Showing papers by "Brian W. Skelton published in 2009"
TL;DR: A Trichoderma harzianum strain, isolated from composted hardwood bark in Western Australia, was found to produce a metabolite with antifungal and plant growth promoting activity, which showed antibiotic activity against Pythium irregulare, Sclerotinia sclerotiorum, and Rhizoctonia solani.
Abstract: A Trichoderma harzianum strain, isolated from composted hardwood bark in Western Australia, was found to produce a metabolite with antifungal and plant growth promoting activity The structure and absolute configuration of the fungal compound, harzianic acid (1), were determined by X-ray diffraction studies Harzianic acid showed antibiotic activity against Pythium irregulare, Sclerotinia sclerotiorum, and Rhizoctonia solani A plant growth promotion effect was observed at low concentrations of 1
184 citations
TL;DR: The results confirm previously observed correlations between the vibrational frequencies and the corresponding bond lengths for complexes of the unsubstituted tu ligand.
Abstract: Several synthetic strategies using copper(I) starting materials or copper(II) compounds and an in situ sulfite reductant have been used to systematically explore the chemistry of copper(I) complexes with thiourea and substituted thiourea ligands. This has resulted in the discovery of several new complexes and methods for the bulk synthesis of some previously reported complexes that had been prepared adventitiously in small quantity. The new complexes are (tu = thiourea, dmtu = N,N′-dimethylthiourea, etu = ethylenethiourea): [I4Cu4(tu)6]·H2O, [Cu4(tu)10](NO3)·tu·3H2O, [BrCu(dmtu)3], [ICu(dmtu)3]2, [BrCu(etu)2]2, [ICu(etu)2], [ICu(etu)2]3. [I4Cu4(tu)6]·H2O has an adamantanoid structure, with four terminal iodide ligands and six doubly bridging tu ligands. In contrast to this, [Cu4(tu)10](NO3)·tu·3H2O contains a tetranuclear cluster in which four of the tu ligands are terminal and the other six are doubly bridging. [BrCu(dmtu)3] is a mononuclear complex with tetrahedral coordination of copper by one bromide ...
80 citations
TL;DR: In this article, the authors investigated the performance of gold-alkynyl transfer reactions between gold-I complexes and a variety of representative inorganic and organometallic complexes featuring metals from groups 8-11, and showed that the reaction products have been characterised by spectroscopic methods.
Abstract: Facile acetylide transfer reactions take place between gold(I) complexes Au(CCAr)(PPh3) (Ar = C6H5 or C6H4Me-4) and a variety of representative inorganic and organometallic complexes MXLn (M = metal, X = halide, Ln = supporting ligands) featuring metals from groups 8–11, to afford the corresponding metal–alkynyl complexes M(CCR)Ln in modest to good yield. Reaction products have been characterised by spectroscopic methods, and molecular structure determinations are reported for Fe(CCC6H4Me-4)(dppe)Cp, Ru(CCC6H4Me-4)(dppe)Cp*, Ru(CCC6F5)(η2-O2)(PPh3)Cp*, Ir(CCC6H4Me-4)(η2-O2)(CO)(PPh3)2, Ni(CCC6H4Me-4)(PPh3)Cp and trans-Pt(CCAr)2L2 (Ar = C6H5, L = PPh3; Ar = C6H4Me-4, L = PPh3, PMe3).
69 citations
TL;DR: A range of mercury-imidazolylidene complexes have been prepared by reaction of imidazolium-linked cyclophanes with mercury(II) acetate.
53 citations
TL;DR: In this article, the reaction of 2,6-bis (3-butylbenzimidazol-1-ium)pyridine dibromide with silver oxide affords a dinuclear complex of the type [L2Ag2]2+ [L = 2, 6-bis(3- butylbenzmanidazolin-2-ylidene) pyridine].
