Dalton Transactions

doi: 10.1039/c0dt90109apmid: N/A

doi: 10.1039/c0dt90111cpmid: N/A

Braunschweig, Holger; Dewhurst, Rian D.

doi: 10.1039/c0dt01181apmid: 21116564

While the vast majority of inorganic chemistry involves electron donation from main-group atoms to metals, an intriguing yet flip-side exists: where Lewis-basic metals donate electron density to Lewis-acidic main-group atoms (most often boron). These so-called “Z-type” ligands, along with other less clear-cut complexes, are examples of this metal-ligand role reversal. This perspective article offers an introduction to metal-to-boron dative bonding, and attempts to correlate spectroscopic and structural data from the complexes..

Wang, Hui; Yu, Yi-Fei; Chen, Qian-Wang; Cheng, Kai

doi: 10.1039/c0dt01170cpmid: 21103603

This communication demonstrates superparamagnetic nanosized particles with a magnetic core and a porous carbon shell (thickness of 11 nm), which can remove 97% of Pb2+ ions from an acidic aqueous solution at a Pb2+ ion concentration of 100 mg L−1. It is suggested that a weak electrostatic force of attraction between the heavy metal ions and the nanoparticles and the heavy metal ions adsorption on the mesopore carbon shell contribute most to the superior removal property.

Wang, Jin-Tao; Li, Yi; Tan, Jia-Heng; Ji, Liang-Nian; Mao, Zong-Wan

doi: 10.1039/c0dt01161dpmid: 21125084

Herein we reported three new platinum(ii)-triarylpyridines complexes with peralkylated ammonium pendants that strongly stabilize G-quadruplex DNA.

Jin, Xiaoyan; Qian, Zhaosheng; Lu, Bangmei; Bi, Shuping

doi: 10.1039/c0dt00594kpmid: 21116586

The mechanisms for the substitution of an aqua ligand with F− in monomeric Al complexes were studied with density functional theory (DFT). Typical mechanisms are modeled to determine the preferred substitution pathway according to the activation energy barriers. The present computational results are in favor of interchange associative (Ia) mechanism for the substitution of F− into Al(H2O)63+, whereas interchange dissociative (Id) mechanism is preferred for the substitution into Al(H2O)5(OH)2+, which is in agreement with the previous experimental findings. This implies the mechanistic changeover from Ia to Id induced by the spectator hydroxyl ligand. Like the water-exchange reaction, the substitution rate is accelerated by OH− ligand. The difference of the computational and experimental activation enthalpy values is interpreted as the DFT errors in energy and the deviation of transmission coefficient from unity.

Willans, Charlotte E.; French, Sara; Anderson, Kirsty M.; Barbour, Leonard J.; Gertenbach, Jan-André; Lloyd, Gareth O.; Dyer, Robert J.; Junk, Peter C.; Steed, Jonathan W.

doi: 10.1039/c0dt01011apmid: 21116573

Zhao, Ying; Li, Chunguang; Li, Feifei; Shi, Zhan; Feng, Shouhua

doi: 10.1039/c0dt01198cpmid: 21125087

Highly water-dispersible Mn3O4 nanocrystals with well-controlled size, size distribution and high crystallinity have been successfully synthesized through a modified polyol process. Poly(acrylic acid) is used as the capping agent, conferring upon the particles high water-dispersion, of which the carboxylate groups partially bind to the nanocrystal surface and the uncoordinated carboxylate groups extend into water. The water-dispersible Mn3O4 nanocrystals can be further transferred to nonpolar solvent by linking oleylamine molecules through electrostatic interaction. The as-prepared Mn3O4 nanocrystals exhibit ferromagnetic behavior at low temperature and weak paramagnetic behavior at room temperature. The Curie–Weiss temperature and the blocking temperature are 40 K and 32 K, respectively.

Zheng, Ai-Xia; Ren, Zhi-Gang; Li, Ling-Ling; Shang, Hai; Li, Hong-Xi; Lang, Jian-Ping

doi: 10.1039/c0dt00620cpmid: 21120237

Reactions of a gold(i) thiolate complex [Au(Tab)2]2(PF6)2 (Tab = 4-(trimethylammonio)benzenethiolate) with equimolar 1,2-bis(diphenylphosphine)ethane (dppe), 1,3-bis-(diphenylphosphine)propane (dppp) or 1,4-bis-(diphenylphosphine)butane (dppb) in MeOH–DMF–CH2Cl2 gave rise to three polymeric complexes [Au2(Tab)2(dppe)]2(PF6)4·2MeOH (1·2MeOH), [Au2(Tab)2(dppp)]Cl2·0.5MeOH·4H2O (2·0.5MeOH·4H2O), and [Au4(μ-Tab)2(Tab)2(dppb)](PF6)4·4DMF (3·4DMF), respectively. Analogous reaction of 1 with dppb in DMF/C2H4Cl2 produced one tetranuclear complex [Au2(μ-Tab)(Tab)2]2Cl4·2DMF·4H2O (4·2DMF·4H2O). Complexes 1–4 were characterized by elemental analysis, IR spectra, UV-vis spectra, 1H and 31P{1H} NMR and single crystal X-ray analysis. Compounds 1 and 2 consist of [Au(Tab)]2 dimeric fragments that are bridged by dppe or dppp ligands to form a 1D linear chain extending along the a axis. For 3, each [Au4(Tab)2(μ-Tab)2] fragment is linked by a pair of dppb ligands to afford another 1D chain extending along the c axis. For 4, the four [Au(Tab)]+ fragments are linked by two Au–Au bonds and two doubly bridging Tab ligands to form a {[Au(Tab)]4(μ-Tab)2} chair-like cyclohexane structure. Hydrogen-bonding interactions in 2 and 4 lead to the formation of interesting 2D hydrogen-bonded networks. The luminescent properties of 1–4 in solid state were also investigated.

Wang, Mingsheng; Zeng, Lingkun; Chen, Qianwang

doi: 10.1039/c0dt00946fpmid: 21125128

Regular tricobalt tetraoxide (Co3O4) nanocubes with tunable sizes have been synthesized by a simple magnetic field assisted hydrothermal reaction. In contrast to other traditional methods, no surfactant is added to the reaction system, the morphology of the product is controlled by the application of an external magnetic field and the size distribution of the product is tuned by simply modifying the ratio of distilled water to ethanol in the solvent. The growth process of Co3O4 nanocubes is investigated and discussed in detail. It is found that the differences in polarity and dielectric constant between distilled water and ethanol and thus the difference of cobalt coordination ions concentration in the different solvents are the major factors that determine the final size distribution of Co3O4 nanocubes. Magnetic properties of Co3O4 nanocubes synthesized under (MF) and not under (ZF) an external magnetic field are then investigated. It is believed that during their growth, the alignment of spins in the Co3O4 particles and thus the magnetic and crystal lattices of Co3O4 are influenced by the external magnetic field. Spins in MF arrange in a less-ordered manner and cannot be totally compensated by each other, therefore makes them have a stronger tendency to align into an ordered figuration, which leads to a relatively larger magnetization and higher Néel temperature (TN) of MF comparing to sample ZF.