Gelidium jelly was traditionally made by boiling processed Gelidium seaweed and allowing the filtrate to congeal into jelly. The processing of Gelidium seaweed was very complicate involved the repeated procedures of water washing and sun drying for 7 times, and the seaweed was originally purple-red in color turned into yellow after the repeated wash and sun drying. This study aimed to evaluate the effects of halogen lamp drying methods in replace of sun drying on the physical-chemical qualities of Gelidium jellies. Properties included the agar yield, gelling temperature, hardness, springiness, rheological parameters, sensory attributes, color, and volatile compounds were investigated. The results demonstrated halogen lamp drying method required 12 times of washing and drying processes to achieve the similar jelly properties compared to sun drying for 7 times in the experimental conditions. Volatiles including heptanal, β-ionone, and (E)-2-decenal could be used as indicators to monitor the washing and drying processing. Halogen lamp was found could be an alternative processing method for seaweed drying, especially at rainy days.

In the last 20 years, a huge amount of experimental results about halogen bonding (XB) has been produced. Most of the systems have been characterized by solid state X-ray crystallography, whereas in solution the only routine technique is the titration (by using ¹H and ¹⁹F NMR, IR, UV-Vis or Raman spectroscopies, depending on the nature of the system), with the aim of characterizing the strength of the XB interaction. Unfortunately, the titration techniques have many intrinsic limitations and they should be coupled with other, more sophisticated techniques to have an accurate and detailed description of the geometry and stoichiometry of the XB adduct in solution. In this review, it will be shown how crucial information about XB adducts can be obtained by advanced NMR techniques, as Nuclear Overhauser Effect-based Spectroscopies (NOESY, ROESY, HOESY…) and diffusion NMR techniques (PGSE or DOSY).

Raman spectra of [TeX6](Y2) (X, Y - Cl, Br, I) were recorded in the temperature range 5-300 K. The vibration frequency of molecular halogens as function on temperature and the type of halogen X- in the [TeX6]2- complex was obtained. The vibration frequency of the molecular halogen Y2 depends on the type of halogen X- complex [TeX6]2- The temperature dependence of the Y2 frequency is anomalous compared to what was expected for a conventional anharmonic oscillator. It is shown that the interpretation of the experimental results based on the concept of traditional chemical bonding is quite satisfactory in all cases. The study was motivated by the need to consider the mechanism of interaction in the X-Y2 contacts.

2,3,5,6-Tetramethyl-1,4-diisocyanobenzene (1), 1,4-diisocyanobenzene (2), and 1,4-dicyanobenzene (3) were co-crystallized with 1,3,5-triiodotrifluorobenzene (1,3,5-FIB) to give three cocrystals, 1·1,3,5-FIB, 2·2(1,3,5-FIB), and 3·2(1,3,5-FIB), which were studied by XRD. Common feature of the three structures is the presence of I···Cisocyanide or I···Nnitrile HaBs occurred between an iodine -hole and the isocyanide C- (or the nitrile N-) atom. The diisocyanide and dinitrile cocrystals, 2·2(1,3,5-FIB) and 3·2(1,3,5-FIB), are isostructural thus providing a basis for accurate comparison of the two types of noncovalent linkages of CN/NC groups in the composition of structurally similar entities and in one crystal environment. The bonding situation was studied by a set of theoretical methods. Diisocyanides are more nucleophilic than the dinitrile and they exhibit stronger binding to 1,3,5-FIB. In all structures, the HaBs are mostly determined by the electrostatic interactions, but the dispersion and induction components also provide a noticeable contribution and make the HaBs attractive. Charge transfer has a small contribution (<5%) to the HaB and it is higher for the diisocyanide than for the dinitrile systems. At the same time, diisocyanide and dinitrile structures exhibit typical electron-donor and -acceptor properties in relation to the HaB donor.

