Dalton Transactions

doi: 10.1039/b602064jpmid: N/A

doi: 10.1039/b602065hpmid: N/A

doi: 10.1039/b602075ppmid: N/A

Braga, Dario; Giaffreda, Stefano L.; Grepioni, Fabrizia; Pettersen, Anna; Maini, Lucia; Curzi, Marco; Polito, Marco

doi: 10.1039/b516165gpmid: 16505902

This deals with solvent-free reactions taking place within solids or between solids or involving a solid and a vapour. The focus is on reactions involving organometallic and coordination compounds and occurring reassembling of non-covalent bonding, hydrogen bonds, and/or formation of ligand–metal coordination bonds. It is argued that reactions activated by mechanical mixing of solid reactants as well as those obtained by exposing a crystalline solid to a vapour can be exploited to “make crystals”, which is the quintessence of crystal engineering. It is demonstrated through a number of examples that solvent-free methods, such as co-grinding, , milling of molecular solids, or reactions of solid with vapours represent viable alternative, when not unique, routes for the preparation of novel molecular and supramolecular solids as well as for the preparation of polymorphic or solvate modifications of a same species. The structural characterization of the products requires the preparation of single crystals suitable for X-ray diffraction, a goal often achieved by

Ainscough, Eric W.; Brodie, Andrew M.; Chaplin, Adrian B.; O'Connor, Joy M.; Otter, Carl A.

doi: 10.1039/b517309bpmid: 16505903

A new diphosphine ligand assembled on the cyclotriphosphazene platform forms linear chelate and dimetallic bridged complexes with Au() and a -chelate complex with Pt().

Bishop, Peter T.; Cowley, Andrew R.; Dilworth, Jonathan R.; Saunders, Andrew J.; Woollard-Shore, John G.

doi: 10.1039/b515244epmid: 16505904

2,4,6-Trialkylbenzenethiols react with [RuCl(PPh)] to give Ru products with the alkyl substituents forming M–C σ bonds, carbene, carbene with a S α-heteroatom, agostic hydrogen interaction or a simple tetrahedral Ru() species, depending on the substituent.

Zhang, Bing-guang; Xu, Jian; Zhao, Yong-gang; Duan, Chun-ying; Cao, Xin; Meng, Qing-jin

doi: 10.1039/b511695cpmid: 16505905

Host–guest complexation of a ferrocenenylphalene dyad , 1,1′-diaceylferrocenyl-3-hydroxyl-2-naphthoylhydrazone, as a fluorescent and electrochemical chemosensor for fluoride anion, was investigated. Crystal structure analysis revealed that the two naphthyl arms of compound positioned in the same side about the ferrocene moiety and interacted through π–π stacking interactions. The intermolecular π–π stacking interactions and the C–H⋯π interactions between the ferrocene moieties and the naphthalene rings linked the molecules together featuring a two-dimensional layered structure. Fluorescence titrations of compound indicated that in the presence of F and HPO, the emission intensities enhanced significantly. Electrochemical titrations revealed that compound sensed the F anion in high selectivity with a cathodic shift of 120 mV, and had no sense in recognizing HPO anion. H NMR titrations demonstrated that while compound hydrogen-bonded to HPO forming simple 1 : 1 host–guest complex, further addition of F induced the deprotonation of compound .

Goetz, Sandrine; Kruger, Paul E.

