Synthesis and characterization of a family of M(2+) complexes supported by a trianionic ONO(3-) pincer-type ligand: towards the stabilization of high-spin square-planar complexes.

High-spin square-planar molecular compounds are rare. In an effort to access this unique combination of geometry and spin state, we report the synthesis of a series of M(II) compounds stabilized by a trianionic pincer-type ligand, highlighting the formation of a high-spin square-planar Co(II) complex. Low-temperature, variable-frequency EPR measurements reveal that the ground electronic state of the Co(II) analogue is a highly anisotropic Kramers doublet (effective g values 7.35, 2.51, 1.48). This doublet can be identified with the lowest doublet of a quartet, S = 3/2 spin state that exhibits a very large ZFS, D ≥ 50 cm(-1). The observation of an effective g value considerably greater than the largest spin-only value 6, demonstrates that the orbital angular moment is essentially unquenched along one spatial direction. Density Functional Theory (DFT) and time-dependent DFT calculations reveal the electronic configurations of the ground and excited orbital states. A qualitative crystal field description of the geff tensor shows that it originates from the spin-orbit coupling acting on states obtained through the transfer of a ß electron from the doubly occupied xy to the singly-occupied {xz/yz} orbitals.

A high-spin square-planar Fe(ii) complex stabilized by a trianionic pincer-type ligand and conclusive evidence for retention of geometry and spin state in solution.

Square-planar high-spin Fe(ii) molecular compounds are rare and the only three non-macrocyclic or sterically-driven examples reported share a common FeO4 core. Using an easily modifiable pincer-type ligand, the successful synthesis of the first compound of this type that breaks the FeO4 motif was achieved. In addition, we present the first evidence that geometry and spin state persist in solution. Extensive characterization includes the first high-field EPR and variable field/temperature Mössbauer spectra for this class of compounds. Analysis of the spectroscopic data indicates this complex exhibits a large and positive zero-field splitting tensor. Furthermore, the unusually small ΔEQ value determined for this compound is rationalized on the basis of DFT calculations.

Zenker's diverticulum, a rare cause of upper gastrointestinal bleeding.

UNLABELLED: The most common complication of Zenker's diverticulum is aspiration pneumonia, compression of the trachea and esophageal obstruction with large diverticulum, and increased risk of development of carcinoma. Thus bleeding occurs rarely, can be massive and life threatening, with ulceration being the most common cause. MATERIAL AND METHODS: We describe a patient with sever upper gastrointestinal bleeding as a result of a Zenker's diverticulum. A 75 year-old woman was referred to the emergency room and hospitalized for hematemesis, melena, asthenia and total dysphagia. In this particular case we preferred open technique because of the diverticulum dimensions and bleeding episode. Left cervicotomy was practiced on the anterior edge of the sternocleidomastoid muscle, being known that Zenker diverticulum extend into the left neck 90% of the time, fact also confirmed by radiology in this case. RESULTS: Postoperatively, the patient showed a complication free recovery. Five days after treatment the patient resumed nourishment. Several days later our patient was able to return home. Follow-up at 12 months after the operation showed complete recovery. Ulcer of the basis of Zenker's diverticulum is a rare entity and, only a few cases were reported in the literature to date. Omitting thecricomyotomy predisposes to fistula or diverticulum recurrence due to the persistence of a high pharyngeal intraluminal pressure that acts on the posterior wall just proximal to the upper esophageal sphincter. CONCLUSIONS: Zenker's diverticulum is an unusual site of origin for clinically significant upper gastrointestinal hemorrhage and differential diagnosis must include other more frequent causes of upper gastrointestinal bleeding. In our opinion, classicalsurgical therapy is indicated when distal esophageal imaging cannot be obtained during endoscopic examination, there is a large diverticulum or in an emergency setting when fast control over the bleeding source is required.

Prognostic factors in colorectal cancer evolution.

BACKGROUND: This paper tries to evaluate prognostic value of various pre and post-operative colorectal cancer markers. MATERIALS AND METHODS: In the study conducted in our clinic over a period of five years we tried to emphasize the biological factors of prognostic value in colorectal cancer, and to demonstrate the important role of these factors in predicting survival, but also of early relapse or, in some cases, resistance to chemotherapy. Most important component of these factors remains molecular tumor markers. RESULTS: Of the markers of tumor load increased preoperative serum levels of carcinoembryonic antigen (CEA) means increased risk of neoplastic recurrence and reducing survival expectancy. Aneuploidy tumor cells would have the same importance. CONCLUSIONS: Although for their study modern and expensive techniques are necessary, molecular tumor markers have an increasingly role appreciated by researchers both in estimating the risk of relapse and neoplastic dissemination and the response rate to adjuvant treatment. It is estimated that the study of molecular/genetic profile of colorectal tumors in the future will dictate therapeutic decisions ahead.