Terpene polyacrylate TPA5 shows favorable molecular hydrodynamic properties as a potential bioinspired archaeological wood consolidant

There is currently a pressing need for the development of novel bioinspired consolidants for waterlogged, archaeological wood. Bioinspired materials possess many advantages, such as biocompatibility and sustainability, which makes them ideal to use in this capacity. Based on this, a polyhydroxylated monomer was synthesised from α-pinene, a sustainable terpene feedstock derived from pine trees, and used to prepare a low molar mass polymer TPA5 through free radical polymerisation. This polymer was extensively characterised by NMR spectroscopy (chemical composition) and molecular hydrodynamics, primarily using analytical ultracentrifugation reinforced by gel filtration chromatography and viscometry, in order to investigate whether it would be suitable for wood consolidation purposes. Sedimentation equilibrium indicated a weight average molar mass Mw of (4.3 ± 0.2) kDa, with minimal concentration dependence. Further analysis with MULTISIG revealed a broad distribution of molar masses and this heterogeneity was further confirmed by sedimentation velocity. Conformation analyses with the Perrin P and viscosity increment ν universal hydrodynamic parameters indicated that the polymer had an elongated shape, with both factors giving consistent results and a consensus axial ratio of ~ 4.5. These collective properties—hydrogen bonding potential enhanced by an elongated shape, together with a small injectable molar mass—suggest this polymer is worthy of further consideration as a potential consolidant.

The HYBOT 3D MF Application and it Integration with CoMFA

The program “HYBOT 3D MF” based on the potential “6-8” modified by using HYBOT hydrogen bonding factors has been developed. An integration with “QSAR and Advanced CoMFA” module of the SYBYL-X is performed by set of macros written in SPL. A full working version of the program is available at http://www.ibmc.msk.ru/HYBOT3D. For a number of sets of chemical compounds having pronounced differences in groups with the hydrogen bonding potential, the use of HYBOT 3D MF fields makes it possible to improve the predictive power of models created by the CoMFA technology.

Supramolecular assembly of oxalatomolybdates controlled by the hydrogen bonding potential of Co(iii)-ammine cations

Six oxalatomolybdate anions of different nuclearities have been obtained in reactions of {[MoO3(ox)]}n2n− and [Mo2O5(ox)2(H2O)2]2− anions with a series of Co(iii)-ammine cations.

Bis(N,N-diethyldithiocarbamato-κ2S,S′)(3-hydroxypyridine-κN)zinc and bis[N-(2-hydroxyethyl)-N-methyldithiocarbamato-κ2S,S′](3-hydroxypyridine-κN)zinc: crystal structures and Hirshfeld surface analysis

The common feature of the molecular structures of the title compounds, [Zn(C5H10NS2)2(C5H5NO)], (I), and [Zn(C4H8NOS2)2(C5H5NO)], (II), are NS4donor sets derived fromN-bound hydroxypyridyl ligands and asymmetrically chelating dithiocarbamate ligands. The resulting coordination geometries are highly distorted, being intermediate between square pyramidal and trigonal bipyramidal for both independent molecules comprising the asymmetric unit of (I), and significantly closer towards square pyramidal in (II). The key feature of the molecular packing in (I) is the formation of centrosymmetric, dimeric aggregates sustained by pairs of hydroxy-O—H...S(dithiocarbamate) hydrogen bonds. The aggregates are connected into a three-dimensional architecture by methylene-C—H...O(hydroxy) and methyl-C—H...π(chelate) interactions. With greater hydrogen-bonding potential, supramolecular chains along thecaxis are formed in the crystal of (II), sustained by hydroxy-O—H...O(hydroxy) hydrogen bonds, with ethylhydroxy and pyridylhydroxy groups as the donors, along with ethylhydroxy-O—H...S(dithiocarbamate) hydrogen bonds. Chains are connected into layers in theacplane by methylene-C—H...π(chelate) interactions and these stack along thebaxis, with no directional interactions between them. An analysis of the Hirshfeld surfaces clearly distinguished the independent molecules of (I) and reveals the importance of the C—H...π(chelate) interactions in the packing of both (I) and (II).

Double zipper helical assembly of deoxyoligonucleotides: mutual templating and chiral imprinting to form hybrid DNA ensembles

Herein, the conventional and unconventional hydrogen bonding potential of adenine in APA for double zipper helical assembly of deoxyoligonucleotides is demonstrated under ambient conditions.