3003-15-4Relevant academic research and scientific papers
A structural investigation of dimethylthallium(III) thiolate and selenolate rings and polymers
Briand, Glen G.,Decken, Andreas,Hunter, Nicole M.,Wright, John A.,Zhou
, p. 5430 - 5436 (2012/01/13)
The effects of increased steric bulk in dimethylthallium(III) chalcogenolates on oligomerization was examined. The facile reaction of Me 3Tl with a series of benzenethiols and-selenols in toluene or thf resulted in the formation of [Me2/s
Structural effects of varied steric bulk in 2,(4),6-substituted dimethylthallium(III) phenoxides
Briand, Glen G.,Decken, Andreas,McKelvey, J. Ian,Zhou, Yukun
, p. 2298 - 2305 (2011/08/03)
The structural effects of varied steric bulk on 2,(4),6-substituted dimethylthallium(III) phenoxides has been examined. The facile reaction of Me3Tl with a series of 2,(4),6-substituted phenols in toluene or diethyl ether resulted in the formation of the species [Me2TlO(2,6- R2C6H3)]2 [R = H (4), Me (5), iPr (6), Ph (7)] and [Me2TlO(2,4,6-tBu3C6H 2)] (8). All compounds have been characterized by elemental analysis as well as their melting point; FTIR, FT-Raman, solution 1H and 13C{1H} NMR spectroscopy; and X-ray crystallography. The structures of 4-7 are dimeric through short intermolecular Tl-O interactions, which yield a symmetric Tl2O2 unit and a distorted seesaw C2O2 bonding environment for thallium. An increase in the steric bulk in 4-6 has little effect on Tl-O bond lengths, whereas the C Me-Tl-CMe bond angle was found to significantly decrease. Further, the phenoxide ligands in 5 and 6 were found to be oriented perpendicular to the Tl2O2 unit to minimize steric interactions. Alternatively, compound 7 shows an increase in Tl-O bond lengths and an increase in the CMe-Tl-CMe bond angle compared to 4-6, and orientation of the phenoxide ligands perpendicular to the Tl 2O2 core. The significant steric bulk imposed by the -O(2,4,6-tBu3C6H2) ligand in 8 precludes dimer formation and allows for isolation of a monomeric species that contains a three-coordinate T-shaped C2O bonding environment for thallium. DFT calculations show that the energetic favorability of dimer formation decreases with increased phenoxide steric bulk.
Polymorphism in the crystal structures of the group 13 trimethyls
Boese, Roland,Downs, Anthony J.,Greene, Timothy M.,Hall, Alexander W.,Morrison, Carole A.,Parsons, Simon
, p. 2450 - 2457 (2008/10/08)
Crystal structure have been determined for trimethylboron, BMe3, and for a new polymorph of trimethylgallium, GaMe3; in addition, the crystal structure of trimethylthallium, TlMe3, has been redetermined. The BMe3 crystal structure represents a new structural type for the group 13 trimethyl derivatives in the solid state. In contrast to its heavier analogues, it consists of layer containing only very weakly interacting BMe3 molecules. GaMe3 forms a ladder-like pseudo-polymer via long gallium-to-methyl intermolecular interactions with Ga...C distances in the range 3.096(3)-3.226(4) A. This is compared with a recently reported crystal structure of a polymorph, which, like InMe3 and TlMe3, is characterized by the formation of pseudo-tetramers. The effects of crystallization and secondary interactions have been analyzed by comparison with related crystallographic, gas-phase electron diffraction, and spectroscopic studies of these and other trimethyl derivatives of the group 13 elements. The energetic differences between polymorphs of BMe3, GaMe3, and InMe3 have been explored by plane wave DFT calculations. The energy differences between the BMe3-like layered structure and the InMe3-like pseudo-tetrameric structure are calculated to be -1.7, +3.6, and +10.4 kJ mol-1 for BMe3, GaMe3, and InMe3, respectively.
