Stabilization of molecular LiF, LiFHF, and Na2SiF6 using metallamacrocyclic hosts

The molecular forms of LiF, LiFHF and Na2SiF6 have been stabilized using trinuclear metallamacrocyclic complexes of (cymene)Ru-II, (Cp*)Rh-III and (Cp*)Ir-III as specific receptors. The host-guest complexes were characterized by NMR spectroscopy and single crystal X-ray diffraction. Based on these results, a highly selective chemosensor for fluoride anions has been developed

Syntheses and characterization of dicarbonyl-nitrosyl complexes of technetium(I) and rhenium(I) in aqueous media: Spectroscopic, structural, and DFT analyses

This work describes new synthetic routes to produce mixed carbonyl-nitrosyl complexes of technetium(I) and rhenium(I) in aqueous media. NaNO2, NOHSO4, and NO2(g) have been used to produce in situ nitrous acid as the primary source of NO+. Starting from the organometallic precursor fac-MX3(CO)(3)](+), 1 (M = Tc-99, Re; X = Cl, Br), the formation of mixed dicarbonyl-mononitrosyl complexes was observed in aqueous hydrochloric and hydrobromic acid. Time-dependent analyses of the reactions by means of HATR-IR and Tc-99 NMR spectroscopy in solution revealed the almost quantitative substitution of one CO ligand by NO+ and, thus, the formation of complexes with facial arrangement of the three pi-acceptor ligands. In the case of technetium, the monomeric complex (NEt4)TcCl3(CO)(2)NO] (3a) and the dimeric, chloride-bridged, neutral complex TcCl(mu-Cl)(CO)(2)NO](2) (4a) were produced. In the case of rhenium, the monomeric species (NEt4)ReBr2X(CO)(2)NO] (X = Br (3b), NO3 (5)) was solely isolated. The X-ray structure of complexes 4a and 5 are discussed. The crystallographic analyses revealed the coordination of the NO+ group trans to the terminal chloride (4a) or the bromide (5), respectively. Crystal data: complex 4a (C4Cl4N2O6Tc2), monoclinic, Cc, a = 18.82(3) Angstrom, b = 6.103(6) Angstrom, c = 12.15(2) Angstrom, alpha = 90degrees, beta = 105.8(2)degrees, gamma = 90degrees, V = 1343(3) Angstrom(3), Z = 4; complex 5 (C10H20N3O6Br2Re), orthorhombic, P2(1)2(1)2(1) a = 10.2054(5)degrees, b = 12.5317(7) Angstrom, c = 13.9781(7) Angstrom, V = 1787.67(16) Angstrom(3), Z = 4. The isolated complexes and their potential facial isomers have been further investigated by density functional theory (DFT) calculations. The energy differences of the isomers are relatively small; however, the calculated energies are consistent with the formation of the observed and isolated compounds. The calculated bond lengths and angles of complex 5 are in good agreement with the data determined by X-ray diffraction. Experiments on the no-carrier-added level starting from fac-Tc-99m(H2O)(3)(CO)(3)](+) revealed the formation of the complex fac-(99)mTcCl((HO)-O-2)(2)(CO)(NO)-N-2](+) in reasonable good yields. This aqueous-based, synthetic approach will enable the future evaluation of this novel, low-valent metal precursor for potential use in radiopharmacy

Water-Exchange Study Revealed Unexpected Substitution Behavior of [(CO)2(NO)Re(H2O)3]2+ in Aqueous Media

Copyright © 2006 American Chemical SocietyMarie-Line Lehaire, Pascal V. Grundler, Stefan Steinhauser, Niklaus Marti, Lothar Helm, Kaspar Hegetschweiler, Roger Schibli, and André E. Merbac

Nature of the reactants and influence of water on the supramolecular assembly

10.1021/ic0344970Inorganic Chemistry42175135-5142INOC

Steric control of a bridging ligand for high-nuclearity metallamacrocycle formation: A highly puckered 60-membered icosanuclear metalladiazamacrocycle

A novel S4-symmetric icosanuclear manganese metalladiazamacrocycle was synthesized using a pentadentate ligand, N-3-phenyl-trans-2-propenoylsalicylhydrazide (H3L), that has a rigid and bulky terminal N-acyl group. A 20 cyclic repeat of an -(Mn-N-N)-linkage resulted in a highly puckered diaza-bridged 60-membered icosanuclear metallamacrocycle. The steric interaction between the ligands in the cyclic system leads to five consecutive MnIII centers in a chemically different -(MnAMnBMnCMnDMn E)- environment, with the chiralities of the metal centers being in a rather complicated -(??????????) (??????????)- sequence.close606