Synthesis of Well-Defined Tower-Shaped 1,3,5-Trisubstituted Adamantanes Incorporating a Macrocyclic Trilactam Ring System

Abstract

We describe the synthesis of two novel well-defined tower-shaped 1,3,5-trisubstituted adamantanes 30 and 33 that incorporate a macrocyclic trilactam ring system. Each nanoscale molecule has a broad tripodal base consisting of three identical sulfur-containing termini as the tripod feet, 4-acetylsulfanylmethylphenyl units in the case of 30 and 3,5-bis(acetylsulfanylmethyl)phenyl units in the case of 33. The sulfur atoms are designed to bind the molecules trivalently to the apex of a gold-coated commercial AFM tip through formation of three S-Au bonds. The rigid adamantane-derived head unit with a single hydrogen atom at the apex is designed to scan the sample. Molecules 30 and 33 are synthesized from 1,3,5-triethynyladamantane by a series of Sonogashira coupling reactions involving terminal alkynes and aryl iodides. A macrocyclic trilactam unit is included for added rigidity. We demonstrate that molecule 30 is sufficiently large and rigid to be visualized by a conventional AFM tip. These nanoscale molecules may also find application as chemically well-defined nanoscale objects for calibration of AFM tips.

Rigid Multivalent Scaffolds Based on Adamantane

“…We suggest that our scaffolds might be of general use as rigid tetravalent building blocks for applications in organic chemistry 43 and material science. 44 Experimental Section 3,5,7-Tricarboxymethyladamantane-1-carboxylic acid 9 1 N solution of potassium hydroxide (0.01 mL, 0.01 mmol) was added to a solution of 1,3,5,7-tetracarboxymethyladamantane 8 (3.68 mg, 0.01 mmol) in 2 mL of acetonitrile/methanol/water (3:2:5). The reaction mixture was stirred for 3 hours and the completion of the reaction was followed by thin layer chromatography.…”

An Adamantane‐Based Building Block for DNA Networks

“…Among the several potential possibilities for a rigid core, the adamantane framework was our structure of choice, as it possesses a T d symmetric nucleus that represents a strong tetrahedral core, which can be selectively functionalized at the tertiary carbon positions, and it represents the best known examples for rigid and high-order molecular constructions in the literature. [32][33][34][35] Adamantane belongs to a class of rigid hydrocarbons processing a high order of symmetry, and is therefore particularly important for use in nanotechnology because the new functionalities could be incorporated at a particular and a Abstract: DNA governs the storage and transfer of genetic information through generations in all living systems with the exception of some viruses. Its physicochemical nature and the Watson-Crick base pairing properties allow molecular constructions at nanometer length, thereby enabling the design of desired structural motifs, which can self-assemble to form large supramolecular arrays and scaffolds.…”

Rigid C3‐Symmetric Scaffolds Based on Adamantane

“…[17] Although some adamantane-based C 3 -symmetric scaffolds 3 are known, they have rarely been used as scaffolds for the assembly of functional molecules with threefold geometry. [18] This is probably due to a lack of proper functional groups in known scaffolds 3 or their difficult chemical synthesis. In this paper we summarize scalable and short syntheses to scaffolds 3 with suitable anchor groups for the conjugation of functional molecules, in particular biomolecules.…”