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Abstract: We wish to report the synthesis of the Ru(II) crown thioether complex, (1,4,7,10,13-pentathiacyclopentadecane)chlororuthenium(II) hexafluorophosphate, [Ru([15]aneS5)Cl](PF6), and a study of its properties utilizing single crystal X-ray diffraction, electronic spectroscopy, NMR spectroscopy, density functional theory calculations and cyclic voltammetry. The crystal structure shows a single [15]aneS5 macrocycle and a chloro ligand coordinated in a distorted octahedral fashion around the ruthenium(II) center. A significant shortening (0.15Å) of the trans Ru–S bond length occurs in this complex compared to the related PPh3 complex (2.4458(10) to 2.283(1)Å) due to the differences in the trans influence of the two ligands. 13C NMR spectroscopy demonstrates that the structure of [Ru([15]aneS5)Cl]+ is retained in solution. As expected for a Ru(II) complex, the electronic absorption spectrum shows two d–d transitions at 402 and 331nm. These are red-shifted compared to hexakis(thioether)ruthenium(II) complexes and consistent with the weaker ligand field effect of the chloro ligand. The electrochemical behavior of the complex in acetonitrile shows a single one-electron reversible oxidation–reduction at +0.722V versus Fc/Fc+ which is assigned as the Ru(II)/Ru(III) couple. DFT calculations for [Ru([15]aneS5)Cl]+ show a HOMO with orbital contributions from a t 2 g type orbital of the Ru ion, a π component from a p orbital of the axial S atom of [15]aneS5, and a p orbital of the chloro ligand while the LUMO consists of orbital contributions of orbital of the Ru center and p orbitals of the four equatorial S donors. [ABSTRACT FROM AUTHOR]

A new synthesis of RuII(bpy)(sal)2 (1) (bpy=2,2′-bipyridyl, sal=salicylaldehyde) has been developed and the separation and characterization of all three geometric isomers have been completed. The isomers are denoted 1a (phenolic oxygens trans), 1b, (aldehyde oxygens trans), and 1c (aldehyde oxygen trans to phenolic oxygen). All three isomers have been characterized by 1H NMR, high resolution FAB-MS, UV–Vis, and cyclic voltammetry. Additionally, 1a has been characterized by solid-state UV–Vis and a single-crystal X-ray structural study. The solid-state packing of the RuII(bpy)(sal)2 molecules in the structure of 1a displays intermolecular π–π interactions between bpy ligands of adjacent molecules. The bpy interactions form infinite π-stacks with alternating short stacking distances of 3.437 and 3.402 Å. Synthesis, separation, and characterization of all three geometric isomers of RuII(bpy)(sal)2 (bpy=2,2′-bipyridyl, sal=salicylaldehyde) was completed. An X-ray structure of one isomer displays short intermolecular π–π interactions (3.437 and 3.402 Å). [Copyright &y& Elsevier]

Abstract: A series of Hg(II) and Cd(II) homoleptic complexes with mixed donor (O,S and N,S) macrocycles is reported. The macrocyclic oxa thiacrowns 9S2O (1-oxa-4,7-dithiacyclononane) and 18S4O2 (1,10-dioxa-4,7,13,16-tetrathiacyclooctadecane) bind to Hg(II) to form distorted tetrahedral S4 geometries without coordination of the oxygen atoms. In contrast, the two macrocycles coordinate to Cd(II) through all ligand donors to form S4O2 environments. We also report the structure of bis(9N2S (1,4-diaza-7-thiacyclononane))cadmium(II), [Cd(9N2S)2]2+ which shows octahedral coordination in a trans N4S2 environment. Furthermore, two new homoleptic Cd(II) complexes with the related hexadentate macrocycles 18N6 (1,4,7,10,13,16-hexaazacyclooctadecane) and 18S6 (1,4,7,10,13,16-hexathiayclooctadecane) are described. Among the Cd(II) complexes, we highlight a trend in 113Cd NMR that shows progressive upfield chemical shifts as secondary amine donors replace thioether S donors. [Copyright &y& Elsevier]

Monoanionic N 2 P 2 beta-diketiminate (BDI) ligands with phosphine pendant arms were prepared and metallated with zinc(II) iodide. With a goal of understanding the ligands' sterics, methyl and methoyx substituents were introduced on the phenyl linkers. Two different binding modes were observed based on the presence of a substituent at position 6. [Display omitted] Monoanionic mixed N 2 P 2 donor beta-diketiminate (BDI) ligands with phosphine pendant arms, 2-(4-tolyl)-bis(2-diisopropylphosphinophenyl)propenediimine (abbreviated as Tol-BDI(DIPPP)2H), were prepared and metallated with zinc(II) iodide. Three ligand variations have been synthesized by incorporating different substituents (methyl or methoxy) on the linker phenyl rings at positions 4 and 6. In the 4-methyl zinc complex [Tol-BDI(DIPPMeP)2ZnI] and 4-methoxy zinc complex [Tol-BDI(DIPPMeOP)2ZnI], the metal is bound to all four donors on the ligand, rendering a distorted square pyramidal geometry around the zinc metal with τ 5 values of 0.25 and 0.29, respectively. However, the crystal structure of the 4,6-dimethyl zinc complex [Tol-BDI(DIPPMe2P)2ZnI] shows a four-coordinate zinc with only one phosphine bound to the metal, resulting in a distorted seesaw geometry around the metal. While X-ray crystallography shows no interactions between the metal center and the unbound phosphine, solution characterization reveals a symmetrical complex with both phosphines bound to the metal center in all three zinc complexes. [ABSTRACT FROM AUTHOR]

Advanced precursors to novel ferrocene-based ligands Cp 2 FeC(O)CH(R)C(O)CH 3 (R = benzyl, allyl) were synthesized from 1-ferrocenylbutane-1,3-dione via active methylene chemistry. Crystal structures were obtained and computational studies carried out to explore the structural features of these new compounds. Addition of carbonyl electrophiles resulted in the formation of unexpected products, which were identified and mechanisms for their formation proposed. [ABSTRACT FROM AUTHOR]