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Organogels are low molar mass organic compounds with the ability to immobilize an incredible quantity of solvent and fibrous aggregation of these compounds formed by noncovalent interaction usually involves hydrogen bonding. For stilbene-cholesterol based gelators, the driving force for molecular aggregation are weak van der Waal interactions developed by the stacking of cholesterol moieties and noncovalent pi-pi interactions between the aromatic rings in the stilbene.

A computational experiment is devised for advanced inorganic laboratory course that allows the students to explore the structure and bonding patterns of ethene and some heavier analogues. The HOMO-LUMO gaps, double bond dissociation energetics, and optimized geometries of ethene, disilene, and digermene are explored.

Research has been conducted on the luminescent platinum(II) diimine complexes and their synthesis. Results indicate that the complexes are emissive in fluid solution.

The perchlorate and tetrafluoroborate salts of the (Fe TPP EtOH 2)1+ cation were characterized. Both (Fe TPP EtOH 2)ClO4 and (Fe TPP EtOH 2)BF4 crystallize in the same monoclinic space group with rhombic crystals at room temperature. The similarity also extends to the length of the axial Fe-O bonds. The temperature-dependent effective magnetic moments of the salts differ, however. Differences in the hydrogen bonding between the ethanol ligands and the anion are presumed to result from the presence or absence of ferromagnetic ordering.

The cocrystal salt tetraaquabis[trans‐1,2‐bis(pyridin‐4‐yl)ethene‐κN]iron(II) bis(1,1,3,3‐tetracyano‐2‐ethoxypropenide)–trans‐1,2‐bis(pyridin‐4‐yl)ethene (1/2), [Fe(C12H10N2)2(H2O)4](C9H5N4O)2·2C12H10N2, is a rare example of a mononuclear FeII compound with trans‐1,2‐bis(pyridin‐4‐yl)ethane (bpe) ligands. The complex cation resides on a crystallographically imposed inversion center and exhibits a tetragonally distorted octahedral coordination geometry. Both the symmetry‐independent bpe ligand and the cocrystallized bpe molecule are essentially planar. The 1,1,3,3‐tetracyano‐2‐ethoxypropenide counter‐ion is nonplanar and the bond lengths are consistant with significant electron delocalization. The extended structure exhibits an extensive O—H...N hydrogen‐bonding network with layers of complex cations joined by the cocrystallized bpe. Both the coordinated and the cocrystallized bpe are involved in π–π interactions. Hirshfeld and fingerprint plots reveal the important intermolecular interactions. Density functional theory was used to estimate the strengths of the hydrogen‐bonding and π–π interactions, and suggest that the O—H...N hydrogen bonds enhance the strength of the π‐interactions by increasing the polarization of the pyridine rings. The solid‐state structure of the cocrystal salt tetraaquabis[trans‐1,2‐bis(pyridin‐4‐yl)ethene]iron(II) bis(1,1,3,3‐tetracyano‐2‐ethoxypropenide)–trans‐1,2‐bis(pyridin‐4‐yl)ethene (1/2) is reported. Density functional theory is used to explore the strengths of the observed O—H...N hydrogen bonding and π–π intermolecular interactions. [ABSTRACT FROM AUTHOR]

Susceptibility measurements of [Fe(OEP) (3-ClPy)] · ClO4(OEP=octaethylporphyrinate) in an external field of 1 T show that its magnetic moment varies from 3.36 to 4.58 β over a temperature range of 6–300 K. The data were analyzed with the ‘‘Maltempo model’’ but could be fitted only when an antiferromagnetic exchange interaction between two neighboring iron atoms within the dimer structure was assumed. The analysis shows that the ground state quartet S=3/2 (81%) is mixed with the nearby sextet S=5/2 (19%) through spin-orbit coupling with an unusually small coupling constant, ζ=150 cm-1. The exchange interaction within the dimer is estimated to be in the range of J=-0.4 to -0.6 cm-1. Mössbauer spectra of a polycrystalline sample of this complex were recorded in a range of temperatures (1.54–128 K) and applied magnetic fields (0–6 T). The analysis of Mössbauer spectra was in excellent agreement with that of susceptibility data. The analysis favors J=-0.6 cm-1. The values of chemical shift, δ=0.36 mm/s (with respect to metallic Fe), and temperature independent quadrupole splitting ΔE=3.23 mm/s, are typical of ferric ions in the admixed-intermediate spin state. Mössbauer analysis also provides the hyperfine coupling constant, P/gNβN =36.3 T/unit spin, a very low value compared with 60 T/unit spin for hemoglobin fluoride. The spectra also show that the system relaxes slowly in the presence of an external field above 5 T at 4.2 K. The rate of relaxation increases if the field is decreased or the temperature is increased. Low temperature spectra with intermediate rates of relaxation could be fitted with the set of parameters mentioned above. Only the direct relaxation process seems to be responsible up to 8 K. The anomalously large value of ΔE and low values of ζ and P are discussed in terms of the formation of molecular orbitals and changing radial wave functions... [ABSTRACT FROM AUTHOR]

