Boere, Rene
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- Item1,3-Diphenylisobenzofuran(International Union of Crystallography, 2008) Boeré, René T.; Dibble, Peter W.; Fischer, Kristapher E.
- Item1,5-(4,4'-Dipyridyl)naphthalene(MDPI, 2015) Hassan, Mohammad R.; Boeré, René T.The title compound has been prepared from 1,5-dibromonaphthalene (obtained from 1,5-diaminonaphthalene) using Suzuki-Miyaura cross-coupling to 4-pyridylboronic acid. The crystal and molecular structure was determined by single-crystal X-ray diffraction.
- Item1-methyl-4-thiocarbamoylpyridin-1-ium iodide(International Union of Crystallography, 2018) Shotonwa, Ibukun O.; Boeré, René T.In the title compound, C7H9N2S+·I−, the thioamide moiety is twisted out of the aromatic plane by 38.98 (4)° and forms N—H...I hydrogen bonds. In the crystal, hydrogen-bonded centrosymmetric dimers [C7H9N2S+·I−]2 are linked via additional short contacts from an aromatic CH group to the iodide anion into ribbons parallel to the (010) plane.
- Item2'-acetonaphthone(International Union of Crystallography, 2012) Shotonwa, Ibukun O.; Boeré, René T.
- Item3,5-diphenyl-1,2,4-dithiazolium tetrabromidoferrate(III)(International Union of Crystallography, 2013) Shotonwa, Ibukun O.; Boeré, René T.
- Item3,7-Di-tert-butyl-1,5,2,4,6,8-dithiatetrazocine(International Union of Crystallography, 1995) Parvez, Masood; Boeré, René T.; Derrick, Sean; Moock, Klaus H.The eight-membered ring in the title compound, C10HI8N4S2, lies about an inversion centre and is essentially planar with normal bond lengths and angles [mean C--S 1.569 (2) and mean C--N 1.326 (3)A].
- Item4-hydrazinopyridinium chloride(International Union of Crystallography, 2009) Boeré, René T.; Hassan, Mohammad R.
- Item4-methyl-N'-(2,2,2-trichloroethanimidoyl)benzene-1-carboximidamide(International Union of Crystallography, 2011) Roemmele, Tracey L.; Boeré, René T.
- Item4-thiocarbamoylpyridin-1-ium iodide(International Union of Crystallography, 2014) Shotonwa, Ibukun O.; Boeré, René T.
- Item(5Z,7Z,9Z)-5,10-dibromobenzo[8]-annulene(International Union of Crystallography, 2013) Bender, Christopher O.; Boeré, René T.
- ItemBackbone-substituted ß-ketoimines and ketoiminate clusters: transoid Li2O2 squares and D2-symmetric Li4O4 cubanes. Synthesis, crystallography and DFT calculations(MDPI, 2017) Gietz, Twyla M.; Boeré, René T.The preparation and crystal structures of four β-ketoimines with bulky aryl nitrogen substituents (2,6-diisopropylphenyl and 2,4,6-trimethylphenyl) and varying degrees of backbone methyl substitution are reported. Backbone substitution “pinches” the chelate ring. Deprotonation with n-butyllithium leads to dimeric Li2O2 clusters, as primary laddered units, with an open transoid geometry as shown by crystal structures of three examples. The coordination sphere of each lithium is completed by one tetrahydrofuran ligand. NMR spectra undertaken in either C6D6 or 1:1 C6D6/d8-THF show free THF in solution and the chemical shifts of ligand methyl groups experience significant ring-shielding which can only occur from aryl rings on adjacent ligands. Both features point to conversion to higher-order aggregates when the THF concentration is reduced. Recrystallization of the materials from hydrocarbon solutions results in secondary laddering as tetramericLi4O4 clusters with a cuboidal core, three examples of which have been crystallographically characterised. These clusters are relatively insoluble and melt up to 250 ◦C; a consideration of the solid-state structures indicates that the clusters with 2,6-diisopropylphenyl substituents form very uniform ball-like molecular structures that will only be weakly solvated.
- ItemBis(tert-butyldimethylsilyl)(2,6-diisopropylphenyl)phosphane: the first structure of an organophosphane with two tert-butyldimethylsily (TBDMS) substituents(International Union of Crystallography, 2012) Boeré, René T.; Taghavikish, Mona
- ItemBulky 2,6-disubstituted aryl siloxanes and a disilanamine(International Union of Crystallography (IUCr), 2020) Marszaukowski, Flavia; Wohnrath, Karen; Boeré, René T.The crystal structures of 5-bromo-1,3-di-tert-butyl-2-[(trimethylsilyl)oxy]benzene, C17H29BrOSi, (I), 1,3-di-tert-butyl-2-[(trimethylsilyl)oxy]benzene, C17H30OSi, (II), and N-(2,6-diisopropylphenyl)-1,1,1-trimethyl-N-(trimethylsilyl)silanamine, C18H35NSi2, (III), are reported. Compound (I) crystallizes in space group P21/c with Z′ = 1, (II) in Pnma with Z′ = 0.5 and (III) in Cmcm with Z′ = 0.25. Consequently, the molecules of (II) are constrained by m and those of (III) by m2m site symmetries. Despite this, both (I) and (II) are distorted towards mild boat conformations, as is typical of 2,6-di-tert-butyl-substituted phenyl compounds, reflecting the high local steric pressure of the flanking alkyl groups. Compound (III) by contrast is planar and symmetric, and this lack of distortion is compatible with the lower steric pressure of the flanking 2,6-diisopropyl substituents.
