Group 9 metallatelluraboranes: Comparison with their sulfur analogues

Publication date: Available online 3 February 2018 Source:Journal of Organometallic Chemistry Author(s): Amr A.A. Attia, Alexandru Lupan, R. Bruce King The lowest energy structures for the Group 9 metallachalcaboranes CpMEB n-2H n-2 (M = Co, Rh, Ir; E = S, Te) are found by density functional theory to have a central closo MEB n–2 deltahedron consistent with their 2n + 2 skeletal electrons. Structures having metal atoms at degree 5 vertices and sulfur atoms at degree 4 vertices are clearly energetically preferred. However, for the 9- and 10-vertex metallatelluraboranes CpMTeB n–2H n–2 (n = 9, 10; M = Co, Rh, Ir) otherwise related structures having tellurium atoms at degree 4 and degree 5 vertices are energetically comparable. The low-energy 11-vertex CpMEB9H9 structures are all based on the 11-vertex closo deltahedron with a unique degree 6 vertex. However, in many of the low-energy 11-vertex structures one of the edges connecting the degree 6 vertex with an adjacent degree 5 vertex is stretched to a non-bonding distance leading to an isonido structure having a quadrilateral face. The three lowest energy structures for the 12-vertex CpMEB10H10 (M = Co, Rh, Ir; E = S, Te) systems are the three possible icosahedral structures with the energy ordering ortho < meta < para. Graphical abstract

Source: Journal of Organometallic Chemistry - February 3, 2018 Category: Chemistry Source Type: research