Chemical-Shift Standards for 199Hg NMR Spectroscopy, 25 Years Later

While 199Hg NMR is a well-established tool for elucidating details of coordination chemistry in biochemical and inorganic complexes, historically the technique has been associated with the use of an extremely toxic chemical, dimethylmercury [Me2Hg or (CH3)2Hg], as a reference standard. In the 25 years since an accidental exposure to Me2Hg led to the tragic death of Dr. Karen Wetterhahn, the community has learned a great deal about the insidious neurotoxicity of this compound as well as more appropriate ways to avoid exposure. Here, we track the general shift toward the use of alternative mercury reference standards and away from Me2Hg.

Facile luminescent tuning of ZnII/HgII complexes based on flexible, semi-rigid and rigid polydentate Schiff bases from blue to green to red: structural, photophysics, electrochemistry and theoretical calculations studies

The photophysical properties of Zn^II/Hg^II Schiff base complexes could be tuned by changing the ligand structures.

Synthesis, crystal structures, and luminescence properties of seven tripodal imidazole-based Zn/Cd(ii) coordination polymers induced by tricarboxylates

New structural patterns made from the “old-fashioned” ligand 1,3,5-tris(1-imidazolyl)benzene have been obtained using three asymmetric V-shaped tricarboxylate ligands together with different metals.

Twin applications of highly selective Cu2+ fluorescent chemosensor and cytotoxicity of 2-(2-phenylhydrazono)-1H-indene-1,3(2H)-dione and 2-(2-(4-methoxyphenyl)hydrazono)-1H-indene-1,3(2H)-dione: molecular docking and DFT studies

Turn on chemosensor for paramagnetic Cu²⁺ have been developed based on indene 1,3-dione. Their ability to inhibit KB cell, molecular docking and DFT studies also carried out.

Pd(II) and Pt(II) Coordination Chemistry with Hybrid Pyridine-Pyrazole Ligands: from 3D-Frameworks Structures in Molecular Complexes

In this paper we studied the reaction of ligands 2-[5-phenyl-1-(3,6,9-trioxodecane)-1H-pyrazol-3-yl]pyridine (L1) and 3,5-bis(2-pyridyl)-1-(3,6,9-trioxodecane)-1H-pyrazole (L2) with [MCl2(CH3CN)2] (M = Pd(ii), Pt(ii)), to obtain monomeric complexes [MCl2(L)] (M = Pd(ii): L = L1 (1), L = L2 (2); M = Pt(ii): L = L1 (3), L = L2 (4)). Additionally, the reaction of [Pd(CH3COO)2] with L1 (5) and L2 (6) was also studied pointing out dimeric structures with bridged acetates between the Pd(ii) atoms. All complexes were characterised by elemental analyses, conductivity measurements, infrared spectroscopy (IR), 1H, 13C{1H}, and 195Pt{1H} NMR spectroscopies, and electrospray ionisation mass spectrometry (MS-ESI(+)). The crystal structure of complex [PtCl2(L1)] (3) was determined by X-ray diffraction methods; it consists of a mononuclear complex where L1 acts as a bidentate chelate ligand. Moreover, we also studied the extended structure observing that the ether, present in the alkyl chain of the ligand, chlorine, and platinum moieties play a fundamental role in the final disposition of the supramolecular structure. All these results show how the design of an appropriate hybrid ligand can strongly influence the structural control of the molecular packing.

TALP: a multisolution direct-space strategy for solving molecular crystals from powder diffraction data based on restrained least squares

TALP is a new direct-space strategy forab initiocrystal structure determination of molecular crystals from powder diffraction data. The strategy is based on a preliminary exploration stage, which considers atomic overlap, followed by a subsequent stage of local incremental scans, both coupled to fast restrained least-squares minimizations with the atomic coordinates as refined parameters. The observed intensities are extracted from the powder pattern by a three-step procedure [Vallcorba, Rius, Frontera, Peral & Miravitlles (2012).J. Appl. Cryst.45, 844–848], and the molecular model and distance restraints are derived from molecular mechanics calculations or from similar reported structures. The solution process consists of several independent trials, each one resulting in a crystal structure proposal with an associated figure of merit. TALP has been tested on laboratory X-ray powder diffraction data of 14 molecular compounds of known crystal structure and of variable complexity. In most cases, the crystal structure is solved in a short time (less than an hour), even for calculated models. For the most complex structures (e.g.13 torsion angles), the general scan is assisted by a rotation function, which provides a ranked list of most probable model orientations. In this way only the positional and conformation parameters need to be explored.