The components of a 4:1 mixture of Rh(III)Cl tetrakis(4-methylphenyl)porphyrin 1 and a bowl-shaped tetra(4-pyridyl)cavitand 4 self-assemble into a 4:1 complex 14•4 via Rh-pyridyl axial coordination bonds. The single-crystal X-ray diffraction analysis and variable-temperature (VT) (1)H NMR study of 14•4 indicated that 14•4 behaves as a quadruple interlocking gear with an inner space, wherein (i) four subunits-1 are gear wheels and four p-pyridyl groups in subunit-4 are axes of gear wheels, (ii) one subunit-1 and two adjacent subunits-1 interlock with one another cooperatively, and (iii) four subunits-1 in 14•4 rotate quickly at 298 K on the NMR time scale. Together, the extremely strong porphyrin-Rh-pyridyl axial coordination bond, the rigidity of the methylene-bridge cavitand as a scaffold of the pyridyl axes, and the cruciform arrangement of the interdigitating p-tolyl groups as the teeth moiety of the gear wheels in the assembling 14-unit make 14•4 function as a quadruple interlocking gear in solution. The gear function of 14•4 was also supported by the rotation behaviors of other 4:1 complexes: 24•4 and 34•4 obtained from Rh(III)Cl tetrakis[4-(4-methylphenyl)phenyl]porphyrin 2 or Rh(III)Cl tetrakis(3,5-dialkoxyphenyl)porphyrin 3 and 4 also served as quadruple interlocking gears, whereas 14•5 obtained from 1 and tetrakis[4-(4-pyridyl)phenyl]cavitand 5 did not behave as a gear. The results of activation parameters (ΔH(⧧), ΔS(⧧), and ΔG(⧧)) obtained from Eyring plots based on line-shape analysis of the VT (1)H NMR spectra of 14•4, 24•4, and 34•4 also support the interlocking rotation (geared coupled rotation) mechanism.

The components of a 1:2 mixture of meso-tetrakis(4-dodecyl-3,5-dihydroxyphenyl)porphyrin (1) and a bowl-shaped tetrakis(4-pyridylethynyl)cavitand (2) in CDCl3 or C6 D6 self-assemble quantitatively into the doubly cavitand-capped porphyrin capsule 2⋅1⋅2 through eight ArOH⋅⋅⋅Npy hydrogen bonds. Capsule 2⋅1⋅2 possesses two cavities divided by the porphyrin ring and encapsulates two molecules of 1-acetoxy-3,5-dimethoxybenzene (G) as a guest to form G/G@(2⋅1⋅2). Remarkable solvent effect was observed, in which the apparent association constant of 2⋅1⋅2 with G in C6 D6 was much greater than that in CDCl3.

To synthesize ladder‐type polyamides by construction of two amide bonds successively, 2,5‐diaminoterephthalic acid derivatives bearing anthranilic acid ester and isatoic anhydride moieties were synthesized and their polymerization was investigated. Polymerization of the methyl ester monomer proceeded in the presence of lithium hexamethyldisilazide (LiHMDS) as a base in tetrahydrofuran (THF). However, mass spectroscopic analysis of the product suggested that not only the bis(trimethylsilyl)amide anion of LiHMDS but also the methoxide anion eliminated at the second amide‐linkage formation reaction decomposed the isatoic anhydride unit of the growing oligomer by nucleophilic attack to disturb the polymerization. To reduce the nucleophilicity of the eliminated anion, methyl ester of the monomer was changed to phenyl ester and its polymerization was studied. The reaction conditions were optimized, and the best result was obtained when the polymerization was conducted in the presence of 1.0 equivalent of LiHMDS without additives in THF at 50 °C. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2365–2372

A 1 : 2 mixture of Zn-meso-tetrakis(4-dodecyl-3,5dihydroxyphenyl)porphyrin (1-Zn) and tetrakis(4pyridylethynyl)cavitand (2) in C 6 D 6 self-assembles quantitatively into the doubly cavitand-capped Zn-porphyrin capsule 2 • 1-Zn • 2 with two cavities divided by the porphyrin ring via eight ArOH•••Npy hydrogen bonds. Simultaneous encapsulation of 1-acetoxy-3,5-dimethoxybenzene (G) and 4-(4-methylphenyl)pyridine (L2) in 2 • 1-Zn • 2 preferentially occurs to form G/L2@(2 • 1-Zn • 2). A 1 : 1 mixture of 1-Zn and 2 in the presence of G and L2 self-assembles into the G-encapsulating half-capsule G@(2 • 1-Zn) • L2 with coordination of L2 at the outer side of 2 • 1-Zn. A 2 : 2 : 1 mixture of 1-Zn, 2, and 1,4diazabicyclo[2.2.2]octane (L3) in the presence of G selfassembles preferentially into the G-encapsulating doubly cavitand-capped double-decker Zn-porphyrin capsule G/G@-(2 • 1-Zn • L3 • 1-Zn • 2) with coordination of L3 between two hydrogen-bonded 1-Zn subunits. Thus, selective formation of these cavitand-porphyrin capsules can be controlled by the stoichiometry of 1-Zn and 2 as well as the character of Nligands.