Toward Crystal Design in Organic Conductors and Superconductors

We have seen that many different types of intermolecular interactions in organic conducting cation radical salts. Hydrogen bonding between the donor molecules and the anions is weak but not negligible. The ionic Madelung energy is insufficient to completely intersperse anions and cations, thus the layers favored by the van der Waals interactions remain intact. The search for new conducting and superconducting salts has been mainly by trial-and-error methods, even though simple substitutions have been employed in order to obtain isostructural analogs of successful (e.g., superconducting) salts. However, even seemingly minor substitutions sometimes destroy the packing type, and different crystal structures result. Simulations with the aim at predicting crystal structures have not succeeded, mainly because the different interaction types are of comparable energy, and the delocalized and partial charges render the calculations of the ionic terms extremely unreliable. Clearly, the development of suitable crystal modeling techniques with predictive capabilities is one of the great needs of the field

Addition of aldehydes and acyl chlorides to [Rh(PiPr3)2Cl]2 : thermodynamics and molecular and crystal structures of Rh(PiPr3)2ClX[C(O)Ph] (X = H, Cl)

Addition of aldehyde (RCHO; R = n-octyl, Ph, p-Tol, p-MeOC(6)H(4), p-CF3C6H4) to [Rh((PPr3)-Pr-i)(2)Cl](2) (1) results in rapid addition of the aldehyde C-H bond to yield Rh((PPr3)-Pr-i)(2)-ClH[C(O)R] (2-R). 2-Ph was isolated, and a single-crystal X-ray diffraction study reveals a trigonal-bipyramidal structure with a small H-Rh-C(acyl) angle of 85(4)degrees. Enthalpies of addition to 1 were measured by solution calorimetry (R, Delta H/(kcal/mol)): octyl, -15.2 +/- 0.3; Ph, -10.8 +/- 0.4; p-Tol, -10.6 +/- 0.4; p-CF3C6H4, -12.7 +/- 0.4; p-MeOC(6)H(4), -10.5 +/- 0.3. Electron-withdrawing para substituents on the aromatic aldehydes favor addition. Addition of nonanal is more favorable than addition of benzaldehydes, probably due to steric effects, particularly the close hydride-phenyl contact found in 2-Ph. 1 reacts with acyl chlorides (RC(O)Cl, R = octyl, Ph) rapidly to give Rh((PPr3)-Pr-i)(2)Cl-2[C(O)R] (3-R). 3-Ph possesses a square-pyramidal structure. The enthalpies of addition were also measured calorimetrically (R, Delta H/(kcal/mol)): octyl, -24.6 +/- 0.3; Ph, -21.7 +/- 0.3. Relative to the addition of acyl chlorides, the exothermicity of aldehyde addition is greater than would be expected on the basis of thermodynamic data for related late-transition-metal complexes

Surgical treatment of pelvic organ prolapse: a historical review with emphasis on the anterior compartment

Item does not contain fulltextINTRODUCTION AND HYPOTHESIS: The objective of this work was to collect and summarize a detailed historical review of the surgical treatment of pelvic organ prolapse (POP) in which we specifically focused on the anterior compartment. METHODS: A literature search in English, Dutch, and German was carried out using the keywords pelvic organ prolapse, anterior colporrhaphy, cystocele, and interposition operations in several databases (e.g., PubMed and HathiTrust Digital Library). Other relevant journal and textbook articles were found by retrieving references cited in previous articles and textbooks. RESULTS: Probably the first explanation of the treatment of POP dates from 1500 B.C. The Egyptians gave a description to "falling of the womb" in the Kahun Papyrus. More than a millennium later, Euryphon, a contemporary of Hippocrates (400 B.C.) described some interesting therapeutic options, from succussion (turning a women upside down for several minutes) to irrigating the displaced uterus with wine. A wide range of techniques has been attempted to repair the prolapsing anterior vaginal wall. By 1866, Sim had already performed a series of operations very similar to a modern anterior repair. The first reviews about the abdominal approach to correcting a cystocele were in 1890. The first description of using mesh to cystoceles was the use of tantalum mesh in 1955. In 1970, the first report of collagen mesh in urogynecology was described. Nowadays, robot-assisted surgery and cell-based tissue engineering are the latest interventions. CONCLUSION: Many surgeons have tried to find the ideal surgical therapy for anterior compartment prolapse, but to date, this has not been achieved