scholarly journals Mono- and di-cationic hydrido boron compounds

2015 ◽  
Vol 44 (32) ◽  
pp. 14359-14367 ◽  
Author(s):  
Rajendra S. Ghadwal ◽  
Christian J. Schürmann ◽  
Diego M. Andrada ◽  
Gernot Frenking
Keyword(s):  
Boron Atom ◽  
Boron Compounds ◽  
Stable Mono

Stable mono- and di-cationic hydrido boron compounds featuring CH2BH2(μ-H)BH2CH2 and CH2BH(μ-H)2BHCH2 cores are readily accessible by dehydrogenative hydride abstractions. NBO calculations revealed the occurrence of two B–H–B 3c–2e bonds in the HB(μ-H)2BH moiety of di-cations (7 and 8), where 43% is located at the H bridges and ∼28% at each boron atom.

Borverbindungen, 8. Mitteilung Umlagerung mittlerer O-B-O-Heterocyclen zu ringförmigen Oligomeren / Boron Compounds, Part 8 Rearrangement of Medium Sized O-B-O Heterocycles to Cyclic Oligomers

1977 ◽  
Vol 32 (12) ◽  
pp. 1408-1415 ◽  
Author(s):  
Ulrich W. Gerwarth
Keyword(s):  
Boron Atom ◽  
Ring Opening ◽  
Boron Compounds ◽  
Cyclic Oligomers ◽  
Boron Heterocycles

The condensation of phenyldihydroxyborane with pentane-1,5-diols yields no 1,3,2-dioxabora-cyclooctanes but oligomeric boron heterocycles. Their formation can be explained by an exchange of ligands of the boron atom, a process analogous to metathetic ring-opening polymerisation.

The application of FEL-EXPERT system in the interpretation of boron compounds toxicity

1990 ◽  
Vol 55 (1) ◽  
pp. 317-329
Author(s):  
Oldřich Štrouf ◽  
Vladimír Mařík
Keyword(s):  
Expert System ◽  
Boron Atom ◽  
High Toxicity ◽  
Production Rules ◽  
Boron Compounds ◽  
Low Toxicity ◽  
Technical University ◽  
Medium Toxicity

The influence of substructural features on boron compounds toxicity (LD50, mice, i.p.) has been studied by FEL-EXPERT system developed at the Czech Technical University of Prague. A set of 108 compounds containing one or two boron atoms in their molecule has been arbitrarily divided into three classes: the compounds with a high toxicity (LD50 < 100 mg/kg), with a medium toxicity (100 mg/kg ⪬ LD50 < 1 000 mg/kg) and with a low toxicity (LD50 ≥ 1 000 mg/kg). The compounds have been represented by 70 substructural fragments, 27 of them being "central substructures" containing boron atom(s). The inference net consists of 118 nodes (74 of the Bayesian type), 362 production rules and 74 context links. The total classification correctness has been 98%. As a case-study, the classification of p-tolylboronic acid (LD50 = 520 mg/kg) and 4-carboxyphenylboronic acid (LD50 = 3 838 mg/kg) has been discussed.

scholarly journals N-Heterocyclic Carbene Adducts of Alkynyl Functionalized 1,3,2-Dithioborolanes

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1690 ◽  
Author(s):  
Richard Böser ◽  
Lars Denker ◽  
René Frank
Keyword(s):  
Boron Atom ◽  
Good Yield ◽  
Optical Materials ◽  
Medicinal Chemistry ◽  
Materials Science ◽  
Building Blocks ◽  
Boron Compounds ◽  
Boronate Esters ◽  
Chelate Effect ◽  
Post Functionalization

Alkynyl functionalized boron compounds are versatile intermediates in the areas of medicinal chemistry, materials science, and optical materials. In particular, alkynyl boronate esters [R1−C≡C−B(OR2)2] are of interest since they provide reactivity at both the alkyne entity, with retention of the B−C bond or alkyne transfer to electrophilic substrates with scission of the latter. The boron atom is commonly well stabilized due to (i) the extraordinary strength of two B−O bonds, and (ii) the chelate effect exerted by a bifunctional alcohol. We reasoned that the replacement of a B−O for a B−S bond would lead to higher reactivity and post-functionalization in the resulting alkynyl boronate thioesters [R1−C≡C−B(S2X)]. Access to this poorly investigated class of compounds starts form chloro dithioborolane cyclo-Cl−B(S2C2H4) as a representative example. Whereas syntheses of three coordinate alkynyl boronate thioesters [R1−C≡C−B(S2X)] proved to be ineffective, the reactions of NHC-adducts (NHC = N-heterocyclic carbene) of cyclo-Cl-B(S2C2H4) afforded the alkyne substituted thioboronate esters in good yield. The products NHC−B(S2C2H4)(C≡C-R1) are remarkably stable towards water and air, which suggests their use as boron-based building blocks for applications akin to oxygen-based boronate esters.

