Niobium tetrahalide complexes with neutral diphosphine ligands

The reactions of NbCl4 with diphosphine ligands o-C6H4(PMe2)2, Me2PCH2CH2PMe2 or Et2PCH2CH2PEt2 in a 1:2 molar ratio in MeCN solution produced eight-coordinate [NbCl4(diphosphine)2]. [NbBr4(diphosphine)2] (diphosphine = o-C6H4(PMe2)2 or Me2PCH2CH2PMe2) were made similarly from NbBr4. X-ray crystal structures show that [NbCl4{o-C6H4(PMe2)2)2}] has a dodecahedral geometry but the complexes with dimethylene backboned diphosphines are distorted square antiprisms. The Nb-P and <P-Nb-P angles are very similar in the two types, but Nb-Cl distances are ~ 0.1Å longer in the square antiprismatic complexes. These paramagnetic (d1) complexes were also characterised by microanalysis, magnetic measurements, IR and UV-visible spectroscopy. Using a 1:1 molar ratio of NbCl4 : diphosphine (diphosphine = Me2PCH2CH2PMe2, Et2PCH2CH2PEt2, Cy2PCH2CH2PCy2 and Ph2PCH2CH2CH2PPh2) afforded [NbCl4(diphosphine)] and [NbBr4(Me2PCH2CH2PMe2)] was obtained similarly. These 1 : 1 complexes are unstable in solution, preventing X-ray crystallographic study, but based upon their diamagnetism, IR, UV-visible and 31P{1H} NMR spectra they are formulated as halide-bridged dimers [(diphosphine)X2Nb(μ-X)4NbX2(diphosphine)] with single Nb-Nb bonds and chelating diphosphines. The Nb(IV) complexes are prone to hydrolysis and oxidation in solution and the structures of the Nb(V) complexes [NbBr4(Me2PCH2CH2PMe2)2][NbOBr4(MeCN)] with a dodecahedral cation, and [{NbOCl3{Et2P(CH2)2PEt2}}2{μ-Et2P(CH2)2PEt2}] which contains seven-coordinate Nb(V) centres with a symmetrical diphosphine bridge are reported. The structure of niobium tetrabromide, conveniently made from NbCl4 and BBr3, is a chain polymer with edge-linked NbBr6 octahedra and alternating long and short Nb-Nb distances, the latter ascribed to Nb-Nb bonds

Retrospective study testing next generation sequencing of selected cancer-associated genes in resected prostate cancer

PURPOSE: Prostate cancer (PCa) has a highly heterogeneous outcome. Beyond Gleason Score, Prostate Serum Antigen and tumor stage, nowadays there are no biological prognostic factors to discriminate between indolent and aggressive tumors. The most common known genomic alterations are the TMPRSS-ETS translocation and mutations in the PI3K, MAPK pathways and in p53, RB and c-MYC genes. The aim of this retrospective study was to identify by next generation sequencing the most frequent genetic variations (GVs) in localized and locally advanced PCa underwent prostatectomy and to investigate their correlation with clinical-pathological variables and disease progression. RESULTS: Identified non-synonymous GVs included TP53 p.P72R (78% of tumors), two CSFR1 SNPs, rs2066934 and rs2066933 (70%), KDR p.Q472H (67%), KIT p.M541L (28%), PIK3CA p.I391M (19%), MET p.V378I (10%) and FGFR3 p.F384L/p.F386L (8%). TP53 p.P72R, MET p.V378I and CSFR1 SNPs were significantly associated with the HI risk group, TP53 and MET variations with T≥T2c. FGFR3 p.F384L/p.F386L was correlated with T≤T2b. MET p.V378I mutation, detected in 20% of HI risk patients, was associated with early biochemical recurrence. EXPERIMENTAL DESIGN: Nucleic acids were obtained from tissue samples of 30 high (HI) and 30 low-intermediate (LM) risk patients, according to D'Amico criteria. Genomic DNA was explored with the Ion_AmpliSeq_Cancer_Hotspot_Panel_v.2 including 50 cancer-associated genes. GVs with allelic frequency (AF) ≥10%, affecting protein function or previously associated with cancer, were correlated with clinical-pathological variables. CONCLUSION: Our results confirm a complex mutational profile in PCa, supporting the involvement of TP53, MET, FGFR3, CSF1R GVs in tumor progression and aggressiveness

Copper-Based Photosensitisers in Water Reduction:A More Efficient in Situ Formed System and Improved Mechanistic Understanding

The reduction of water has been achieved through a non-noble-metal-based homogeneous catalyst system that is formed in situ. Optimisation of the ligand quantities increased catalyst turnover numbers compared to preformed complexes. Mechanistic studies confirm a heteroleptic Cu complex as the active photosensitiser (PS) and an in situ formed Fe-phosphido dimer complex as the water reduction catalyst. The in situ method has been used to screen a range of ligands for the active PS, which has led to the identification a number of structural features important to longevity and performance. Cheap ′n′ easy H2: The reduction of water was achieved through a non-noble-metal-based homogeneous catalyst system that is formed in situ. Mechanistic studies confirm a heteroleptic Cu complex as the active photosensitiser (PS) and an in situ formed Fe-phosphido dimer complex as the water reduction catalyst (see scheme). The in situ method was used to screen a range of ligands for the active PS, which led to the identification of a number of structural features important to longevity and performance.</p