Dalton Transactions

doi: 10.1039/b802874ppmid: N/A

doi: 10.1039/b802875npmid: N/A

Sasamori, Takahiro; Tokitoh, Norihiro

doi: 10.1039/b715033dpmid: 18322615

There has been much interest in the synthesis and properties of doubly bonded systems between heavier Group 15 elements, i. e. heavier analogues of azo-compounds (dipnictenes), from the viewpoints of fundamental and material chemistry. Although such double-bond compounds between heavier main group elements are known to be highly reactive, too much so to be isolated as stable compounds, a number of reports on the synthesis of kinetically stabilized diphosphenes (RPPR), diarsenes (RAsAsR), and phosphaarsenes (RPAsR) bearing bulky substituent have been published since 1980. We have also succeeded in the synthesis of the first stable distibene (RSbSbR) and dibismuthene (RBiBiR) by taking advantage of efficient steric protection groups, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (Tbt) and 2,6-bis[bis(trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl (Bbt), and revealed their structures and properties systematically. Thus, the doubly bonded compounds between heavier Group 15 elements are no longer imaginary species but are those with real existence which are stable, even in the case of the heaviest non-radioactive element bismuth, when they are appropriately protected by bulky substituents. This Perspective describes our research on the chemistry of kinetically stabilized double-bond compounds between heavier Group 15 elements.

Charmant, Jonathan P. H.; Haddow, Mairi F.; Mistry, Rakesh; Norman, Nicholas C.; Orpen, A. Guy; Pringle, Paul G.

doi: 10.1039/b719404hpmid: 18322616

Treatment of the diphosphines ortho-B10H10C(PtBu2)C(PR2) (R = Et, Cy, Ph) with HCl gives the zwitterionic, nido-12-vertex species B10H10C(PHtBu2)C(PClR2); these reactions are reversed by the addition of NEt3.

Tong, Wah-Leung; Lai, Lo-Ming; Chan, Michael C. W.

doi: 10.1039/b715495jpmid: 18322617

Novel phosphorescent conjugated oligo(phenylene–ethynylene)s featuring a central tunable platinum(ii) Schiff base signalling unit with promising photophysical properties have been investigated to pave their development towards polymeric congeners for sensing applications.

Mitchell, Scott G.; Ritchie, Chris; Long, De-Liang; Cronin, Leroy

doi: 10.1039/b715885hpmid: 18322618

Three discrete cobalt-substituted silicotungstates, [Co3(H2O)(B-β-SiW9O34)(B-β-SiW8O29(OH)2)]12− (1), [Co3(H2O)(B-α-SiW9O34)(B-β-SiW8O31)]14− (2), and [Co9Cl2(OH)3(H2O)9(B-β-SiW8O31)3]17− (3), have been synthesized using a synthetic approach involving Co(ii) ions, the dilacunary [γ-SiW10O36]8− polyanion and a bulky organic cation in basic media; all three compounds have been fully characterized and their position as structural intermediates in Co-containing silicotungstate chemistry is described.

Karasawa, Satoru; Yoshihara, Daisuke; Watanabe, Natsuki; Nakano, Motohiro; Koga, Noboru

doi: 10.1039/b800087ppmid: 18322619

A combination of cobalt(ii) complexes and pyridine ligands carrying organic spins, aminoxyl and carbene, provided single-molecule magnets with Stotal = 3/2 in diluted frozen solutions.

Manceau, Alain; Nagy, Kathryn L.

doi: 10.1039/b718372kpmid: 18322620

Extended X-ray absorption fine structure (EXAFS) spectroscopy is a sensitive structural probe of the coordination environments of Hg(ii) with thiol (sulfhydryl) groups, and is equally applicable to solid and aqueous organic or inorganic matter. Information on the number and geometric arrangement of S ligands can be derived from metal–ligand distances because the distances vary with Hg stereochemistry and can be accurately measured by the EXAFS technique. To improve the reliability of determining coordination structures of Hg with thiol groups, correlations among Hg–S bond distance, Hg coordination, and S–Hg–S angle in homoleptic Hg(ii)-thiolates were calculated from analysis of the structures of the 162 Hg(SR)n motifs (n = 2, 3, 4) contained in the Cambridge Structural Database v. 5.28. Graphical correlations of bond distance with coordination number and with bond angle show distinct ranges of values characteristic of specific structural configurations.

Yao, Weifeng; Iwai, Hideo; Ye, Jinhua

doi: 10.1039/b713338cpmid: 18322621

Transition metal doping has always suffered from the disadvantage of reduction of photocatalytic activity because the dopant ions can form a discrete level in the forbidden band of the photocatalyst resulting in low mobility of electrons and holes in the dopant level and thus lowered activity. However, in this study the photocatalytic activity of an efficient visible-light sensitive photocatalyst, BiVO4, for water oxidation or organic compound degradation was found to be remarkably enhanced by molybdenum doping. The role of molybdenum doping in enhancing the photocatalytic activity of BiVO4 was investigated and discussed based on the changes of the surface acidity of the photocatalyst.

Nesterova, Oksana V.; Petrusenko, Svitlana R.; Kokozay, Vladimir N.; Skelton, Brian W.; Jezierska, Julia; Linert, Wolfgang; Ozarowski, Andrew

doi: 10.1039/b713252bpmid: 18322622

A novel heterometallic 1D coordination polymer [{Ni(en)2}2(µ-NCS)4Cd(NCS)2]n·nCH3CN (en = ethylenediamine) has been prepared using the self-assembly process in a one-pot reaction of cadmium oxide, nickel and ammonium thiocyanates with an acetonitrile solution of ethylenediamine. The complex consists of an uncommon cis-Cd(SCN)4(NCS)24− fragment and a rare combination of cis-Ni(en)22+ and trans-Ni(en)22+ building blocks linked by µ1,3-NCS bridges into a double-stranded zigzag chain structure. Each chain is comprised of [Ni2Cd2(µ-NCS–N,S)4)] macrocycles with chair-like and rectangular-like shapes arrayed alternately. The shortest intrachain Cd⋯Cd separations are 9.535(1) and 10.868(2) Å, while the nearest Ni⋯Ni distances are 5.418(1) and 6.612(2) Å. A network of weak N–H⋯S hydrogen bonds, involving the terminal NCS ligands and NH2-groups of en, links the infinite chains and results in the formation of an extended supramolecular three-dimensional framework. Variable-temperature (1.8–300 K) magnetic susceptibilities show a slight change of the µB value at low temperature, indicative of weak antiferromagnetic interactions (J = 1.55 cm−1) between magnetic canters. High-field, high-frequency (100–400 GHz) EPR spectra were simulated using S = 1 ground state for separate Ni2+ ions with the spin Hamiltonian parameters g = 2.165, D = 0.45 cm−1 and E = 0.03 cm−1. According to DFT calculations, the D and E parameters are −0.35 cm−1 and 0.049 cm−1 for the cis arrangement of Ni2+ and 0.58 cm−1 and 0.012 cm−1 for trans.