Binuclear lead(II) and copper(II) complexes of 1,4-dihydrazinophthalazine (DHPH). Stabilization of copper(II) in the presence of a hydrazine moiety and x-ray crystal structure and magnetic properties of [Cu2(DHPH)2 (H2O)2(ClO4)2](ClO4)2

Anion-tunable configuration isomerism and magnetic coupling in a tetranuclear discrete, one-dimensional (1D) chiral chain and 1D-decker copper(II) complexes of a carbohydrazine derivative

The reactions of ligand N'-[(pyridin-2-yl)methylene]pyrazine-2-carbohydrazide (ppcd) with different copper salts (1, acetate; 2, perchlorate; 3, sulfate) in MeOH could afford one acetate-bridge tetranuclear discrete [Cu2(ppcd)(ac)2(H2O)(OH)]2·H2O (1), one-dimensional (1D) chiral chain [Cu(ppcd)]ClO4 (2), and a 1D-decker complex of a trinuclear copper(II) subunit, Cu3(ppcd)2(H2O)4(SO4)2 (3). Single-crystal X-ray analysis revealed that conformation isomerism of the ppcd ligand was associated with the configuration of -N-N- (trans or cis) and could induce the versatile coordination mode in the presence of different anions. The 1D chiral chain was interestingly obtained from the achiral rigid ligand in complex 2. Magnetic studies indicated that the magnitude of the antiferromagnetic coupling can be tuned because of the configuration isomerism [compound 1 is practically diamagnetic at room temperature (J ≈ -1000 cm(-1)), with a strong antiferromagnetic one (J = -255.4 cm(-1)) for 2 in the 1D uniform chain and an antiferromagnetic one (J = -123.6 cm(-1)) for 3 within the trinuclear copper subunit].

Mixed-ligand hydroxocopper(ii)/pyridazine clusters embedded into 3D framework lattices

Three types of polynuclear Cu(ii) clusters rely on the compatibility of short-distance hydroxo-, carboxylato and pyridazine bridges and are applicable for the construction of 3D MOF structures.

Copper(II) Mediated Anion Dependent Formation of Schiff Base Complexes

A tetranuclear mixed ligand copper(II) complex of a pyrazole containing Schiff base and a hydroxyhexahydropyrimidylpyrazole and copper(II) and nickel(II) complexes of the Schiff base having N-donor atoms have been investigated. A 2 equiv amount of 5-methyl-3-formylpyrazole (MPA) and 2 equiv of 1,3-diamino-2-propanol (1,3-DAP) on reaction with 1 equiv of copper(II) nitrate produce an unusual tetranuclear mixed ligand complex [Cu4(L1)2(L2)2(NO3)2] (1), where H2L1 = 1,3-bis(5-methyl-3-formylpyrazolylmethinimino)propane-2-ol and HL2 = 5-methyl-3-(5-hydroxyhexahydro-2-pyrimidyl)pyrazole. In contrast, a similar reaction with nickel(II) nitrate leads to the formation of a hygroscopic intractable material. On the other hand, the reaction involving 2 equiv of MPA and 1 equiv each of 1,3-DAP and various copper(II) salts gives rise to two types of products, viz. [Cu(T3-porphyrinogen)(H2O)]X2 (X = ClO4, NO3, BF4 (2)) (T3-porphyrinogen = 1,6,11,16-tetraza-5,10,15,20-tetrahydroxy-2,7,12,17-tetramethylporphyrinogen) and [Cu(H2L1)X]X x H2O (X = Cl (3), Br (4)). The same reaction carried out with nickel(II) salts also produces two types of compounds [Ni(H2L1)(H2O)2]X2 [X = ClO4 (5), NO3 (6), BF4 (7)] and [Ni(H2L1)X2] x H2O [X = Cl (8), Br (9)]. Among the above species 1, 3, and 5 are crystallographically characterized. In 1, all four copper atoms are in distorted square pyramidal geometry with N4O chromophore around two terminal copper atoms and N5 chromophore around two inner copper atoms. In 3, the copper atom is also in distorted square pyramidal geometry with N4Cl chromophore. The nickel atom in 5 is in a distorted octahedral geometry with N4O2 chromophore, where the metal atom is slightly pulled toward one of the axial coordinated water molecules. Variable-temperature (300 to 2 K) magnetic susceptibility measurements have been carried out for complex 1. The separations between the metal centers, viz., Cu(1)...Cu(2), Cu(2)...Cu(2)A, and Cu(2)A...Cu(1)A are 3.858, 3.89, and 3.858 A, respectively. The overall magnetic behavior is consistent with strong antiferromagnetic interactions between the spin centers. The exchange coupling constants between Cu(1)...Cu(2) and Cu(2)...Cu(2A) centers have turned out to be -305.3 and -400.7 cm(-1), respectively, resulting in a S = 1/2 ground state. The complexes are further characterized by UV-vis, IR, electron paramagnetic resonance, and electrochemical studies.

Interactions of metal ions with a 2,4-diaminopyrimidine derivative (trimethoprim). Antibacterial studies

The interaction of copper (II), zinc(II) and cadmium(II) with Trimethoprim (2,4-diamino-5-(3',4',5'-trimethoxybenzyl) pyrimidine) has been studied. The crystal structures of [Zn(Trim)2Cl2] (2) and [Cd(Trim)Cl2(CH3OH)]n (4) are reported. Compound (2) exhibits a distorted tetrahedral environment around the metal center and crystallizes in the triclinic space group P1 with a=10.2397(6), b=10.4500(6), c=16.3336(16) A, alpha=96.141(8), beta=106.085(5), gamma=96.551(5) degrees and Z=2. In complex (4), the Cd(II) centers are bridged sequentially by two chlorine ions to form infinite chains and present a six-coordinated environment; the compound crystallizes in the monoclinic P2(1)/C space group with a=13.958(5), b=7.532(2), c=18.390(2) A, alpha=90, beta=97.32(5), gamma=90 degrees and Z=4. In both structures the Trimethoprim acts as a monodentate ligand through the pyrimidinic nitrogen N(1) atom. The characterization of the Cu(Trim)2(CH3O)(ClO4) complex through EPR and magnetic measurements suggests a binuclear or polinuclear nature, with bridging methoxo groups. The complexes were screened for their activity against several bacteria, showing activity similar to that of trimethoprim.