Data on LEGO sets release dates and worldwide retail prices combined with aftermarket transaction prices in Poland between June 2018 and June 2023.

The dataset contains LEGO bricks sets item count and pricing history for AI-based set pricing prediction. The data spans the timeframe from June 2018 to June 2023. The data was obtained from three sources: Brickset.com (LEGO sets retail prices, release dates, and IDs), Lego.com official web page (ID number of each set that was released by Lego, its retail prices, the current status of the set) and promoklocki.pl web page (the retail prices for Poland, prices from aftermarket transactions). The data was merged based on the official LEGO set ID. With high granularity of the data (averaged monthly prices per LEGO set) the dataset permits the computation of variables at the set level and could support both aggregate and time-series analyses whereas the sparseness of the data permits the analysis of collector behavior allowing pinpointing of expected qualities from the purchased products and their resale potential. This may be useful to a broad range of researchers and data scientists using statistical methods and machine-learning techniques for price prediction.

Photos and rendered images of LEGO bricks.

The paper describes a collection of datasets containing both LEGO brick renders and real photos. The datasets contain around 155,000 photos and nearly 1,500,000 renders. The renders aim to simulate real-life photos of LEGO bricks allowing faster creation of extensive datasets. The datasets are publicly available via the Gdansk University of Technology "Most Wiedzy" institutional repository. The source files of all tools used during the creation of the dataset were made publicly available via GitHub repositories. The images, both photos and the renders were annotated with the unique brick ID and category from the official LEGO catalog. The proposed datasets are stored in easy-to-read formats and are labeled via directory structure allowing easy manipulation and conversion of metadata to other formats.

Pillar[4]pyridinium: a square-shaped molecular box.

Numerous applications of Stoddart's 'blue-box', a pyridinium containing macrocycle of rectangular shape, encouraged us to seek successors of this amazing molecule. Using a one-step cyclization reaction we synthesized a square-shaped cyclic tetramer consisting of 4-methylenepyridinium units - pillar[4]pyridinium (P[4]P). Pillar[4]pyridinium is a quadruply positively charged water-soluble macrocycle with a highly symmetric, strained structure and an electron-deficient cavity. These features impel the macrocycle to assemble into channel networks in the solid state and render it an effective fluoride receptor in water.

Hybrid [n]arenes through thermodynamically driven macrocyclization reactions.

Hybrid [n]arenes, the class of medium-sized macrocyclic compounds consisting of different alkoxybenzene units, were obtained by a simple, one-pot, direct condensation of two different alkoxybenzenes with formaldehyde catalyzed by a Brønsted acid (trifluoroacetic acid). We have shown that, under Brønsted acid catalysis, this reaction is reversible and therefore governed by the relative stability of the products. The main macrocyclic products are hybrid [n]arenes consisting of four alkoxybenzene units of [2 + 2] or [3 + 1] stoichiometry. However, an unusual [3 + 2] hybrid macrocycle was also obtained as a main product of the condensation between 1,4-dimethoxybenzene, 1,3,5-trimethoxybenzene, and formaldehyde. The stability of the hybrid products and the reversibility of the reaction were further confirmed by a scrambling experiment, involving pillar[5]arene and per-O-methylated resorcin[4]arene. The scrambling experiment has given hybrid macrocycles in yields comparable with those obtained in condensation reactions. NMR spectra and X-ray structures of hybrid [n]arenes indicate that 1,2- and 1,3-dialkoxybenzene units are flexible parts of macrocyclic rings. However, the 1,4-dialkoxybenzene units present considerable steric hindrance, resulting in the formation of isomers and inherently chiral macrocycles due to inhibited rotation. The recognition properties toward various organic cations were also determined. Highly selective recognition of the N-methylpyridinium cation was observed for the [3 + 2] hybrid macrocycle.