50 citations
TL;DR: In this article, a larger metallocycle of the form [L2Ag2]2+ [where L = Para-bis(N-methylimidazolylidene)xylylene] has been isolated from the reaction of para-oxylylene-bis (N-methylidazolium) chloride and Ag2O.
Abstract: Mononuclear silver and mercury complexes bearing bis-N-heterocyclic carbene (NHC) ligands with linear coordination modes have been prepared and structurally characterised. The complexes form metallocyclic structures that display rigid solution behaviour. A larger metallocycle of the form [L2Ag2]2+ [where L = para-bis(N-methylimidazolylidene)xylylene] has been isolated from the reaction of para-xylylene-bis(N-methylimidazolium) chloride and Ag2O. Reaction of silver- and mercury-NHC complexes with Pd(NCCH3)2Cl2 affords palladium-NHC complexes via NHC-transfer reactions, the mercury case being only the second example of a NHC-transfer reaction using a mercury-NHC complex.
47 citations
TL;DR: Kinetics analyses of the polymerization of L-lactide by compounds 1 and 5 indicated pseudo-first order response with respect to L- lactide.
Abstract: Treatment of an array of bis(phenol)s H2Lx {Lx = [(−OC6H2(2,4-R)(6-CH2))2 NCH2CH2X], where X = CH2NMe2, NMe2, NEt2, OMe and R = But, Pet where Pet = C(CH3)2Et} with [Ln(N(SiMe3)2)2(THF)2] (Ln = Yb, Sm) in a 1:1 molar ratio in hexanes afforded a multitude of new divalent lanthanide bis(phenolate) complexes: [L2cYb]2 (X = NEt2, R = But) 1, [L2bYb]2 (X = CH2NMe2, R = But) 2, [L3aYb]2 (X = NMe2, R = Pet) 3, [L3bYb]2 (X = OMe, R = Pet) 4, [L2cSm] (X = NEt2, R = But) 5, [L3cYb] (X = NEt2, R = Pet) 6, [L3cSm] (X = NEt2, R = Pet) 7. X-Ray crystallographic analyses of compounds 1 and 3 reveal dimeric, centrosymmetric structures with 5-coordinate ytterbium centers arising from bridging and terminal phenolate groups. A selection of divalent compounds (1, 3, 4, 5, 6 and 7) were tested as catalyst precursors in the polymerization of e-caprolactone and/or L-lactide which resulted in high molecular weight polymers with PDIs of 1.11–2.81 and 1.13–1.56 for e-caprolactone and L-lactide respectively. All polymerization studies were performed in either toluene or THF and at room temperature (e-caprolactone) or 70 °C (L-lactide) at a variety of catalyst:monomer ratios (1:100–1:300). Kinetics analyses of the polymerization of L-lactide by compounds 1 and 5 indicated pseudo-first order response with respect to L-lactide.
45 citations
TL;DR: Three new diterpenoids including two pimaranes (1 and 2) and a labdane (3) were isolated from the whole herb of Plectranthus ernstii and exhibited antimycobacterial activity against three strains of rapidly growing mycobacteria.
Abstract: Three new diterpenoids including two pimaranes (1 and 2) and a labdane (3) were isolated from the whole herb of Plectranthus ernstii. The structures of these compounds were determined as rel-15(zeta),16-epoxy-7alpha-hydroxypimar-8,14-ene (1) and rel-15(zeta),16-epoxy-7-oxopimar-8,14-ene (2), and compound 3 was elucidated as 1R,11S-dihydroxy-8R,13R-epoxylabd-14-ene on the basis of single-crystal X-ray structural analysis. Compound 1 exhibited moderate antistaphylococcal activity against a range of multidrug-resistant (MDR) and methicillin-resistant (MRSA) strains of Staphylococcus aureus with a minimum inhibitory concentration (MIC) of 32 microg/mL. All three diterpenes exhibited antimycobacterial activity against three strains of rapidly growing mycobacteria with MIC values ranging from 8 to 128 microg/mL.