doi: 10.1039/b514580epmid: 16505906

The condensation of 5-chlorocarbonyl-2,2′-bipyridine with a variety of rigid aromatic diamines, L, gave a series of new bisamido-2,2′-bipyridine based ligands (L = 4,4′-methylenediamine, ; L = 1,1-bis(4-aminophenyl)cyclohexane, ; L = 1,1-bis(4-amino-3,5-dimethylphenyl)cyclohexane, ) capable of forming dinuclear triple helicate complexes on coordination to Fe(). The reaction of various Fe() salts with gave: {[Fe(L1)](BF), ; [Fe(L1)](ClO), ; [Fe(L1)]Cl, ; [Fe(L1)](SO), ; [Fe(L2)](BF), ; [Fe(L2)]Cl, ; [Fe(L3)](BF); ; [Fe(L3)]Cl, ; and [Fe(L3)](SO), , as determined by UV-Vis, IR and H NMR spectroscopy, electrospray mass spectrometry (ESMS) and elemental analyses. A UV-Vis complexometric titration experiment between and Fe(BF) established conclusively a [Fe(L3)] product species. H NMR spectroscopy showed that the complexes exist as both -(helical) and -(non-helical) isomers in DMSO-d6 solution at 298 K. were designed such that following complexation, six amide hydrogen atoms would line an inter-strand intrahelical cavity of sufficient size to facilitate the binding of guest species within it. Indeed, ESMS studies showed characteristic peaks typical of complex–anion species in solution. Furthermore, H NMR titration experiments showed that anions bind within the intrahelical cavity as titration of , and with BuNCl showed significant downfield shifts in the amide and bipyridyl H proton resonances to yield a species of 1 : 2 host to guest stoichiometry. Moreover, addition of BuNCl to , and shifted the -/-species distribution from 1 : 2 in favour of the - to 100% in favour of the -isomer, showing that Cl ions favour the formation of the triple helicate species in DMSO-d6 solution.

Ekeltchik, Irina; Gun, Jenny; Lev, Ovadia; Shelkov, Rimma; Melman, Artem

doi: 10.1039/b513719epmid: 16505907

A new versatile family of chelating agents based on bis(hydroxyamino)-1,3,5-triazines, BHTs, is described. The properties of different BHT ligands are determined by electrochemistry, spectroscopy and titrimetry revealing high redox stability, transparency in the visible range, and diprotic acid-like behaviour in the 5–9 pH range. The iron() and iron()–BHT complexes were studied revealing high affinity of BHTs to iron(). Electrochemical studies show exceptional preference of the BHT ligands to iron() over iron(), this, in addition to their small size and their fast and reversible electrochemistry makes them potentially useful electrochemical redox couples for the low end of the aqueous potential window (<0.6 V, . NHE). The synthetic versatility of the new ligands allows easy tuning of the hydrophobicity, redox potential, and to some extent the stability constant of the complexes by alteration of the peripheral groups appended to the BHTs.

Lyashenko, Ganna; Jancik, Vojtech; Pal, Aritra; Herbst-Irmer, Regine; Mösch-Zanetti, Nadia C.

doi: 10.1039/b514873apmid: 16505908

Stepwise addition of one equivalent of -butyllithium and trimethylsilyl chloride to 2--butylmercaptoaniline affords the new ligand 1-(MeSiNH)-2-(-BuS)CH (LH), that reacts with one equivalent of butyllithium to its lithium salt LLi. Dioxodichloromolybdenum [MoOCl] and dioxodichlorotungsten dimethoxyethane [WOCl(dme)] react in tetrahydrofuran solution at low temperature with two equivalents LLi to monomeric dioxomolybdenum() [MoOL] () and dioxotungsten() complex [WOL] () employing two bidentate amido thioether ligands. The crystallographic determination of the molecular structures of and show evidence for M⋯S contacts. The reaction of [MoOCl] with LLi in tetrahydrofuran solution at room temperature leads next to to two compounds where silyl group migration from nitrogen to oxygen atoms occurs forming [Mo(NL′)(OSiMe)] () and [Mo(NL′)(OSiMe)L] (, L′ = N-2--BuSCH) as determined by NMR spectroscopy. Compound was isolated in low yield and its molecular structure determined by X-ray crystallography. Higher yields of a bisimido complex can be obtained by the direct reaction of one equivalent of LLi with [Mo(NAr)Cl(dme)] (Ar = 2,6-MeCH) forming [Mo(NAr)LCl] ().