A one-dimensional copper(II) coordination polymer incorporating succinate and N,N-diethylethylenediamine ligands: crystallographic analysis, vibrational and surface features, and DFT analysis.

Transition metal atoms can be bridged by aliphatic dicarboxylate ligands to produce chains, layers and frameworks. The reaction of copper sulfate with succinic acid (H2succ) and N,N-diethylethylenediamine (deed) in basic solution produces the complex catena-poly[[[(N,N-diethylethylenediamine-κ2N,N')copper(II)]-µ-succinato-κ2O1:O4] tetrahydrate], {[Cu(C4H4O4)(C6H16N2)]·4H2O}n or {[Cu(succ)(deed)]·4H2O}n. Each carboxylate group of the succinate ligand coordinates to a CuII atom in a monodentate fashion, giving rise to a square-planar coordination environment. The succinate ligands bridge the CuII centres to form one-dimensional polymeric chains. Hydrogen bonds between the ligands and water molecules link these chains into sheets that lie in the ab plane. Density functional theory (DFT) calculations were used to support the experimental data. From these calculations, a good linear correlation was observed between the experimental and theoretically predicted structural and spectroscopic parameters (R2 ∼ 0.97).

Two new chelidamate complexes with the 4-methoxypyridine: A combined theoretical and experimental study.

Two new mixed chelidamate complexes, [M(chel)(mhpOCH3)·2H2O]·2H2O [M=Ni(II) (1); Co(II) (2); chel: chelidamate or 4-hydroxypyridine-2,6-dicarboxylate; mhp: 4-methoxypyridine], were prepared and characterized through a combination of X-ray diffraction method, FT-IR and UV-Vis spectroscopy. The central M(II) ion in complex (1) and (2) is coordinated by the mhp nitrogen atom, the chel nitrogen and oxygen atoms and aqua oxygen atoms, forming the distorted octahedral geometry. Intra and intermolecular hydrogen bonds and π-π stacking interactions appear to be effective in the stabilization of the crystal structures. Also, the fully optimized geometries and vibrational frequencies have been calculated using density functional theory (DFT)-B3LYP with 6-31G (d) basis set. The vibrational frequencies were interpreted by means of potential energy distribution (PED). The energetic behaviors of the complexes in methanol solvent were examined using by time-dependent DFT (TD-DFT) method by applying the polarizable continuum model (PCM). The molecular stability and charge delocalization were analyzed using natural bond orbital (NBO) analysis.

A combined theoretical and experimental study of chelidamate cadmium (II) complex, [Cd2(dpa)2(chel)2]⋠2[Cd(dpa)(chel)]⋠6H2O.

A new chelidamate complex of Cd (II) ion, [Cd2(dpa)2(chel)2]⋅2[Cd(dpa)(chel)]⋅6H2O [(chel: chelidamate or 4-hydroxypyridine-2,6-dicarboxylate, dpa: di (2-picolyl)amine)] was synthesized and characterized by spectroscopic (UV-Vis and FT-IR spectroscopy) and structural (single-crystal X-ray diffraction) methods. Quantum chemical calculations were carried out by using Hartree Fock (HF) and Density Functional Theory (DFT)/B3LYP methods Stuttgart/Dresden (SDD) basis set. The asymmetric unit of the title compound contains two symmetry unrelated monomeric units, one dimeric unit and six water molecules of crystallization. The geometries around the Cd (II) metal centers in the units can be described as distorted octahedral for the monomeric units and distorted monocapped trigonal prism for the dimeric unit. The electronic structure of the complex was calculated using time dependent DFT (TD-DFT) method with polarizable continuum model (PCM). Molecular stability and bond strength were investigated by applying natural bond orbital analysis (NBO). The computed frequencies were compared with experimental frequencies.

An experimental and theoretical approach of spectroscopic and structural properties of a new chelidamate copper (II) complex.

