A series of [2+2]-photocycloadditions of 1,4-naphthoquinone with various alkenes and diphenylacetylene were investigated under batch and continuous-flow conditions. Acetone-sensitization furnished the corresponding photoadducts in good to excellent yields and purities. Compared to batch operations that demanded exhaustive irradiation times of 10-13 h, the flow process generally gave superior conversions and subsequently yields with a residence time of just 60 min.
View Article and Find Full Text PDFReaction of lanthanoid tris(3,5-dimethylpyrazolate) compounds, [Ln(Mepz)(thf)] (Ln=La 1 a, Ce, Pr, Dy 1 b, Yb, Lu) with potassium or lithium bistrimethylsilylamide and with or without added 3,5-dimethylpyrazole, or of lanthanoid tris(bistrimethylsilyl)amide complexes with potassium bistrimethylsilylamide and 3,5-dimethylpyrazole have yielded a variety of oxide centred Ln or Ln/(K or Li) multinuclear cages, namely, [LaO(Mepz) K(thf)] (2 a), [LaO(Mepz)Li(MepzH)]⋅0.5Hexane (2 b), [LaO(Mepz)(MepzH)] (2 c) (from heating 1 a in toluene), [CeO(Mepz)K(dme)] (3 a), [CeO(Mepz)Li(thf)]⋅0.5Hexane (3 b) and [Ce(Mepz)Li(thf)] (3 c), which crystallized together, [CeO(Mepz)K(thf)] (3 d), [PrO(Mepz)K(thf)] (4), [DyO(Mepz)K(thf)]⋅THF (5), [YbO(Mepz)K(thf)]⋅THF (6), and [LuO(Mepz)K(thf)]⋅THF (7).
View Article and Find Full Text PDFRare earths, scandium, yttrium, and the fifteen lanthanoids from lanthanum to lutetium, are classified as critical metals because of their ubiquity in daily life. They are present in magnets in cars, especially electric cars; green electricity generating systems and computers; in steel manufacturing; in glass and light emission materials especially for safety lighting and lasers; in exhaust emission catalysts and supports; catalysts in artificial rubber production; in agriculture and animal husbandry; in health and especially cancer diagnosis and treatment; and in a variety of materials and electronic products essential to modern living. They have the potential to replace toxic chromates for corrosion inhibition, in magnetic refrigeration, a variety of new materials, and their role in agriculture may expand.
View Article and Find Full Text PDFPt coordination complexes are of interest as prodrugs of Pt anticancer agents, as they can avoid deactivation pathways owing to their inert nature. Here, we report the oxidation of the antitumor agent [Pt(-BrCF)NCHCHNEt}Cl(py)], (py = pyridine) to dihydroxidoplatinum(IV) solvate complexes [Pt{(-BrCF)NCHCHNEt}Cl(OH)(py)].HO, with hydrogen peroxide (HO) at room temperature.
View Article and Find Full Text PDFComplexes of the alkali metals Li-Cs with 3-thiophenecarboxylate (3tpc), 2-methyl-3-furoate (2m3fur), 3-furoate (3fur), 4-hydroxycinnamate (4hocin), and 4-hydroxybenzoate (4hob) ions were prepared via neutralisation reactions, and the structures of [Li(3tpc)] (); [K(3tpc)] (); [Rb(3tpc)(HO)] (); [Cs{H(3tpc)}] (); [Li(2m3fur)(HO)] (i); [K(2m3fur)(HO)] (); [Li(3fur)](i); [K(4hocin](HO)] (); [Rb{H(4hocin)}].nHO (); [Cs(4hocin)(HO)] (); [Li(4hob)] (); [K(4hob)(HO)] (); [Rb(4hob)(HO)] (); and [Cs(4hob)(HO)] () were determined via X-ray crystallography. Bulk products were also characterised via XPD, IR, and TGA measurements.
View Article and Find Full Text PDFReductive dimerization of fulvenes using low-valent metal precursors is a straightforward one-step approach to access ethylene-bridged metallocenes. This process has so far mainly been employed with fulvenes carrying one or two substituents in the exocyclic position. In this work, a new synthesis of the unsubstituted exocyclic 1,2,3,4-tetraphenylfulvene (), its full structural characterization by NMR spectroscopy and single-crystal X-ray diffraction, as well as some photophysical properties and its first use in reductive dimerization are described.
View Article and Find Full Text PDFThis paper describes a novel and simple method - direct reaction of lanthanoid metals with equimolar amounts of iodine and a formamidine under ultrasonication as an effective, metal-based route to lanthanoid(III) diiodide formamidinates, namely I. N,N'-Bis(2,6-diisopropylphenyl)formamidinatodiiodidolanthanoid(III) complexes [Ln(DippForm)I (thf) ] (Ln=La, 1, Ce, 2, Tb, 3, Ho, 4, Er, 5, Tm, 6); II. N,N'-Bis(2,6-diethylphenyl)formamidinatodiiodidolanthanoid(III) complexes [Ln(EtForm)I (thf) ] (Ln=Ce, 7, Nd, 8, Gd, 9, Tb, 10, Dy, 11, Ho, 12, Er, 13, Lu, 14).
