A pinboard by
Richard Manzano

PhD candidate, Australian National University


Creating new and exciting molecular architectures that aim to mimic wires on a molecular level.

It is known that computers have become an important asset to the advancement of technology and has integrated itself into our day to day lives. As the as we have advanced in technology we have seen computer technology become more powerful, faster, but also much smaller and compact (e.g. iPhones). This observation had been predicted and was coined as Moore’s Law (the number of transistors in an integrated circuit will double every two years). Currently there has been a slowing down of Moore’s Law and it has been thought that circuits will be designed on the molecular level.

The current research area that I am studying within the organometallic field. This field is relatively young in the chemistry realm and has already achieved a magnitude of results. The discipline essentially is the study of molecules that contain a metal atom (e.g. iron, gold, platinum) attached to carbon based architecture as well as other non-metallic atoms to create many compounds that contain many interesting properties. A few organometallic molecules that have amazing properties are: haemoglobin (an essential protein that contains an active iron metal centre), cis-platin (a drug used in chemotherapy), and dye-sensitised solar cells (ruthenium and platinum based solar cells).

My research aims to aid this area by designing new molecular wires that can may potentially deliver and connect information through a molecular wire. These wires will need to come in different lengths and sizes with my research mainly focusing on the creation of new organometallic molecular architectures with odd numbered carbon chains yet to exist anywhere in the universe. This current research is fundamentally based but should start as a stepping stone in the molecular wire research will potentially play a role for future designs and technologies.


Insulated molecular wires: inhibiting orthogonal contacts in metal complex based molecular junctions.

Abstract: Metal complexes are receiving increased attention as molecular wires in fundamental studies of the transport properties of metal|molecule|metal junctions. In this context we report the single-molecule conductance of a systematic series of d(8) square-planar platinum(ii) trans-bis(alkynyl) complexes with terminal trimethylsilylethynyl (C[triple bond, length as m-dash]CSiMe3) contacting groups, e.g. trans-Pt{C[triple bond, length as m-dash]CC6H4C[triple bond, length as m-dash]CSiMe3}2(PR3)2 (R = Ph or Et), using a combination of scanning tunneling microscopy (STM) experiments in solution and theoretical calculations using density functional theory and non-equilibrium Green's function formalism. The measured conductance values of the complexes (ca. 3-5 × 10(-5)G0) are commensurate with similarly structured all-organic oligo(phenylene ethynylene) and oligo(yne) compounds. Based on conductance and break-off distance data, we demonstrate that a PPh3 supporting ligand in the platinum complexes can provide an alternative contact point for the STM tip in the molecular junctions, orthogonal to the terminal C[triple bond, length as m-dash]CSiMe3 group. The attachment of hexyloxy side chains to the diethynylbenzene ligands, e.g. trans-Pt{C[triple bond, length as m-dash]CC6H2(Ohex)2C[triple bond, length as m-dash]CSiMe3}2(PPh3)2 (Ohex = OC6H13), hinders contact of the STM tip to the PPh3 groups and effectively insulates the molecule, allowing the conductance through the full length of the backbone to be reliably measured. The use of trialkylphosphine (PEt3), rather than triarylphosphine (PPh3), ancillary ligands at platinum also eliminates these orthogonal contacts. These results have significant implications for the future design of organometallic complexes for studies in molecular junctions.

Pub.: 06 Jul '17, Pinned: 02 Aug '17