The Vibrational Spectra of Complexes with Planar Monothiooxamides. IV. The Copper(II) and Copper(I) Complexes of Neutral Monothiooxamides

The new complexes CuX₂(LH₂), CuX₂ (SH₃) (X = Cl, Br), CuX(LH₂), CuX(SH₃) (X = Cl, Br, I), CuX(H₄MTO)₂ (X = Cl, Br), Cul(H₄MTO) and CuX(H₃MMTO)₂ (X = Cl, Br, I), where LH₂ = N.N′-dimethyl-monothiooxamide, SH₃ = N(s)-methylmonothiooxamide, H₄MTO = monothiooxamide and H₃MMTO = N_(o)-methylmonothiooxamide, have been prepared. The complexes were characterized by elemental analyses, conductivity measurements, magnetic moments and spectroscopic (UV/VIS, FT-IR, Laser-Raman) studies. The vibrational analysis of the complexes has been given using NH/ND, CH₃/CD₃ and ⁶³cu/⁶⁵cu isotopic substitutions. The neutral monothiooxamides behave as monodentate ligands in the Cu(I) complexes coordinating through their thioamide sulfur atom. The ligands LH2 and SH₃ act as bidentate chelating agents in the Cu(II) complexes with ligated atoms being the thioamide sulfur and the amide oxygen.     

Dinuclear versus trinuclear complex formation in zinc(II) benzoate/pyridyl oxime chemistry depending on the position of the oxime group

The initial employment of pyridine-3-carbaldehyde oxime, (3-py)C(H)NOH, and pyridine-4-carbaldehyde oxime, (4-py)C(H)NOH, in zinc(II) carboxylate chemistry is reported. The syntheses, crystal structures and IR characterization are described for [Zn₃(O₂CPh)₆{(3-py)C(H)NOH}₂] (1) and [Zn₂(O₂CPh)₄{(4-py)C(H)NOH}₂] (2). The trinuclear molecule of 1 has a linear structure, with one monoatomically bridging η¹:η²:μ and two syn, syn-η¹:η¹:μ benzoate groups spanning each pair of Zn^II ions; the terminal metal ions are each capped by one (3-py)C(H)NOH ligand coordinating through its pyridyl nitrogen. Complex 2 exhibits a dinuclear paddle–wheel structure with a Zn···Zn distance of 2.990(2) Å; each Zn^II ion has a square pyramidal geometry with four carboxylate oxygens in the basal plane and the pyridyl nitrogen of one monodentate (4-py)C(H)NOH ligand at the apex. Both complexes form 1D architectures by virtue of hydrogen bonding interactions involving the free oxime group as donor and the oxime nitrogen (1) or carboxylate oxygens (2) as acceptors. IR data are discussed in terms of the known structures and coordination modes of the ligands.     

Metal ion-assisted transformations of 2-pyridinealdoxime and hexafluorophosphate

Metal-ion mediated reactions of 2-pyridinealdoxime and hexafluorophosphate lead to Zn(II) complexes containing picolinic acid, picolinamide and monofluorophosphate (-2) as ligands.     

Investigation of the zinc(II)-benzoate-2-pyridinealdoxime reaction system

The employment of pyridine-2-carbaldehyde oxime (paoH) in zinc(II) benzoate chemistry, in the absence or presence of azide ions, is described. The syntheses, crystal structures and spectroscopic characterization are reported for the complexes [Zn(O(2)CPh)(2)(paoH)(2)] (1), [Zn(12)(OH)(4)(O(2)CPh)(16)(pao)(4)] (2) and [Zn(4)(OH)(2)(pao)(4)(N(3))(2)] (3). The Zn(II) centre in octahedral 1 is coordinated by two monodentate PhCO(2)(-) groups and two N,N'-chelating paoH ligands. The metallic skeleton of 2 describes a tetrahedron encapsulated in a distorted cube. The {Zn(12)(μ-OH)(4)(μ(3)-ΟR)(4)}(16+) core of the cluster can be conveniently described as consisting of a central {Zn(4)(μ(3)-ΟR)(4)}(4+) cubane subunit (RO(-) = pao(-)) linked to four {Zn(2)(μ-OH)}(3+) subunits via the OH(-) group of each of the latter, which becomes μ(3). The molecule of 3 has an inverse 12-metallacrown-4 topology. Two triply bridging hydroxido groups are accommodated into the metallacrown ring. Each pao(-) ligand adopts the η(1)?:?η(1)?:?η(1)?:?μ coordination mode, chelating one Zn(II) atom and bridging a Zn(II)(2) pair. Complexes 1 and 2 display photoluminescence with maxima at ～355 nm and ～375 nm, upon maximum excitation at 314 nm; the origin of the photoluminescence is discussed.     

Longitudinal surveys on effects of changes in road traffic noise-annoyance, activity disturbances, and psycho-social well-being

The adverse effects of long-term exposure to a high volume of road traffic were studied in socio-acoustic surveys in 1997 and in 1999 after a substantial reduction in road traffic. The results obtained in 1997 showed a similar response pattern as in previously performed studies in the area in 1986 [Ohrstr?m, J. Sound Vib. 122, 277-290 (1989)]. In 1999, road traffic had been reduced from 25000 to 2400 vehicles per day, and this resulted not only in a large decrease in annoyance and activity disturbances, but also in a better general well-being. The results suggest that a reduction in both noise and other pollutants from road traffic contribute to these effects. To be able to use the outdoor environment and to have the possibility to keep windows open is essential for general well-being and daily behavior, which implies that access both to quiet indoor and outdoor sections of the residency is of importance for achievement of a healthy sound environment. More knowledge of long-term health consequences of exposure to noise and simultaneous pollutants from road traffic is needed. Studies should focus more on "softer" health outcomes and well-being than hitherto and preferably be performed in connection with traffic abatement measures.     

