The Coordination Chemistry of Some Sulphur-Nitrogen Ligands

<p>Some nickel(II) and copper(II) complexes of 2-(benzylthio)ethylamine have been isolated and characterised with respect to infrared and electronic spectra. With nickel(II) only the bis salts were obtained and they were all paramagnetic. An investigation of the nickel(II) and copper(II) complexes of three tetradentate ligands, each containing two sulphur and two nitrogen donor atoms, has been made. One of these, 1,9-diamino 3,7-dithianonane has been compared to the nitrogen analogue, 1,9-diamino 3,7-diazanonane. Attempts to bridge and cyclise complexes using reactions of acetone with coordinated amino groups and halides with coordinated thiol groups are also reported. Finally a novel S-detritylation reaction is discussed.</p>

The Coordination Chemistry of Some Sulphur-Nitrogen Ligands

<p>Some nickel(II) and copper(II) complexes of 2-(benzylthio)ethylamine have been isolated and characterised with respect to infrared and electronic spectra. With nickel(II) only the bis salts were obtained and they were all paramagnetic. An investigation of the nickel(II) and copper(II) complexes of three tetradentate ligands, each containing two sulphur and two nitrogen donor atoms, has been made. One of these, 1,9-diamino 3,7-dithianonane has been compared to the nitrogen analogue, 1,9-diamino 3,7-diazanonane. Attempts to bridge and cyclise complexes using reactions of acetone with coordinated amino groups and halides with coordinated thiol groups are also reported. Finally a novel S-detritylation reaction is discussed.</p>

Two-Dimensional Nitronyl Nitroxide–Cu Networks Based on Multi-Dentate Nitronyl Nitroxides: Structures and Magnetic Properties

Two multi-dentate nitronyl nitroxide radicals, namely, bisNITPhPy ([5-(4-pyridyl)-1,3-bis(1′-oxyl-3′-oxido-4′,4′,5′,5′-tetramethyl-4,5-hydro-1H-imidazol-2-yl)]benzene) and NIT-3Py-5-4Py (2-{3-[5-(4-pyridyl)]pyridyl}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), were assembled with CuII ions to obtain two-dimensional heterospin 2p–3d coordination polymers [Cu7(hfac)14(bisNITPhPy)2]n (1) and [Cu2(hfac)4(NIT-3Py-5-4Py)]n (2) (hfac: hexafluoroacetylacetonate). In both compounds, the bisNITPhPy and NIT-3Py-5-3Py radicals acted as pentadentate and tetradentate ligands, respectively, to connect with CuII ions, generating a 2D layer structure. The analysis of the magnetic behavior indicated that strong antiferromagnetic coupling and ferromagnetic interaction (J = 17.1 cm−1) coexisted in 1. For 2, there were ferromagnetic couplings between the CuII ion and NO group, as well as the CuII ion and radical via the pyridine ring with J1 = 32.8 and J2 = 2.2 cm−1, respectively.

Synthesis, computational, anticancerous and antiproliferative effects of some copper, manganese and zinc complexes with ligands derived from symmetrical 2,2’-diamino-4,4’-dimethyl-1,1’-biphenyl-salicylaldehyde

Four new symmetrical Schiff bases derived from 2,2’-diamino-4,4’-dimethyl-1,1’-biphenyl-salicylaldehyde have been synthesized and characterized by elemental analysis and different spectroscopic techniques. The reaction of 2,2’-diamino-4,4’-dimethyl-1,1’-biphenyl with two equivalents of 5-tert-butyl-, 3,5-dinitro-, 3,5-dibromo- and 3-tert-butyl-salicylaldehyde yielded 2,2’-bis(5-tert-butyl-salicylideneamino)-4,4’-dimethyl-1,1’-biphenyl (A1) as well as the 3,5-dinitro- (A2), 3,5-dibromo- (A3) and 3-tert-butyl- (A4) substituted derivatives. The tetradentate ligands were then reacted with copper-, manganese- and zinc-acetate producing the tetra-coordinate metal complexes which were characterized by FTIR, UV-Visible spectroscopy, magnetic susceptibility and elemental analysis. Zinc complexes were characterized by 1H-NMR spectroscopy. Density functional theory (DFT) calculations at the B3LYP/6-31G(d) level of theory were carried out to fully optimize and examine the molecular geometries of complexes. Subsequently, IR vibrational and UV-Vis absorption spectra were computed and correlated with the observed values and the results are in good agreement with the experimental data. The anticancerous and antiproliferative activity of the A3 ligand and its metal complexes were determined.

Tetradentate organophosphines in Pt(η4–A4L) (A = P4, P3Si, P2X2 (X2 = N2, S2, C2), PX3 (X3 = N3, N2O)): Structural aspects

We report herein structural characterization of monomeric platinum complexes of the composition: Pt(η4–P4L), Pt(η4–P3SiL), Pt(η4–P2N2L), Pt(η4–P2S2L), Pt(η4–P2C2L), Pt(η4–PN3L), and Pt(η4–PN2OL). The tetradentate ligands with 10-, 11-, 12-, 14-, and 16-membered macrocycles create a variety of chelate bond angles. A distorted square-planar geometry about Pt(II) atoms with cis–configuration by far prevail. There is an example Pt(η4–P3SiL) in which the respective donor atoms build up a trigonal-pyramidal geometry about Pt(II) atom.

Slow magnetic relaxation in high-coordinate Co(ii) and Fe(ii) compounds bearing neutral tetradentate ligands

7-coordinate Co(ii) compound has a very large positive D value (56.2 cm−1) with an effective spin-reversal barrier of Ueff = 100 K (71.4 cm−1). In contrast, the 8-coordinate Fe(ii) compound exhibits uniaxial magnetic anisotropy.

Tuneable structures and magnetic property in pseudohalo-bridged dinuclear Ni(II) complexes derived from {N4} and {N3O} donor ligands

Tetradentate ligands with {N4}-donor (L1 and L2) and {N3O}-donor (HL3) groups prepared from a traditional Schiff base condensation reaction of N,N-dimethyldipropylenetriamine with pyridine-2-aldehyde or 2-acetylpyridine or 3-ethoxysalicylaldehyde, respectively, were used...

Complexes of Th(iv) with neutral O–N–N–O hybrid ligands: a thermodynamic and crystallographic study

Thermodynamics of the Th(iv) complexes with two tetradentate ligands bearing hybrid N- and O-donors in CH3OH/10%(v)H2O solutions were determined at 25 °C.