Catalytic Fluorination of Boron Compounds at a Bismuth Redox Platform

2019 ◽  
Author(s):  
Oriol Planas ◽  
Feng Wang ◽  
Markus Leutzsch ◽  
Josep Cornella
Keyword(s):  
Transition Metal ◽  
Main Group ◽  
Group Element ◽  
Oxidation States ◽  
Boron Compounds ◽  
Main Text ◽  
Main Group Element ◽  
Rational Ligand Design ◽  
Supplementary Material

The ability of bismuth to maneuver between different oxidation states in a catalytic redox cycle, mimicking the canonical organometallic steps associated to a transition metal, is an elusive and unprecedented approach in the field of homogeneous catalysis. Herein we present a catalytic protocol based on bismuth, a benign and sustainable main-group element, capable of performing every organometallic step in the context of oxidative fluorination of boron compounds; a territory reserved to transition metals. A rational ligand design featuring hypervalent coordination together with a mechanistic understanding of the fundamental steps, permitted a catalytic fluorination protocol based on a Bi(III)/Bi(V) redox couple, which represents a unique example where a main-group element is capable of outperforming its transition metal counterparts.<br>A main text and supplementary material have been attached as pdf files containing all the methodology, techniques and characterization of the compounds reported.<br>

Building a Picture of Heteroborane Isomerisation: Synthesis and Characterisation of the 10-(Dialkyl- sulfane)-7,8-diphenyl-7,8-dicarba-nido-undecaboranes 7,8-Ph2-10-L-7,8-nido-C2B9H10 (L = SMe2, SMeEt, SEt2) and of Intermediate and Isomerised Products Arising from Metallation of the First of These

1999 ◽  
Vol 64 (6) ◽  
pp. 1013-1027 ◽  
Author(s):  
Shirley Dunn ◽  
Rhona M. Garrioch ◽  
Georgina M. Rosair ◽  
Lorraine Smith ◽  
Alan J. Welch
Keyword(s):  
Boron Atom ◽  
Experimental Information ◽  
Crystallographic Study

Three new, substituted, nido carboranes, 7,8-Ph2-10-(SMe2)-7,8-nido-C2B9H10 (1a), 7,8-Ph2-10- (SMeEt)-7,8-nido-C2B9H10 (1b) and 7,8-Ph2-10-(SEt2)-7,8-nido-C2B9H10 (1c) have been synthesised and characterised, including a crystallographic study of the first. Deprotonation of 1a followed by treatment with (MeCN)2(CO)2MoBr(η-C3H5) at 0 °C affords the non-icosahedral 1,2-Ph2-4-(SMe2)-5-(η-C3H5)-5,5-(CO)2-5,1,2-closo-MoC2B9H8 (2a), which on subsequent warming transforms into icosahedral 2,8-Ph2-5-(SMe2)-1-(η-C3H5)-1,1-(CO)2-1,2,8-closo- MoC2B9H8 (3a). It is argued that under the conditions of these rearrangements the B-S bond is likely to remain intact, and consequently that the identity of the SMe2-labelled boron atom in 3a affords useful experimental information on the course of the isomerisation.

scholarly journals Synthesis and Characterisation of a Boron-Rich Symmetric Triazine Bearing a Hypoxia-Targeting Nitroimidazole Moiety

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 202
Author(s):  
Tobias Hartwig Bünning ◽  
Luigi Panza ◽  
Abdel Kareem Azab ◽  
Barbara Muz ◽  
Silvia Fallarini ◽  
...  
Keyword(s):  
Tumor Tissue ◽  
High Ratio ◽  
Neutron Capture Therapy ◽  
Boron Compounds ◽  
The Core ◽  
Boron Neutron Capture ◽  
Starting Point ◽  
Primary Fibroblasts ◽  
Normal Human ◽  
Hypoxia Markers