41 citations
TL;DR: High-yielding syntheses involving reactions in the diffusion zone between solid reactants are demonstrated in studies of complex formation between copper(i) thiocyanate and ethylenethiourea.
40 citations
TL;DR: The pendant bipyridyl moiety of transition metal σ-acetylide complexes incorporating the 5-ethynyl-2,2′-bipyridine moiety provides a site of chelation for additional metal centers and facile access to multinuclear complexes as model systems for organometallic wires as mentioned in this paper.
36 citations
TL;DR: New PdBr(2)-bis(N-heterocyclic carbene) complexes derived from 4,7-dibutoxybenzimidazole and 5,6- dibutaldehyde-based complexes have been synthesized and structurally and spectroscopically characterized, showing much greater solubility and interesting structural characteristics dependent on the position of the butoxy substituents.
Abstract: New PdBr2-bis(N-heterocyclic carbene) complexes derived from 4,7-dibutoxybenzimidazole and 5,6-dibutoxybenzimidazole have been synthesized and structurally and spectroscopically characterized. The complexes show much greater solubility compared to the parent complex derived from benzimidazole, and interesting structural characteristics dependent on the position of the butoxy substituents. The complexes display high activities in the coupling of aryl iodides in the Mizoroki–Heck reaction and moderate activities in the Suzuki–Miyaura coupling of inactivated aryl bromides at low catalyst loadings, although activity differences between pre-catalysts has been observed. Structural studies suggest electronic effects within the complexes to be strongly affected by steric interactions between the hydrogen atoms of the o-xylyl bridges and the benzimidazole components and their substituents.
TL;DR: An investigation of the silver(I) nitrate/thiourea ("tu") system, exploiting the uniquely powerful access provided by the recently developed combination of mechanochemical synthesis coupled with vibrational spectroscopy, has resulted in the identification of solid adducts AgNO3/tu for x:y, which provide the basis for establishing a correlation between nu(AgS) and the Ag-S bond length d( AgS) for silver complexes involving the tu ligand.
Abstract: An investigation of the silver(I) nitrate/thiourea (“tu”) system, exploiting the uniquely powerful access provided by the recently developed combination of mechanochemical synthesis coupled with vibrational spectroscopy, has resulted in the identification of solid adducts AgNO3/tu (x:y) for x:y = 1:1, 1:1.5, 15:23 (= 1:1.5333), and 1:3. This contrasts with previously published claims for the existence of 1:2 and 1:4 complexes and was confirmed in the case of the 1:3 and 15:23 complexes by X-ray crystal structure determinations on samples prepared by crystallization from aqueous solution. The 1:3 sulfate and perchlorate complexes were also prepared for comparison with the corresponding nitrate compound. In the 1:3 nitrate complex, the one independent silver atom major component (0.78(1)) is closely trigonal planar AgS3 (Ag−S 2.518(2)−2.592(1) A, Σ(S−Ag−S) 359.70°); there are minor nearby components (0.11(1)) which may be regarded as four-coordinate, forming a putative one-dimensional polymer. The sulfate, ...
TL;DR: Redeterminations of the structures of AgSCN : tu, etu (1 : 2) ('etu' = ethylenethiourea, (CH2NH)2CS)) with quasi-trigonal silver atom environments, are recorded as a basis for an IR spectroscopic characterization of the [(NCS)Ag(S-xtu)2] array.
