Reaction of RuCl 3 ‚xH 2 O with 1-methoxy-1,4cyclohexadiene in an alcohol solvent, ROH, gives [RuCl 2 -(η 6 -C 6 H 5 OR)] 2 (R ) Me, Et, or HOCH 2 CH 2 ) in up to 79% yield. The crystal structures of [Ru 2 (µ-Cl 3 )(η 6 -C 6 H 5 -OEt) 2 ] + [BPh 4 ]and [RuCl 2 (η 6 -C 6 H 5 OCH 2 CH 2 OH)] 2 are also reported.

In its crystal structure the one-dimensional coordination polymer [Ag 4 (O 2 C(CF 2 ) 2 CF 3 ) 4 (TMP) 3 ] n (1) (TMP ¼ 2,3,5,6-tetramethylpyrazine) adopts a zig-zag arrangement in which pairs of silver(I) centres bridged by two fluorocarboxylate ligands are linked alternately via one or two neutral TMP ligands. This material can reversibly absorb/desorb small alcohols (ROH) in single-crystal-to-single-crystal transformations, despite the lack of porosity in the crystals, to yield a related material of formulaThe absorption process includes coordination of the alcohol to silver(I) centres and, in the process, insertion of the alcohol into one-quarter of the Ag-O bonds of coordination polymer. When in place, the alcohol molecule is also supported by formation of an O-H/O hydrogen bond to the now partially dissociated carboxylate group. The reverse process leading to desorption of the alcohol takes place upon mild heating to regenerate 1. Upon further heating, 1 can release molecules of TMP into the vapour phase resulting in a separate chemical and structural transformation to yield a two-dimensional layered material of composition. This new transformation occurs via dissociation of Ag-N bonds upon ligand release and formation of new Ag-O bonds. The whole series of transformations has been followed in situ by single-crystal and/or powder X-ray diffraction and studied by thermogravimetric analysis. As a mechanistic probe to explore transport within formally nonporous 1, gravimetric CO 2 gas sorption/desorption has been conducted. It is proposed that transport of small molecules occurs through the fluorous layers in the crystal.

The different complexation methods of a proton transfer compound, (phenH)2(pydc) (phen=1,10‐phenanthroline; pydcH2= pyridine‐2,6‐dicarboxylic acid), are discussed and formation of [Sn(pydc)(phen)(OH)2]·3H2O (1), {[Sb(pydc)(phen)]2O}·2DMSO·4H2O(2) and [(Tl(pydcH)]n (3) complexes are reported. The characterization was performed using IR spectroscopy and X‐ray diffraction. The structures of Sn(IV) and Sb(III) complexes show that both cationic and anionic fragments of the starting proton transfer compound have been involved in the complexation. Whereas the structure of Tl(I) complex demonstrates that only the anionic fragment of (phenH)2(pydc) is contributed to the complexation. The complexes 1‐3 show a variety of structural features including mononuclear, binuclear and polymeric structures. In compounds (1), (2) and (3) a large number of hydrogen bonds are observed. These interactions play an important role in the formation and stabilization of supramolecular systems in the crystal lattices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The importance of dopamine (DA) detection as a biomarker for several diseases, especially Parkinson''s disease, has persuaded scientists to develop new nanomaterials for efficient sensing of DA in clinical samples. Ultrathin metal−organic nanosheets due to their exceptional thickness, large surface area, and flexibility are endowed with many accessible active sites and optimal surface interaction with the target analyte molecules. In this regard, a novel layered fluorescent metal−organic nanomaterial with a honeycomb topology based on europium, [Eu(pzdc)(Hpzdc)(H 2 O)] n (ECP) (H 2 pzdc = 2,3-pyrazine dicarboxylic acid), was synthesized. X-ray crystallography revealed that the 3D supramolecular architecture of ECP is constructed from noncovalent interactions of coordinated water molecules between the 2D layers along the b axis. These layers that are only ∼4 nm thick were conveniently separated through ultrasound-induced liquid phase exfoliation. Optical studies show that the reduction of ECP thickness enhances the fluorescence intensity and serves as an efficient optical marker for DA detection. ECP nanoflakes exhibited fast response and high selectivity for DA detection in clinical samples. Good linearity for DA detection in the range of 0.1−10 μM with a detection limit of 21 nM proves the potential of ECP nanoflakes in DA sensing applications.

Chemical reactions in the crystalline organic solid state, although uncommon, are well-established and involve covalent bond formation between neighboring molecules as a result of photochemical or thermal activation. [1][2][3][4] Carboncarbon bond forming dimerizations, oligomerizations, and polymerizations involving alkene and alkyne moieties in metal-containing crystals (salts and coordination compounds) have also been studied for many years, [5] though in most cases not in crystal-to-crystal transformations. By comparison, reactions within crystals of organometallic or coordination compounds in which metal-ligand bonds are formed or broken are very limited, not only in number of reports but in variety of reaction observed. [6][7][8] Most common are reactions that involve loss of coordinated solvent in a porous transitionmetal coordination framework compound or solvent-molecule re-coordination upon uptake by the evacuated framework. Typically, a single metal-ligand bond is broken or formed, and transport of the solvent (ligand) molecule in and out of the crystal is relatively facile owing to the available channels.[9] Thermal treatment of the crystal is often needed for solvent removal. A much rarer example of a solid-state metal-ligand bond cleavage reaction is the photolytic cleavage of a Mn À CO bond within a host-guest structure reported by Fujita and co-workers. [10] Three examples of reversible ligand coordination to transition-metal centers involving sorption/desorption in nonporous crystals have been reported. In one case, PtÀS bonds are formed and broken in the reversible absorption of gas-phase SO 2 molecules by a platinum complex; [11] in another, a trinuclear iron complex exchanges coordinated H 2 O with MeOH through cleavage and formation of an Fe À O bond; [12] and most recently, reversible loss of a weakly bound pyridine ligand from square-pyramidal copper(II) complexes has been reported. [13] However, all of these examples involve simple cleavage and formation of an individual metal-ligand bond. In recent studies by Rosseinsky and co-workers, [14] from our own work [15,16] and in that of Orpen, [17] the complexity of reactions has been expanded to include the reversible release and uptake of small molecules, involving breaking and formation of more than one covalent bond within crystalline coordination compounds. The present study involves a new class of reactions within nonporous crystals of a coordination polymer in which separate coordination bonds are formed and broken in a ligand-substitution reaction at a silver(I) center.Previously we have demonstrated the synthesis of coordination network structures based upon silver carboxylate dimer units linked through neutral diimine and diamine ligands. The behavior of Ag + ions in these structures has similarities to the behavior of hydrogen ions in structures of carboxylic acids, [18,19] such that the O À Ag À O coordinationbond arrangement in the former mimics the more wellestablished OÀH···O hydrogen-bond arrangement in the latter (Scheme 1). He...