title: Design of a flexible organometallic tecton: host-guest chemistry with picric acid and self-assembly of platinum macrocycles.
abstract: The synthesis and characterization of a new pyrazine-based "flexible" and ditopic platinum(ii) organometallic molecule (3) is being reported. Flexibility in this molecule is due to the presence of ether functional groups that bridge the rigid core and periphery. Due to the presence of square planar Pt(ii) centers at the two ends, the molecule's potential to act as an acceptor building block in the construction of metallamacrocycles was tested. Upon reaction of 3 with various dicarboxylates in a 1 : 1 stoichiometric ratio, [2 + 2] self-assembled neutral metallacycles (M1-M3) were obtained in high yields. M1-M3 were characterized using multinuclear NMR, high resolution mass spectrometry and elemental analyses. The shape and dimensions of these supramolecular structures were also confirmed by optimizing the geometry using the density functional theory (DFT) approach. Computational studies suggest that M1-M3 are nanoscalar macrocyles. Furthermore, using isothermal titration calorimetry (ITC), it was shown that 3 can bind with picric acid (PA) to yield a 3·(PA)2host-guest complex. The magnitude of the binding constant indicates that 3 has significant affinity for PA.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Patna, Patna 801103, Bihar, India. neeladri@iitp.ac.in neeladri2002@yahoo.co.in.
authors.forename: Achintya
authors.initials: A
authors.lastname: Jana
authors.affiliation: Department of Chemistry, Indian Institute of Technology Patna, Patna 801103, Bihar, India. neeladri@iitp.ac.in neeladri2002@yahoo.co.in.
authors.forename: Sourav
authors.initials: S
authors.lastname: Bhowmick
authors.affiliation: Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
authors.forename: Supreet
authors.initials: S
authors.lastname: Kaur
authors.affiliation: Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
authors.forename: Hemant K
authors.initials: HK
authors.lastname: Kashyap
authors.affiliation: Department of Chemistry, Indian Institute of Technology Patna, Patna 801103, Bihar, India. neeladri@iitp.ac.in neeladri2002@yahoo.co.in.
authors.forename: Neeladri
authors.identifier: http://orcid.org/0000-0003-3476-1097
authors.initials: N
authors.lastname: Das