Abstract: Syntheses and single crystal X-ray structural characterizations, together with infrared spectroscopic studies, are recorded for 1:1 adducts of silver(I) thiocyanate with thiourea (‘tu’) and N,N′-diethylthiourea (‘detu’≡ (EtNH)2CS). The two complexes display novel and different polymeric forms. That formed with tu is a double-stranded form, comprising a pair of Ag(μ-S-tu)Ag(μ-… strands linked by pairs of μ-SCN anions, the whole array having quasi-2 symmetry about the polymer axis. The detu adduct takes the ionic form [Ag(detu)2](∞|∞)[Ag(SCN)2](∞|∞), both cation and anion being one-dimensional polymers lying in parallel, and both of the form …Ag(μ-S-L)2Ag(μ-… (L = SCN or detu), disposed about crystallographic axes. Redeterminations of the structures of AgSCN:tu, etu (1:2) (‘etu’ = ethylenethiourea, (CH2NH)2CS)) with quasi-trigonal silver atom environments (the etu adduct the more closely so), are also recorded as a basis for an IR spectroscopic characterization of the [(NCS)Ag(S-xtu)2] array. A mechanochemical/infrared study of the AgSCN:etu (1:1) system showed that no 1:1 complex exists in this case, the product being a mixture of the 1:2 complex and a novel 1:0.5 complex. The latter complex was prepared both mechanochemically and from solution, and characterized by infrared spectroscopy. Diagnostic ligand and metal–ligand bands in the IR and far-IR spectra are assigned for all of the complexes studied and for AgSCN and are discussed in relation to the structures of the complexes. The double degeneracy of the δ(SCN) mode of the coordinated thiocyanate is lifted and the first overtone of this band at gains intensity in the IR in the 1:1 complexes, behaviour that is not observed for the terminal bonding mode that is present in the 1:2 complexes.
TL;DR: Cytotoxicity studies in two human breast cancer lines and two matched liver progenitor cell lines indicate that [Cu(d2pype)(2)]Cl is non selectively toxic to both non-tumourigenic and tumourigenIC cells.
Abstract: The 1 : 2 adducts of copper(I) halides with 1,2-bis(2-pyridylphosphino)ethane (d2pype) have been synthesized and solution properties characterized by variable temperature (1)H, (31)P and (65)Cu NMR spectroscopy. Single-crystal structure determinations for the chloride, bromide and iodide complexes show these to crystallize from acetonitrile in the triclinic space group P1 as isostructural centrosymmetric dimers [(d2pype)Cu(mu-d2pype)(2)Cu(d2pype)]X(2).(solvent) with a approximately 12.6, b approximately 12.7, c approximately 15.3 A, alpha approximately 84, beta approximately 67, gamma approximately 84 degrees. In contrast to the analogous AuCl:2(d2pype) and AgNO(3):2(d2pype) adducts, in solution these CuX:2(d2pype) adducts (where X = Cl, Br and I) exist almost exclusively as bis-chelated monomeric [Cu(d2pype)(2)]X; evidence for an equilibrium between monomeric and dimeric forms is detected only for the CuCl adduct in methanol. Cytotoxicity studies in two human breast cancer lines and two matched liver progenitor cell lines indicate that [Cu(d2pype)(2)]Cl is non selectively toxic to both non-tumourigenic and tumourigenic cells. However, the analogous Au(I) compound [Au(d2pype)(2)]Cl, is toxic to highly tumourigenic cells and more selective in its toxicity to tumourigenic cells compared to non-tumourigenic cells. The significance of these results to the further development of selective, mitochondria-targeted, Au(I) antitumour complexes is discussed.
TL;DR: In this paper, a variety of adducts of silver salts with ethylenethiourea (etu) were described for X-ray structural and spectroscopic characterizations.
Abstract: Syntheses, single crystal X-ray structural and spectroscopic characterizations are described for a variety of adducts of silver salts with ethylenethiourea (etu). Ag2SO4/etu (1:6) is isomorphous wi...
TL;DR: A new [ONO] tridentate phenolate ligand (H2LI) containing an aliphatic alcohol as a side arm has been synthesized, deprotonated and attached to lanthanide(II) and (III) ions, which are employed as catalysts for ring-opening polymerization of cyclic esters.