Mössbauer spectra of polycrystalline [Fe(OEP)(2-MeHIm)]ClO4 · CHCl3 (OEP=octaethylporphyrinate; 2-meHIm=2-methylimidazole) were recorded over a range of temperatures (1.54 to 195 K) and applied magnetic fields (0–6 T). Magnetic susceptibility was measured at both 0.2 and 1 T in the temperature range 6–300 K. Mössbauer parameters δ=0.40 mm/s and ΔE=1.39 mm/s at 4.2 K, and the high temperature susceptibility Neff=6 at 300 K indicated high spin iron, but no simple spin Hamiltonian would reproduce the rapid decrease of Neff below 50 K. We interpret the data by assuming a zero field splitting D=12 cm-1 and invoking an antiferromagnetic exchange interaction J=-0.8 cm-1 between the five-coordinate iron atoms of closely spaced face-to-face heme pairs in the crystal. Slow spin relaxation at low temperature permits observation of level crossing and confirms the interpretation. It also permits the detection, through low field Mössbauer measurements, of a small rhombic distortion with E=0.024 cm-1. Mössbauer spectra of the same compound but as a dibromomethane solvate, [Fe(OEP)(2-MeHIm)]ClO4 · CH2Br2, yield generally similar parameter values, but suggest a slightly larger coupling, J=-0.85 cm-1, consistent with the fact that the paired iron atoms are known to be closer in this material. [ABSTRACT FROM AUTHOR]

An understanding of the driving forces resulting in crystallization vs organogel formation is essential to the development of modern soft materials. In the mol­ecular structure of the title compound, methyl 10-[4-(4-hydroxyphenyl)phen­oxy]decanoate (MBO10Me), C23H30O4, the aromatic rings of the biphenyl group are canted by 6.6 (2)° and the long-chain ester group has an extended conformation. In the crystal, mol­ecules are linked by O—H⋯O hydrogen bonds, forming chains along [10...]. The chains are linked by C—H⋯O hydrogen bonds, forming layers parallel to the ac plane. The layers are linked by C—H⋯π inter­actions, forming a three-dimensional supra­molecular structure. The extended structure exhibits a lamellar sheet arrangement of mol­ecules stacking along the b-axis direction. Each mol­ecule has six nearest neighbors and the seven-mol­ecule bundles stack to form a columnar superstructure. Inter­action energies within the bundles are dominated by dispersion forces, whereas inter­columnar inter­actions have a greater electrostatic component. [ABSTRACT FROM AUTHOR]

The photophysical properties of transition metal complexes of the 5,6-dimethyl-2-(pyridin-2-yl)-1-(pyridin-2-ylmethyl)-1 H-benzimidazole ligand are of interest. Dichlorido[5,6-dimethyl-2-(pyridin-2-yl)-1-(pyridin-2-ylmethyl)-1 H-benzimidazole-κ2 N2, N3]platinum(II), [PtCl2(C20H18N4)], is luminescent in the solid state at room temperature. The compound displays a distorted square-planar coordination geometry. The Pt-N(imidazole) bond length is shorter than the Pt-N(pyridine) bond length. The extended structure reveals that symmetry-related molecules display weak C-H...N, C-H...Cl, and C-H...Pt hydrogen-bonding interactions that are clearly discernable in the Hirshfeld surface and fingerprint plots. The intermolecular C-H...Pt and C-H...N interactions have been explored using density functional theory. The result of an analysis of the distance dependence of C-H...Pt yields a value consistent with that observed in the solid-state structure. The energy of interaction for the C-H...Pt interaction is found to be about −11 kJ mol−1. [ABSTRACT FROM AUTHOR]

The synthesis of a novel benzimidazole derivative with a long-chain-ester substituent, namely methyl 8-[4-(1 H-benzimidazol-2-yl)phenoxy]octanoate, (3), is reported. Ester (3) shows evidence of aggregation in solution and weak gelation ability with toluene. The octan-1-ol solvate, methyl 8-[4-(1 H-benzimidazol-2-yl)phenoxy]octanoate octan-1-ol monosolvate, C22H26N2O3·C8H18O, (4), exhibits a four-molecule hydrogen-bonded motif in the solid state, with N-H...O hydrogen bonds between benzimidazole molecules and O-H...N hydrogen bonds between the octan-1-ol solvent molecules and the benzimidazole unit. The alkyl chains of the ester and the octan-1-ol molecules are in unfolded conformations. The phenylene ring is canted by 10.27 (6)° from the plane of the benzimidazole ring system. H...C contacts make up 20.7% of the Hirshfeld surface coverage. Weak C-H...π interactions involving the benzimidazole alkyl chain and three aromatic rings are observed. [ABSTRACT FROM AUTHOR]

Imidazole-containing compounds exhibit a myriad of pharmacological activities. Two tetrachloridozincate salts of 4-carboxy-1H-imidazol-3-ium, ImHCO2H+, are reported. Bis(4-carboxy-1H-imidazol-3-ium) tetrachloridozincate monohydrate, (C4H5N2O2)2[ZnCl4]·H2O, (I), crystallizes as a monohydrate salt, while bis(4-carboxy-1H-imidazol-3-ium) tetrachloridozincate bis(1H-imidazol-3-ium-4-carboxylato) monohydrate, (C4H5N2O2)2[ZnCl4]·2C4H4N2O2·H2O, (II), is a co-crystal salt with six residues: two ImHCO2H+ cations, two formula units of the zwitterionic 1H-imidazol-3-ium-4-carboxylate, ImHCO2, one tetrachloridozincate anion and one water molecule disordered over two sites in a 0.60 (4):0.40 (4) ratio. The geometric parameters of the ImHCO2H+ and the ImHCO2 moieties are the same within the standard uncertainties of the measurements. Both compounds exhibit extensive hydrogen bonding, including involvement of the tetrachloridozincate anion, resulting in interconnected chains of anions joined by water molecules. [ABSTRACT FROM AUTHOR]