MS21-P07 'Pancake' bonding: a charge density perspective Delia Haynes (Department of Chemistry & Polymer Science, Stellenbosch University, Stellenbosch, South Africa)email: class of thiazyl radicals, 1,2,3,5-dithiadiazolyls (R-CNSSN, hereafter DTDAs), have been the focus of much investigation due to their potential as building blocks for magnetic and conducting materials. [1] However, these molecules tend to dimerise in the solid state via a spin-pairing interaction known as 'pancake bonding' [2], rendering them diamagnetic. Experimental charge density analysis has been carried out on a number of DTDA homodimers, heterodimers and monomers. [3] These data, as well as various computational results, are assessed to probe the nature of the 'pancake bonds' in DTDAs.

1. Haynes, D.A. (2011). CrystEngComm, 13, 4793-4805.

2. see for example Cui, Z., Lischka, H., Beneberu, H.Z. and Kertesz, M. (2014). J. Am. Chem. Soc., 136, 12958–12965.

3. Domagała, S., Kość, K., Robinson, S.W., Haynes, D.A. and Wozniak, K. (2014). Cryst. Growth Des., 14, 4834-4848; Domagała, S. and Haynes, D.A. (2016). CrystEngComm, 18, 7116-7125.

Keywords: dithiadiazolyls, pancake bonding