Dalton Transactions Blog

In this HOT article, Layfield and coworkers have studied the reactions of the heteroleptic lithium amide [Li₃(μ-hmds)₂(μ,μ-hpp)], where [hmds]^– =
hexamethyldisilazide and [hpp]^– = hexahydropyrimidopyrimidide, with MnCl₂, CoCl₂ or ZnBr₂ resulting in the formation of the separated ion-pairs [MLi₇(μ₈-O)(μ,μ-hpp)₆]+[A]^–, which each consists of a {MLi₇} oxo-centred cube structural motif (M = Mn, Co, Zn), with each face of the cube being bridged by an [hpp]^– ligand. The method potentially could permit access to a range of cage compounds with magnetic properties that are influenced by μ-amido ligands rather than by μ-(O-donor) ligands.

Read more about cage compounds and serendipitous assembly for FREE until the 4th October at:

Synthesis and structure of cationic guanidinate-bridged bimetallic {Li₇M} cubes (M = Mn, Co, Zn) with inverse crown counter anions
Daniel Woodruff, Michael Bodensteiner, Daniel O. Sells, Richard. E. P. Winpenny and Richard A. Layfield
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT10999E

Read the following Dalton Transactions Hot Article to find out which structures of Ru(II) half sandwich compounds are active as possible anti-cancer drugs and why face-capping ligand is all important in combating cancer cells……

Free to read until the 16th September!

New half sandwich-type Ru(II) coordination compounds characterized by the fac-Ru(dmso-S)3 fragment: influence of the face-capping group on the chemical behavior and in vitro anticancer activity
Ioannis Bratsos, Camilla Simonin, Ennio Zangrando, Teresa Gianferrara, Alberta Bergamo and Enzo Alessio
Dalton Trans., 2011, DOI: 10.1039/C1DT11043H

Check out the recent Dalton Trans. Hot Article reporting new polytopic ligands, ddta and tptd. Each contains N-donor dipyridylamino binding sites as well as separate and distinct mono-aza-15-crown-5 binding sites. Murray and colleagues use these ligands to make spin crossover compounds…..read more in their hot article now – free to access until the 16th September.

Spin crossover in polymeric and heterometallic FeII species containing polytopic dipyridylamino-substituted-triazine ligands
Tamsyn M. Ross, Boujemaa Moubaraki, Stuart R. Batten and Keith S. Murray
Dalton Trans., 2011, DOI: 10.1039/C1DT10818B

Feliu Maseras and co-workers from ICIQ in Tarragona, Spain examine the complicated, yet ubiquitous, process that is oxidative addition (OA). The team use DFT to systematically study OA of CH₃Br to palladium bis-phosphine and mono-phosphine complexes. A number of trends can be identified, resulting in a complex picture where the nature of the phosphine and the solvent can be tuned to favor one of the two possible mechanisms, with the corresponding stereochemical implications that can be extrapolated to the behaviour of more sophisticated substrates. Access for free until the 16th September…………

Phosphine and solvent effects on oxidative addition of CH3Br to Pd(PR3) and Pd(PR3)2 complexes
Maria Besora, Christophe Gourlaouen, Brian Yates and Feliu Maseras
Dalton Trans., 2011, DOI: 10.1039/C1DT10983A

In this HOT article, Yuliang Li and coworkers synthesized p–n axial heterojunction inorganic/organic semiconductor nanowire arrays on porous anodic aluminum oxide (AAO) templates via electrochemical deposition. This novel synthesis is based on a common concept of using an AAO template. The electrical properties of the heterojunctions of these organic–inorganic materials were investigated, indicating a diode nature and a rectifying feature. These heterojunction nanowire arrays are at the frontier of the materials field, for next-generation electrical and optoelectronic devices.

Read more for FREE until 24th September about these nanowire arrays at:
Synthesis and characterization of axial heterojunction inorganic–organic semiconductor nanowire arrays
Nan Chen, Xuemin Qian, Haowei Lin, Huibiao Liu, Yongjun Li and Yuliang Li
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT10926J

The formation of peptide or protein aggregates is a common feature of many different forms of neurodegenerative disorders including Alzheimer’s disease, Parkinson’s disease and prion diseases. It is also widely accepted that various metal ions can play a significant role in the conformational changes of these peptides/proteins.

In this HOT article, Kállay and co-workers report on the synthesis and study of the copper complexes of rIAPP fragments. First of all the terminally protected tridecapeptide rIAPP(17–29) was investigated in which the potentially metal binding amino acid residues are located in the N-terminus. The surprisingly high affinity of this peptide towards complexation with copper(II) promoted a systematic study on the shorter fragments including rIAPP(17–22) (Ac-VRSSNN-NH₂), rIAPP(17–20) (Ac-VRSS-NH₂), its mutant peptides (Ac-VASSNH₂ and Ac-VRAA-NH₂) and rIAPP(19–22) (Ac-SSNN-NH₂). The peptides can be classified into two different categories: (i) the tetrapeptides Ac-VRSS-NH₂, Ac-VASS-NH₂ and Ac-VRAA-NH₂ can interact with copper(II) only under strongly alkaline conditions (pH > 10.0) and the formation of only one species with four amide nitrogen coordination can be detected; (ii) the peptides Ac-VRSSNNLGPVLPP-NH₂, Ac-VRSSNN-NH₂ and Ac-SSNN-NH₂ can form complexes above pH 6.0 with the major stoichiometries [CuH₋₂L], [CuH₋₃L]⁻ and [CuH₋₄L]²⁻. The data supports the idea that  rIAPP(17–29) can interact with copper(II) ions under physiological conditions and the SSNN tetrapeptide fragment can be considered as the shortest sequence responsible for metal binding.

Read more for FREE until 21st September at:
Copper(II) complexes of rat amylin fragments
Csilla Kállay, Ágnes Dávid, Sarolta Timári, Eszter Márta Nagy, Daniele Sanna, Eugenio Garribba, Giovanni Micera, Paolo De Bona, Giuseppe Pappalardo, Enrico Rizzarelli and Imre Sóvágó
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT10835B