Abstract: A new [ONO] tridentate phenolate ligand (H2LI) containing an aliphatic alcohol as a side arm has been synthesized, deprotonated and attached to lanthanide(II) and (III) ions, which are employed as catalysts for ring-opening polymerization of cyclic esters. In contrast to many other mono-phenolate lanthanide compounds, these have been found to be inert to polymer incorporation during the polymerization reactions. Three new divalent ytterbium compounds have been synthesized in high yield containing ancillary ligands; two via a transamination reaction between [Yb(N(SiMe3)2)2(THF)2] and one equivalent of the phenols, HOC6H2-(2,4-tBu)-6-CH2N(Me)CH2CH2OH (H2LI) or HOC6H2-(2,4-tBu)-6-CH2N(Me)CH2CH2N(Me)CH2-6-(2,4-tBu)-C6H2OH (H2LII) in hexanes to yield [Yb(LI)]2 (1) and [Yb(LII)]2 (2), respectively. The third divalent ytterbium compound [Yb(L2)] (3) was prepared by treatment of [Yb(N(SiMe3)2)2(THF)2] with two equivalents of a related monoanionic ancillary phenol, HOC6H2-(2,4-tBu)-6-CH2N(Me)CH2CH2NMe2 (HL) in hexanes. Additionally, the oxidation chemistry of these divalent systems was explored where compound 1 was treated with silver triflate and phenol to form corresponding heteroleptic trivalent ytterbium phenolate complexes [Yb(LI)(O3SCF3)(THF)] (4) and [Yb(LI)(OPh)] (5), respectively. Finally, three new heteroleptic trivalent lanthanide silylamido compounds were synthesized via a ligand exchange transamination reaction between the homoleptic trivalent [Ln(N(SiMe3)2)3] compound and one equivalent of the new dianionic ligand (H2LI) in THF {[La(LI)(N(SiMe3)2)(THF)2] (6); [Sm(LI)(N(SiMe3)2)(THF)] (7); [Yb(LI)(N(SiMe3)2)(THF)] (8)}. These lanthanide(II) and (III) compounds were assessed as catalyst precursors towards the ring-opening polymerization of both L-lactide and e-caprolactone. End-group analyses and detailed kinetics studies {rate law: −d[LA]/dt = k[LA]1[catalyst]1} of the most efficacious lanthanum compound (6) further corroborated the substitutionally inert characteristics of the new stationary ancillary [ONO] tridentate dianionic ligand.
TL;DR: In this article, a body of crystallographic information concerning metal(ii) and metal(iii) complexes of macrobicyclic hexamine ligands and some of their derivatives provides evidence for the action of a variety of intermolecular forces within the lattices.
Abstract: Dedication: One of Alan Sargeson’s great abilities was to seek out knowledge on topics of which he was not the master from those people with the expertise. This led occasionally to publications with a ‘cricket team’ of authors but with a rich brew of information, often international. Alan also insisted that all authors were equal since, without any one, the paper would not be what it was. Hence, he endeavoured to pursue the policy, difficult to maintain over a period where an obsession with absurdities such as the order of authors and point-scoring based on meaningless publication indices became so important in the maintenance of research, of listing authors simply in alphabetical order. In describing work begun while he was still with us, we have attempted to adhere to his principles. Analysis of a body of crystallographic information concerning metal(ii) and metal(iii) complexes of macrobicyclic hexamine ligands and some of their derivatives provides evidence for the action of a variety of intermolecular forces within the lattices. Hydrogen bonding is universal and its forms depend strongly upon the oxidation state and the particular nature of the metal ion bound to the macrobicycle. The introduction of both aliphatic and aromatic substituents leads to lattices in which these substituents associate, although, in the case of aromatic substituents, this is not necessarily a consequence of ‘π-stacking’, despite the fact that the aromatic ring planes form parallel arrays. At least in the case of CoIII, stable enantiomers of the complexes can be obtained, and in {Δ-(+)589-[Co{(NH3)(CH3)sar}]}2Cl2(C6(CO2)6)·26H2O (sar = 3,6,10,13,16,19-hexa-azabicyclo[6.6.6]icosane), the benzene hexacarboxylate anion adopts a chiral conformation in the presence of the optically active cation.
