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Various modern electronic structure methods are now days used to teach computational chemistry to undergraduate students. Such quantum calculations can now be easily used even for large size molecules.

Various modern electronic structure methods are now days used to teach computational chemistry to undergraduate students. Such quantum calculations can now be easily used even for large size molecules.

The resonance Raman (RR) and surface-enhanced resonance Raman (SERRS) spectra of M(PAN)2 complexes (M=Cd and Hg, PAN(super -) =1-(2-pyridylazo)-2naphtholate were reported and assigned, and the nature if the adsorbed species were determined. Alterations in the Raman spectrum upon adsorption were interpreted by ab initio calculations of the interaction of M(PAN)2 complexes with surface silver atoms binding through the azo group alpha-nitrogen atoms.

Experimental and ab initio calculations are performed to determine the way the nature of the sulfate species is modified as a function of loading and its influences on the acidity and catalytic activity. Results show that calculations do not provide correlation with activity, as neighboring pairs are most likely involved in the active site arrangement.

The bond distance and the vibrational spectrum of the chromate(VI) ion were calculated using HF-SCF and SCF- density functional (SCF-DFT) methods. The calculations of vibrational spectra have enabled complete sets of force constants and potential energy distributions to be derived.

Surface-enhanced resonance Raman scattering (SERRS) from the alpha-dimine complexes [Ru(bpm)(sub 3)](super 2+) and [Ru(bpz)(sub 3)](super 2+) is reported at a roughened silver electrode. The SERRS spectra of [Ru(spm)(sub 3)](super 2+) were found to change slightly with a change in applied potential.

Scaled quantum chemical normal coordinate analyses are performed on [Ru(LL')3](super 2+) and the calculations are presented. The vibrational bands can be better understood by the experimental data provided by the calculated infrared and Raman spectra.

[Ni(C2H4)] is used as a model to elucidate the most efficient method for performing ab initio calculations on the geometric structure and vibrational spectra of transition-metal-alkene complexes, and possibly adsorbed species on metal surfaces. The results of ab initio calculations on different metal-(0)-ethene complexes reveal that the simple model used can reproduce the trends shown in the most cases on going from metal to metal.

Research has been conducted on nickel(II) tetraazaannulene complexes. The authors have measured the IR and resonance Raman spectra of these complexes, have compared these spectra with ab initio calculations of the vibrational wavenumbers, and have discovered an excellent fit between the calculated and experimental data.

The single crystal X-ray structure of the novel steroid derivative, 6E-hydroximino-androst-4-ene-3,17-dione (C19H25NO3) (code name RB-499), possessing antiproliferative activity against various cell lines is presented. The analysis produced the following results: chemical formula C19H25NO3; Mr = 315.40; crystals are orthorhombic space group P212121 with Z = 4 molecules per unit cell with a = 6.2609(2), b = 12.5711(4), c = 20.0517(4) Å,Vc = 1578.18(7) Å3, crystal density Dc = 1.327 g/cm³. Structure determination was performed by direct methods, Fourier and full-matrix least-squares refinement. Hydrogens were located in the electron density and refined in position with isotropic thermal parameters. The final R-index was 0.0324 for 3140 reflections with I > 2σ and 308 parameters. The Absolute Structure Parameter − 0.07(5) confirms the correct allocation of the absolute configuration. The presence of the double bond C=O at position 3 in Ring A has caused a distortion from the usual chair conformation and created an unusual distorted sofa conformation folded across an approximate m-plane through C(1)-C(4). Ring B is a distorted chair, its conformation being influenced by the presence of the C(6)=N(6)-O(6)H group in position 6. Ring C is a symmetrical chair. Ring D exhibits both a distorted mirror symmetry conformation [influenced by the C(17)=O(17) group] and a distorted twofold conformation. DFT calculations indicated some degree of flexibility in rings A, C and D with ring A showing the greatest variation in torsion angles. The crystal packing is governed by H-bonds involving O(3), O(6) and O(17). DFT calculations of bond distances and angles, optimized at the B3LYP/6-31++G(d,p) level, were in good agreement with the X-ray structure.Graphical Abstract: Ring A conformations: (a) Experimental and (b) Calculated. The differences in torsion angle values indicate a degree of flexibility in the ring. The ring conformations are shown in Figures (ii) and (iv) respectively (drawn with BIOVIA [12]. Regions A1 and A2 are approximately planar in both, being planar within 0.048 Å and 0.105 Å respectively. [ABSTRACT FROM AUTHOR]