Crystal structure, Hirshfeld surface analysis, and physicochemical studies of a new Cu(II) complex with 2-amino-4-methylpyrimidine

International audienceThe chemical preparation, crystal structure, magnetic study and spectroscopic characterization of the new Cu(II) complex with the monodentate ligand 2-amino-4-methylpyrimidine [Cu2(CH3COO)4(C5N3H7)2] are reported. The copper atoms are surrounded by one nitrogen atom from one 2-amino-4-methylpyrimidine ligand and four oxygen atoms of CH3COO − groups yielding to a penta-coordination of the metal ion. In the structural arrangement, the amino group and the pyrimidine nitrogen atom of neighboring molecules are linked together through a pair of N-H…N hydrogen bonds forming a 1-D corrugated chain running along the [111] direction wherein the complex molecules are located parallel to the (a, c) plane at z = ½. Intermolecular interactions were investigated by Hirshfeld surfaces and contact enrichment tools. Mulliken charge distribution, molecular electrostatic potential (MEP) maps and HOMO and LUMO energy gaps have been computed. The vibrational absorption bands were identified by infrared spectroscopy. Magnetic properties were also studied to characterize the complex

Solvent dependent nuclearity of manganese complexes with a polydentate hydrazone-based ligand and thiocyanate anions

The reaction of Mn(II) chloride with the 2-benzoylpyridyl-(2-picolyl)-hydrazone ligand (HL) and thiocyanate anions in different solvent systems affords mono- [Mn(HL)2(SCN)2] (1), di- [Mn2(HL)2(SCN)4] (2) and a tetra-nuclear complex [Mn4(L)4(SCN)4].2(CH3CN) (3) with concomitant different coordination modes of the ligands. Remarkably, the nuclearity of the complexes only depends on the solvent used, ethanol for 1, n-propanol for 2 and acetonitrile for 3. The complexes have been characterized by elemental analysis, IR spectroscopy technique and the molecular structures determined by single crystal X-ray analysis. In 1 and 2 the ligands are present in its neutral form, while they are deprotonated in 3, but more significantly in all structures a different denticity of ligands was detected: in complex 1 one molecule is tridentate coordinated though the N,N,O donor set, the other bidentate through N,O; in 2 the ligands is of N,N,O-tridentate; finally in 3 each ligand, acting as N,N,O,N-tetradentate species, bridges two metals to form a tetranuclear assembly. The crystal structures have been described using the Hirshfeld surface analysis. Finally, we have studied the ability of the thiocynato ligand to participate in H-bonding and C\u2013H/\u3c0 interactions by means of DFT calculations (B3LYP/6-31+G 17 17)

Methoxido‐Bridged Lacunary Heterocubane Oxidovanadium(IV) Cluster with Azo Ligands: Synthesis, X‐ray Structure, Magnetic Properties, and Antiproliferative Activity

The new μ 3 ‐methoxido bridged trinuclear vanadium(IV) complexes [V IV 3 O 3 (μ 3 ‐OMe)(μ 2 ‐OMe) 3 (L 1,2 ) 2 ] ( 1 and 2 ) have been synthesized using the azo ligands 1‐(2‐(thiazol‐2‐yl)diazenyl)naphthalene‐2‐ol (HL 1 ) and 2‐(2‐(thiazol‐2‐yl)diazenyl)‐4‐methylphenol (HL 2 ). X‐ray crystallography revealed a trinuclear structure with a lacunary heterocubane {(VO) 3 (μ 3 ‐OMe)(μ 2 ‐OMe) 3 } 2+ core unit for complex 1 , which contains a central μ 3 ‐methoxido bridge. All three vanadium centers are in a slightly distorted octahedral coordination environment. Magnetic and theoretical studies reveal an antiferromagnetic coupling between the three vanadium(IV) centers within the triangular arrangement in 1 . The complexes were also screened for in vitro cytotoxicity study against HeLa and HT‐29 cancer cell lines. The results indicated that both the complexes are cytotoxic but possess varying specificity towards different cell types

