Molecular Models of Metal Complexes of Dithiocarbamates

Abstract

Our focus this month is on the dithiocarbamate (DTC) complexes whose synthesis is described in the paper by Malin Backlund Walker, Kimberly Edwards, and Patrick J. Farmer (1). Molecules added to the collection include disulfiram, the diethyldithiocarbamate anion (deDTC), and copper and zinc complexes of diethyldithiocarbamate (Figure 1).Dithiocarbamate complexes are found for both transition metals and main group elements, and have broad applications in medicine and other fields, as mentioned in ref 1. One might envision introducing the primary literature to a group of students, in either majors or nonmajors courses, with assignments that involve finding how such complexes are currently being used, and the nature of ongoing research involving these species. Additionally, Volume 53 of Progress in Inorganic Chemistry is devoted entirely to dithiocarbamate complexes across the periodic table (2).Dithiocarbamate complexes are also interesting from a structural viewpoint. They exhibit a wide range of coordination geometries and modes of bonding. Diethyldithiocarbamate is found as a unidentate ligand, a bridging ligand, and as a bidentate in both symmetrical and unsymmetrical environments (3). These complexes can serve as the basis for a number of exercises in computational chemistry. Included in the collection are the copper(II) and zinc(II) complexes synthesized in ref 1. The structures that are given arise from DFT (B3LYP/631-G(d)) calculations on gas phase molecules. The copper complex has a slightly distorted square planar arrangement about the copper, and the zinc complex, as expected, shows a distorted tetrahedral coordination structure. Students could be asked to predict, and then calculate, structures with different metals and/or different oxidation states, to assess the effect of these on the overall structure. They might find that the calculations are more tractable using model compounds, and included here is a copper complex with dithiocarbonate that might serve as a starting point for calculation. Many other questions could be

Teaching Three-Dimensional Structural Chemistry Using Crystal Structure Databases. 2. Teaching Units That Utilize an Interactive Web-Accessible Subset of the Cambridge Structural Database

“…The crystallographic databases have grown and matured over the same time scale and provide the ready ability for students to visualize and manipulate 3D structures, a facility that has been shown to enhance students’ conceptual understanding and spatial abilities − . Using these databases to examine the geometry of individual structures, and sets of related structures, is a natural extension of simple visualization that has already been exemplified and discussed in textbooks and in this Journal − . These latter references cover a broad spectrum of educational applications of the CSD, including inorganic, organic, and medicinal chemistry, and combined applications of the CSD and the Protein Data Bank at the chemistry−biology interface.…”