Synthesis and structural analysis of cis-bis(1,10-phenanthroline)dicarbonyl ruthenium(II) 1.72-trifluoromethanesulfonate 0.28-hexafluoridophosphate

Ruthenium(II) complexes containing both 1,10-phenanthroline (Phen) and carbonyl (CO) ligands are important molecules for various applications including catalysis. In this work, the molecular structure of [Ru(Phen)2(CO)2]2+ was determined via X-ray diffraction analysis for the first time. The complex exhibits substitutional disorder of one of counter-anions in the asymmetric unit, with different occupancies for CF3SO3- (0.72) and PF6- (0.28). The ruthenium atom is coordinated in a distorted octahedral environment by two carbonyl carbon atoms and four nitrogen atoms from bis-Phen ligands. The cation displays a cis configuration of the carbonyl ligands. Several hydrogen bonds and π-π interactions are present in the crystal. In addition to structural characterization, IR spectral data for the complex is compared with calculated values. These results provide fundamental data for understanding various properties of related ruthenium complexes.

Synthesis and crystal structure of a new chiral α-aminooxime nickel(II) complex

A dinuclear nickel complex with (S)-limonene based aminooxime ligand has been isolated and its crystal structure determined. The resolved structure of dichloridobis{(2S,5R)-2-methyl-5-(prop-1-en-2-yl)-2-[(pyridin-2-yl)methylamino]cyclohexan-1-one oxime}dinickel(II), [Ni2Cl2(C16H23ClN3O)2], at 100 K has monoclinic (P21) symmetry. The two NiII ions in the dinuclear complex are each coordinated in a distorted octahedral environment by three nitrogen atoms, a terminal chloride and two μ bridging chlorides. Each oxime ligand is coordinated to nickel(II) by the three nitrogen atoms, leading to two five-membered chelate rings, each displaying an envelope conformation. In the crystal, numerous intermolecular and intramolecular hydrogen bonds lead to the formation of a three-dimensional network structure.

Crystal structure of hexakis(N,N-dimethylformamide-κO)iron(III) μ-chlorido-bis(trichloridocadmium)

The title compound, [Fe(C3H7NO)6][Cd2Cl7], crystallizes in the trigonal space group R\overline{3} and is assembled from discrete [Fe(DMF)6]3+ cations (DMF = N,N-dimethylformamide) and [Cd2Cl7]3− anions. In the cation, the iron(III) atom, located on a special position of \overline{3} site symmetry, is coordinated by six oxygen atoms from DMF ligands with all Fe—O distances being equal [2.0072 (16) Å]. A slight distortion of the octahedral environment of the metal comes from the cis O—Fe—O angles deviating from the ideal value of 90° [86.85 (7) and 93.16 (7)°] whilst all the trans angles are strictly 180°. The central Cl atom of the [Cd2Cl7]3− anion is also located on a special position of \overline{3} site symmetry and bridges two corner sharing, tetrahedrally coordinated CdII atoms. The two Cd atoms and the central Cl atom are colinear. The two sets of terminal chloride ligands on either side of the dumbbell-like anion are rotated relative to each other by 30°. In the crystal, the cations and anions, stacked one above the other along the c-axis direction, are held in place principally by electrostatic interactions. There are also C—H...Cl and C—H...O interactions, but these are rather weak. Of the six crystal structures reported to date for ionic salts of [Fe(DMF)6] n+ cations (n = 2, 3), five contain FeII ions. The title compound is the second example of a stable compound containing the [Fe(DMF)6]3+ cation. The existence of both [Fe(DMF)6]2+ and [Fe(DMF)6]3+ cations shows that the DMF ligand coordination sphere can accommodate changes in the charge and spin states of the metal centre.

SYNTHESIS AND STRUCTURE OF IRON(III) COMPLEX WITH 2-ACETYLPYRIDINE-AMINOGUANIDINE

Schiff bases represent an interesting class of compounds due to a wide range of possible applications, especially their biological activity. Having in mind that the biological activity of the ligand could be closely related to its coordinating properties, we examined the synthesis and structure of a novel Fe(III) complex with the Schiff base of aminoguanidine and 2-acetylpyridine. Bis(ligand) complex of iron(III), of the formula [Fe(L–H)2]2(NCS)Cl, was obtained by the reaction of FeCl3 and the thiocyanate ligand salt in a mole ratio 1:1 in the presence of lithium-acetate as a deprotonating agent. The complex is obtained in the form of brown single crystals and is characterized by elemental analysis data, conductometric measurements, IR spectra, and X-ray analysis. The latter revealed that the chelating ligand is coordinated in its monoanionic form via pyridine, azomethine, and nitrogen atoms of the aminoguanidine fragment, forming octahedral environment.

catena-Poly[[chloridotris(1,3-thiazolidine-2-thione-κS)cadmium(II)]-μ-chlorido]

The synthesis and characterization of poly[dichloridotri(1,3-thiazolidine-2-thione)cadmium(II)], [CdCl2(C3H5NS2)3] n , prepared from CdCl2·H2O and C3H5NS2 (tzdSH) in a 1:3 ratio, are described. The CdII cation is coordinated by three 1,3-thiazolidine-2-thione molecules and three Cl− anions in a distorted octahedral environment. The Cd metal centres are connected via Cl− ligands, creating polymeric chains running along the a-axis direction. The conformation of the chains is stabilized by N—H...Cl hydrogen bonds.

trans-Diaquabis(N,N,N′-trimethylethylenediamine)nickel(II) dichloride

In the title salt, [Ni(C5H12N2)2(H2O)2]Cl2, the asymmetric unit is comprised of half of the complex cation and a chloride ion with the NiII atom of the cation situated about a twofold rotation axis. The six-coordinate NiII atom of the cation is connected to four N atoms from two methyl-substituted ethyelenediamine ligands and two water molecules in a slightly distorted octahedral environment. The five-membered chelate ring is in a slight envelope conformation. The crystal packing features O—H...Cl and N—H...Cl intermolecular interactions with the Cl− ion forming weak bifurcated hydrogen bonds with nearby water molecules and N—H interactions, leading to a three-dimensional supramolecular network structure.