One-dimensional cadmium(II)/bicinate(−1) complexes : The role of the alkali metal ion used in the reaction medium

The initial employment of N,N-bis(2-hydroxyethyl)glycine (bicine; bicH₃) in CdCl₂ chemistry is reported, and the syntheses, IR spectra and crystal structures of the 1D coordination polymers [CdCl(bicH₂)]_n·nH₂O (1·H₂O) and [CdNaCl₂(bicH₂)(MeOH)]_n (2) are described. The identity of the products depends on the solvent, the reaction temperature and the alkali metal ion of the base used. The structure of 1·H₂O consists of zig-zag chains. The 7-coordinate Cd^II atoms are bridged by η¹:η¹:μ₂ carboxylate groups of the 2.21111 (Harris notation) bicH₂⁻ ligand. The coordination geometry of the metal center can be either described as a very distorted pentagonal bipyramidal or as a distorted capped octahedral. In the structure of 2 the Cd^II atoms form an almost linear chain with neighboring Na^I atoms on opposite sites of the chain. Every pair of Cd^II atoms is linked by two chloro ligands and the two oxygen atoms of the bicinate carboxylate group. The Cd^II and Na^I atoms are bridged by one μ₂ carboxylate bicinate oxygen and one μ₃ chloro ligand. The 3.2_1,21₁1₂1₂1₂ coordination mode of bicH₂⁻ is unprecedented. The CdCl₄(O_carboxylate)₂ and Na(O_hydroxyl)₂(O_carboxylate)(O_MeOH)NCl coordination spheres are octahedral and trigonal prismatic, respectively. IR data of the complexes are discussed in terms of the coordination modes of bicH₂⁻ and the known structures.     

Preparation, structural characterization and vibrational spectroscopic studies of transition metal complexes of singly- and doubly-deprotonated N-methyl-2-thiooxamic acid

Summary Synthetic procedures are described that allow access to the new monomeric complexes [M(HA)₂(H₂O)₂]·2H₂O (M = Mn or Co), [M(HA)₂(H₂O)₂] (M = Fe, Ni or Zn) and [Cu(HA)₂], and to the polymeric compounds [MA(H₂O)] _n (M = Mn, Co, Ni or Zn) and [CuA] _n , where H₂A = N-methyl-2-thiooxamic acid. The X-ray crystal structure of [Mn(HA)₂(H₂O)₂]·2H₂O reveals a trans, cis, cis octahedral geometry around the metal ion. The singlydeprotonated ligand behaves as a bidentate chelate with ligated atoms being the neutral thioamide sulfur and one of the carboxylate oxygens. The complexes were characterized by elemental analyses, conductivity measurements, X-ray powder patterns, magnetic susceptibilities and spectroscopic (e.s.r., ligand field, i.r., far-i.r., Raman) studies. The vibrational analysis of the complexes is presented using OH/OD, NH/ND, CH₃/CD₃ and metal isotopic substitutions. All data are discussed in terms of the nature of bonding in conjunction with known or assigned structures. The dianion A^2– acts as a bis-bidentate O,N/O,S bridging ligand yielding highly symmetrical squares planar (Cu^II) and octahedral (Mn^II, Co^II, Ni^II and Zn^II) polymeric compounds.Dedicated to the memory of Professor Andreas G. Galinos     

Gel-based versus gel-free proteomics: a review

With the sequencing of the genome of over 150 organisms, the field of biology has been revolutionised. Instead of studying one gene or protein at the time, it is now possible to study the effect of physiological or pathological changes on the expression of all genes or proteins in the organism. Proteomics aims at the simultaneous analysis of all proteins expressed by a cell, tissue or organism in a specific physiological condition. Because proteins are the effector molecules in all organisms, it is evident that changes in the physiological condition of an organism will be reflected by changes in protein expression and/or processing. Since the formulation of the concept of proteomics in the mid 90's proteomics has relied heavily on 2 dimensional gel electrophoresis (2DGE) for the separation and visualization of proteins. 2DGE, however, has a number of inherent drawbacks. 2DGE is costly, fairly insensitive to low copy proteins and cannot be used for the entire proteome. Therefore, over the years, several gel-free proteomics techniques have been developed to either fill the gaps left by 2DGE or to entirely abolish the gel based techniques. This review summarizes the most important gel-free and gel-based proteomics techniques and compares their advantages and drawbacks.     

Transition metal complexes with neutral and deprotonated malonamide

Summary New complexes of the general formulae [M(LH₂)₂Cl₂] (M = Mn, Fe, Co, Ni, Cu, Zn), [Mn(LH₂)₂X₂] (X = Br, I), [Cu(LH₂)₂Br₂], [Ni(LH₂)₂X₂] (X = Br, NCS, ONO₂), [Cu(LH₂)X₂]_n (X = Cl, Br), K₂[NiL₂]·2H₂O and K₂-[CuL₂]·H₂O, where LH₂ = malonamide, were isolated. The complexes were characterized by elemental analyses, X-ray powder patterns, magnetic susceptibilities and spectroscopic (variable-temperature ⁵⁷Fe-Mössbauer, e.s.r., u.v.-vis., i.r., far-i.r., Raman) studies. Monomeric trans pseudo-octahedral stereochemistries for the neutral 12 complexes and square planar structures of D _2h symmetry for the two ionic complexes are assigned in the solid state. Dimeric or polymeric five-coordinate structures are proposed for the 11 copper(II) compounds. LH₂ and L^2– behave as bidentate chelating ligands binding through oxygen and deprotonated nitrogen atoms, respectively. A detailed comparison of the studied complexes with the corresponding oxamide complexes is also presented.