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Arene Ring (arene + ring)

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Chemistry	100%

Selected Abstracts

Ruthenium-to-Platinum Interactions in ,6,,1 NCN-Pincer Arene Heterobimetallic Complexes: An Experimental and Theoretical Study

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 29 2010
Sylvestre Bonnet
Abstract A series of ,6,,1 -heterobimetallic complexes have been prepared in which a [Ru(,6 -arene)(C5R5)]+ fragment (R = H or Me) and an ,1 -NCN-pincer platinum fragment are combined within the same molecule. In complexes [2]+ and [3]+, the ruthenium and platinum centers are ,6 and ,1 coordinated, respectively, to the same arene ring, whereas in [4A]+ and [5A]+ they are coordinated to two different arene rings that are linked with a covalent bond ([4A]+) or an ethyl bridge ([5A]+). Upon changing the organic manifold between both metal centers, very strong ([2]+) to very weak ([5A]+) ruthenium-to-platinum interactions are obtained. Experimentally, X-ray crystal structures show an increaing steric hindrance when the Ru,Pt distance diminishes, and electrochemical and 195Pt NMR spectroscopic studies show a decreasing electron density on platinum from [5A]+ to [2]+. Theoretical DFT calculations were undertaken, which show an increasing charge on platinum from [5A]+ to [2]+. Our theoretical analysis shows that the particularly strong ruthenium-to-platinum electronic interactions in [2]+ and [3]+ do not come from binding of ruthenium to platinum, but from the pincer Cipso sharing its electron density between both metal centers, which decreases the , donation to platinum, and from increased backdonation of the platinum d electrons into the , system of the arene ring. [source]

The twinned crystal structure of tripotassium benzene-1,3,5-tris(trifluoroborate)

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2010
Daniel Franz
The title compound, 3K+·C6H3B3F93,, crystallizes as discrete anions and cations which are connected by K...F and K..., interactions. Two of the ,BF3 residues attached to the aromatic ring adopt a conformation with all F atoms out of the plane of the aromatic ring, whereas the third residue has an almost synperiplanar conformation for one of the F,B,C,C torsion angles. It is remarkable that only one of the K+ cations interacts with the arene ring and that only one side of the aromatic ring coordinates to a K+ cation. As a result, a sandwich structure does not occur. All K+ ions show a coordination mode that cannot be conveniently described with a polyhedron. The anions are located in the (102) planes with the K+ cations located between these planes. The investigated crystal was a nonmerohedral twin with the fractional contribution of the minor twin component being 0.405,(4). The title compound is the first example of a structure containing a benzene ring substituted with three ,BF3 groups. Only eight other structures have been reported in which a benzene ring carries at least one ,BF3 group. Just five of these contain a K+ ion, but in none of these is the K+ ion coordinated to the aromatic ring. [source]

A structural systematic study of four isomers of difluoro- N -(3-pyridyl)benzamide

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2009
Joyce McMahon
The four isomers 2,4-, (I), 2,5-, (II), 3,4-, (III), and 3,5-difluoro- N -(3-pyridyl)benzamide, (IV), all with formula C12H8F2N2O, display molecular similarity, with interplanar angles between the C6/C5N rings ranging from 2.94,(11)° in (IV) to 4.48,(18)° in (I), although the amide group is twisted from either plane by 18.0,(2),27.3,(3)°. Compounds (I) and (II) are isostructural but are not isomorphous. Intermolecular N,H...O=C interactions form one-dimensional C(4) chains along [010]. The only other significant interaction is C,H...F. The pyridyl (py) N atom does not participate in hydrogen bonding; the closest H...Npy contact is 2.71,Å in (I) and 2.69,Å in (II). Packing of pairs of one-dimensional chains in a herring-bone fashion occurs via,-stacking interactions. Compounds (III) and (IV) are essentially isomorphous (their a and b unit-cell lengths differ by 9%, due mainly to 3,4-F2 and 3,5-F2 substitution patterns in the arene ring) and are quasi-isostructural. In (III), benzene rotational disorder is present, with the meta F atom occupying both 3- and 5-F positions with site occupancies of 0.809,(4) and 0.191,(4), respectively. The N,H...Npy intermolecular interactions dominate as C(5) chains in tandem with C,H...Npy interactions. C,H...O=C interactions form R22(8) rings about inversion centres, and there are ,,, stacks about inversion centres, all combining to form a three-dimensional network. By contrast, (IV) has no strong hydrogen bonds; the N,H...Npy interaction is 0.3,Å longer than in (III). The carbonyl O atom participates only in weak interactions and is surrounded in a square-pyramidal contact geometry with two intramolecular and three intermolecular C,H...O=C interactions. Compounds (III) and (IV) are interesting examples of two isomers with similar unit-cell parameters and gross packing but which display quite different intermolecular interactions at the primary level due to subtle packing differences at the atom/group/ring level arising from differences in the peripheral ring-substitution patterns. [source]

Ruthenium-to-Platinum Interactions in ,6,,1 NCN-Pincer Arene Heterobimetallic Complexes: An Experimental and Theoretical Study

Conformational disorder in 4-(5,5,-dibromo-2,-chloro-4,4,-bipyridyl-2-yl)benzaldehyde: role of ,,, and halogen interactions

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2010
Mohamed Abboud
The crystal packing of the title compound, C17H9Br2ClN2O, is governed by strong ,,, stacking, where molecules are tightly bound within infinite (100) planes; these planes interact mainly through non-optimal ,,, stacking where arene rings are noticeably displaced from perfect overlap, and also through halogen,halogen interactions. The aldehyde group shows conformational disorder, with a significant population difference between the two conformers; this difference is rationalized by the energetic analysis of the crystal packing using the PIXEL method, which also allows a decomposition of intermolecular interaction energy into Coulombic, polarization, dispersion and repulsion contributions. Using such an analysis, it is found that the main reason for this unequal population of the two conformers in the crystal is two hydrogen bonds that are present only for the major conformer. [source]

catena -Poly[[aqua(11-chloropyrido[2,,3,:2,3]pyrimidino[5,6- f][1,10]phenanthroline-,2N4,N5)cadmium(II)]-,-benzene-1,4-dicarboxylato-,3O1,O1,:O4]: an inclined interpenetrating (6,3) network

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009
Zhi-Guo Kong
The asymmetric unit of the title compound, [Cd(C8H4O4)(C17H8ClN5)(H2O)]n, contains one CdII atom, two half benzene-1,4-dicarboxylate (1,4-bdc) anions, one 11-chloropyrido[2,,3,:2,3]pyrimidino[5,6- f][1,10]phenanthroline (L) ligand and one coordination water molecule. The 1,4-bdc ligands are on inversion centers at the centroids of the arene rings. The CdII atom is six-coordinated by two N atoms from one L ligand, three carboxylate O atoms from two different 1,4-bdc ligands and one water O atom in a distorted octahedral coordination sphere. Each CdII center is bridged by the 1,4-bdc dianions to give a one-dimensional chain. ,,, stacking interactions between L ligands of neighboring chains extend adjacent chains into a two-dimensional supramolecular (6,3) network. Neighboring (6,3) networks are interpenetrated in an unusual inclined mode, resulting in a three-dimensional framework. Additionally, the water,carboxylate O,H...O hydrogen bonds observed in the network consolidate the interpenetrating nets. [source]