View Article and Find Full Text PDFOwing to the strict hard/soft dichotomy between the lanthanoids and tellurium atoms, and the strong affinity of lanthanoid ions for high coordination numbers, low-coordinate, monomeric lanthanoid tellurolate complexes have remained elusive as compared to the lanthanoid complexes with lighter group 16 elements (O, S, and Se). This makes the development of suitable ligand systems for low-coordinate, monomeric lanthanoid tellurolate complexes an appealing endeavor. In a first report, a series of low-coordinate, monomeric lanthanoid (Yb, Eu) tellurolate complexes were synthesized by utilizing hybrid organotellurolate ligands containing N-donor pendant arms.
View Article and Find Full Text PDFDivalent lanthanoid pseudo-Grignard reagents PhLnBr (Ln=Sm, Eu and Yb) can be easily prepared by the oxidative addition of bromobenzene (PhBr) to lanthanoid metals in tetrahydrofuran (THF). PhLnBr reacts with bulky N,N'-bis(2,6-di-isopropylphenyl)formamidine (DippFormH) to generate Ln complexes, namely [Ln(DippForm)Br(thf) ] ⋅6thf (1; Sm, 2; Eu), and [Yb(DippForm)Br(thf) ] ⋅2thf (3; Yb). Samarium and europium (in 1 and 2) are seven coordinate, whereas ytterbium (in 3) is six coordinate, and all are bromine-bridged dimers.
View Article and Find Full Text PDFUnexpectedly, a mixture of bismuth ,'-bis(2,6-diisopropylphenyl)formamidinates in three different oxidation states namely, [BiI2(DippForm)] (1), [BiII2(DippForm)(CF)] (2) and [Bi(DippForm)(CF)] (3), together with [Pr(DippForm)F(thf)]·PhMe (4), [-HCFDippForm]·0.5thf (5), and a ring-opened tetrahydrofuran [-HCFO(CH)DippForm] (6) was obtained by the reaction of an excess of praseodymium metal with tris(pentafluorophenyl)bismuth, [Bi(CF)]·0.5dioxane, and bulky ,'-bis(2,6-diisopropylphenyl)formamidine (DippFormH) in tetrahydrofuran.
View Article and Find Full Text PDFReductive trapping of the cyclooctatetraenyl dianion (COT) by treatment of [Sm(DippForm)(thf)] (DippFormH = ,'-bis(2,6-diisopropylphenyl)formamidine; thf = tetrahydrofuran) with 1,3,5,7-cyclooctatetraene (CH) in toluene yields an inverse sandwich dinuclear complex [Sm(DippForm)(COT)] (1), but [Sm(DippForm)(COT)(thf)] (2) and [Sm(DippForm)(O-CH-DippForm)(thf)] (3) in thf, and 1 yields 2 and 3 on treatment with thf.
View Article and Find Full Text PDFIn this study, two types of Rare Earth (RE) 3-furoate complexes were synthesized by metathesis reactions between RE chlorides or nitrates and preformed sodium 3-furoate. Two different structural motifs were identified as Type and Type . The Type monometallic complexes form 2D polymeric networks with the composition [RE(3fur)(HO)] ( = 1La, 1Ce, 1Pr, 1Nd, 1Gd, 1Dy, 1Ho, 1Y; 3furH = 3-furoic acid) while Type bimetallic complexes form 3D polymeric systems [NaRE(3fur)] ( = 2Ho, 2Y, 2Er, 2Yb, 2Lu).
View Article and Find Full Text PDFA series of mononuclear lanthanoidate complexes isolated as [BuN][Ln(QCl)] 1Ln (QCl = 5-chloro-8-quinolinolate; Ln = Eu, Gd, Tb, Dy, Ho, and Er) have been prepared, characterised, and used as facile precursors to obtain a series of new heterobimetallic complexes as crystalline materials. Reaction of 1Ln with manganese nitrate forms [LnMn(QCl)] (2Ln, where Ln = Tb, Dy, Er and Yb) which have been structurally characterised in the cases of 2Tb and 2Yb. The heteroleptic trinuclear complex [Dy(QCl)Cl(OH)], 3, has also been obtained.