Boron Neutron Capture Therapy (BNCT) is a binary therapy that promises to be suitable in treating many non-curable cancers. To that, the discovery of new boron compounds able to accumulate selectively in the tumour tissue is still required. Hypoxia, a deficiency of oxygen in tumor tissue, is a great challenge in the conventional treatment of cancer, because hypoxic areas are resistant to conventional anticancer treatments. 2-Nitroimidazole derivatives are known to be hypoxia markers due to their enrichment by bioreduction in hypoxic cells. In the present work, 2-nitroimidazole was chosen as the starting point for the synthesis of a new boron-containing compound based on a 1,3,5-triazine skeleton. Two o-carborane moieties were inserted to achieve a high ratio of boron on the molecular weight, exploiting a short PEG spacer to enhance the polarity of the compound and outdistance the active part from the core. The compound showed no toxicity on normal human primary fibroblasts, while it showed noteworthy toxicity in multiple myeloma cells together with a consistent intracellular boron accumulation.

scholarly journals Assessment of boron-containing compounds and oleoylethanolamide supplementation on the recovery trend in patients with COVID-19: A structured summary of a study protocol for a randomized controlled trial

Trials ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Helda Tutunchi ◽  
Majid Mobasseri ◽  
Samira Pourmoradian ◽  
Hamid Soleimanzadeh ◽  
Behnam Kafil ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Sample Size ◽  
Complete Blood Count ◽  
Controlled Clinical Trial ◽  
Medical Sciences ◽  
Boron Compounds ◽  
Double Blind ◽  
Link Type ◽  
Nutrition Research ◽  
Full Protocol

Abstract Objectives In this study, we investigate the effect of boron-containing compounds and oleoylethanolamide supplementation on the recovery trend in patients with COVID-19. Trial design The current study is a single-center, randomized, double-blind, placebo-controlled clinical trial with parallel groups. Participants The inclusion criteria include male and female patients≥18 years of age, with a confirmed diagnosis of SARS-CoV-2 infection via polymerase chain reaction (PCR) and/or antibody test and with written informed consent to participate in this trial. The exclusion criteria include regular use of any other supplement, severe and critical COVID-19 pneumonia, pregnancy and breastfeeding. This study is being conducted at Imam Reza Hospital, Tabriz University of Medical Sciences, Tabriz, Iran. Intervention and comparator Patients are randomly assigned to four groups. The first group (A) will take one capsule containing 5 mg of boron compounds twice a day for two weeks. The second group (B) will take one capsule containing 200 mg oleoylethanolamide twice a day for two weeks. The third group (C) will take one capsule containing 5 mg boron compounds with 200 mg oleoylethanolamide twice a day for two weeks, and the fourth group (D) does not receive any additional treatment other than routine treatments. Boron-containing compounds and oleoylethanolamide capsules will be synthesized at Nutrition Research Center of Tabriz University of Medical Sciences. Main outcomes The primary end point of this study is to investigate the recovery rate of clinical symptoms, including fever, dry cough, and fatigue, as well as preclinical features, including complete blood count (CBC), the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) profiles within two weeks of randomization. Randomisation Patients are randomized into four equal groups in a parallel design (allocation ratio 1:1). A randomized block procedure is used to divide subjects into one of four treatment blocks (A, B, C, and D) by a computer-generated allocation schedule. Blinding (masking) The participants and investigators (enrolling, assessing, and analyzing) are blinded to the intervention assignments until the end of the study and data analysis. Numbers to be randomised (sample size) The calculated total sample size is 40 patients, with 10 patients in each group. Trial Status The protocol is Version 1.0, May 17, 2020. Recruitment began May 19, 2020, and is anticipated to be completed by October 19, 2020. Trial registration This clinical trial has been registered by the title of “Assessment of boron-containing compounds and oleoylethanolamide supplementation on the recovery trend in Patients with COVID-19: A double-blind randomized placebo-controlled clinical trial” in the Iranian Registry of Clinical Trials (IRCT). The registration number is “IRCT20090609002017N35”, https://www.irct.ir/trial/48058. The registration date is 17 May 2020. Full protocol The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Spectra and structure of phosphorus-boron compounds

1974 ◽  
Vol 20 (3) ◽  
pp. 471-485 ◽  
Author(s):  
J.D. Odom ◽  
S. Riethmiller ◽  
S.J. Meischen ◽  
J.R. Durig
Keyword(s):  
Boron Compounds
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