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Bridging Oxygen Atoms (bridging + oxygen_atom)
Selected AbstractsBorate Accelerates Rates of Steady Oxygen-Isotope Exchange for Polyoxoniobate Ions in WaterCHEMISTRY - A EUROPEAN JOURNAL, Issue 29 2010Borate: guilty and charged! The borate ion, and possibly carbonate, enhances rates of steady oxygen-isotope exchanges at some, but not all, structural sites in polyoxometalate ions. Addition of an oxygen atom to an incoming neutral boric acid molecule (blue=boron) from a bridging oxygen atom on a decametalate ion is shown here. [source] Synthesis and characterization of diorganotin compounds {[R2Sn(ON=CHC6H5)]2O}2 and crystal structure of {[(CsH5CH2)2Sn(ON=CHC6H5)]2O}2CHINESE JOURNAL OF CHEMISTRY, Issue 10 2004Han-Dong Yin Abstract Diorganotin compounds ([R2Sn(ON=CHC6H5)]2O)2 [R=C6H5CH2 (1), 2-FC6H4CH2 (2), 4-FC6H4CH2 (3), 2-ClC6H4CH2 (4), 4-ClC6H4CH2 (5)] were synthesized by the reaction of R2SnO with HON=CHC6H5 in 1:1 molar ratio in refluxing anhydrous benzene or toluene. They were characterized by elemental analysis, IR, 1H NMR and 119Sn NMR spectroscopy. And two sets of 119Sn chemical shifts were observed in the 119Sn NMR spectra of these compounds, indicating the presence of two types of environment around the tin atoms. The crystal structure of compound 1 was determined by X-ray single crystal diffraction analysis. The results showed that the crystal of compound 1 belongs to a monoclinic system with space group P21/c and unit cell dimensions: ,=1.0718(9) nm, b=1.9666(17) nm, c=2.0480(17) nm, ,=96.4371(14)°, Dc=1.450 g/cm3, Z=2, F(000)=1888, V=4.290(6) nm3, ,=1.206 mm,1, R1=0.0405, wR2=0.0786. The compound 1 belongs to centrosymmetric dimer structure mode with a four-membered central endo-cyclic Sn2O2 unit in which the bridging oxygen atoms are hi-coordinated. Each bridging oxygen atom also connects with an em-cyclic tin atom. The endo - and exo -cyclic tin atoms are both five-coordinated, and have coordination geometry of distorted trigonal bipyramid. [source] Gas-Phase Chemistry of Vanadium Oxide Cluster Cations VmOn+ (m = 1,4; n = 1,10) with Water and Molecular OxygenEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 31 2008Sandra Feyel Abstract Bare vanadium oxide cluster cations VmOn+ (m = 1,4; n =1,10) generated by electrospray ionization are investigated with respect to their reactivity toward water and molecular oxygen by using mass spectrometric techniques. Besides ion hydration, the ion/molecule reactions of VmOn+ with oxygen-labeled water (H218O) also lead to 16O/18O exchange reactions of the vanadium oxide clusters cations. Although the probability of degenerate 16O/18O exchange between VmOn+ and water is fairly high for the cluster cations with a medium valence state of vanadium, oxygen-atom exchange reactions between VmOn+ and 18O2 can only be accomplished by VO+, V3O6+, and V4O8+. Particularly interesting is the fact that not only oxygen atoms from vanadyl units are exchanged in the cluster cations, but bridging oxygen atoms are also most likely involved in the processes. Other reaction channels for the interaction of VmOn+ cluster cations with molecular oxygen are reported as well, such as oxidative degradation of the low-valent cluster cations upon collision with O2 and formation of association complexes for the high-valent cluster cations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis and Investigations of the Crystal