Smart materials represent an elegant class of (macro)-molecules endowed with the ability to react to chemical/physical changes in the environment. Herein, we prepared new photo responsive azobenzenes possessing halogen bond donor groups. The X-ray structures of two molecules highlight supramolecular organizations governed by unusual noncovalent bonds. In azo dye I-azo-NO2, the nitro group is engaged in orthogonal H···O···I halogen and hydrogen bonding, linking the units in parallel undulating chains. As far as compound I-azo-NH-MMA is concerned, a non-centrosymmetric pattern is formed due to a very rare I···π interaction involving the alkene group supplemented by hydrogen bonds. The Cambridge Structural Database contains only four structures showing the same I···CH₂=C contact. For all compounds, an ¹⁹F NMR spectroscopic analysis confirms the formation of halogen bonds in solution through a recognition process with chloride anion, and the reversible photo-responsiveness is demonstrated upon exposing a solution to UV light irradiation. Finally, the intermediate I-azo-NH2 also shows a pronounced color change due to pH variation. These azobenzenes are thereby attractive building blocks to design future multi-stimuli responsive materials for highly functional devices.

The reactivity of 3,5-di-(pyridin-4-yl)-1,2,4-thiadiazole (L1) with 1,4-diiodotetrafluorobenzene (1,4-DITFB) was explored and the halogen-bonded 1:1 co-crystal (1) was successfully isolated and structurally characterized.

The synthesis and crystal structure of pyrazine-2,5-diyldimethanol (pzydmH2, C8H8N2O2) a new symmetric water-soluble N,O-chelating tetra-dentate organic ligand is reported and an environmentally friendly method was used to synthesize coordination compounds in water under ambient conditions from the reaction of pzydmH2 with the halide salts of Cu(II), Zn(II), Hg(II) and Cd(II): {[Cu(pzydmH2)0.5(µ-Br)(Br)(H2O)]·H2O}n 1, {[Zn2(pzydmH2)(µ-Cl)(Cl)3(H2O)]·H2O}n 2, [Hg2(pzydmH2)0.5(µ-Cl)2(Cl)2]n 3, {[Cd2(pzydmH2)(µ-Cl)4]·H2O}n 4, and {[Cd2(pzydmH2)(µ-Br)4]·H2O}n 5. Single-crystal X-ray diffraction analysis revealed that 1-3 are 1D coordination polymers and 4 and 5 are 3D coordination networks, all constructed by bridging pyrazine-2,5-diyldimethanol and halogen ions. The hydroxyl groups in the organic linker extend the 1D chains to non-covalent 3D networks. In all non-covalent and covalent 3D networks water molecules were trapped by strong hydrogen bond interactions. Supramolecular analysis revealed strong O-H···O, O-H···N, O-H···X and week of C-H···O, C-H···X (X = Cl, Br) hydrogen bonds, as well as π-π(pyrazine ring), metal-halogen···π(pyrazine ring) and O-H···ring(5-membered chelate ring) interactions. Also X···O weak halogen bonds are present in 1-5 (X = Cl and Br).

Light sources tend to affect images captured in any automatic optical inspection (AOI) system. In this study, the effectiveness of metal-halide lamps, quartz-halogen lamps, and LEDs as the light sources in AOI systems for the detection of the 3rd and 4th layers electrodes of thin-film-transistor liquid crystal displays (TFT-LCDs) is examined experimentally. The results show that the performance of LEDs is generally comparable or better than that of metal-halide and quartz-halogen lamps. The best optical performance is by the blue LED due to its spectrum compatibility with the time-delay-integration charged-coupled device (TDI CCD) sensor and its better spatial resolution. The images revealed by the blue LED are sharper and more distinctive. Since current LEDs are more energy efficient and environmentally friendly, using LEDs as the light source for AOI is very beneficial. As the blue LED performs the best, it should be adopted for AOI using TDI CCD sensors.