TL;DR: In this article, a pentanuclear molecule is formed by a previously unknown combination of incomplete cube M3(μ3-X)(μ-X)3 and triangle bipyramidal M3 (μ3X)2(μ-x)2 fragments, resulting in a zigzag arrangement of metal centers within one molecule.
Abstract: Heterotrimetallic complex [CuII2CoIINiII2(Me2Ea)5Cl5(H2O)]·CH3CN·H2O has been prepared in a one-pot reaction of zero-valent copper with cobalt and nickel chlorides in an acetonitrile solution of 2-(dimethylamino)ethanol (HMe2Ea) in the open air. The metal stoichiometry obtained by atomic absorption analysis was further confirmed by single-crystal X-ray diffraction investigations. The pentanuclear molecule is formed by a previously unknown combination of incomplete cube M3(μ3-X)(μ-X)3 and triangle bipyramidal M3(μ3-X)2(μ-X)2 fragments, resulting in a zigzag arrangement of metal centers within one molecule. This type of arrangement is very uncommon for pentanuclear complexes and in particular for complexes with an odd number of metal centers. A search of the Cambridge Structural Database showed that the number of coordination compounds possessing an even number of metals is significantly greater than those containing an odd number. Possible reasons for such a distribution, as well as the synthetic and structural features of the presented compound, are discussed.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
TL;DR: Reactions of Group 8 metal ethynyls with tetracyanoethene afford tricyanovinylethynyl-metal derivatives, while homo- and hetero-metallic derivatives are obtained by coordination of one of the remaining CN groups to other metal-ligand fragments.
Abstract: Reactions of Group 8 metal ethynyls with tetracyanoethene afford tricyanovinylethynyl–metal derivatives, M{CCC(CN)C(CN)2}(PP)Cp′ [2; M = Ru, Os; PP = (PPh3)2, dppe; Cp′ = Cp, Cp*; not all combinations]; a similar reaction occurs with the vinylidene RuCl(CCHPh)(PPh3)Cp. Further replacement of a CN group in 2 occurs with nucleophiles, while homo- and hetero-metallic derivatives are obtained by coordination of one of the remaining CN groups to other metal–ligand fragments.
TL;DR: An unusually complete array of copper(i) halides is shown, with the central copper atoms in quasi-trigonal planar environments, as shown by single crystal X-ray studies, in turn providing a platform for comparative spectroscopic studies.
Abstract: Crystallization of the copper(I) halides (CuX; X = Cl, Br, I) with N,N′-diphenylthiourea (‘dptu’ = (PhNH)2CS) in 1 : 2 ratio from acetonitrile solution in ambient conditions yields a mononuclear isomorphous series of complexes of the form [XCu(dptu)2]·H2O, an unusually complete array, with the central copper atoms in quasi-trigonal planar environments, as shown by single crystal X-ray studies, in turn providing a platform for comparative spectroscopic studies. Under anhydrous conditions, anhydrous compounds may be obtained, a full series again being accessible, but now of the binuclear form [(dptu)XCu(μ-S-dptu)2CuX(dptu)], the chloride being a bis(acetonitrile) solvate, the isomorphous bromide and iodide pair being unsolvated. A (solvated) sulfate salt is found to be of the form [Cu(dptu)2]2(SO4), providing a novel example of a copper(I) atom being (quasi-)linearly coordinated by the pair of unidentate (dptu) sulfur ligands, Cu–S 2.1770(5), 2.1811(5) A, S–Cu–S 162.18(2)°. The ν(CuX) vibrational frequencies are assigned in the far-IR spectra of [XCu(dptu)2]·H2O (X = Cl, Br, I) at 274, 207, and 190 cm−1 respectively. The broadline static 65Cu NMR spectra of [Cl2Cu2(dptu)4]·2CH3CN and [X2Cu2(dptu)4] (X = Br, I) have been recorded at 9.4 and 7.05 T, and the spectra have been analysed to yield the 65Cu nuclear quadrupole coupling and chemical shift parameters. The 63,65Cu nuclear quadrupole resonance frequencies of [XCu(dptu)2]·H2O (X = Cl, Br, I) have also been measured, and the resulting 65Cu quadrupole coupling constants are ca. 4× those of the dimeric [X2Cu2(dptu)4] compounds.
