2417adapted version of D N M R~.~ NMR probe temperatures were calibrated by using the method of van Geet4' and are considered accurate to *2 K. 13C{lH) EXSY spectra were obtained with either broad-band or composite-pulse 'H decoupling, using the Bruker automation microprogram NOESY (Dl-~/2-D(hr/2-D9-~/2-FID-acquire). The data table was acquired by using 1024 words in the F2 dimension and 256 words in the F1 dimension zero-filled to 512.Spectral widths were typically 1 kHz, and recycle delays (Dl) typically 4-6 8. The initial value of the incremented delay DO was 3 ps. For the low-temperature experiments, a cycle of either 8 or 16 scans were acquired for each F2 FID, with total acquisition times of ca. 4-8 h. A random variation of *15% was applied to the mixing time delay t , (D9) to reduce any correlations arising from scalar coupling. Apodization was applied to all data seta before Fourier transform, using either n/6 shifted sine-bell or exponential line-broadening (LB = 2) functions. EXSY spectra were symmetrized about the F1 = F2 diagonal. For complex 4 the volume integrals, corresponding to the diagonal and off-diagonal elements of the intensity matrix, were obtained by integration of the submatrix rows of the EXSY spectra containing the most intense peaks (usually six to ten rows). For complex 3 integrations were carried out both in the above manner and also by using the box-integral routine of the Bruker AP2D display program. Errors in the integrals were estimated from the inte-(46) Kleier, D. A.; Binsch, G. QCPE 1970, 11, 165. (47) van Geet, A. L. Anal. Chem. 1970,42, 679.grated intensity of identical sized boxes in noise areas of the EXSY spectrum. There was satisfactory agreement between the derived rate data using either method. Individual exchange rate constants were obtained from the intensity matrix by using the program D Z D N M R .~~Due to the possibility that apodization functions could adversely affect relative line widths, and hence relative intensities, the effect of using (a) no apodization, (b) n/6 shifted sine-bell, and (c) Lorentz-Gaussian line narrowing on the data for 3 at 225 K was examined. Apart from the rates associated with the b/c/e tripodal rotation, which appear ill-conditioned in this analysis, there were no serious discrepancies. Rates for the exchanges associated with the PtL3 rotation varied from ca. 0.1 to 0.2 s-l, which are within the range of the reported rate errors. The discrepancies seen for the b/c/e exchange rate constants (which must be regarded as unreliable at 225 K) are attributed to experimental errors arising from the broadness of the diagonal peaks and cross-peaks associated with this process, overlap of some lgsPt satellites, and generally poor S/N ratios. In order to a ensure a reasonably constant temperature over the whole experiment, the low-temperature acquisitions were limited to a ca. 8 h time period, allowing only a maximum of 16 transients per DO increment. Acknowledgment. Dr. David Stephenson (Exeter) is thanked for a copy of t h e 2D EXSY kinetic anal...

The original article to which this Erratum refers was published in International Journal of Quantum Chemistry (2004) 100(6) 1170–1178.

No abstract

The nature of the copper-copper interaction in copper( 11) acetate dihydrate has been reconsidered from the niolecular orbital viewpoint. The proposed bonding scheme appears t o be adequate for explaining the magnetic and spectral properties of the complex. These results are interpreted to be consistent with the previously proposed bonding models, although a more sophisticated treatment would tend to favor the &bond model.

Electronic structures and chemical bonding within the NdO and UOmolecules have been studied computationally via the QR-SCMEH-MO (quasirelativistic-self-consistent modified extended Hückel-molecular orbital) method. This is a non-ab initio, self-consistent, nonempirical routine that accounts for correlation in an approximate way. It also incorporates other features so as to account for all electron interactions. Both molecules were found to be bonding [contrary to a report based on ab initio density functional theory (DFT)-SCF relativistic calculations on UO]. The covalency in UO is somewhat greater than that of NdO, which for all practical purposes is mostly electrostatic. Good agreement between calculated and observed bond dissociation energies and ionization potentials have been obtained. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem 90: 629-633, 2002