51 research outputs found
Structural variations, electrochemical properties and computational studies on monomeric and dimeric Fe-Cu carbide clusters, forming copper-based staple arrays
The halide ligands of [Fe4C(CO)12(CuCl)2]2- (1) and [Fe5C(CO)14CuCl]2- (2) can be displaced by N-, P- or S-donors. Beside substitution, the clusters easily undergo structural rearrangements, with loss/gain of metal atoms, and formation of Fe4Cu/Fe4Cu3 metallic frameworks. Thus, the reaction of 1 with excess dppe yielded [{Fe4C(CO)12Cu}2(\uf06d-dppe)]2- (3). [{Fe4C(CO)12Cu}2(\uf06d-pyz)]2- (4) was obtained by reaction of 2 with Ag+ and pyrazine. [Fe4C(CO)12Cu-py]- (5) was formed more directly from [Fe4C(CO)12]2-, [Cu(NCMe)4]+ and pyridine. [Fe4Cu3C(CO)12(\uf06d-S2CNEt2)2]- (6) and [{Fe4Cu3C(CO)12(\uf06d-pz)2}2]2- (7) were prepared by substitution of the halides of 1 with diethyldithiocarbammate and pyrazolate, in the presence of Cu(I) ions. All these products were characterized by X-ray analysis. 3 and 4 and 5 are square based pyramids, with iron in the apical sites, the bridging ligands connect the two copper atoms in 3 and 4. 6 and 7 are octahedral clusters with an additional copper ion held in place by the two bridging anionic ligands, forming a Cu3 triangle with Cu-Cu distances ranging 2.63-3.13 \uc5. In 7, an additional unbridged cuprophilic interaction (2.75 \uc5) is formed between two such cluster units. DFT calculations were able to reproduce the structural deformations of 3-5, and related their differences to the backdonation from the ligand to Cu. Additionally, DFT found that, in solution, the tight ion pair [NEt4]27 is almost isoenergetic with the monomeric form. Thus, 3, 4 and 7 are entities of nanometric size assembled either through conventional metal-ligand bonds, or weaker electrostatic interactions. None of them allows electronic comunication between the two monomeric units, as shown by electrochemistry and spectroelectrochemical studies
Guidelines for the management of pregnancy in women with cystic fibrosis
Women with cystic fibrosis (CF) now regularly survive into their reproductive years in good health and wish to have a baby. Many pregnancies have been reported in the literature and it is clear that whilst the outcome for the baby is generally good and some mothers do very well, others find either their CF complicates the pregnancy or is adversely affected by the pregnancy. For some, pregnancy may only become possible after transplantation. Optimal treatment of all aspects of CF needs to be maintained from the preconceptual period until after the baby is born. Clinicians must be prepared to modify their treatment to accommodate the changing physiology during pregnancy and to be aware of changing prescribing before conception, during pregnancy, after birth and during breast feeding. This supplement offers consensus guidelines based on review of the literature and experience of paediatricians, adult and transplant physicians, and nurses, physiotherapists, dietitians, pharmacists and psychologists experienced in CF and anaesthetist and obstetricians with experience of CF pregnancy. It is hoped they will provide practical guidelines helpful to the multidisciplinary CF teams caring for pregnant women with CF
Electron Density Analysis of Metal Clusters with Semi-Interstitial Main Group Atoms. Chemical Bonding in [Co6X(CO)16]- Species
In this work, we propose a careful and thorough analysis of the chemical bond nature in high nuclearity metal carbonyl clusters having semi-interstitial main group atoms. We investigated the species [Co6X(CO)16]-(X = As, P), known for a rather interesting conformational flexibility of the cluster (leading to open or closed cages) and a corresponding polymorphism in the solid state (observed at least for X = As). The factors that trigger the molecular isomerism and the nature of X-Co and Co-Co interactions emerge from theoretical calculations and high resolution X-ray diffraction. Both energy and charge density atomic partitioning (QTAIM, EDA, IQA) are employed for this analysis, with the aim of revealing the stabilizing/destabilizing factors of the interaction between the cage and the semi-interstitial atoms in the various conformations
FT-IR spectroscopy and DFT calculations on flurinated macromers diols: IR intensities and association properties
Copolymerization of Fe4Cu2C(CO)12 Moieties with Bidentate N-Ligands: Synthesis and Crystal Structure of the [Fe4Cu2(u6-C)(CO)12(u-bipy)]4•2THF Square Tetramer and the Infinite [Fe4Cu2(u6-C)(CO)12(u-N-Ar-N)]∞ Zigzag Chains
THE VIBRATIONS OF BRIDGING CARBONYL GROUPS AS MORE SENSITIVE INDICATORS OF MOLECULAR GEOMETRY THAN TERMINAL CARBONYL GROUPS IN TRANSITION METAL CARBONYL CLUSTER COMPOUNDS. PART 2, SOME M5 SPECIES.
Electron Density Analysis of Metal Clusters with Semi-Interstitial Main Group Atoms. Chemical Bonding in [Co 6
Copolymerization of Fe4Cu2C(CO)12 moieties with bidentate N-ligands: synthesis and crystal structure of the [Fe4Cu2(6-C)(CO)12(-bipy)]4\u20228THF square tetramer and the infinite [Fe4Cu2(6-C)(CO)12(-L\u2013L)] zigzag chains
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