- ItemButylbis[µ-4-(2,4,6-trimethylphenylamino)pent-3-en-2-onato][4-(2,4,6-trimethylphenylamino)pent-3-en-2-onato]dimagnesium(International Union of Crystallography, 2009) Boeré, René T.; Gietz, Twyla M.
- ItemChemical and electrochemical oxidations of tris(3,5-di-tert-butylphenyl)phosphine. High Z’ crystal structures and conformational effects associated with bulky meta substituents(2018) Guimaraes, Ivelise Dimbarre Lao; Garcia, Jarem Raul; Wohnrath, Karen; Boeré, René T.Synthesis and single crystal X-ray diffraction structures of (3,5-tBu2-C6H3)3P, (3,5-tBu2-C6H3)3PO∙H2O, (3,5-tBu2C6H3)3PS and (3,5-tBu2-C6H3)3PSe are reported. The structure of (3,5-tBu2-C6H3)3P has Z' = 4, with both M and P enantiomers of a helical conformation and a conformation with one flat ring in the same lattice. The pyramidality index, ∑{CPC}, is smaller for the helical compared to the flat conformers. All four have structures that are more pyramidal than the corresponding Ph3P(E) derivatives, which is attributed to stronger intramolecular dispersion forces. The oxide crystallizes with Z' = 2 as a water-bridged dimer that is the most separated such dimer amongst 26 known structures, providing evidence for a distal (or perimeter) steric effect. Cyclic voltammetry in CH3CN/[nBu4N][ClO4] indicated anodic peak potentials of +0.785 V for (3,5tBu2-C6H3)3P, +0.745 for (3,5-Me2-C6H3)3P, +0.735 V for (4-MeO-3,5-Me2-C6H3)3P and +0.535 V for (4-MeOC6H3)3P, all relative to Fc+/0. On this scale, Ph3P oxidizes at +1.04 V. The unexpectedly high oxidation potentials for the first three phosphines is attributed to a more pyramidal structure resulting in lowering of the HOMO energy compared to expectations from Hammett constants and 1J(P,Se) NMR coupling constants.
- ItemCoordination complexes of thiazyl rings: Synthesis, structure and DFT computational analysis of CpCr(CO)x (x = 2,3) complexes of fluorinated and non-fluorinated 1lamda^3-1,2,4,6-thiatriazinyls, with differing Cr—S bond orders.(NRC Research Press, 2015) Ang, Chwee Y.; Kuan, Seah L.; Tan, Geok K.; Goh, Lai Y.; Roemmele, Tracey L.; Yu, Xin; Boeré, René T.Reaction of [3,5-Ph2-C2N3S]2 with [CpCr(CO)3]2 in toluene at RT forms an adduct via a Cr—S bond, formulated as CpCr(CO)3SN3C2Ph2, which has fitting NMR, IR and combustion analysis data. The structure was determined by a single-crystal X-ray structure diffraction study (P21/n, a = 8.4611(17)Å; b = 20.509(4) Å, c = 11.757(2) Å, = 104.453(7)°). The Cr—S bond-length = 2.4908(11) Å corresponds to a bond-order of 1.0 from > 90 values for CpCr(CO)x or Cp*Cr(CO)x moieties (x = 2,3) bonded to S which are used to establish a Pauling-type bond order scale specific to this class of compounds. Similar reactions of fluorinated thiatriazinyls derived from [3-Ph-5-CF3-C2N3S]2 or [4-MeOC6H4-5-CF3-C2N3S]2 are accompanied by the loss of CO to produce CpCr(CO)2SN3C2PhCF3 (P, a = 8.0929(8) Å; b = 10.3160(10) Å, c = 11.2405(11), = 70.032(2)°, = 72.076(2)°, = 82.375(2)° ) and CpCr(CO)2SN3(CCF3)(C6H4OCH3) (P21/c, a = 8.1311(7)Å; b = 24.284(2) Å, c = 9.1025(8) Å, = 97.218(2)°), also fully characterized by spectroscopy and crystallography. Their measured Cr—S bond-lengths, 2.2987(14) Å and 2.2965(11) Å, correspond to bond orders of 1.5. (U/R)B3PW91/6-311+G(2df,2p)//B3PW91/6-31G(2d,p) hybrid DFT calculations show that the tricarbonyl complex has an unusual bond. However, the dicarbonyl complexes of the fluorinated thiatriazinyls are -bonded.
