Multistep self-assembly of heteroleptic magnesium and sodium-magnesium benzamidinate complexes

Reaction of the magnesium bis-alkyl Mg(CH2SiMe3)(2) and the sodium amide NaHMDS (where HMDS = N(SiMe3)(2)) with benzonitrile yields the homometallic heteroleptic complex [PhC(NSiMe3)(2)Mg{mu-NC(CH2SiMe3)Ph}](2) (1). It appears that at least six independent reactions must have occurred in this one-pot reaction to arrive at this mixed benzamidinate ketimido product. Two benzonitrile solvated derivatives of Mg(CH2SiMe3)(2) (5a and 5b) have been synthesized, with 5a crystallographically characterized as a centrosymmetric (MgC)(2) cyclodimer. When, the components of 5a are allowed to react for longer, partial addition of the Mg-alkyl unit across the C N triple bond occurs to yield the trimeric species (Me3SiCH2)(2)Mg-3[mu-N=C(CH2SiMe3)Ph](4)center dot 2N CPh (6), with bridging ketimido groups and terminal alkyl groups. Finally, using the same starting materials as that which produced 1, but altering their order of addition, a magnesium bis-alkyl unit is inserted into the Na-N bonds of a benzamidinate species to yield a new sodium magnesiate complex, PhC(NSiMe3)(2)Mg(mu-CH2SiMe3)(2)Na center dot 2TMEDA (7). The formation of 7 represents a novel (insertion) route to mixed-metal species of this kind and is the first Such example to contain a bidentate terminal anion attached to the divalent metal center. All new species are characterized by H-1 and C-13 NMR spectroscopy and where appropriate by IR spectroscopy. The solid-state structures of complexes 1, 5a, and 7 have also been determined and are disclosed within

Remote functionalisation via sodium alkylamidozincate intermediates : access to unusual fluorenone and pyridyl ketone reactivity patterns

Treating fluorenone or 2-benzoylpyridine with the sodium zincate [(TMEDA)center dot Na(mu-Bu-t)(mu-TMP)Zn(Bu-t)] in hexane solution, gives efficient Bu-t addition across the respective organic substrate in a highly unusual 1,6-fashion, producing isolable organometallic intermediates which can be quenched and aerobically oxidised to give 3-tert-butyl-9H-fluoren-9-one and 2-benzoyl-5-tert-butylpyridine respectively

Control of the diffusible hydrogen content in different steel phases through the targeted use of different welding consumables in underwater wet welding

Due to the rising number of offshore structures all over the world, underwater wet welding has become increasingly relevant, mainly as a repair method. Welding in direct contact with water involves numerous challenges. A topic focused by many studies is the risk of hydrogen-induced cracking in wet weldments due to hardness values of up to 500 HV 0.2 in the heat-affected zone (HAZ) and high levels of diffusible hydrogen in the weld metal. The risk of cracking increases as the equivalent carbon content rises, because the potential to form martensitic structures within the HAZ rises too. Thus, high-strength steels are especially prone to hydrogen-induced cracking and are considered unsafe for underwater wet repair weldments. © 2020 The Authors. Materials and Corrosion published by Wiley-VCH Gmb

Induction Heating in Underwater Wet Welding—Thermal Input, Microstructure and Diffusible Hydrogen Content

Hydrogen-assisted cracking is a major challenge in underwater wet welding of high-strength steels with a carbon equivalent larger than 0.4 wt%. In dry welding processes, post-weld heat treatment can reduce the hardness in the heat-affected zone while simultaneously lowering the diffusible hydrogen concentration in the weldment. However, common heat treatments known from atmospheric welding under dry conditions are non-applicable in the wet environment. Induction heating could make a difference since the heat is generated directly in the workpiece. In the present study, the thermal input by using a commercial induction heating system under water was characterized first. Then, the effect of an additional induction heating was examined with respect to the resulting microstructure of weldments on structural steels with different strength and composition. Moreover, the diffusible hydrogen content in weld metal was analyzed by the carrier gas hot extraction method. Post-weld induction heating could reduce the diffusible hydrogen content by −34% in 30 m simulated water depth

Structural elaboration of the surprising ortho-zincation of benzyl methyl ether

Breaking with convention, the reaction of the sodium zincate, [(TMEDA)Na(μ-TMP)(μ-tBu)Zn(tBu)] with benzyl methyl ether (PhCH2OMe) produces exclusively an ortho-zincated intermediate [(TMEDA)Na(μ-TMP)(μ-C6H4CH2OMe)Zn(tBu)] instead of the expected 'thermodynamic' α-metallated product

Gene expression profiling of mucinous ovarian tumors and comparison with upper and lower gastrointestinal tumors identifies markers associated with adverse outcomes.

PURPOSE: Advanced-stage mucinous ovarian carcinoma (MOC) has poor chemotherapy response and prognosis and lacks biomarkers to aid stage I adjuvant treatment. Differentiating primary MOC from gastrointestinal (GI) metastases to the ovary is also challenging due to phenotypic similarities. Clinicopathologic and gene-expression data were analyzed to identify prognostic and diagnostic features. EXPERIMENTAL DESIGN: Discovery analyses selected 19 genes with prognostic/diagnostic potential. Validation was performed through the Ovarian Tumor Tissue Analysis consortium and GI cancer biobanks comprising 604 patients with MOC (n = 333), mucinous borderline ovarian tumors (MBOT, n = 151), and upper GI (n = 65) and lower GI tumors (n = 55). RESULTS: Infiltrative pattern of invasion was associated with decreased overall survival (OS) within 2 years from diagnosis, compared with expansile pattern in stage I MOC [hazard ratio (HR), 2.77; 95% confidence interval (CI), 1.04–7.41, P = 0.042]. Increased expression of THBS2 and TAGLN was associated with shorter OS in MOC patients (HR, 1.25; 95% CI, 1.04–1.51, P = 0.016) and (HR, 1.21; 95% CI, 1.01–1.45, P = 0.043), respectively. ERBB2 (HER2) amplification or high mRNA expression was evident in 64 of 243 (26%) of MOCs, but only 8 of 243 (3%) were also infiltrative (4/39, 10%) or stage III/IV (4/31, 13%). CONCLUSIONS: An infiltrative growth pattern infers poor prognosis within 2 years from diagnosis and may help select stage I patients for adjuvant therapy. High expression of THBS2 and TAGLN in MOC confers an adverse prognosis and is upregulated in the infiltrative subtype, which warrants further investigation. Anti-HER2 therapy should be investigated in a subset of patients. MOC samples clustered with upper GI, yet markers to differentiate these entities remain elusive, suggesting similar underlying biology and shared treatment strategies