Showing papers in "Inorganic Chemistry in 1980"

Ferrocene as an internal standard for electrochemical measurements

Abstract: Electrochemistry is an increasingly popular technique for the characterization of new compounds. The basic thermodynamic quantity that is assigned to an electrode process is the standard or formal reduction potential (E^o or E^f). In aqueous solution the measurement of reduction potentials is facilitated by the use of reliable and universally accepted reference electrodes such as the normal hydrogen electrode (NHE) or the saturated calomel electrode (SCE). In many instances electrochemical measurements in water are impossible due to insolubility or instability of the compound. Unfortunately, no universal reference electrode exists for nonaqueous solvents.

Cis-trans isomerism in (trpy)(PPh3)RuC12. Comparisons between the chemical and physical properties of a cis-trans isomeric pair

Abstract: The syntheses of complexes derived from the planar, tridentate ligand 2,2',2''-terpyridine (trpy) of the type (trpy)Ru/sup II/(L)Cl/sub 2/ where L = PPh/sub 3/, P(p-C/sub 6/H/sub 4/Me)/sub 3/, or pyridine are described. Some rather striking differences in the properties of the cis and trans-isomers of the phosphine derivatives are reported. (BLM).

Porphyrins. 40. Electronic spectra and four-orbital energies of free-base, zinc, copper, and palladium tetrakis(perfluorophenyl)porphyrins

Abstract: Absorption and emission spectra and emission quantum yields are given for free-base (H/sub 2/), Zn, Cu, and Pd derivatives of tetrakis(perfluorophenyl)porphyrin (TFPP). The four-orbital model is used to rationalize differences in the optical properties among the derivatives of TFPP and the same derivatives of porphine (P), octaethylporphyrin (OEP), and tetraphenylporphyrin (TPP). It is concluded from absorption data that the energy difference between the two excited singlets, i.e., /sup 1/E(a/sub 2u/,e/sug g/) - /sup 1/E(a/sub 1u/,e/sub g/), decreases along the series Pd > Cu > Zn > H/sub 2/ and also along the series OEP > P > TFPP > TPP. The theory and date are reviewed, and it is concluded that the energy difference between the two excited triplets, i.e., /sup 3/E(a/sub 2u/,e/sub g/) - /sup 3/E(a/sub 1u/,e/sub g/), also decreases along these series. However the condition of degeneracy, e.g., /sup 1/E(a/sub 2u/,e/sub g/) - /sup 1/E(a/sub 1u/,e/sub g/) = 0, occurs for different molecules in the singlet and triplet cases. Theory also suggests that if /sup 3/E(a/sub 2u/,e/sub g/) > /sup 3/E(a/sub 1u/,e/sub g), the molecule should form a /sup 2/A/sub 1u/ cation radical and if /sup 3/E(a/sub 2u/,e/sub g/) < /sup 3/E(a/sub 1u/,e/sub g/) the molecule should formmore » a /sup 2/A/sub 2u/ radical. 4 figures, 2 tables.« less

Synthetic applications of photosubstitution reactions of poly(pyridyl) complexes of ruthenium (II)

Abstract: Two new methods for the photochemical synthesis of complexes of the type Ru(bpy)/sub 2/LX/sup +/ and Ru(bpy)/sub 2/X/sub 2/ (L = pyridine, CH/sub 3/CN, etc.; X = ClO/sub 4/, NO/sub 3/, NCS, Br, etc.) have been developed. The photochemistry is based on photosubstitution reactions of the parent complexes Ru(bpy)/sub 2/L/sub 2//sup 2 +/ most notably where L is pyridine in solvents of low polarity like dichloromethane. The photochemical methods are versatile and give products in good yield and purity. Mechanistically, the reactions appear to involve a dissociative step at the metal; a quantum yield of 0.18 is found for monosubstitution in Ru(bpy)/sub 2/(py)/sub 2//sup 2 +/, which is independent of the chemical identity and concentration of the entering ligand, X/sup -/. Some deductions about the photochemical behavior of the related complex Ru(bpy)/sub 3//sup 2 +/ based on our observations with Ru(bpy)/sub 2/L/sub 2//sup 2 +/ are also presented, and the possibility of a special medium effect in low-polarity solvents like dichloromethane is discussed.

Divalent lanthanide chemistry. Bis (pentamethylcyclopentadienyl) europium(II) and -ytterbium(II) derivatives: crystal structure of bis (pentamethylcyclopentadienyl) (tetrahydrofuran ytterbium(II) -hemitoluene at 176 K

Abstract: LBL-1 0490C, Preprint Submi BIS(PENTAMETHYLCYCLOPENTADIENYL) VATI : CRYSTAL STRUCTURE IUM(II)TETRAHYDROFURAN T, Don Tilley, Helen a Ruben, , Brock Spencer, David H. Templeton April 1 TWO-WEEK LOAN COPY is a Library Copy which may borrowed two weeks. For a personal copy, Tech. Info. Division, Ext. 6782. for the U.S. of under Contract

Studies of a series of haloaluminum, -gallium, and -indium phthalocyanines

Abstract: Abstract : Physical and chemical studies have been carried out on the series of phthalocyanines AlPcF, AlPcCl, AlPcBr, AlPcI, GaPcF, GaPcCl and InPcCl. It is concluded on the bases of mass spectroscopic, infrared, microscopic, x-ray, and other data collected in these studies that AlPcF and GaPcF are polymeric and have (M-F) sub x backbones, It is further concluded that the remaining compounds are non-polymeric. (Author)

Preparation of oxobis(dithiolato) complexes of technetium(V) and rhenium(V)

Abstract: A series of oxobis(dithiolato)metalate(V) complexes of technetium and rhenium have been synthesized and studied by various physical techniques, including infrared and optical spectroscopy and cyclic voltammetry. Physical properties of the complexes are compared with respect to periodicity and the substituents on the ligand backbones. The stability of these five-coordinate complexes contradicts the current notion that Tc(V) and Re(V) complexes are inherently unstable in aqueous solution.