The crystal structure of new chelidamate complex of copper (II) ion, [Cu(chel)H2O(pym)]·H2O [chel: chelidamate or 4-hydroxypyridine-2,6-dicarboxylate; pym: 2-Pyridylmethanol] has been determined by single crystal X-ray crystallographic method. The complex was characterized by IR and UV-Vis spectroscopic techniques. The magnetic environment of copper (II) ion has been defined by electron paramagnetic technique (EPR). The central copper (II) ion is six-coordinate with a distorted octahedral geometry, which exhibits Jahn-Teller distortions along one of the O-Cu-O axes with tetragonality of 0.81. Chelidamate behaved as a tridentate ligand was bonded to Cu(II) ion through carboxyl oxygens with nitrogen. The crystal structure is stabilized by O-H⋯O hydrogen bond and π-π interactions. Theoretical calculations have been carried out by using the DFT method. The modeling of copper (II) complex was made by geometric optimization. The geometry optimization and EPR study were carried out using the following unrestricted hybrid density functionals: LSDA, BPV86, B3LYP, B3PW91, MPW1PW91 and HCTH. Frontier molecular orbital energies, absorption wavelengths and excitation energy were computed by time dependent DFT (TD-DFT) method with polarizable continuum model. IR spectra were discussed and compared to other relevant complexes together with theoretical results. The natural charges on the atoms and second-order interaction energies were derived from natural bond orbital analysis (NBO).

Combined experimental and theoretical approaches to the molecular structure of 4-(1-formylnaphthalen-2-yloxy)phthalonitrile.

The novel compound 4-(1-formylnaphthalen-2-yloxy)phthalonitrile, C(19)H(10)N(2)O(2,) has been synthesized and characterized by IR, UV-vis, NMR and X-ray single-crystal determination. The title compound, is built up from two planar groups (naphthalen and phthalonitrile), with a dihedral angle of 64.10(4)° between them. The crystal structure is stabilized by weak C-H···O hydrogen-bond and π-π interactions. The structural and spectroscopic data of the compound in the ground state have been calculated using density functional theory (DFT) and Hartree-Fock (HF) with the 6-31G(d,p) basis set. The vibrational study was interpreted in terms of potential energy distribution (PED). The observed wave number in FT-IR spectra was analyzed and assigned to different normal modes of the molecule. Using the TD-DFT and TD-HF methods, electronic absorption spectra of the title compound were predicted and good agreement with the TD-DFT method and the experimental determination was found. Isotropic chemical shifts ((13)C and (1)H NMR) were calculated using the gauge-invariant atomic orbital (GIAO) method. The HOMO and LUMO analyses were used to elucidate information regarding charge transfer within the molecule.

Spectroscopic characterization, X-ray structure, antimicrobial activity and DFT calculations of novel dipicolinate copper(II) complex with 2,6-pyridinedimethanol.

Novel dipicolinate complex of copper(II) ion, [Cu(dmp)(dpc)]·0.8H(2)O [dmp: 2,6-pyridinedimethanol; dpc: dipicolinate or pyridine-2,6-dicarboxylate], has been prepared and fully characterized by single crystal X-ray structure determination. The central copper(II) ion is bonded to dpc and dmp ligands through pyridine nitrogen atom together with two oxygen atom, forming the distorted octahedral geometry. The complex molecules, connected via O-H···O hydrogen bonds, form a supramolecular structure. H(2)dpc, [Cu(dpc)(H(2)O)(3)] and [Cu(dmp)(dpc)]·0.8H(2)O were screened for antimicrobial activity against Gram-positive, Gram-negative bacteria and yeast. H(2)dpc and [Cu(dpc)(H(2)O)(3)] exhibited antibacterial and antifungal activity, while [Cu(dmp)(dpc)]·0.8H(2)O exhibited activity only for Gram-positive bacteria. The geometry optimization and EPR parameters were carried out using the following unrestricted hybrid density functionals: LSDA, BPV86, B3LYP, B3PW91, MPW1PW91, PBEPBE and HCTH. Although the supramolecular interactions have some influences on the molecular geometry in solid state phase, calculated data show that the predicted geometries can reproduce the structural parameters. The electronic station in the frontier orbitals of the copper complex calculated from the experimental data is compared to the results of time-depended DFT calculations with the polarizable continuum model. Calculated vibrational frequencies are consistent with the experimental IR data.