Selective synthesis and crystal structures of manganese(I) complexes with a bi- or tridentate terpyridine ligand

The crystal structures of two manganese(I) complexes with a different coordination mode of the supporting ligand are reported: fac-bromidotricarbonyl(4′-phenyl-2,2′:6′,2′′-terpyridine-κ2 N,N′)manganese(I), [MnBr(C21H15N3)(CO)3], I, and cis-bromidodicarbonyl(4′-phenyl-2,2′:6′,2′′-terpyridine-κ3 N,N′,N′′)manganese(I), [MnBr(C21H15N3)(CO)2], II. In both complexes, the manganese(I) atom is coordinated by terminal carbonyl ligands, a bromide ion, and a 4′-phenyl-2,2′:6′,2′′-terpyridine ligand within a distorted octahedral environment. In I, the metal ion is facially coordinated by three carbonyl ligands and the terpyridine ligand binds in a bidentate fashion. The non-coordinating nitrogen atom in the terpyridine ligand is positioned on the side opposite to the bromido ligand. In II, the metal ion is coordinated by two carbonyl ligands in a cis configuration and the terpyridine ligand binds in a tridentate fashion; notably, one carbonyl and the trans bromido ligand are mutually disordered over two positions. In I, the complex molecules are linked by C—H...Br hydrogen bonds. In II, aromatic π–π contacts are present, as well as pairs of C—H...Br and C—H...O hydrogen bonds.

Spin Cross-Over (SCO) Anionic Fe(II) Complexes Based on the Tripodal Ligand Tris(2-pyridyl)ethoxymethane

Reactions of Fe(II) with the tripodal chelating ligand 1,1,1-tris(2-pyridyl)ethoxymethane (py3C-OEt) and (NCE)− co-ligands (E = S, Se, BH3) give a series of mononuclear complexes formulated as [Fe(py3C-OEt)2][Fe(py3C-OEt)(NCE)3]2·2CH3CN, with E = S (1) and BH3 (2). These compounds are the first Fe(II) spin cross-over (SCO) complexes based on the tripodal ligand tris(2-pyridyl)ethoxymethane and on the versatile co-ligands (NCS)− and (NCBH3)−. The crystal structure reveals discrete monomeric isomorph structures formed by a cationic [Fe(py3C-OEt)2]2+ complex and by two equivalent anionic [Fe(py3C-OEt)(NCE)3]− complexes. In the cations the Fe(II) is facially coordinated by two py3C-OEt tripodal ligands whereas in the anion the three nitrogen atoms of the tripodal ligand are facially coordinated and the N-donor atoms of the three (NCE)− co-ligands occupy the remaining three positions to complete the distorted octahedral environment of the Fe(II) centre. The magnetic studies show the presence of gradual SCO for both complexes: A one-step transition around 205 K for 1 and a two-step transition for compound 2, centered around 245 K and 380 K.

Dichloridobis[2-(pyridin-2-yl-κN)-1H-benzimidazole-κN 3]nickel(II) monohydrate

In the title complex, [NiCl2(C12H9N3)2]·H2O, a divalent nickel atom is coordinated by two 2-(pyridin-2-yl)-1H-benzimidazole ligands in a slightly distorted octahedral environment defined by four N donors of two N,N′-chelating ligands, along with two cis-oriented anionic chloride donors. The title complex crystallized with a water molecule disordered over two positions. In the crystal, a combination of O—H...Cl, O—H.·O and N—H...Cl hydrogen bonds, together with C—H...O, C—H...Cl and C—H...π interactions, links the complex molecules and the water molecules to form a supramolecular three-dimensional framework. The title complex is isostructural with the cobalt(II) dichloride complex reported previously [Das et al. (2011). Org. Biomol. Chem. 9, 7097–7107].

An unusual partial occupancy of labile chloride and aqua ligands in cocrystallized isomers of a nickel(II) complex bearing a tripodal N 4-donor ligand

A novel Ni2+ complex with the N 4-donor tripodal ligand bis[(1-methyl-1H-imidazol-2-yl)methyl][2-(pyridin-2-yl)ethyl]amine (L), namely, aqua{bis[(1-methyl-1H-imidazol-2-yl-κN 3)methyl][2-(pyridin-2-yl-κN)ethyl]amine-κN}chloridonickel(II) perchlorate, [NiCl(C17H22N6)(H2O)]ClO4 or [NiCl(H2O)(L)Cl]ClO4 (1), was synthesized and characterized by spectroscopic and spectrometric methods. The crystal structure of 1 reveals an interesting and unusual cocrystallization of isomeric complexes, which are crystallographically disordered with partial occupancy of the labile cis aqua and chloride ligands. The Ni2+ centre exhibits a distorted octahedral environment, with similar bond lengths for the two Ni—N(imidazole) bonds. The bond length increases for Ni—N(pyridine) and Ni—N(amine), which is in agreement with literature examples. The bond lengths of the disordered labile sites are also in the expected range and the Ni—Cl and Ni—O bond lengths are comparable with similar compounds. The electronic, redox and solution stability behaviour of 1 were also evaluated, and the data obtained suggest the maintenance of structural integrity, with no sign of demetalation or decomposition under the studied conditions.