, solubility data, and X-ray crystallography. The structural study revealed the details of the anion binding and solid state supramolecular architectures provided by the combination of the plethora of intermolecular interactions including strong charge assisted and conventional hydrogen bonds of NH F, OH F types along with O Br contacts and p–p interactions. The relationship between the salts structure and physico-chemical properties is discussed

Mono(imidazolin-2-iminato) Titanium Complexes for Ethylene Polymerization at Low Amounts of Methylaluminoxane

The polymerization of ethylene with titanium complexes bearing one bulky imidazolin-2-iminato ligand (L) in the presence of MAO and/or TTPB as cocatalysts have been explored. The complex LTiCl3 and its methylated forms were prepared to shed light on the

Unexpected molecular flip in solid-state photodimerization.

Three cocrystals of the light-stable compound 1,1,6,6-tetraphenyl-2,4-hexadiyne-1,6-diol (I) with light-sensitive molecules 1,2-dimethyl-2(1H)-pyridinone (a), 6-methyl-2(1H)-pyridinone (b), and 2-methyl-2(1H)-pyridinone (c) were exposed to UV light. The light-sensitive molecules undergo molecular flip. The estimated activation energy of the flip is 9.72 kJ/mol. The kinetics of the reaction of I-c was studied showing sigmoidal behavior with Avrami exponent of n = 0.95(6), suggesting homogeneous reaction

Unexpected Molecular Flip in Solid-State Photodimerization

Three cocrystals of the light-stable compound 1,1,6,6-tetraphenyl-2,4-hexadiyne-1,6-diol (I) with light-sensitive molecules 1,2-dimethyl-2(1H)-pyridinone (a), 6-methyl-2(1H)-pyridinone (b) and 2-methyl-2(1H)-pyridinone (c) were exposed to UV light. It was found that the molecules undergo molecular flip perpendicular to the molecular plane (rotation of ∼180°). In the first two cocrystals, the light-sensitive molecules are disordered, which means that the space provided for them is larger than needed for ordered molecules. Therefore, rotation can take place. Moreover, in I-b, the flip is temperature dependent and takes place without exposure to UV light. Crystal structures at four different temperatures enable one to estimate the activation energy of the flip to be 9.72 kJ/mol. The kinetics of the reaction of I-c was studied at room temperature and revealed a sigmoidal behavior with Avrami exponent of n = 0.95(6) that could be explained by the JMAK model for crystal growth. It means that the nucleation rate is constant over time and that the reaction is homogeneous with equal probability to occur in any region of the sample. This could be explained by the fact that the voids where the reaction and the flip take place are isolated from each other