Synthesis, crystal structures and intermolecular interactions of two Mn(II) complexes with 4,4′-bipy and methyl benzoates

Synthesis and crystal structure of poly[[bis(aqua-κO)tetrakis(μ-4,4′-bipyridine-κ2 N:N′)hexakis(3-chlorobenzoato)-κ5 O;κ2 O:O′-tricobalt(II)] methanol disolvate]

A novel ladder-chain cobalt(II) coordination polymer, {[Co3(C7H4ClO2)6(C10H8N2)4(H2O)2]·2CH3OH} n , was synthesized and characterized. The structure contains two CoII centres with different octahedral environments, [Co(1)N3O3] and [Co(2)N2O4]. The O-donating 3-chlorobenzoate anions (3-Clbenz) act as the terminal ligands, while the N-donating 4,4′-bipy molecules play the role of linkers. The Co(1) ions are linked by 4,4′-bipy molecules into linear chains. Two such chains are joined by [Co(2)(3-Clbenz)2(H2O)2] units via two 4,4′-bipy bridging ligands, thus forming the ladder-chain structure. The crystal packing of the title compound is stabilized by supramolecular interactions, such as hydrogen bonding, π–π and halogen...π contacts, giving a three-dimensional framework. The spectroscopic and thermal properties of the title compound have also been investigated.

Chemical composition and surfactant characteristics of marine foams investigated by means of UV-vis, FTIR and FTNIR spectroscopy

In this study, we collected the ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR) and Fourier transform near-infrared (FTNIR) spectra of marine foams from different sites and foams produced by marine living organisms (i.e. algae and molluscs) to retrieve information about their molecular and structural composition. UV-vis spectra gave information concerning the lipid and pigment contents of foams. FTIR spectroscopy gave a more detailed qualitative information regarding carbohydrates, lipids and proteins in addition with information about the mineral contents of foams. FTNIR spectra confirmed the presence of carbohydrates, lipids and proteins in foams. Then, due to the higher content of structural information of FTIR spectroscopy with respect to FTNIR and UV-vis, we join the FTIR spectra of marine foams to those of humic substance from marine sediments and to the spectra of foams obtained by living organisms. We submitted this resulting FTIR spectral dataset to statistical multivariate methods to investigate specific aspects of foams such as structural similarity among foams and in addition, contributions from the organic matter of living organisms. Cluster analysis (CA) evidenced several cases (i.e. clusters) of marine foams having high structural similarity with foams from vegetal and animal samples and with humic substance extracted from sediments. These results suggested that all the living organisms of the marine environment can give contributions to the chemical composition of foams. Moreover, as CA also evidenced cases of structural differences within foam samples, we applied two-dimensional correlation analysis (2DCORR) to the FTIR spectra of marine foams to investigate the molecular characteristics which caused these structural differences. Asynchronous spectra of two-dimensional correlation analysis showed that the structural heterogeneity among foam samples depended reasonably on the presence and on the qualitative difference of electrostatic (hydrogen bonds) and nonpolar (van der Waals and π-π) interactions involving carbohydrate proteins and lipids present. The presence and relevance of these interactions agree with the supramolecular and surfactant characteristics of marine organic matter described in the scientific literature.