We report the synthesis and characterization of a series of BNP-incorporated borafluorenate heterocycles formed via thermolysis reactions of pyridylphosphine and bis(phosphine)-coordinated borafluorene azides. The use of diphenyl-2-pyridylphosphine (PyPhP), trans-1,2-bis(diphenylphosphino)ethylene (PhP(H)C═C(H)PPh), and bis(diphenylphosphino)methane (PhPC(H)PPh) as stabilizing ligands resulted in Staudinger reactions to form complex heterocycles with four- (BNP, BNPC, PN) and five-membered (BNPC and BNPC) rings, which were successfully isolated and fully characterized by multinuclear NMR and X-ray crystallography. However, when bis(diphenylphosphino)benzene (PhP-Ph-PPh) was used as the ligand in a reaction with 9-bromo-9-borafluorene (BF-Br), due to the close proximity of the donor P atoms, the diphosphine-stabilized borafluoronium ion with an unusual borafluorene dibromide anion was formed.
View Article and Find Full Text PDFSubstitution of a C=C bond by an isoelectronic B-N bond is a well-established strategy to alter the electronic structure and stability of acenes. BN-substituted acenes that possess narrow energy gaps have attractive optoelectronic properties. However, they are susceptible to air and/or light.
View Article and Find Full Text PDFSelective and site-specific boron-doping of polycyclic aromatic hydrocarbon frameworks often give rise to redox and/or photophysical properties that are not easily accessible with the analogous all-carbon systems. Herein, we report ligand-mediated control of boraphenanthrene closed- and open-shell electronic states, which has led to the first structurally characterized examples of neutral bis(9-boraphenanthrene) (-) and its corresponding biradical (). Notably, compounds and show intramolecular charge transfer absorption from the 9-boraphenanthrene units to -quinodimethane, exhibiting dual (red-shifted) emission in solution due to excited state conjugation enhancement (ESCE).
View Article and Find Full Text PDFA series of BN-incorporated borafluorenate heterocycles, bis(borafluorene-phosphinimine)s (-), have been formed via molecular Staudinger-type reactions. The reactions were promoted by light or heat using monodentate phosphine-stabilized 9-azido-9-borafluorenes (RP-BF-N; -) and involve the release of dinitrogen (N), migration of phosphine from boron to nitrogen, and oxidation of the phosphorus center (P to P). Density functional theory (DFT) calculations provide mechanistic insight into the formation of these compounds.
View Article and Find Full Text PDFHerein, we describe the redox reaction of bis(germylene) PhC(NBu)Ge-Ge(NBu)CPh with different equivalents of MeSiN affording two distinct products. The reaction of MeSiN with bis-germylene in a 1:1 molar ratio results in compound at -78 °C; however, treatment of bis-germylene with a 2.1 equiv of MeSiN at room temperature results in compound .
View Article and Find Full Text PDFCurr Dev Nutr
April 2022
Background: Infant and young child feeding (IYCF) practices directly impact the health of <2-y-old children. Minimum dietary diversity (MDD) is an IYCF indicator to assess feeding practices of children aged 6-23 mo. The definition of MDD has recently been updated by the WHO and UNICEF, substituting "≥4 out of 7 food groups" (MDD-7FG) with "≥5 out of 8 food groups" (MDD-8FG).
View Article and Find Full Text PDFHerein, we report the design and synthesis of far-red emissive boryl-thiophene-BODIPY triads . The π-conjugation length and electronic communication between borane and BODIPY moieties are tuned by judiciously varying the size of the oligothiophene spacer in these triads (, terthiophene; , quarterthiophene; and , pentathiophene). Conjugates showed intriguing triple emissions in the blue to far-red regions.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2021
Herein, we report the stabilization of nitrene reagents as the source of a nitrogen atom to synthesize nitrogen-incorporated R LSi-N←SiLR (1) [L=PhC(NtBu) ; R =NTMS , R =NTMS]. Compound 1 is synthesized by reacting LSi(I)-Si L with 3.1 equivalents of Me SiN at low temperature to afford a triene-like structural framework.
View Article and Find Full Text PDFHerein, we report on a facile and selective one-pot synthetic route to silicon-boron radicals. Reduction of BrBTip (Tip = 2,4,6-PrCH) with KC in the presence of LSi-R affords LSi(Bu)-B(Br)Tip () and LSi(N(TMS))-B(Br)Tip () [L = PhC(NBu)]. These first examples of silicon-boron isolated radical species feature spin density on the silicon and boron atoms.
View Article and Find Full Text PDFIsolation of two-coordinate compounds of heavier Group 15 elements in low oxidation state is challenging due to the preferential formation of dimers or oligomers. Herein, we report the first examples of donor-stabilized two-coordinate Sb(I) and Bi(I) ions. The reduction of antimony and bismuth trihalides with KC in the presence of cyclic alkyl(amino) carbene (cAAC) afforded Sb(I) and Bi(I) cations in the form of triflate salts [(cAAC)Sb][OTf] () and [(cAAC)Bi][OTf] ().
View Article and Find Full Text PDFSynthesis and bonding aspects of mononuclear bis-amidinate indium(iii) monohalides L2InX (1-3), where L = PhC(NtBu)2; X is F (1), Br (2) or I (3) and β-diketiminate (NacNac) stabilized In(ii) dimer (MesNacNac)2In2Br2 (4) with In-In bond are reported along with the single-crystal X-ray structures of 2-4.
View Article and Find Full Text PDFThree new triads [bis(mesityl)boryl (MesB)-vinylbithiophene-BODIPY] bearing zero (), two (), and four () methyl groups on the BODIPY core are synthesized, and their optical properties are reported. The vinyl linker between the thiophene rings in the spacer moiety improved the electronic communication between the boryl and BODIPY units. It displayed a bathochromic shift in the absorption and emission spectra compared to the MesB-bithiophene-BODIPY triad reported elsewhere.