Aqua-(di-2-pyridyl-amine-κN,N)(pyridine-2,6-dicarboxyl-ato-κO,N,O)zinc monohydrate.

In the title compound, [Zn(C(7)H(3)NO(4))(C(10)H(9)N(3))(H(2)O)]·H(2)O, the Zn(II) atom has a distorted octa-hedral coordination geometry. One of the water mol-ecules is coordinated with the Zn(II) ion and this mol-ecule forms an O-H⋯O inter-action with the lattice water mol-ecule. The pyridine-2,6-dicarboxyl-ate ligand is almost planar (r.m.s. deviation = 0.0242 Å). In the crystal, C-H⋯O, C-H⋯N, O-H⋯O and N-H⋯O hydrogen bonds are present.

Synthesis, crystal structure, EPR spectra of Cu2+ doped [Zn(methylisonicotinate)2(H2O)4]·(sac)2 single crystal.

The tetraaquabis(methylisonicotinate)zinc(II) disaccharinate [hereafter, [Zn(mein)2(H2O)4]·(sac)2], complex has been synthesized and characterized by spectroscopic IR, EPR and X-ray diffraction technique. The octahedral Zn(II) ion, which rides on a crystallographic centre of symmetry, is coordinated by two monodentate mein ligands through the ring nitrogen and four aqua ligands to form discrete [Zn(mein)2(H2O)4] unit, which captures two saccharinate ions in up and down positions, each through intermolecular hydrogen bonds. The magnetic environments of Cu2+ doped [Zn(mein)2(H2O)4]·(sac)2 complex have been identified by electron paramagnetic resonance (EPR) technique. EPR spectra of Cu2+ doped [Zn(mein)2(H2O)4]·(sac)2 single crystals have been studied between 113 and 300 K in three mutually perpendicular planes. The calculated results of the Cu2+ doped [Zn(mein)2(H2O)4]·(sac)2 indicate that Cu2+ ion contains two different complexes and each complexes are located in different chemical environments and each environment contains two magnetically inequivalent Cu2+ sites in distinct orientations occupying substitutional positions in the lattice. The vibrational spectra of this compound were discussed in relation to other compounds containing methyl isonicotinate and saccharinate complexes. The assignments of the observed bands were discussed.

Crystal structure and EPR studies of doped Cu(2+) ion in [Zn(sac)(2)(en)(2)] single crystal.

The tran-bis(ethylenediamine)bis(saccharinato)Zinc(II), [Zn(sac)(2)(en)(2)] (ZSED), (en: ethylenediamine and sac: saccharinate) complex has been synthesized and its crystal structure has been determined by X-ray diffraction analysis. The compound crystallizes in space group P2(1)/c. The Zn(II) ion is hexa-coordinated by four nitrogens of two bidentate en ligands composing the basal plane and two nitrogen atoms from the monodentate two sac ligands (N-bonded) occuping the axial sites, adopting an elongated octahedral sphere. Both en and sac ligands occupy the trans positions of the coordination octahedron. The Zn(II) ion in title compound sits on a inversion centre and is octahedrally coordinated two bidentate en (ethylenediamine) and two sac (saccharinate) (N-bonded) ligands. The magnetic environments of Cu(2+) doped [Zn(sac)(2)(en)(2)] complex have been identified by electron paramagnetic resonance (EPR) technique. Cu(2+) doped ZSED single crystals have been studied at room temperature in three mutually perpendicular planes. The calculated results of the Cu(2+) doped ZSED indicate that Cu(2+) ion contains two magnetically inequivalent Cu(2+) sites in distinct orientations occupying substitutional positions in the host lattice and show very high angular dependence.

Surgical treatment of saphenous vein graft aneurysms after coronary artery revascularization.