TL;DR: In this article, a series of new N-heterocyclic carbene (NHC) and Palladium(II) complexes bearing electron-rich benzimidazolin-2-ylidene ligands are described and structurally and spectroscopically characterised.
Abstract: A series of new N-heterocyclic carbene (NHC)–palladium(II) complexes bearing electron-rich benzimidazolin-2-ylidene ligands are described and structurally and spectroscopically characterised. These (benzimidazolin-2-ylidene)palladium complexes bear butoxy groups to increase the solubility and perhaps influence the catalytic activity by increasing the electron density around the metal centre. The effect of varying the ancillary ligands is investigated, although these ligands do not appear to significantly alter the activity of the complexes as precatalysts. Preliminary studies indicate the complexes act as precatalysts with moderate activity in the Mizoroki–Heck and Suzuki–Miyaura coupling reactions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
TL;DR: The first reported synthesis of these compounds under basic conditions was reported in this article, where the reaction of electron-rich 3-aryl-substituted 4-6-dimethoxyindoles in the presence of base with triflic anhydride results in biaryl coupling, producing both 2,2′- and 2,7′-biindoles.
TL;DR: In this paper, the allylation of indigo results in the one-step synthesis of two unique complex heterocyclic systems: a spiroindoline-pyridoindolone arising from the addition of three allyl moieties and a fused pyrido-indolo-azepino indolone generated by cyclisation of two allyl mixtures.
TL;DR: "Broken symmetry"
Abstract: The reaction of zerovalent copper with cadmium iodide and triethanolamine (H3L) in dimethylformamide (dmf) carried out under open-air conditions afforded a novel heterometallic complex [Cu3(HL)3CdI2]2·4dmf. The crystal lattice consists of an octanuclear molecule [Cu3(HL)3CdI2]2, which has an inversion center at the midpoint of the central Cu2O2 unit, and of two non-coordinating dmf molecules. Eight metal atoms linked by alkoxide arms of triethanolamine ligands form a zigzag Cd−Cu1−Cu2−Cu3−Cu4−Cu5−Cu6−Cd chain with the separations between bridged Cu atoms in the range 2.935(2)−3.403(2) A. The complex is further stabilized by intramolecular O−H···O hydrogen bonds. High-field electron paramagnetic resonance (EPR) spectra of the S = 1 spin state with D(S=1) = −0.843 cm−1, E(S=1) = −0.081 cm−1 were observed. Fitting the magnetic susceptibility temperature dependence by using the exchange Hamiltonian HHDVV = J1(S1S2 + S5S6) +J2(S2S3 + S4S5 )+ J3S3S4, to which terms expressing the zero-field splitting and Zeeman...
TL;DR: In this article, the synthesis of samarium, holmium, and ytterbium complexes of trisamide calix[4]arene is described, and the resulting structures are compared with the previously reported gadolinium complex.
Abstract: The syntheses of samarium, holmium, and ytterbium complexes of a tris-amide calix[4]arene are described, and the resulting structures are compared with the previously reported gadolinium complex. The syntheses involved the reaction of 5,11,17,23-tetra-tert-butyl-24-hydroxy-26,27,28-tris(diethylcarbamoylmethoxy)calix[4]arene with the appropriate lanthanide picrate hydrate. Structural studies demonstrated that a picrate anion acts as a quasi-bidentate ligand with Sm (and Gd), is unidentate in the Ho complex, but is found in the second coordination sphere for the smallest lanthanide cation (Yb) investigated.