3D Printing & Open Access Databases for Crystallographic College Education

Presentation gives an overview of available open access databases of crystals and crystal structures, as well as discussions of how newly developed 3D printing technologies can be used to teach crystallography at the college level. Offers advice regarding conversion of crystallographic information files to 3D printing files, and shares news from the 3D printing of crystallographic models community

Crystallographic Education in the 21st Century

There are many methods that can be used to incorporate concepts of crystallography into the learning experiences of students, whether they are in elementary school, at university or part of the public at large. It is not always critical that those who teach crystallography have immediate access to diffraction equipment to be able to introduce the concepts of symmetry, packing or molecular structure in an age- and audience-appropriate manner. Crystallography can be used as a tool for teaching general chemistry concepts as well as general research techniques without ever having a student determine a crystal structure. Thus, methods for younger students to perform crystal growth experiments of simple inorganic salts, organic compounds and even metals are presented. For settings where crystallographic instrumentation is accessible (proximally or remotely), students can be involved in all steps of the process, from crystal growth, to data collection, through structure solution and refinement, to final publication. Several approaches based on the presentations in the MS92 Microsymposium at the IUCr 23rd Congress and General Assembly are reported. The topics cover methods for introducing crystallography to undergraduate students as part of a core chemistry curriculum; a successful short-course workshop intended to bootstrap researchers who rely on crystallography for their work; and efforts to bring crystallography to secondary school children and non-science majors. In addition to these workshops, demonstrations and long-format courses, open-format crystallographic databases and three-dimensional printed models as tools that can be used to excite target audiences and inspire them to pursue a deeper understanding of crystallography are described

Monomeric and dimeric oxidomolybdenum(V and VI) complexes, cytotoxicity, and DNA interaction studies: molybdenum assisted C═N bond cleavage of salophen ligands

Four novel dimeric bis-μ-imido bridged metal–metal bonded oxidomolybdenum(V) complexes [MoV2O2L′21–4] (1–4) (where L′1–4 are rearranged ligands formed in situ from H2L1–4) and a new mononuclear dioxidomolybdenum(VI) complex [MoVIO2L5] (5) synthesized from salen type N2O2 ligands are reported. This rare series of imido- bridged complexes (1–4) have been furnished from rearranged H3L′1–4 ligands, containing an aromatic diimine (o-phenylenediamine) “linker”, where Mo assisted hydrolysis followed by −C═N bond cleavage of one of the arms of the ligand H2L1–4 took place. A monomeric molybdenum(V) intermediate species [MoVO(HL′1–4)(OEt)] (Id1–4) was generated in situ. The concomitant deprotonation and dimerization of two molybdenum(V) intermediate species (Id1–4) ultimately resulted in the formation of a bis-μ-imido bridge between the two molybdenum centers of [MoV2O2L′21–4] (1–4). The mechanism of formation of 1–4 has been discussed, and one of the rare intermediate monomeric molybdenum(V) species Id4 has been isolated in the solid state and characterized. The monomeric dioxidomolybdenum(VI) complex [MoVIO2L5] (5) was prepared from the ligand H2L5 where the aromatic “linker” was replaced by an aliphatic diimine (1,2-diaminopropane). All the ligands and complexes have been characterized by elemental analysis, IR, UV–vis spectroscopy, NMR, ESI- MS, and cyclic voltammetry, and the structural features of 1, 2, 4, and 5 have been solved by X-ray crystallography. The DNA binding and cleavage activity of 1–5 have been explored. The complexes interact with CT-DNA by the groove binding mode, and the binding constants range between 103 and 104 M–1. Fairly good photoinduced cleavage of pUC19 supercoiled plasmid DNA was exhibited by all the complexes, with 4 showing the most promising photoinduced DNA cleavage activity of ∼93%. Moreover, in vitro cytotoxic activity of all the complexes was evaluated by MTT assay, which reveals that the complexes induce cell death in MCF-7 (human breast adenocarcinoma) and HCT-15 (colon cancer) cell lines