- ItemCoordination polymers from main group ring compounds(Taylor & Francis, 2016) Okeh, Saturday A.; Boeré, René T.4,7-dicyano-2,1,3-benzothiadiazole, L1, and diethyl-4,7-dicarboxylato-2,1,3 benzothiadiazole, L2, form coordination polymers with silver(I) salts of weakly-coordinating anions. Synthesis was achieved by the slow diffusion of benzene solutions of the silver salts into dichloromethane solutions of L1 or L2. Slow growth of crystals occurred with partial evaporation of the solvent, leading to a number of different crystalline coordination polymers. For L1, both the nitrile and ring N atoms can coordinate with great variability of structural motifs, whereas for L2 a chelating geometry is always found in which each Ag+ is coordinated by two N and two carbonyl O from different ligands. The resulting coordination polymers form layer structures that tend to fill with solvent benzene molecules in a stoichiometric fashion; the benzenes are found to π-coordinate to silver.
- ItemThe copper sulfate hydration cycle. Crystal structures of CuSO4 (Chalcocyanite), CuSO4·H2O (Poitevinite), CuSO4·3H2O (Bonattite) and CuSO4·5H2O (Chalcanthite) at low temperature using non-spherical atomic scattering factors(Royal Society of Chemistry, 2022) Ibrahim, Mukaila A.; Boeré, René T.New structure determinations of CuSO4, CuSO4 H2O, CuSO4 3H2O and CuSO4 5H2O are reported from X-ray diffraction experiments at 100 (1) K. Combined density functional theory (ORCA) and non-spherical atomic scattering factor (NoSpherA2) computations enabled a Hirshfeld Atom Refinement (HAR) using custom atom scattering factors, accurately polarized and charge-compensated atom electron densities and accurate placement and shapes of the water hydrogen atoms. The results clearly demonstrate that all H atoms are involved in conventional H-bonding in the structures of the hydrates, contrary to an early X-ray diffraction determination on CuSO4 3H2O. Comparison to neutron diffraction results demonstrates the efficacy of this new HAR method. Colour variation in copper sulfates is interpretable by considering the relative number of sulfato and aqua ligands, given the lower crystal field splitting of the former relative to the latter.
- ItemCoupling of CpCr(CO)3 and heterocyclic dithiadiazolyl radicals: synthetic, X-ray diffraction, dynamic NMR, EPR, CV and DFT studies(ACS Publications, 2008) Lau, Hiu F.; Ang, Chwee Y.; Ng, Victor W. L.; Kuan, Seah L.; Goh, Lai Y.; Borisov, Alexey S.; Hazendonk, Paul; Roemmele, Tracey L.; Boeré, René T.; Webster, Richard D.The reaction of 1,2,3,5-dithiadiazolyls, (4-R-C6H4CN2S2)2 (R = Me, 2a; Cl, 2b; OMe, 2c; and CF3, 2d) and (3-NC-5-tBu-C6H3CN2S2)2 (2e) with (CpCr(CO)3]2 (Cp = η5-C5H5) (1) at ambient temperature, yielded respectively the complexes CpCr(CO)2(η2-S2N2CC6H4R) (R = 4-Me, 3a; 4Cl, 3b; 4-OMe, 3c; and 4-CF3, 3d) and CpCr(CO)2(η2-S2N2CC6H3-3-(CN)-5-(tBu)) (3e) in 35 – 72 % yields. The complexes 3c and 3d were also synthesized via a salt metathesis method from the reaction of NaCpCr(CO)3 (1B) and the 1,2,3,5-dithiadiazolium chlorides, 4-R-C6H4CN2S2Cl (R = OMe, 8c; CF3, 8d) with much lower yields of 6 and 20 %, respectively. The complexes were characterized spectroscopically, and also by single crystal X-ray diffraction analysis. Cyclic voltammetry experiments were conducted on 3a-e, EPR spectra were obtained of one-electron reduced forms of 3a-e, and variable temperature 1H NMR studies were carried out on complex 3d. Hybrid DFT calculations were performed on the model system [CpCr(CO)2S2N2CH] and comparisons are made with the reported CpCr(CO)2(π-allyl) complexes.
- ItemCrystal structure of a dimeric ß-diketiminate magnesium complex(International Union of Crystallography, 2016) MacNeil, Connor S.; Johnson, Kevin R. D.; Hayes, Paul G.; Boeré, René T.The solid-state structure of a dimeric ß-diketiminate magnesium(II) complex is discussed. The compound, di- -iodido-bis[({4-amino-1,5-bis[2,6-bis(propan-2- yl)phenyl]pent-3-en-2-ylidene}azanido- 2N,N0)magnesium(II)] toluene sesquisolvate, [Mg2(C29H41N2)2I2] 1.5C7H8, crystallizes as two independent molecules, each with 2/m crystallographic site symmetry, located atWyckoff sites 2c and 2d. These have symmetry-equivalent magnesium atoms bridged by -iodide ligands with very similar Mg—I distances. The two Mg atoms are located slightly below ( 0.5 A ° ) the least-squares plane defined by N–C—C–N atoms in the ligand scaffold, and are approximately tetrahedrally coordinated. One and one-half toluene solvent molecules are disordered with respect to mirror-site symmetry at Wyckoff sites 4i and 2a, respectively. In the former case, two toluene molecules interact in an off-center parallel stacking arrangement; the shortest C to C0 ( – ) distance of 3.72 (1) A ° was measured for this interaction.