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1.
Tobias Rüffer Björn Bräuer Bernhard Walfort Annie K. Powell Lorenzo Sorace 《Inorganica chimica acta》2007,360(12):3777-3784
The new mononuclear bis(oxamato) complex [n-Bu4N]2[Cu(obbo)] (1) (obbo=o-benzyl-bis(oxamato)) has been synthesized as a precursor for trinuclear oxamato-bridged transition metal complexes. Starting from 1 the homotrinuclear complexes [Cu3(obbo)(pmdta)2(NO3)](NO3)·CH2Cl2·H2O (2) and [Cu3(obbo)(tmeda)2(NO3)2(dmf)] (3) have been prepared, where pmdta = N,N,N′,N″,N″-pentamethyldiethylenetriamine, tmeda = N,N,N′,N′-tetramethylethylenediamine and dmf = dimethylformamide. The crystal structures of 1-3 were solved. The magnetic properties of 2 and 3 were studied by susceptibility measurements versus temperature. For the intramolecular J parameter values of −111 cm−1 (2) and −363 cm−1 (3) were obtained. 相似文献
2.
Two new mononuclear bis(oxamato) complexes with the formula [nBu4N]2[M(nabo)] M = Ni (4), Cu (5), with nabo = 2,3-naphthalene-bis(oxamato) have been synthesized as precursors for trinuclear oxamato-bridged transition metal complexes. Starting from 5 the homo-trinuclear complex [Cu3(nabo)(pmdta)2(BF4)](BF4) · MeCN · Et2O (7), with pmdta = N,N,N′,N″,N″-pentamethyldiethylenetriamine, has been prepared. The central N,N′-2,3-naphthalene bridge of 7 is so far the most extended π-conjugated bridge of trinuclear bis(oxamato) type transition metal complexes. The goal of this work was to verify the N,N′-2,3-naphthalene bridge of 7 on its magnetic properties in comparison to the N,N′-o-phenylene bridge of the related homo-trinuclear complex [Cu3(opba)(pmdta)2(NO3)](NO3) · 2MeCN (6) (opba = o-phenylene-bis(oxamato)). The crystal structures of 4-7 were solved. The magnetic properties of 6 and 7 were studied by susceptibility measurements versus temperature. For the intramolecular J parameter, values of −89 cm−1 (6) and −113 cm−1 (7) were obtained. The different J values are discussed based on the crystal structures of 6 and 7. 相似文献
3.
Ba L. Tran 《Inorganica chimica acta》2007,360(6):1961-1969
Twelve new dioxo W(VI) complexes of a family of heteroscorpionate ligands of the type [(L)WO2Y], where L = N2X ligand and Y = Cl or OR, have been synthesized and characterized. With the more sterically bulky ligands we show that these complexes exist as isolable cis and trans isomers and compare the rate of such isomerization with their corresponding dioxo Mo(VI) analogs. 相似文献
4.
A potentially heptadentate ligand H3L (N,N′-bis(2-hydroxybenzyl)-1,3-bis[(2-aminoethyl)amino]-2-propanol) and its two Ni(II) complexes, [Ni(H2L)H2O](H2O)3ClO4 (1) and [Ni(H2L)(H2O)](H2O)Cl (2) were prepared and characterized. X-ray structural analyses indicate that complex 1 has a distorted octahedral coordination geometry, with four amine N atoms of H2L− defining the equatorial plane, one aqua O atom and one phenoxo O atom of the ligand occupying two axial positions, respectively. The Ni(II) center of 2 has coordination geometry similar to that of 1. IR and electronic spectra of 1 and 2 are in agreement with their crystal structural features. Approximately along the ab plane, 2D supramolecular structure of 1 is assembled through multiple hydrogen bonds between hydroxy groups of the ligands, coordinated and crystal lattice H2O and π-π stacking interactions between adjacent phenyl rings of the ligands, while for that of 2, probably along the a axis, 1D chain structure is also formed by multiple hydrogen bonds, but lack of π-π stacking interactions. 相似文献
5.