Structure of aDinuclear Diazadiene Molybdenum Oxo-Imido Complex with a Unique N3Mo(,-O)2MoN3 CoreEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 24 2005Alexei Merkoulov Abstract Ligand metathesis of the diimido and dioxo precursor complexes [Mo(X)2Cl2(DME)] (X = O, NtBu) leads to the mixed oxo-imido derivative [Mo(NtBu)(O)Cl2(DME)] (1). By treatment with Li2DAD (DAD = 1,4-di- tert -butyl-1,4-diazabuta-1,3-diene), 1 is converted into the complex [Mo(NtBu)(O)(DAD)]2 (2). The crystal structure determination on a nonmerohedral twin of 2 reveals a dinuclear molecular structure with nearly symmetrical bridging oxygen atoms. The smaller oxo ligand tends to be a better bridging functionality than the imido ligand; the unprecedented N3Mo(,-O)2MoN3 configuration is favored over a ON2Mo(,-N)2MoN2O core. Compared to other known molybdenum DAD complexes, 2 reveals some degree of pyramidalization at the nitrogen atoms of the DAD ligand. In accord with the Mo,N, N,C, and C,C bond lengths, complex 2 is best described as an ene-diamido complex of formally six-valent molybdenum. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Synthesis, Crystal Structure and in vitro Antitumor Activity of Di- n -butyltin p -[N, N -Bis(2-chloroethyl)amino]benzoatesCHINESE JOURNAL OF CHEMISTRY, Issue 12 2005Zhong-Wei Zhang Abstract Di- n -butyltin oxide reacted with p- [N,N -bis(2-chloroethyl)amino]benzoic acid to yield the compounds {{4-[(ClCH2CH2)2N]C6H4COOSnBu2}2O}2 (1) and {4-[(ClCH2CH2)2N]C6H4COO}2SnBu2 (2), which have been characterized by IR and 1H NMR spectra. The X-ray diffractional studies of 1 reveal the structure of the molecule to be a dimer, in which the two Bu2Sn groups were linked via two bridging oxygen atoms to form a central Bu4Sn2O2 unit. And the tin atom adopts two carbons from two n -butyl groups and three oxygen atoms from the acid and the bridging oxygen. In vitro test showed compound 1 to exhibit high cytotoxicity against P388 and HL-60 cell lines. [source] Synthesis and characterization of diorganotin compounds {[R2Sn(ON=CHC6H5)]2O}2 and crystal structure of {[(CsH5CH2)2Sn(ON=CHC6H5)]2O}2CHINESE JOURNAL OF CHEMISTRY, Issue 10 2004Han-Dong Yin Abstract Diorganotin compounds ([R2Sn(ON=CHC6H5)]2O)2 [R=C6H5CH2 (1), 2-FC6H4CH2 (2), 4-FC6H4CH2 (3), 2-ClC6H4CH2 (4), 4-ClC6H4CH2 (5)] were synthesized by the reaction of R2SnO with HON=CHC6H5 in 1:1 molar ratio in refluxing anhydrous benzene or toluene. They were characterized by elemental analysis, IR, 1H NMR and 119Sn NMR spectroscopy. And two sets of 119Sn chemical shifts were observed in the 119Sn NMR spectra of these compounds, indicating the presence of two types of environment around the tin atoms. The crystal structure of compound 1 was determined by X-ray single crystal diffraction analysis. The results showed that the crystal of compound 1 belongs to a monoclinic system with space group P21/c and unit cell dimensions: ,=1.0718(9) nm, b=1.9666(17) nm, c=2.0480(17) nm, ,=96.4371(14)°, Dc=1.450 g/cm3, Z=2, F(000)=1888, V=4.290(6) nm3, ,=1.206 mm,1, R1=0.0405, wR2=0.0786. The compound 1 belongs to centrosymmetric dimer structure mode with a four-membered central endo-cyclic Sn2O2 unit in which the bridging oxygen atoms are hi-coordinated. Each bridging oxygen atom also connects with an em-cyclic tin atom. The endo - and exo -cyclic tin atoms are both five-coordinated, and have coordination geometry of distorted trigonal bipyramid. [source] | ||||||||||