Syntheses, structures, in vitro cytostatic activity and antifungal activity evaluation of four diorganotin(iv) complexes based on norfloxacin and levofloxacin

Four organotin(iv) complexes have been designed and synthesized from the reactions of R2SnO (R = Me, Ph) with the corresponding ligands norfloxacin and levofloxacin. And the cytostatic and antifungal activity test have been done.

Tailoring Structural Diversity in Dimethyltin Carboxylates by the pH-Controlled Hydrothermal Approach

The study presents a rational synthesis of new dimethyltin carboxylates, Me₂Sn(H₂btec) (1), Me₂Sn(btec)_0.5(2), [Me₂Sn(H₂O)₂(btec)_0.5]·H₂O (3), and [{Me₂SnOSn(OH)Me₂}(Me₂SnOH)(btec)_0.5]·H₂O (4), derived from tetratopic 1,2,4,5-benzenetetracarboxylic acid (H₄btec). The method relies upon hydrothermal reaction (130 °C, 72 h) of dimethyltin dichloride and H₄btec under optimized pH (2 < pH < 8) conditions that allow control over dimethyltin speciation in aqueous medium as well as degree of deprotonation of the tetrafuntional carboxylic acid. The formation of a three-dimensional assembly in 1 is assisted by the bridging bidentate (μ₂) mode of the carboxylate and O-H···O hydrogen bonds involving -COOH groups. The structure represents a unique example of the diorganotin framework derived from a partially deprotonated polyfuntional carboxylic acid. The structure of 2 adopts a three-dimensional motif wherein each pair of μ₂-carboxylate groups (designated by C1 and C4) of the tetraanionic ligand form different spatial arrangements. For 3, the formation of one-dimensional motif with eight-coordinated tin atoms is assisted by the anisobidentate character of the carboxylate groups. The structure of 4 includes linear chains comprised of [Me₂Sn(μ₂-OH)]₂ and the carboxylate ligand which extend to a layered motif with symmetrically substituted ladder-like distannoxanes acting as linkers. The underlying nets of 1, 2, and 4 exhibit sqc11, scu(sqc170), and sql topologies, respectively. Notably, these assemblies are extremely robust and show no sign of degradation upon exposure to neutral as well as weakly acidic/basic aqueous medium for 7 days.

Molecular Tectonics with Di- and Trinuclear Organotin Compounds

Di- and trinuclear organotin(IV) complexes, in which the metal atoms are separated by large aromatic connectors, are useful building blocks for self-assembly. This is demonstrated by the preparation of [1+1], [2+2], and [2+3] macrocyclic and cage-type structures in combination with organic aromatic dicarboxylates. The linkage of the metal atoms by organic binders and the option of varying the number of reactive M-X sites generate versatile building blocks enabling molecular tectonics instead of the node-based strategy generally employed in metallo-supramolecular self-assembly.

Air and moisture stable covalently-bonded tin(ii) coordination polymers

Compounds (1)–(4) display 1D, 2D or 3D coordination networks, in which the Sn(ii) cations exhibit distorted disphenoidal geometries due to the stereochemically active electron lone pairs.

Syntheses, structures and anti-tumor activity of four organotin(iv) dicarboxylates based on (1,3,4-thiadiazole-2,5-diyldithio)diacetic acid

Four novel organotin complexes, derived from flexible (1,3,4-thiadiazole-2,5-diyldithio)diacetic acid (H₂tzda), have been synthesized and characterized by elemental analysis, FT-IR, NMR and X-ray crystallography.

Poly[[trans-diaquabis(mu(2)-biphenyl-2,2'-dicarboxylato)bis(mu(2)-4,4'-bipyridine)dicobalt(II)] biphenyl-2,2'-dicarboxylic acid disolvate]

In the title compound, {[Co(2)(C(14)H(8)O(4))(2)(C(10)H(8)N(2))(2)(H(2)O)(2)].2C(14)H(10)O(4)}(n), each Co(II) ion is six-coordinate in a slightly distorted octahedral geometry. Both Co(II) ions are located on twofold axes. One is surrounded by two O atoms from two biphenyl-2,2'-dicarboxylate (dpa) dianions, two N atoms from two 4,4'-bipyridine (bpy) ligands and two water molecules, while the second is surrounded by four O atoms from two dpa dianions and two N atoms from two bpy ligands. The coordinated dpa dianion functions as a kappa(3)-bridge between the two Co(II) ions. One carboxylate group of a dpa dianion bridges two adjacent Co(II) ions, and one O atom of the other carboxylate group also chelates to a Co(II) ion. The Co(II) ions are bridged by dpa dianions and bpy ligands to form a chiral sheet. There are several strong intermolecular hydrogen bonds between the H(2)dpa solvent molecule and the chiral sheet, which result in a sandwich structure.

Increased dimensionalities of zinc–diphenic acid coordination polymers by simultaneous or subsequent addition of neutral bridging ligands

Three coordination polymers containing zinc and diphenic acid (H2dpa) were synthesised by solvothermal reaction. Zn(dpa)(H2O) is a one-dimensional coordination polymer that consists of parallel ladder-like chains. One carboxylate group of the diphenic acid coordinates two zinc atoms forming a dinuclear unit which composes the steps of the ladder. The other carboxylate connects to a zinc atom in the next step of the ladder. The fourth coordination site at the zinc atom is occupied by water. Attempts to crosslink the chains by replacing the water molecule with the neutral ligands triethylenediamine (dabco) or 4,4'-bipyridyl lead to the compounds Zn2(dpa)2(dabco) and Zn(dpa)(4,4'-bpy). Their structures can be rationalised as being derived from action of the neutral ligand on Zn(dpa)(H2O), and while they are most conveniently prepared in a one-pot synthesis, it is also possible to obtain them by exposing Zn(dpa)(H2O) to the respective neutral ligand. Zn2(dpa)2(dabco) is a layered two-dimensional coordination polymer in which dinculear zinc carboxylate paddle wheel units and the dabco ligand form infinite linear chains. The chains are interconnected by the dpa unit. The structure of Zn(dpa)(4,4'-bpy) consists of two identical interpenetrating three-dimensional networks. In the network, helical Zn(dpa) chains are interconnected by the rigid 4,4'-bipyridine ligand. Thermogravimetric analysis indicates a high thermal stability of this coordination polymer with decomposition occurring in the range 350-450 degrees C. This is complemented by X-ray thermodiffractometry that indicates a phase transition at 337 degrees C and the final loss of crystallinity at 427 degrees C. The room temperature phase expands drastically along one axis and contracts along the other two axes on heating.