View Article and Find Full Text PDFWe report the design, synthesis, structure, bonding, and reaction of a neutral 2π aromatic three-membered disilaborirane. The disilaborirane is synthesized by a facile one-pot reductive dehalogenation of amidinato-silylene chloride and dibromoarylborane with potassium graphite. Despite the tetravalent arrangement of atoms around silicon, the three-membered silicon-boron-silicon ring is aromatic, as evidenced by NMR spectroscopy, nucleus independent chemical shift calculations, first-principles electronic structure studies using density functional theory (DFT) and natural bond orbital (NBO) based bonding analysis.
View Article and Find Full Text PDFNeutral, mononuclear aluminum and gallium radicals, stabilized by cyclic (alkyl)(amino)carbene (cAAC), were synthesized. LMCl upon reduction with KC in the presence of cAAC afforded the radicals LMCl(cAAC), where L = PhC(NBu) and M = Al (), Ga (). The radicals were characterized by X-ray crystallography, electron paramagnetic resonance (EPR) spectroscopy, and mass spectrometry.
View Article and Find Full Text PDFTypically, molecules with a twisted donor-acceptor (D-A) architecture have been exploited for constructing thermally activated delayed fluorescence (TADF) materials. Herein, we report the first example of a thiophene-based thermally activated delayed fluorescent molecule without a D-A architecture. Compound 1 (2,5-bis(2,2-di(thiophen-2-yl)vinyl)thiophene) is conformationally flexible and shows weak fluorescence in the solution state but displays bright TADFin both condensed and solid states.
View Article and Find Full Text PDFChalcogen-bonded silicon phosphinidenes LSi(E)-P- cAAC (E=S (1); Se (2); Te (3); L=PhC(NtBu) ; cAAC=C(CH )(CMe ) N-2,6-iPr C H )) were synthesized from the reactions of silylene-phosphinidene LSi-P- cAAC (A) with elemental chalcogens. All the compounds reported herein have been characterized by multinuclear NMR, elemental analyses, LIFDI-MS, and single-crystal X-ray diffraction techniques. Furthermore, the regeneration of silylene-phosphinidene (A) was achieved from the reactions of 2-3 with L'Al (L'=HC{(CMe)(2,6-iPr C H N)} ).
View Article and Find Full Text PDFHerein, we report the synthesis and characterization of the metal free low valent fluoroborylene [(Me-cAAC)BF] (1) stabilized by cyclic (alkyl)(amino) carbene (cAAC). The fluoroborylene 1 is obtained by the reductive defluorination of Me-cAAC:BF with 2.0 equivalents of KC in the presence of 1.
View Article and Find Full Text PDFDespite the notable progress in the stabilization of main group radicals by NHCs and cAACs, no germanium radicals have been isolated so far due to synthetic challenges. Stabilization of neutral [:ER] (E = Si, Ge) radicals is an uphill task, as these reactive transient species are highly susceptible to dimerization. Herein, we report the synthesis of acyclic neutral germanium(I) radicals Cy-cAAC:GeN(SiMe)Dip (1) and Me-cAAC:GeN(SiPh)Mes (2) obtained by the reduction of [Ar(SiR)NGeCl] with KC in the presence of cAAC.
View Article and Find Full Text PDFThe design, synthesis and aggregation-induced emission properties of a new series of triarylborane-oligothiophene-dicyanovinyl (DCV) conjugates 4-6 (A-D-A' type molecular configuration) are reported. The optical properties of 4-6 can be modulated by judiciously varying the number of thiophene units between electron deficient boryl and dicyanovinyl units. Compound 6 with terthiophene spacer showed highly red-shifted absorption and emission compared to 5 and 4 with bithiophene and monothiophene spacers, respectively.
View Article and Find Full Text PDFThe design and synthesis of two structurally close and complementarily fluorescent boron based molecular siblings 2 and 3 are reported. The luminescence properties of individual triads are modulated to complement each other by controlling the intramolecular energy transfer in 2 and 3. The binary mixture of 2 and 3 emits white-light.
View Article and Find Full Text PDFThree new triarylborane conjugated dicyanovinyl chromophores (Mes2B-π-donor-DCV); donor: N-methyldiphenylamine () and triphenylamine ( and [with two BMes2 substitutions]) of type A-D-A (acceptor-donor-acceptor) are reported. Compounds exhibit intense charge transfer (CT) absorption bands in the visible region. These absorption peaks are combination CT bands of the amine donor to both the BMes2 and DCV units.
View Article and Find Full Text PDFDiffuse alveolar hemorrhage (DAH) is characterized by the presence of hemoptysis, anemia, and the presence of diffuse parenchymal infiltrates on imaging studies. Idiopathic pulmonary hemosiderosis (IPH) is an uncommon cause of diffuse alveolar hemorrhage (DAH) and is classically known to present in childhood. Adult-onset IPH is extremely rare.
View Article and Find Full Text PDFBackground: Chronic obstructive pulmonary disease (COPD) is characterized by progressive deterioration of respiratory function along with systemic effects which have a great impact on health-related quality of life (HRQoL). Classification of severity of airflow limitation in COPD does not represent the clinical consequences of COPD. Hence, combined COPD assessment should be preferred.
View Article and Find Full Text PDFThe design and synthesis of a new tri- and tetracoordinate boron conjugate is reported. The conjugate shows broad near-IR emission (∼625-850 nm) and is found to be a selective colorimetric and ratiometric sensor for fluoride ions.
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