Stereochemistry of 5-Co-ordinated Compounds. IV. The Reaction of Nitrosyl Halides with Phosphine Complexes of Nickel and Cobalt.

Spin delocalization in square-planar spin-triplet benzene- and toluenedithiolatecobaltate(III)

“…A Weiss constant of approximately zero was found. The drawn curve is a least-squares fit to the experimental values of the expression of the susceptibility of a spin-triplet state in an axially distorted environment as given in eq l,18 where + (1) temperature-independent D and g values are assumed. In the limits of very low and very high temperatures, eq 1 be- The resulting parameters for Bu4NCo(bdt)2 are D = 37.4 cm-1,g¿ = 2.31, and gu =2.19 and for Bu4NCo(tdt)2 are D = 39.4 cm"1 ,gy =2.27, andgn =2.09.…”

“…As is well known, proton magnetic resonance spectra of paramagnetic complexes in solution can be obtained if the electron spin relaxation time is sufficiently short.21'22 Large temperature-dependent shifts are then obtained, proportional to the timeaveraged value of the electron spin. The hyperfine fields at the proton sites are determined by two quantities: (1) the hyperfine coupling constant, a measure of the spin density at the nucleus, and (2) the anisotropy in the susceptibility if present; this implies that the magnetic dipole-dipole interaction between electron and nuclear spin is not averaged to zero by tumbling in the liquid. The two effects are the Fermi-contact shift and pseudocontact shift, respectively.…”

Variable-temperature Raman and infrared spectra of the copper acetate dimer Cu2(O2CCH3)4(H2O)2 and its derivatives

“…4 The infrared and Raman spectra have been determined in some detail for dimolybdenum tetraacetate and related compounds.5 6 '7 In agreement with the presence of a quadrupole bond, the Mo-Mo stretch in this compound is quite high and the metal isotope effects on the stretching frequency indicate that the acetato bridges contribute little to the Mo-Mo restoring force. 5 The present vibrational spectroscopic study of the copper acetate dimer was undertaken to explore the opposite extreme of metal-metal bonding and to determine if any manifestations can be found in the vibrational spectra for the equilibrium between singlet and triplet electronic states. The electronic structure of the copper acetate dimer, which has been the topic of many experimental and theoretical investigations,2,3•8 is well documented; however, the vibrational spectroscopy of this molecule is largely unsettled.…”

Moni- and di(tertiary phosphine and arsine) complexes of ruthenium(II) and ruthenium(III)

“…The ability of NOX (X = Cl, Br), NOBF4, and NOPF6 to act as oxidizing agents has been noted previously. [36][37][38] If on the other hand, the green solution prepared as above is left to stand in a stoppered flask under nitrogen at room temperature for several days, the color slowly lightens to yellow and crystals of the Ru(II) nitrosyl complex 22 precipitate.…”