- New antimony(III) bromide complexes with thioamides: Synthesis, characterization, and cytostatic properties
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New antimony(III) bromide complexes with the heterocyclic thioamides, thiourea (TU), 2-mercapto-1-methylimidazole (MMl), 2-mercapto-benzimidazole (MBZlM), 2-mercapto-5-methyl-benzimidazole (MMBZIM), 5-ethoxy-2-mercapto- benzimidazole (EtMBZIM), 2-mercapto
- Ozturk, Ibrahim I.,Hadjikakou, Sotiris K.,Hadjiliadis, Nick,Kourkoumelis, Nikolaos,Kubicki, Maciej,Tasiopoulos, Anastasios J.,Scleiman, Hanadi,Barsan, Mirela M.,Butler, Ian S.,Balzarini, Jan
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- N-Heterocyclic carbene adducts of the heavier group 15 tribromides. Normal to abnormal isomerism and bromide ion abstraction
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The reactivity of the heavier group 15 tribromides, SbBr3 and BiBr3, towards 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene (IPr) is described. These reactions quantitatively afford Lewis acid-base adducts, (IPr)EBr3 (E = Sb 1; Bi 2), which readily react with AlBr3 yielding cationic species [(IPr)EBr2]+ (E = Sb 3; Bi 4). Under thermal treatment, the N-heterocyclic carbene ligands in 1 and 2 will readily isomerise to afford the abnormally-bonded (or mesoionic) complexes (aIPr)EBr3 (E = Sb 5; Bi 6). As with 1 and 2, bromide abstraction from such compounds readily affords the cationic complexes [(aIPr)EBr2]+ (E = Sb 7; Bi 8). Finally, in an effort to elucidate the isomerisation process which allows for the conversion of 1 and 2 to the abnormally bonded systems (compounds 5 and 6), compound 1 was reacted with a further equivalent of IPr to afford the cationic species [(aIPr)2SbBr2]+ (9). This strongly suggests that the normal to abnormal isomerisation of the N-heterocylic carbene ligands in compounds 1 and 2 is mediated by the presence of free IPr. Compound [9]Br can be used to access the dicationic species [(aIPr)2SbBr]2+ (10), which we have identified spectroscopically. Single crystal X-ray structures and spectroscopic data for all compounds are discussed.
- Waters, Jordan B.,Chen, Qien,Everitt, Thomas A.,Goicoechea, Jose M.
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p. 12053 - 12066
(2017/09/25)
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- Bromide mediated oxidation of antimony(III) by cerium(IV) in aqueous sulphuric acid medium
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The micro amount (10-3 mol dm-3) of bromide mediated oxidation of antimony(III) by cerium(IV) in an aqueous sulphuric acid medium has been studied spectrophotometrically at 25°C and I = 3.10 mol dm -3. In the presence of bromide, one mole of antimony(III) requires two moles of cerium(IV). The reaction is first order with respect to [cerium(IV)] and [bromide], whereas the order with respect to [antimony(III)] is less than unity. Increase in [sulphuric acid] accelerates the reaction rate. The order with respect to [H+ ion] is less than unity. Added products, cerium(III) and antimony(V) do not have any significant effect on the rate of reaction. The active species of oxidant is identified as H 3Ce(SO4)4-, whereas that of reductant as SbBr2+. The possible reaction mechanism is proposed and the activation parameters determined and discussed.
- Munavalli,Thabaj,Chimatadar,Nandibewoor
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p. 1579 - 1584
(2008/03/27)
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- On the chemical transport of molybdenum using SbBr3 - Experiments and thermochemical calculations
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Mo migrates in a temperature gradient from the region of higher temperature to the lower temperature using SbBr3 as transport agent. For various mean transport temperatures (750 1 + T2); T2 - T1 = 100 °C) we observed small transport rates (m ≤0,6 mg/h) which rise up to 16 mg/h for higher transport agent concentrations. Small amounts of MoO2 and Sb were detected beside Mo in the sink. The observed solid phases in the sink are in agreement with thermodynamical calculations by CVTrans which also demonstrate that the formation of MoO2 and Sb as well as the transport effect of SbBr3 are caused by traces of H2O from the quartz glass wall. The sequence of deposition of Mo, MoO2 and Sb in the examined temperature range can be calculated (CVTrans) and measured with the transport balance.
- Pausch,Burggraf,Gruehn
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p. 1835 - 1842
(2008/10/09)
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- SOME CO-ORDINATION COMPOUNDS OF TaCl3S AND TaBr3S. X-RAY CRYSTAL STRUCTURE OF
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The reaction of TaX5 (X = Br or Cl) with Sb2S3 (molar ratio 3:1) led to the formation of TaX3S.With L these species form complexes of formulation TaX3S*2L (L = dimethyl sulphide, tetrahydrothiophene, or MeCN) and TaX3S*L .The exact nature of the complexes was ascertained by a single-crystal X-ray study on TaCl3S*bpte.The crystals are monoclinic, space group P21/c, Z = 4 with a = 15.538(20), b = 7.352(8), c = 16.619(20) Angstroem, and β = 110.88(10) deg. 2 003 Independent reflections with I>4?(I) were used in the refinement and a R value of 0.062 obtained.The structural study showed that the metal atom was in a distorted octahedral environment with a terminal Ta=S bond , three metal-chlorine interactions , and two bonds to the sulphur atoms of the ligand.The bond trans to the terminal sulphur atom is longer than the bond that is cis .The Ta=S fragment has the expected influence on the three angles it forms at the metal with the three chlorine atoms that are bound cis to it, increasing the angles to ca. 100 deg.This is concomitant with a surprisingly small value of 86.5(2) deg for the angle S=Ta-S(cis).
- Drew, Michael G. B.,Rice, David A.,Williams, David M.
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p. 845 - 848
(2007/10/02)
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