View Article and Find Full Text PDFEuropium bis(tetraphenylborate) [Eu(thf)][BPh]⋅thf containing a fully solvated [Eu(thf)] cation, was synthesized by protolysis of "EuPh" (from Eu and HgPh) with EtNHBPh, and the structure was determined by single-crystal X-ray diffraction. Efforts to characterize the putative "PhLn" (Ln = Eu, Yb) reagents led to the synthesis of a mixed-valence complex, [(thf)Yb(-Ph)Yb(Ph)(thf)]⋅2thf, resulting from the reaction of Yb metal with HgPh at a low temperature. This mixed-valence Yb/Yb compound was studied by Yb-NMR spectroscopy and single-crystal X-ray diffraction, and the oxidation states of the Yb atoms were assigned.
View Article and Find Full Text PDFThe samarium(II) calix[4]pyrrolide complex [Sm(NEt)(thf)] (NEt = -octaethylcalix[4]pyrrolide) undergoes selective oxidation of one Sm site on reaction with a range of metal carbonyls giving mixed valence Sm(II/III) complexes. Thus, reactions with TM(CO) (TM = Mo or Cr) entrap M(CO) ions between two mixed valence hosts in [{(thf)Sm(NEt)Sm(thf)(μ-OC)TM(CO)}]·PhMe (TM = Mo, ; Cr, ), while W(CO) on a different stoichiometry traps W(CO) in [{(thf)Sm(NEt)Sm}{(μ-OC)W(CO)}]·PhMe in which the isocarbonyl group is disordered over two sites. In contrast, [Sm(NEt)(thf)] reacts with dicobalt octacarbonyl, (cyclopentadienyl)tetracarbonyl diiron, and dimanganese decacarbonyl to give the mixed valence species [(thf)Sm(NEt)Sm(thf)(μ-OC)TM(CO)]·2PhMe (TM = Co, ; Fe, ) and [(thf)Sm(NEt)Sm(thf)(μ-OC)Mn(CO)]·1.
View Article and Find Full Text PDFA new porous metal-organic framework, [Co (oba) (bpdh)]·(DMF) (TMU-63), containing accessible nitrogen-rich diazahexadiene groups was successfully prepared with the solvothermal assembly of 5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene (4-bpdh), 4,4'-oxybis(benzoic) acid (oba), and Co(II) ions. The combination of Lewis basic functional groups and porosity leads to high performance in CO adsorption and conversion in the cycloaddition reaction of epoxides under solvent-free conditions. To further enhance the catalytic efficiency of TMU-63, we introduced a highly acidic malonamide ligand into the structure solvent-assisted ligand exchange (SALE) as a postsynthesis method.
View Article and Find Full Text PDFThe synthesis of two new tetra- and penta-phenycyclopentadienyldiphenylphosphine pro-ligands which readily undergo selective C-P bond cleavage has allowed for the facile synthesis of bulky divalent octa- and deca-phenylmetallocenes of europium, ytterbium and samarium.
View Article and Find Full Text PDFSeveral new trivalent dinuclear rare earth 2,2'-methylenebis(6-tert-butyl-4-methylphenolate) (mbmp ) complexes with the general form [Ln (mbmp) (thf) ] (Ln=Sm 1, Tb 2 (n=3), and Ho 3, Yb 4 (n=2), and a tetravalent cerium complex [Ce(mbmp) (thf) ] (5) have been synthesised by RTP (redox transmetallation/protolysis) reactions from lanthanoid metals, Hg(C F ) and the biphenol mbmpH . These new complexes and some previously reported partially protonated rare earth biphenolate complexes [Ln(mbmp)(mbmpH)(thf) ] react with lithium, aluminium, potassium and zinc organometallic reagents to form lanthanoid-main group heterobimetallic species. When reaction mixtures containing the Ln biphenolate complexes were treated with n-butyllithium, both molecular ([Li(thf) Ln(mbmp) (thf) ] (Ln=La 6, Pr 7 (n=2) and Er 8, Yb 9, and Lu 10 (n=1)) and charge separated ([Li(thf) ][Ln(mbmp) (thf) ] (Ln=Y 11, Sm 12, Dy 13, and Ho 14) complexes were isolated.
View Article and Find Full Text PDFUnique outcomes have emerged from the redox transmetallation/ protolysis (RTP) reactions of europium metal with [Ag(C F )(py)] (py=pyridine) and pyrazoles (RR'pzH). In pyridine, a solvent not normally used for RTP reactions, the products were mainly Eu complexes, [Eu(RR'pz) (py) ] (RR'pz=3,5-diphenylpyrazolate (Ph pz) 1; 3-(2-thienyl)-5-trifluoromethylpyrazolate (ttfpz) 2; 3-methyl-5-phenylpyrazolate (PhMepz) 3). However, use of 3,5-di-tert-butylpyrazole (tBu pzH) gave trivalent [Eu(tBu pz) (py) ] 4, whereas the bulkier N,N'-bis(2,6-difluorophenyl)formamidine (DFFormH) gave divalent [Eu(DFForm) (py) ] 5.