BACKGROUND: Saphenous vein graft (SVG) aneurysms (SVGAs) after coronary artery bypass grafting (CABG) occur rarely. Most reports are anecdotal. To determine early and late outcomes of surgical treatment, we reviewed our experience with management of this rare complication of surgical revascularization. METHODS: From July 1975 to October 2007, 16 patients (15 men), mean age, 60.9 +/- 14.6 years, underwent repair of aortocoronary SVGAs. RESULTS: Chest pain was present in 11 of 16 patients. The rest were asymptomatic. The average maximum diameter of the SVGA was 64 +/- 30 mm. The concern of SVGA rupture was the primary indication for operation in 9 patients (56%). Repair in the remaining patients occurred during other cardiac operations. A pseudoaneurysm (75%) at the body or anastomotic sites of the SVG was the most common cause of SVGA. In 8 patients (50%), the aneurysm involved SVG anastomotic sites. Thirteen patients (81%) had intraluminal thrombi. Vein grafts with aneurysm were patent in 9 patients (56%). Surgical procedures included excision of the aneurysm and direct distal coronary target vessel revascularization in 10 (63%), excision and interposition vein graft in 5 (31%), and exclusion by ligation in 1 (6%). Median follow-up was 7 years (maximum, 20 years). Survival was 83% at 5 years and 72% at 10 years after SVGA repair. CONCLUSIONS: Ischemic symptoms often accompany SVGA, and operation is indicated to prevent rupture. Ligation or excision of SVGA with simultaneous revascularization appears to be the optimal therapy, with satisfactory midterm and long-term results.

Structural characterization and EPR spectral studies on mononuclear copper(II) complex of saccharin with ethylnicotinate.

Mononuclear copper(II) saccharinate (sac) complex containing ethylnicotinate (enc), [Cu(enc)(2)(sac)(2)(H(2)O)].1.4H(2)O has been synthesized and characterized by spectroscopic (IR, UV-vis, EPR), X-ray diffraction technique and electrochemical methods. It crystallizes in the tetragonal crystal systems with space group I4(1)cd and Z=8. The copper(II) ion presents a CuN(4)O distorted square pyramidal coordination. Based on EPR and optical absorption studies, spin-Hamiltonian and bonding parameters have been calculated. The g-values, calculated for title complex in polycrystalline state at 298 K and in frozen DMF (110K), indicate the presence of the unpaired electron in the d(x)(2)-(y)(2) orbital. The evaluated metal-ligand bonding parameters showed strong in-plane sigma and in-plane pi-bonding. Some comparisons with related structures are made and the most important features of its IR spectrum were also discussed. The cyclic voltammogram of the title complex investigated in DMF (dimethylformamide) solution exhibits only metal centred electroactivity in the potential range +/-1.25 V vs. Ag/AgCl reference electrode.

Synthesis, crystal structure, EPR spectra of doped VO(2+) and Cu(2+) ions in [Zn(ethylisonicotinate)(2)(H(2)O)(4)].(sac)(2) single crystal.

The tetraaquabis(ethylisonicotinate)zinc(II) disaccharinate, [Zn(ein)(2)(H(2)O)(4)].(sac)(2) (ZENS) (ein: ethylisonicotinate and sac: saccharinate) complex has been synthesized and its crystal structure has been determined by X-ray diffraction analysis. The magnetic environments of VO(2+) and Cu(2+) doped Zn(II) complex have been identified by electron paramagnetic resonance (EPR) technique. The title complex crystallizes in monoclinic system with space group P2(1)/c, Z=4. The octahedral Zn(II) ion, rides on a crystallographic centre of symmetry, is coordinated by two monodentate ein ligands through the ring nitrogen and four aqua ligands to form discrete [Zn(ein)(2)(H(2)O)(4)] unit, which captures two saccharinate ions in up and down positions, each through intermolecular hydrogen bonds. Cu(2+) and VO(2+) doped ZENS single crystals have been studied at room temperature in three mutually perpendicular planes. The calculated results of the Cu(2+) and VO(2+) doped in ZENS indicate that Cu(2+) and VO(2+) ion substitute with the Zn(2+) ion in the host lattice. The angular variations of the EPR spectra have shown that two different Cu(2+) and VO(2+) complexes are located in different chemical environments, and each environment contains two magnetically inequvalent Cu(2+)and VO(2+)sites in distinct orientations occupying substitutional positions in the lattice and show very high angular dependence. The ground state wave functions of the unpaired electron of Cu(2+) ion have been constructed and type of the distortion has, then, been determined.

