Non-covalent polymerisation in the solid state: halogen–halogenvs. methyl–methyl interactions in the complexes of 2,4-di(2-pyridyl)-1,3,5-triazine ligands

X-ray Structure Analyses and Biological Evaluations of a New Cd(II) Complex with S-Triazine Based Ligand

The crystal structure of a new penta-coordinated Cd(II) complex of the formula [Cd(BPMT)Br2] was presented. This Cd(II) complex was synthesized by mixing Cd(NO3)2·4H2O and 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (BPMT) in the presence of KBr. It crystallized in the monoclinic crystal system and P21/n space group. The crystal parameters are a = 11.3680(8) Å, b = 11.1648(8) Å, c = 15.8593(11) Å, and β = 103.563(2)°, while the unit cell volume is 2190.6(12) Å3 and it comprised four molecules. The supramolecular structure of the [Cd(BPMT)Br2] complex is mainly controlled by the intermolecular Br∙∙∙H interactions. Hirshfeld calculations predicted the H∙∙∙H (38.1%), Br∙∙∙H (24.3%), C∙∙∙H (11.1%), and N∙∙∙H (9.5%) interactions are the most dominant. Biological evaluations for the antimicrobial and anticancer properties of the studied complex are presented. The Cd(II) complex has better anticancer and antibacterial activities than the free BPMT ligand. The anticancer activity against lung carcinoma (A-549) is higher for the former (18.64 ± 1.09 µg/mL) compared to the latter (372.79 ± 13.64 µg/mL). Additionally, the best antibacterial activity for the Cd(II) complex was found against B. subtilis.

Achieving dynamic behaviour and thermal expansion in the organic solid state via co-crystallization

Molecular motion of an azo functional group is ‘unlocked’ via co-crystallizations.

Thermal expansion involves a response of a material to an external stimulus that typically involves an increase in a crystallographic axis (positive thermal expansion (PTE)), although shrinking with applied heat (negative thermal expansion (NTE)) is known in rarer cases. Here, we demonstrate a means to achieve dynamic molecular motion and thermal expansions in organic solids via co-crystallizations. One co-crystal component is known to exhibit dynamic behaviour in the solid state while the second, when varied systematically, affords co-crystals with linear thermal expansion coefficients that range from colossal to nearly zero. Two co-crystals exhibit rare NTE. We expect the approach to guide the design of molecular solids that enable predesigned motion related to thermal expansion processes.

A family of Ru(ii) complexes built on a novel sexipyridine building block: synthesis, photophysical properties and the rare structural characterization of a triruthenium species

A new sexipyridine ligand and its Ru(ii) family of complexes is described along with its characterization by electrochemical and photophysical methods as well as a rare X-ray analysis of a triruthenium polypyridine complex.

Role of Fluorine in Weak Interactions in Co-crystals

The presence of the C–F bond (commonly referred to as organic fluorine) in a large number of pharmaceutically relevant compounds suggests that it may be used in the production of novel salts and co-crystals that have intermolecular interactions involving fluorine. There is an ongoing debate in this context as fluorine is characterized by its high electronegativity, relatively small size and very low polarizability. The propensity of hydrogen to participate in generating highly directional and energetically stable hydrogen bonds has been exploited in the design of co-crystals and salts of many pharmaceutical compounds. A direct extension of this property to fluorine, however, is not plausible and thus intermolecular interactions involving fluorine must be quantified. Recent results and new approaches designed to evaluate organic fluorine which provide useful inputs for the design of co-crystals and salts are discussed in this chapter.

[2-Amino-4,6-bis-(2-pyrid-yl)-1,3,5-tri-azine-κN,N,N]dichloridocadmium(II)

In the title compound, [CdCl₂(C₁₃H₁₀N₆)], the 2-amino-4,6-bis(pyridin-2-yl)-1,3,5-triazine (HABPT) ligand adopts a tridentate tripyridyl coordination mode. The Cd^II atom is five-coordinated by three N atoms from the HABPT ligand and two chloride ions. In the crystal, mol­ecules are linked via N—H⋯N, N—H⋯Cl and C—H⋯Cl hydrogen bonds into a supra­molecular network.

Supramolecular interactions in a copper(II) 4'-(4-bromophenyl)-2,2':6',2''-terpyridine complex

The title compound, [4'-(4-bromophenyl)-2,2':6',2''-terpyridine]chlorido(trifluoromethanesulfonato)copper(II), [Cu(CF(3)O(3)S)Cl(C(21)H(14)BrN(3))], is a new copper complex containing a polypyridyl-based ligand. The Cu(II) centre is five-coordinated in a square-pyramidal manner by one substituted 2,2':6',2''-terpyridine ligand, one chloride ligand and a coordinated trifluoromethanesulfonate anion. The Cu-N bond lengths differ by 0.1 Å for the peripheral and central pyridine rings [2.032 (2) (mean) and 1.9345 (15) Å, respectively]. The presence of the trifluoromethanesulfonate anion coordinated to the metal centre allows Br···F halogen-halogen interactions, giving rise to the formation of a dimer about an inversion centre. This work also demonstrates that the rigidity of the ligand allows the formation of other types of nonclassical interactions (C-H···Cl and C-H···O), yielding a three-dimensional network.