View Article and Find Full Text PDF[Pt{(-BrCF)NCH═C(Cl)NEt}Cl(py)] () is the product of the hydrogen peroxide oxidation of the Pt anticancer agent [Pt{(-BrCF)NCHCHNEt}Cl(py)] (). Insights into electron delocalization and bonding in [Pt{(-BrCF)NCH═C(Cl)NEt}Cl(py)] () obtained by electrochemical oxidation of have been gained by spectroscopic and computational studies. The process is chemically and electrochemically reversible on the short time scale of voltammetry in dichloromethane (0.
View Article and Find Full Text PDFA number of formamidinatoiodidolanthanoid(III) complexes, [Ln(DFForm)I(thf)] and [Ln(DFForm)I(thf)] (DFFormH = ,'-bis(2,6-difluorophenyl)formamidine) and [Ln(DippForm)I(thf)] (DippFormH = ,'-bis(2,6-diisopropylphenyl)formamidine) have been synthesized in good yields by one-pot direct reactions of the corresponding free metals with iodine and DFFormH or DippFormH in suitable ratios and are stable to rearrangement.
View Article and Find Full Text PDFA series of rare earth biphenolate complexes of the general form [Ln(mbmp)(mbmpH)(thf)] (Ln = Y (1), Nd (2), Gd (3), Dy (4), Er (5), Tm (6) and Lu (7)) have been synthesised by redox transmetallation/protolysis (RTP) from the free rare earth metal, Hg(CF) and 2,2'-methylenebis(6--butyl-4-methylphenol) (mbmpH). The rare earth metal is six coordinate with one chelating biphenolate mbmp ligand and one unidentate monophenolate mbmpH ligand. The yttrium complex, when crystallised from hot toluene or deuterated benzene, loses a coordinated thf and exhibits coordination through all three phenolate oxygen atoms, as well as the oxygen of the phenol, yielding two solvates [Y(mbmp)(mbmpH)(thf)]·solv (solv = PhMe, = 1 (8a) or CD, = 2 (8b)).
View Article and Find Full Text PDFActa Crystallogr C Struct Chem
September 2021
Formamidinatoantimony(I/III) complexes have been successfully synthesized as monomers or dimers in the solid state featuring a variety of coordination geometries and have also been comprehensively characterized. The antimony(I) formamidinate complex bis[μ-N,N'-bis(2,6-diisopropylphenyl)formamidinato]diantimony(I)(2 Sb-Sb) tetrahydrofuran heptasolvate, [Sb(CHN)]·7CHO or [Sb(DippForm)]·7THF, (1), was obtained by a metathesis reaction between sodium bis(trimethylsilyl)amide [NaN(SiMe)] and N,N'-bis(2,6-diisopropylphenyl)formamidine (DippFormH), followed by SbCl. A range of trivalent haloformamidinatoantimony(III) complexes, namely, bis[N,N'-bis(2,6-diisopropylphenyl)formamidinato]chloridoantimony(III), [Sb(CHN)Cl] or [Sb(DippForm)Cl], (2), bis[N,N'-bis(2,6-diisopropylphenyl)formamidinato]bromidoantimony(III), [SbBr(CHN)] or [SbBr(DippForm)], (3), bis[N,N'-bis(2,6-diisopropylphenyl)formamidinato]iodidoantimony(III), [Sb(CHN)I] or [Sb(DippForm)I], (4), [N,N'-bis(2,6-diisopropylphenyl)formamidinato]dibromidoantimony(III), [SbBr(CHN)] or [SbBr(DippForm)], (5), and [N,N'-bis(2,6-diisopropylphenyl)formamidinato]diiodidoantimony(III), [Sb(CHN)I] or [Sb(DippForm)I], (6), were also synthesized by adding DippFormH and MN(SiMe) (M = Li or Na) to the corresponding antimony halides SbX (X = Cl, Br or I) in differing ratios.
View Article and Find Full Text PDFOxidation of the anti-tumour agent [Pt{(p-BrCF)NCHCHNEt}Cl(py)], 1 (py = pyridine) with hydrogen peroxide under a variety of conditions yields a range of organoenamineamidoplatinum(II) compounds [Pt{(p-BrCF)NCH=C(X)NEt}Cl(py)] (X = H, Cl, Br) as well as species with shared occupancy involving H, Cl and Br. Thus, oxidation of the -CH-CH- backbone (dehydrogenation) occurs, often accompanied by substitution. Oxidation of 1 with HO in acetone yielded 1:1 co-crystallized [Pt{(p-BrCF)NCH=CHNEt}Cl(py)], 1H and [Pt{(p-BrCF)NCH=C(Cl)NEt}Cl(py)], 1Cl.
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