chemistry journal of moldova

I. Ogurtsov, A. Tihonovschi / Chem.J.Mold. 2008, 3 (1), 112-117One-electron energy levels and molecular orbitalsMolecular orbitals close to HOMO orbital are given in Table 2. Orbitals below 206 and above 211 are of ligandnature and (or) are placed far away from HOMO orbital.Table 2One-electron states considered as active in CI calculations Sym Energy Composition211 a -0.0575 LigandbipyV V *210(LUMO) b -0.0581 0.11dxy dxyLigand bipyV V *O bipy bipy*209(HOMO) a -0.1819 0.11 p p 0.09 p 0.14 dV V *V V * bipy bipy*208 b -0.1822 x dx 0.12 pxz xzx xVV *V V *0.40d 2 2 d 2 2 0.67 d 2 d 2x y x yz zz p V V *207 b -0.2292 0.25dyz dyzVV *V V *V V * 0.40d2 2 d 2 2 0.67d2 d 2 0.25d dyz206 a -0.2296 x y x yz zyz205 a -0.4177 Ligand bipybipy bipy* and in the Table 2 are linear combinations of p-orbitals located on nitrogen and carbon atoms of thebipyridine ligands laying perpendicularly to V-V axis:bipyNN2C1C2 0.29p 0.28p 0.33p 0.31p1 xxxx... 0.29p 0.28p 0.33p 0.31pbipy* N 1 *N2*C1*C2*xxxxC 1and C 2(C 1*and C 2*) are two carbon atoms connecting pyridine cycles in the bipyridine molecule (Fig. 1).In the state with the total spin value equal to S=2 four electronic orbitals beginning with 206 are populatedby one electron each. It is seen that two of these molecular orbitals (206 and 207) are composed from the vanadiumd-orbitals and two MO (208 and 209) are the combinations of the vanadium p- and d-orbitals as well as of the -oxygenp z-orbital and p x-orbitals of the bipyridine ligands perpendicular to V-V axis. In the Fig. 2 these four states are given inpicture form....Fig. 2. ROHF one-electron states114