title: Nucleus-independent chemical shift analysis of the electronic states of the (CO)4, (CS)4, and (CSe)4 molecules.
abstract: NICS(1) calculations have been performed on the 8π and 10π singlet states and the 9π triplet state of (CO)4, (CS)4, and (CSe)4. The results show that transfer of electrons from the b2g σ MO into the a2u π MO decreases the NICS(1) value, indicating an increase in the diamagnetic ring current. The decreases in the calculated NICS(1) values are substantially larger in (CO)4 than in (CS)4 or (CSe)4. This finding is rationalized by the larger coefficients on the carbons in the a2u MO of (CO)4 than in the a2u MOs of (CS)4 and (CSe)4.
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, Jiangsu, 215123, China.
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, Jiangsu, 215123, China.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Bao
authors.affiliation: Department of Chemistry and the Center for Advanced, Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas, 76203-5070.
authors.forename: Weston Thatcher
authors.initials: WT
authors.lastname: Borden
keywords: cyclobutane-1,2,3,4-tetraone; cyclobutane-1,2,3,4-tetraselenone; cyclobutane-1,2,3,4-tetrathione; molecular orbitals; nucleus-independent chemical shift