Reaction of bis(2-hydroxybenzyl)-1,3-diaminopropane (H2bhbd) with copper(II) perchlorate and copper(II) chloride in methanol, respectively, leads to linear trinuclear clusters, namely [Cu3(bhbd)2(CH3OH)2(ClO4)2] (1) and [Cu3(bhbd)2Cl2](CH3OH)4 (2). These coordination compounds were characterized by X-ray crystallography, UV-Vis, IR and EPR spectroscopy, and magnetic susceptibility measurements. Both complexes have a linear trinuclear array of copper ions bridged by means of phenolato O atoms and separated by a distance of 2.985(4) Å (1) and 2.937(4) Å (2). Strong antiferromagnetic interactions between these adjacent CuII ions govern the magnetochemistry of 1 (J = −303(1) cm−1) and 2 (J = −482(3) cm−1) resulting in S = 1/2 ground states fully populated below 150 K. A correlation between the interaction parameter J and the angles within the trinuclear clusters is proposed. 相似文献
6.
Alexander Hoffmann 《Inorganica chimica acta》2009,362(4):1185-9227
The synthesis of four guanidine-pyridine hybridligands and their spectroscopic features in MeCN are described. In order to demonstrate their coordinating properties, the corresponding cobalt(II)chloride complexes have been prepared and completely characterised by means of X-ray structure analysis, UV/Vis spectroscopy and mass spectrometry. The neutral complexes {1,1,3,3-tetramethyl-2-(quinolin-8-yl)guanidine}cobalt(II)-dichloride [Co(TMGqu)Cl2] and {N-(1,3-dimethylimidazolidin-2-yliden)pyridin-8-amine}cobalt(II)-dichloride [Co(DMEGpy)Cl2] exhibit a tetrahedral coordination of the cobalt atom, whereas in bis[chlorobis{N-(1,3-dimethylimidazolidin-2-yliden)quinolin-8-amine}cobalt(II)]tetrachlorocobaltate [Co(DMEGqu)2Cl]2[CoCl4] and chlorobis{1,1,3,3-tetramethyl-2-((pyridin-2-yl)methyl)guanidine}cobalt(II)chloride [Co(TMGpy)2Cl]Cl, the cobalt atom is coordinated in a trigonal pyramidal environment. These trigonal pyramidal complex cations represent the first bis(chelated) guanidine cobalt complexes in which the pyridine donor resides on the apical position and the guanidine donor forms with the chlorine atom the base of the pyramid. Besides the structural characterisation, the quenching effect of the cobalt(II) ion (d7) on the ligand fluorescence has been studied. 相似文献
7.
A linear tri-nuclear oxamato bridged copper(II) complex [Cu3(pba)(dpa)2(H2O)(ClO4)](ClO4)·H2O (1) (pbaH4 = 1,3-propanediylbis(oxamic acid), dpa = 2,2′-dipyridylamine) was isolated from the reaction mixture of Na2[Cu(pba)]·3H2O, copper perchlorate hexahydrate and dipyridylamine in methanol. On reaction with dpa or DMF in basic medium (KOH) at ambient temperature complex 1 changed to dinuclear oxalate bridged copper(II) derivatives, [Cu2(μ-C2O4)(dpa)4](ClO4)2 (2) and [Cu2(μ-C2O4)(dpa)2(DMF)2](ClO4)2 (3), respectively. The complexes 1, 2 and 3 have been characterized by physicochemical and spectroscopic tools, and also by the X-ray single crystal analysis. The hydrolysis of 1 in basic medium and thermo-gravimetric analysis has been studied. Absorption and emission spectral studies showed that complex 1 interacts with calf thymus-DNA (CT-DNA) with a binding constant (Kb) of 4.01 × 104 M−1 and linear Stern-Volmer quenching constant (Ksv) of 6.9 × 104. A strong anti-ferromagnetic interaction with a coupling constant JCuCu of 320.0 ± 0.3 cm−1 was observed from the study of magnetic behavior of complex 1 in the temperature range of 2-300 K. Electrochemical equivalency of three copper(II) ions in 1 was identified by getting only one quasi reversible cyclic voltammogram. 相似文献
8.
