Host–Guest Feature of DPPP Bridged Arene–Ruthenium Clip Derived Molecular Rectangle Suman Dhara Mohd. Asif Ansari Goutam Kumar Lahiri 10.1021/acs.inorgchem.9b01468.s001 https://acs.figshare.com/articles/journal_contribution/Host_Guest_Feature_of_DPPP_Bridged_Arene_Ruthenium_Clip_Derived_Molecular_Rectangle/9201788 The development of DPPP<sup>2–</sup> (H<sub>2</sub>DPPP = 2,5-dihydro-3,6-di-2-pyridylpyrrolo­(3,4-<i>c</i>)­pyrrole-1,4-dione) bridged (<i>NN∩NN</i>) diruthenium complexes [(Cym)­(X)­Ru<sup>II</sup>(μ-dppp)­Ru<sup>II</sup>(X)­(Cym)] (Cym = <i>para</i>-cymene and X = OTf<sup>–</sup> (<b>1</b>), SCN<sup>–</sup> (<b>2</b>), N<sub>3</sub><sup>–</sup> (<b>3</b>), NO<sub>2</sub><sup>–</sup>(<b>4</b>)) are considered as the probable molecular clips for the construction of metallarectangle. Crystal structures of <b>2</b>–<b>4</b> established anticonfiguration with respect to monodentate SCN<sup>–</sup>, N<sub>3</sub><sup>–</sup> and NO<sub>2</sub><sup>–</sup> groups, respectively. Though molecular clips <b>2</b>–<b>4</b> failed to provide the desired metallarectangle in combination with the 4,4′-bipyridine spacer, <b>1</b> with the labile OTf groups facilitated to achieve the metallarectangle <b>5</b>. The crystal structure of <b>5</b> revealed that two twisted 4,4′-bipyridine spacers bridged between the two units of dimeric <b>1</b> in symmetric fashion, which in effect led to the newer class of molecular rectangle <b>5</b> with a hydrophobic cavity size of the cationic host of 8.32 × 11.11 Å<sup>2</sup>. Furthermore, the host–guest interaction potential of <b>5</b> with special reference to the guest molecule, pyrene, was explored. The crystal structure of the resultant molecule <b>6</b> ascertained the partial encapsulation of two pyrene molecules inside the hydrophobic cavity of <b>5</b>, due to the twisted 4,4′-bipyridine spacer units between the two ruthenium clips. It also attributed a noncovalent CH−π interaction involving protons of pyrene and the π-electron cloud of 4,4′-bipyridine as well as a weak interaction between pyrene protons and the pendant CO group of DPPP. Encapsulation of the guest molecule (pyrene) inside the cavity of the metallarectangle was also monitored by following the quenching of florescent intensity of pyrene on addition of <b>5</b>. 2019-07-31 18:33:43 CH spacer π- electron cloud pyrene bipyridine H 2 DPPP SCN cavity host interaction NN metallarectangle crystal structure clip guest molecule II