TL;DR: The metalloamphiphile [Zn(1-decylammonio-8-methylsarcophagine)](ClO4)3·2H2O crystallises in the non-centrosymmetric space group P1 to give a polar crystal, which can be converted to one with a centroid-mw lattice (space groupI2/a) through deprotonation as mentioned in this paper.
Abstract: The metalloamphiphile [Zn(1-decylammonio-8-methylsarcophagine)](ClO4)3·2H2O crystallises in the non-centrosymmetric space group P1 to give a polar crystal, which can be converted to one with a centrosymmetric lattice (space groupI2/a) through deprotonation.
TL;DR: The hybrid composites [Cu(Hdea)(H2dea)]2[CdX4], X=Br (1), I (2) have been prepared in reactions of zero-valent copper with cadmium halide in air-exposed solution containing the corresponding ammonium salt and diethanolamine (H 2dea), and X-ray crystallographic analysis reveals ionic solids of non-symmetric H-bonded dimeric [ Cu ( Hdea ) ( H 2 dea ) ] 2 2 +
TL;DR: The fluorinated complexes show significantly different solvation properties from those of the analogous unfluorinated compounds, particularly with respect to their behavior in common organic solvents and their good scCO(2) solubility.
Abstract: A series of ruthenium and osmium complexes containing highly fluorous diphosphine ligands FP∧PF = (F13C6C6H4-p)2P(CH2)2P(p-C6H4C6F13)2 (dfppe) and (F13C6C6H4-p)2P(CH2)3P(p-C6H4C6F13)2 (dfppp) has been prepared. The fluorous diphosphine ligands incorporate four C6F13 “fluoro-ponytails”, and these have been effective in solubilizing the complexes in supercritical carbon dioxide (scCO2). Precise solubility measurements in scCO2 were performed for some of the complexes. The new complexes [MX2(FP∧PF)2] and [MX(FP∧PF)(η-C5H5)], M = Ru, Os, X = Cl, Br, have been characterized by a number of spectroscopic techniques and their electrochemical properties measured, three of the ruthenium complexes also being characterized by single-crystal X-ray studies. The noncovalent interactions observed in the X-ray structures have been analyzed by the Hirshfeld surface approach, putting them on a more solid footing. The fluorinated complexes show significantly different solvation properties from those of the analogous unfluorinated compounds, particularly with respect to their behavior in common organic solvents and their good scCO2 solubility.
TL;DR: In this paper, the 1:1 and 2:1 adducts of diphosphine ligands R2P(R′)nPR2 with silver methanesulfonate have been synthesized and characterized both in solution (1H, 31P NMR) and in the solid state (IR, single crystal X-ray structure analysis).
TL;DR: The crystal structures of tetrachloroferrate(III) complexes having stoichiometry (BH)+ [FeCl4]− (where B = isoquinoline and 4-aminopyridine) were determined at 100 K as mentioned in this paper.
Abstract: The crystal structures of tetrachloroferrate(III) complexes having stoichiometry (BH)+ [FeCl4]− (where B = isoquinoline and 4-aminopyridine) were determined at 100 K. While weak interactions, particularly N–H···Cl hydrogen bonds, are evident in the structures, distances between the Fe(III) centers are quite long in both cases. The structure of the compound with B = quinoline was compared with that previously established at room temperature, and showed that neither solid-solid nor magnetic phase transitions occurred in this temperature range. Magnetic measurements on the paramagnetic powders indicate weak antiferromagnetic interactions transmitted through the crystal lattice, giving rise to Neel temperatures that are significantly below 10 K. Comparisons are made with other characterized [FeCl4]− compounds having similar organic base cations, enabling clarification of the superexchange mechanism.