Brendan R.A. Bland George Vamvounis T. Stanley Cameron 《Inorganica chimica acta》2005,358(13):3927-3936
Three diadduct complexes of the mixed-valent form of diruthenium tetraacetate, [Ru2(μ-O2CCH3)4L2](PF6), where L are the biologically relevant ligands imidazole, 1, 7-azaindole, 2, and caffeine, 3, were synthesized and characterized by elemental analysis, IR and UV-Vis spectroscopy and X-ray crystallography. In order to further elucidate the potential interactions of these dimers with DNA, the nature of the ligand coordination and the secondary inter- and intramolecular hydrogen-bonding interactions in all three complexes were assessed. Complex 1 · CH2Cl2 shows, exclusively, intermolecular interactions with the counterion whereas complexes 2 · ClCH2CH2Cl and 3 · OC(CH3)2 · H2O, in addition to extensive intermolecular interactions, show intramolecular hydrogen bonding from the axial ligand to the bridging acetate oxygens, locking the ligand mean planes in place between the bridging acetate mean planes. In addition, all three complexes display π-π stacking of axial ligand rings on adjacent diadduct units. 相似文献
9.
A covalent-bonded one-dimensional (1D) chain, [Mn(bpe)2(SCN)2]n (1) [bpe=1,2-bis(4-pyridyl)ethane], and a hydrogen-bonded two-dimensional (2D) sheet, [Mn(tbp)2(H2O)2(SCN)2] (2) [tbp=trans-1,2-bis(4-pyridyl)ethylene], have been prepared. Complex 1 can be viewed as a purely coordinative-bonded 1D motif doubly bridged by the bpe ligand that is a gauche conformational isomer with a large dihedral angle of 73.9°. The two bridging bpe ligands feature a shape of square with a dimension of 10.064 Å × 9.776 Å. The compound 2 possesses non-covalent bonding forces of hydrogen bonds and π-π interactions responsible for the fabrication of the 2D architecture. Magnetic susceptibility data for 1 were fitted by employing the infinite chain model (H=−J∑Si·Si+1) to give parameters of J=−0.052 cm−1 and g=2.00, indicating the presence of a weak anti-ferromagnetic coupling. 相似文献
10.
The ligand exchange reaction of the anionic binuclear rhenium complexes (R = H (1), or Me (2)) has been studied with the bifunctional ligands 2-aminophenol (3), 4-hydroxypyridine (4), 3-hydroxybenzoic acid (5), and 3-pyridylcarbinol (6). The reactivity the pendant pyridyl group of 6 was studied in reactions with the Lewis acids ZnCl2 (7), and AgPF6 (8). Crystal structure determinations for several of these derivatives have been carried out which reveal both discrete and polymeric complexes upon addition of the Lewis base. 相似文献
11.
A new series of chiral carboxylate-bridged complexes of Mn(II), Co(II), and Ni(II) has been synthesized by reaction of M(II) salts with (S)-2-hydroxy-2-methyl-butanedioic acid ((S)-citramalic acid) under solvothermal conditions. The Mn(II) compound 1 is obtained as a crystalline powder, whereas the Co(II) and Ni(II) compounds (2 and 3 respectively) are obtained as single crystals. All the compounds crystallize in orthorhombic chiral space group P212121. Compounds 2 and 3 are isostructural, and their structure consists in helicoïdal chains of M(II) centres linked by carboxylate bridges. The magnetic data indicate a rather weak coupling interaction between paramagnetic centres. The Mn(II) compound 1 exhibits antiferromagnetic ordering at TN = 2.64 K. The Co(II) and Ni(II) compounds show ferromagnetic interactions within the chains. For 3, the chains couple antiferromagnetically, which leads to a metamagnetic behaviour with TN = 1.69 K. 相似文献
12.
Two new nickel(II) complexes with the composition [Ni(L+H)(CH3CN)2](ClO4)3 (1) and [Ni(L)(tp)]·6H2O (2), (L = 3,10-bis{3-(1-imidazolyl)propyl}-1,3,5,8,10,12-hexaazacyclotetradecane, tp = terephthalate) have been synthesized and structurally characterized by a combination of analytical, spectroscopic and X-ray diffraction methods. The structure of 1 consists of monomeric cations of the formula [Ni(L+H)(CH3CN)2]3+ and perchlorate ions. The nickel(II) ion is six-coordinate with bonds to the four nitrogen atoms of the macrocycle and two nitrogen atoms of the axial acetonitrile ligands. One of the protonated imidazole pendants of the macrocycle is hydrogen bonded to the imidazole group of the neighboring nickel(II) macrocycle, forming an undulated 1D supramolecule. Then, the two 1D supramolecular chains are further interconnected by C-H···π interactions between the methyl group of the acetonitrile ligand and one of the imidazole groups to form a 2D double stranded supramolecular polymer. In the structure of 2, the 1D coordination polymer is formed with nickel(II) macrocycles and bridging terephthalate ions, where each 1D chain is interconnected with π-π interactions of pendant imidazole moieties of the macrocycles, resulting in the formation of a 2D supramolecule. 相似文献
13.