Diaqua-bis(ethyl-enediamine-κN,N')copper(II) 2,2'-dithio-dinicotinate sesquihydrate.

In the title compound, [Cu(C(2)H(8)N(2))(2)](C(12)H(6)N(2)O(4)S(2))·1.5H(2)O, there are two half-molecules of the cationic complex in the asymmetric unit. The Cu(2+) ions lie on inversion centres and are octa-hedrally coordinated by two ethyl-enediamine (en) and two aqua ligands in a typical Jahn-Teller distorted environment with the water O atoms in the axial positions. Two 2-mercaptonicotinate units (mnic) are linked by a disulfide bridge. All the ethyl-enediamine N-H and O-H groups form inter-molecular hydrogen bonds with acceptor O and N atoms, giving rise to a three-dimensional network. One of the uncoordinated water molecules has a site occupation factor of 0.5.

Crystal structure and EPR studies of mixed ligand complex of cobalt(II) with saccharin and ethylisonicotine.

The tetraaquabis(ethylisonicotinate)cobalt(II) disaccharinate, [Co(ein)2(H2O)4].(sac)2, (CENS), (ein: ethylisonicotinate and sac: saccharinate) complex has been synthesized and its crystal structure has been determined by X-ray diffraction analysis. The title complex crystallizes in monoclinic system with space group P2(1)/c and Z=2. The Co(II) cations present a slightly distorted CoN2O4 octahedral environment, with equatorially coordinated water molecules and axially pyridine N-bound ethylisonicotinate ligands. The magnetic environments of Cu2+-doped Co(II) complex have been identified by electron paramagnetic resonance (EPR) technique. Cu2+-doped CENS single crystals have been studied at room temperature in three mutually perpendicular planes. The calculated results of the Cu2+-doped CENS indicate that Cu2+ ion substitute with the Co2+ ion in the host lattice. The angular variations of the EPR spectra have shown that two different Cu2+ complexes are located in different chemical environments, and each environment contains two magnetically inequivalent Cu2+sites in distinct orientations occupying substitutional positions in the lattice and show very high angular dependence. The cyclic voltammogram of the title complex investigated in dimethylformamide (DMF) solution exhibits only metal centered electroactivity in the potential range -1.0-1.25V versus Ag/AgCl reference electrode.

EPR study of Cu(2+)-doped tetraaqua-di(nicotinamide)Co(II) saccharinate single crystals.

The electron paramagnetic resonance spectra of Cu(2+) impurities in [Co(nicotinamide)(2)(H(2)O)(4)](saccharinate)(2) single crystals have been studied at ambient temperature in three mutually perpendicular planes. The angular variation of the spectra shows that the Cu(2+) ion substitutes the Co(2+) site in the lattice. The EPR spectra of Cu(2+) ions are characteristic of tetragonally elongated octahedral site. The spin-Hamiltonien parameters were obtained from the single crystal EPR analysis. The ground-state wave function of Cu(2+) ion in the lattice has been constructed.

Stent-graft applications in peripheral non-atherosclerotic arterial lesions.

PURPOSE: To retrospectively evaluate peripheral arterial lesions treated with stent-grafts in various territories and to identify the role of computed tomography angiography (CTA), both in diagnosis and follow-up. MATERIALS AND METHODS: The study included 19 patients (11 male, 8 female) aged between 24 and 85 years. In all, 24 stent-grafts were used to seal an extravasation in 3 patients, a pseudoaneurysm/aneurysm in 12 patients, and an arteriovenous fistula in 4 patients. Self-expandable and balloon-expandable stent-grafts were used, all of which were covered with polytetrafluoroethylene material. Iatrogenic etiologies were responsible in 11 of the patients. In total, 5 superficial femoral, 2 deep femoral, 4 external iliac, 3 common iliac, 1 common carotid, 1 internal carotid, 1 subclavian, 1 renal artery, and 1 thyrocervical trunk lesion were treated. RESULTS: The technical success rate was 100%, with no periprocedural complications. Mean follow-up was 18 months (range: 1-72 months). CTA was performed in 10 patients for diagnosis and in 7 patients for follow- up. There was no stent migration, but 1 stent crush. The total vessel occlusion rate was 16.6%, all diagnosed using CTA. CONCLUSION: Stent-graft applications offer quick, single-step treatment, with few procedural complications. However, long-term durability remains a major concern. CTA is a very valuable tool, both for diagnosis and follow- up. Pseudoaneurysms and extravasations can be demonstrated successfully, as well as incomplete arteriovenous fistula closure, and patent or occluded stent-grafts.