In organic synthesis, due to their high electrophilicity and leaving group properties, halogens play pivotal roles in the activation and structural derivations of organic compounds. Recently, cyclizations induced by halogen groups that allow the production of diverse targets and the structural reorganization of organic molecules have attracted significant attention from synthetic chemists. Electrophilic halogen atoms activate unsaturated and saturated hydrocarbon moieties via the generation of halonium intermediates, followed by the attack of carbon-, nitrogen-, oxygen-, and sulfur-containing nucleophiles to give highly functionalized carbo- and heterocycles. Interestingly, new transformations of halogenated organic molecules that can control the formation and stereoselectivity of the products according to the difference in the size and number of halogen atoms have recently been discovered. These unique cyclizations may possibly be used as efficient synthetic strategies with future advances. In this review, innovative reactions controlled by halogen groups are discussed as a new concept in the field of organic synthesis.

The activation of halogen bonding by the substitution of the pentafluorosulfanyl (SF5) group was studied using a series of SF5-substituted iodobenzenes. The simulated electrostatic potential values of SF5-substituted iodobenzenes, ab initio molecular orbital calculations of intermolecular interactions of SF5-substituted iodobenzenes with pyridine, and the 13C NMR titration experiments of SF5-substituted iodobenzenes in the presence of pyridine or tetra (n-butyl) ammonium chloride (TBAC) indicated the obvious activation of halogen bonding, although this was highly dependent on the position of SF5-substitution on the benzene ring. 3,5-Bis-SF5-iodobenzene was the most effective halogen bond donor followed by o-SF5-substituted iodobenzene, while the m- and p-SF5 substitutions did not activate the halogen bonding of iodobenzenes. The 2:1 halogen bonding complex of 3,5-bis-SF5-iodobenzene and 1,4-diazabicyclo[2.2.2]octane (DABCO) was also confirmed. Since SF5-containing compounds have emerged as promising novel pharmaceutical and agrochemical candidates, the 3,5-bis-SF5-iodobenzene unit should be an attractive fragment of rational drug design capable of halogen bonding with biomolecules.

To date, theoretical analyses have provided several useful methods/algorithms for studying transition states and non-covalent interactions. Potential Energy Scan (PES) is one such method that has found wide application in the physicochemical community. Analyzing the PES profiles of the catalytic system of FeBr3 in Electrophilic Aromatic Substitution (EAS) with molecular halogens, one can notice an obvious difference from the modern textbook mechanisms proposed in this area of study. Moreover, the newly presented Graphic Methodology (GM) allows a simple and reliable transition state determination even for very weakly bound charge transfer complexes using second-order derivatives as an efficient tool in the graphical analysis. Relative errors that can be reduced to a few parts per thousand in transition state estimation make this method a potentially very useful tool in further graphical studies of non-covalent interactions. Studies performed using high-precision semiempirical methods suggest that the process of halonium ion quenching proceeds along a completely different pathway, suggesting a possible novel transition metal-nonmetal catalytic system involved in the EAS electrophilic quenching step. The results presented here strongly suggest a future GM application that is widely used and the introduction of pseudo and pre-transition states as new terms in the description of non-covalent interactions.

A typical halogen-free flame-retardant (HFFR) formulation for electric cables may contain polymers, various additives, and fire-retardant fillers. In this study, composites are prepared by mixing natural magnesium hydroxide (n-MDH) with linear low-density polyethylene (LLDPE) and a few types of ethylene-octene copolymers (C₈-POE). Depending on the content of LLDPE and C₈-POE, we obtained composites with different crystallinity that affected the final mechanical properties. The nucleation effect of the n-MDH and the variations in crystallinity caused by the blending of C₈-POE/LLDPE/n-MDH were investigated. In the C₈-POE/LLDPE blend, we found a decrease in the crystallization temperature of LLPDE compared to pure LLDPE and an increase in the crystallization temperature of C₈-POE compared to pure C₈-POE. On the contrary, the addition of n-MDH led to an increase in the crystallization temperature of LLDPE. As expected, the increase in the crystallinity of the polyolefin matrix of composites led to higher elastic modulus, higher tensile strength, and lower elongation at break. Overall, these results show how to obtain the required mechanical features for halogen-free flame-retardant compounds for electric cable applications depending on the quantities of the two miscible components in the final blend.