A series of carboxylate-bridged manganese(III) complexes derived from Schiff bases obtained by the condensation of salicylaldehyde or 5-bromo-salicylaldehyde and different types of diamine have been synthesized and characterized and, in the case of [Mn2(L1)2(μ-ClCH2COO)](ClO4) (1), the structure has been obtained by X-ray crystallography. The structure of 1 consists of two manganese atoms separated by 5.487(3) Å and bridged by a carboxylate anion. This dinuclear structural unit is linked by bridging phenoxy oxygens to adjacent dinuclear units to produce a one-dimensional chain. Cyclic voltammograms of all the compounds exhibit grossly similar features consisting of a reversible or quasi-reversible MnIII/MnII reduction and a MnIII/MnIV oxidation. It has been observed that bromo-substitution stabilizes the lower oxidation state in the MnIII/MnII couple and destabilizes the higher oxidation state in the MnIII/MnIV couple. Variable temperature magnetic susceptibility measurements of 1 show a weak antiferromagnetic interaction. The magnetic behavior is satisfactorily modeled by inclusion of zero-field splitting and an intermolecular interaction component. 相似文献
14.
An efficient procedure for the synthesis of the novel bidentate ligand 4-(diphenylphosphinomethyl)pyridine (PMP-41, 1) has been developed and its coordination behavior with Ag(I) has been studied. Reaction of the PMP-41 ligand with the silver(I) salts of tetrafluoroborate , trifluoromethanesulfonate (Otf−), and trifluoroacetate (tfa−) produces discrete molecules and polymeric structures that depend on the varying degrees of interaction of the corresponding anion with the metal centers. When the proportion of ligand to metal is 1:1, a bimetallic box conformation is obtained with AgBF4 and AgOtf (2 and 5, respectively). Varying the ratio to 2:1, a polymeric chain of bimetallic boxes is constructed when the salt is used (3). With Agtfa two distinct structural motifs are formed (8A and 8B), arising from the crystallization process of using two different solvent systems. Further reaction of the AgBF4/PMP-41 and AgOtf/PMP-41 adducts with the chelating 5,5′-dimethyl-2,2′-bipyridine or the bridging 4,4′-bipyridine ligands affords dimeric and bridged structural motifs, depending upon the coordination ability of the corresponding bipyridine fragment. Addition of the 5,5′-dimethyl-2,2′-bipyridine ligand to a solution containing AgBF4 and PMP-41 results the capping of the silver atoms by the bipyridine fragment 4, and the disruption of the bimetallic box in the AgOtf(PMP-41) structure to generate an infinite chain in a 1:1:1 ratio of the reactants 6. As expected, the 4,4′-bipyridine acts as a bridging ligand by connecting [AgOtf(PMP-41)]2 molecules, which results in the formation of compound 7. Low-temperature luminescence spectra were also collected for all compounds and are compared. 相似文献
15.
Two new Mn(II) coordination polymers with bis(5-tetrazolyl)methane (H2btm), [Mn(btm)(phen)(H2O)] · H2O (1) and [Mn(btm)(2,2′-bpy)] · 1.5H2O (2), have been synthesized and their structures determined by X-ray diffraction. In complex 1, the btm ligands assume the μ2-1,1′:4 coordination mode and interlink Mn(II) ions into infinite one-dimensional chains. The chains are assembled into a three-dimensional architecture via hydrogen bonds and π-π interactions. For 2, Mn(II) ions are connected by btm ligands in the μ3-1,1′:2:3′ mode to produce two-dimensional (6,3) coordination network. Magnetic investigations revealed that interactions through the btm bridges in both 1 and 2 are antiferromagnetic. 相似文献
16.