µ-Squarato-κO:O-bis-{[2-(2-amino-ethyl)pyridine-κN,N']aqua-nickel(II)} squarate 0.25-hydrate.

The asymmetric unit of title compound, [Ni(2)(C(4)O(4))(C(7)H(10)N(2))(4)(H(2)O)(2)]C(4)O(4)·0.25H(2)O, contains one-half of a squarate ligand, one-half of an uncoordinated squarate dianion, two 2-(2-amino-ethyl)pyridine ligands and one aqua ligand, all coordinated to an Ni(II) ion. The compound also contains 0.25 solvent water mol-ecules. The Ni(II) ion has distorted octa-hedral geometry. The squarate ligand adopts a µ-1,2 coordination mode, the intra-dimer Ni(II)⋯Ni(II) separation being 7.1442 (7) Å, while the other squarate unit acts as a counter-anion. The crystal structure is stabilized by inter-molecular O-H⋯O and N-H⋯O hydrogen-bond inter-actions, forming a three-dimensional network.

Synthesis, spectroscopy, X-ray structure and redox behaviors of 4-(N-R-salicylideneimine)-2,6-diphenylphenols.

A series of sterically hindered 4-(N-R-salicylaldimine)-2,6-diphenylphenols (X), where R=H (1), 3-CH3 (2), 5-CH3 (3), 3-OCH3 (4), 4-OCH3 (5), 5-OCH3 (6), 3-tBu (7), 5-tBu (8), 3,5-tBu2(9) and 5,6-benzo(10), were synthesized and their structure as well as redox behavior studied by analytical, spectroscopic [1H, (13C) NMR, IR, UV-vis and mass spectrometry] and cyclic voltammetric (CV) techniques. Single crystal X-ray diffraction studies of 7 evidenced its existence as non-planar enol-imine tautomer structure, in which the phenol ring of the molecule is twisted around C-N single bond by 21.5(2) degrees. The packing structure of 7 is stabilized by C-H...pi(Ph) and O...O and C...O intermolecular short contact interactions. The CV of X display rate is dependent on irreversible and quasi-reversible redox waves in the anodic and cathodic regions due to oxidation and reduction of phenolic and iminic groups, respectively. As evidenced by ESR and UV-vis study, chemical oxidation of X by PbO2 and (NH4)2Ce(NO3)6 in MeCN and CHCl3 generates stable phenoxyl radicals [(g approximately 2.005 and lambda approximately 450 nm (1600-8200 M(-1) cm(-1))].

Synthesis, spectroscopic and structural studies of new Schiff bases prepared from 3,5-Bu2t-salicylaldehyde and heterocyclic amines: X-ray structure of N-(3,5-di-tert-butylsalicylidene)-1-ethylcarboxylato-4-aminopiperidine.

Two new sterically hindered salicylaldimines, N-(2,2,6,6-tetramethyl-piperidine-4)-3,5-Bu2t-salicylaldimine (I) and N-(1-carboxyethyl piperidine-4)-3,5-Bu2t-salicylaldimine (II), have been prepared and characterized by IR, UV-vis, 1H NMR, 13C NMR techniques and the structure of II has been examined by X-ray crystallography. No intermolecular H-bonding, pi-pi stacking or C--H...pi interactions are observed in the structure. The crystal structure the was mainly governed by intermolecular steric repulsions, due to bulky tert-butyl groups and the tendency of salicylaldimine rings to pack in parallel mode forms one-dimensional columns.