Rhenium and Technetium tricarbonyl Core based Supramolecular Metallocavitands and Helicates

Abstract

Chapter 1 begins with the general introduction of supramolecular chemistry and its two main newlinebranches, i.e., host-guest chemistry and self-assembly. Further, the developments and applications newlineof metallosupramolecular chemistry, including metallacalixarene and metallo- helicate/ mesocates, newlineare discussed with a very short classification of calixarenes, helicates, and mesocates. The chapter newlinehighlights the rhenium and technetium-based metallocycles, their basic design principle, and mainly newlineliterature survey and discussion on various aspects of the chemistry of Re(CO)3 core-based newlinemetallacalix[n]arenes (n = 3, 4), metallo-helicates, meso-helicates, and Tc(CO)3 core based newlinemetallocycles. newlineScheme 1. Various known examples of M(I) core-based (M = Re/Tc) metallacycles. newlineX newlineChapter 2: Re(I)-based Irregular Pentagonal-shaped Metallocavitands: newlineSelf-Assembly and Molecular Recognition Studies. newlineThis chapter describes the design and synthesis of three new neutral ditopic flexible N-donor newlineligands (Ln = (L1 = bis(4-(naphtho[2,3-d]imidazol-1-ylmethyl)phenyl)methane, L2 = bis(4- newline(benzimidazol-1-ylmethyl)phenyl)methane and L3 = bis(4-(2-nonyl benzimidazol-1- newlineylmethyl)phenyl)methane)) possessing bis(4-methylphenyl)methane spacer with multi-arene fused newlineimidazole donor unit. The Ln were further utilized to develop metallocavitands analogous of newlinecalix[5]arene framework with larger cavity. The metallocavitands 1-4 were assembled from newlineRe2(CO)10, rigid bis-chelating donor (H2-dhaq = 1,4-dihydroxy-9,10-anthraquinone and H2-CA = newlinechloranilic acid) and Ln via solvothermal approach. The ligands and metallocavitands were newlinecharacterized by analytical and spectroscopic methods and further 1 and 4 were confirmed by single newlinecrystal X-ray diffraction analysis which reveals that a toluene molecule is residing in the newlinehydrophobic cavity. The Ln and 1-4 are emissive at room temperature. The internal cavity of the newlinemetallocavitand acts as host for aromatic guest molecules. The host-guest interaction properties of 1 newlinewith various nitroaromatic and polyaromatic hydroca