Kil Sik Min 《Inorganica chimica acta》2007,360(6):1854-1858
The reaction of [FeII(H2O)6](BF4)2 with tris(2-pyridylmethyl)amine (TPyA) and triethylamine in methanol under aerobic conditions forms [(TPyA)FFeIIIOFeIIIF(TPyA)](BF4)2 · 0.5MeOH (1), in which each Fe(III) ion is coordinated to a TPyA and an F− ion as well as an oxo ion (O2−) linking two Fe(III) ions. 1 has offset face-to-face π-π interactions between the dimers, and possesses a supramolecular network structure. The magnetic susceptibility of 1 can be fit with g = 2.0, J/kB = − 153 K (106 cm−1), and θ = − 0.3 K [H = − 2JSa · Sb]. These indicate that very strong antiferromagnetic interactions occur via the oxo bridge within the Fe(III) dimer and weak antiferromagnetic interactions between the dimers. 相似文献
17.
The single-crystal structure of a previously reported Ru(II) complex salt, Δ-[Ru(bpy)2(S-tyr)]ClO4 · benzene (bpy = 2,2′-bipyridyl; tyr = tyrosinato) has been refined in its correct setting. The salt contains the cation that is thermodynamically unstable in aqueous solution at 298 K with respect to the Λ diastereoisomer. Its stability in the solid state is ascribed to the influence of intramolecular NH-π and CH-π interactions involving the aromatic ring of the aminoacidate with the amine group and a pyridyl ring of one of the diimine ligands. The benzene of crystallization is involved with similar CH-π, π-π and π-facial interactions with the bpy and tyrosinato ligands, and this too may serve to stabilize the particular diastereoisomer in the lattice. 相似文献
18.
Ravera M Gabano E Sardi M Ermondi G Caron G McGlinchey MJ Müller-Bunz H Monti E Gariboldi MB Osella D 《Journal of inorganic biochemistry》2011,105(3):400-409
The syntheses, structures and biological evaluation of a series of cisplatin-like complexes containing bis(imidazole) derivatives - the so-called Joseph ligands - are described. Their cytotoxicity is discussed in terms of their polar surface area, rate of aquation, and lipophilicity. The X-ray crystal structure of the platinum diiodido derivative of dimethyl 2-(di(1H-imidazol-2-yl)methyl)malonate) is reported and compared to those of related systems. Molecular modeling studies are focused on the hydrogen bonding properties of such systems, and their relevance to antitumor activity. 相似文献
19.
Sudipta Dalai Durga Sankar Chowdhuri Abhinandan Rana Ennio Zangrando 《Inorganica chimica acta》2010,363(14):3700-3705
Two coordination polymers of cadmium with formula [Cd(pyp)2(H2O)2]n (1) and {[Cd2(pyzca)3(atr)(H2O)]·H2O}n (2) [pypH = 3-pyridinepropionic acid, pyzcaH = 2-pyrazinecarboxylic acid and atrH = 5-aminotetrazole] have been synthesized and structurally characterized by X-ray single crystal diffraction analysis. Both complexes display 2D structures that extend into a 3D network by means of hydrogen bonding. The crystal packing of both complexes is reinforced by π-π interactions between adjacent aromatic rings. The fluorescence study indicates intraligand π-π* charge transfer, which is the reason for emission in both the complexes. 相似文献
20.
Adrian E. Ion 《Inorganica chimica acta》2007,360(13):3925-3931
The synthesis of two nickel(II) complexes based on a central bridging triaminoguanidine scaffold and a capping ligand per metal ion is reported. When 2,2′-bipyridine (bipy) is utilized as co-ligand the complex [Ni3LBr(bipy)3(H2O)3]NO3 · 9H2O · 1.5DMF (1) is obtained which crystallizes in the hexagonal space group P63/m. Complex 1 shows an interesting supramolecular structure pattern with alternating hydrophilic and hydrophobic layers characterized by extensive hydrogen-bonding and π-π-stacking, respectively. With 2,4,6-(2-pyridyl)-1,3,5-triazine (tptz) as capping ligand, complex [Ni3LBr(tptz)3]ClO4 · 7H2O · 1.5DMF (2) is obtained. The magnetic susceptibility data can be fitted using an equilateral triangle model () with an isotropic coupling constant of J=-31.0±0.6 for 1 and for 2. 相似文献