Warren V. Miller

Fluorescent lanthanide complexes with 2,2′-bipyridine 1,1′-dioxide

Abstract The syntheses and physical properties of the crystalline compounds [Eu(bipyO2)4](ClO4)3 and [Tb(bipyO2)4](ClO4)3(bipyO2-2,2′-bipyridine, 1,1′-dioxide) are reported. The compounds are characterized by i.r. spectra and conductance measurements. Both complexes are observed to fluorescence in both the solid state and in nitromethane solution, and the fluorescence spectra for both the europium and terbium complexes in solution are reported.

Amides as ligands—X: Complexes of γ-butyrolactam with lanthanide nitrates

Abstract The syntheses and physical properties of the crystalline compounds [Ln(BuL) 8 ](NO 3 ) 3 (Ln  La, Nd, Gd) (BuL = γ-butyrolactam), and [Ln(BuL) 3 (NO 3 ) 3 ] (Ln  Dy, Er, Yb) are reported. Infra-red spectra of these complexes indicate that in the solid state the La, Nd, and Gd complexes contain ionic nitrate, while the Dy, Er, and Yb complexes contain covalent nitrato groups. Both molecular weight and conductance data indicate that the complexes containing ionic nitrate dissociate in solution. Both analyses and spectral studies indicate that the larger lanthanide ions have coordination numbers of eight, while the smaller lanthanides are seven coordinated.

Some lanthanide complexes of cyclic amides

Abstract The syntheses and physical properties of the crystalline compounds [Ln(BuL)8](ClO4)3 (Ln = La, Pr, Nd, Sm, Gd, Dy, Er, Yb, Y) (BuL = γ-butyrolactam), [Ln(NMBuL)8](ClO4)3(Ln = La, Pr, Nd, Sm, Gd) (NMBuL = N-methyl-γ-butyrolactam), and [Ln(NMBuL)7](ClO4)3 (Ln = Dy, Er, Yb, Y) are reported. For most of the complexes the infrared, visible, and ultraviolet spectra are reported, as well as the magnetic susceptibilities, molar conductivities, X-ray powder patterns, and molecular weights. Both the composition of these compounds and the X-ray data indicate clearly the existence of two isomorphous series of NMBuL-complexes, one including compounds of the formulas [Ln(NMBuL)8](ClO4)3 and other compounds of the formulas [Ln(NMBuL)7](ClO4)3.

Substitution reactions of metallic complexes of β,δ′,β″-triaminotriethylamine. VIII. Kinetics of acid hydrolysis reaction of the chlorobromo (β,β′,β″-triaminotriethylamine)cobalt(III) ion

Abstract The stoichiometry and kinetics of the acid hydrolysis reaction of Co(tren)ClBr − (tren = β,β′,β″-triaminotriethylamine) in 0.1 M HClO 4 have been investigated. In the acid hydrolysis process the data are consistent with two parallel reactions, probably due to the presence of two isomers in the reactant. One reaction is the release of Cl − in the α-isomer, and the other is the release of Br − in the β-isomer. The pseudo-first-order rate constants for these reactions in 0.1 M HClO 4 at 25.0°C were found to be 3.21 × 10 −3 sec −1 (k α ) and 3.38 × 10 −2 (k β ), respectively. Both rate constants were independent of the acid concentration below pH value 6, and independent of ionic strength from 0.10 to 0.15. Added sulfate ion accelerates the reaction rate. The activation enthalpies and entropies were calculated: ΔH α * = 18.3± 08 kcal mol −1 , ΔH β * = 16.0±0.2 kcal mol −1 ; and ΔS α * = −13.5±2.7 cal mol −1 deg −i , ΔS β * = −9.0±0.7 cal mol −1 deg −1 . The relative rate constants (k β /k α = 10) provide further evidence of the effect of steric strain and crowding on the reactivities of dihalo cobalt(III) tren complexes.

Synthesis and characterization of some octahedral cobalt(III) complexes with β, β′, β″-(triaminotriethylamine)

Abstract The preparation of several new octahedral cobalt(III) complexes of the type [Co(tren) X 2 ] A (tren = β, β′, β″-triaminotriethylamine; X = NO 2 , NCS; N 3 ; A = anion) is reported, as well as those of several mixed complexes of the type [Co(tren) XY ] A ( X = NO 2 , NCS; Y = F, Cl, Br; X = Cl, Y = Br). The chelating anion C 2 O 4 2− forms a complex with the formula [Co(tren)C 2 O 4 ] A . The visible spectra of some of the tren complexes in water, and as Nujol mull indicate that the average ligand field around the cobalt ion can be higher or lower than in the corresponding ethylenediamine complexes, depending upon the nature of the cis anionic ligands. The i.r. spectra of the complexes [Co(tren)BrClO 4 ]Br.H 2 O and [Co(tren) X SO 4 ].H 2 O ( X = Cl, Br) indicates that the perchlorate and sulfate ions are coordinated in the solid state.

Transition metal nitrate complexes of γ-butyrolactam

Abstract The syntheses, conductance measurements, molecular weight measurements, i.r. spectra, magnetic susceptibilities and electronic spectra of a series of transition metal nitrate complexes of γ-butyrolactam (BuL) are reported. The ligand field parameters Dq, B′, and β are calculated for some of these complexes. The trends of nitrate vs. BuL as competing ligand for nickel(II) ion are discussed.