Crystalline azobenzene composites as photochemical phase-change materials

Crystalline binary mixtures of azobenzene and 4-methoxyazobenzene are reported and form photochemical phase change materials that possess working temperatures in the range of −58 °C to 31 °

Crystal structure of chlorido-methanol-(N-(2-(oxy)-3-methoxybenzylidene)pyridine-4-carbohydrazonato-κ3O,N,O′)-(4-methylphenyl)methyl-tin(IV), C23H24ClN3O4Sn

C23H24ClN3O4Sn, triclinic, P¯1 (no. 2), a=9.7536(2) Å, b=10.0755(2) Å, c=12.4215(3) Å, α=84.928(2)°, β=72.544(2)°, γ=74.382(2)°, V =1121.44(4) Å3, Z =2, Rgt(F)=0.021, wRref(F2)=0.054, T =100(2) K

Crystal structure of bis(μ2-di-n-butyldithiocarbamato-κ3S,S′:S;κ3S:S:S′)-hexacarbonyl-di-rhenium(I), C24H36N2O6Re2

C24H36N2O6Re2, triclinic, P¯1 (no. 2), a=10.3013(2) Å, b=11.3471(2) Å, c=14.5967(3) Å, α=72.540(2)°, β=73.074(2)°, γ=85.369(2)°, V =1557.05(6) Å3, Z =2, Rgt(F)=0.0214, wRref(F2)=0.0466, T =100(2) K

Long-Term Solar Energy Storage under Ambient Conditions in a MOF-Based Solid–Solid Phase-Change Material

This paper demonstrates a metal−organic framework (MOF) containing photoswitches within the pores as a hybrid solar thermal fuel (STF) and solid−solid phase-change material (ss-PCM). A series of azobenzene-loaded MOFs were synthesized with the general formula Zn2(BDC)2(DABCO)(AB)x (BDC = 1,4-benzenedicarboxylate, DABCO = 1,4- diazabicyclo[2.2.2]octane, AB = azobenzene, where x = 1.0, 0.9, 0.5, 0.3), herein named 1⊃AB1.0, 1⊃AB0.9, 1⊃AB0.5, and 1⊃AB0.3 respectively. X-ray powder diffraction, solid-state NMR, and density functional theory calculations were used to explore in detail the structural changes of the host framework that take place upon loading with the AB guest molecules. Differential scanning calorimetry measurements reveal a reversible phase change, which is absent from the evacuated framework. Upon irradiation with 365 nm light, 40% of the AB guests converted from the trans to the higher-energy cis isomeric form in 1⊃AB1.0. The energy stored within the metastable cis isomers is released upon heating and balances the endotherm associated with the phase transition. However, the exotherm associated with the phase transition is retained upon cooling, resulting in a net energy release over a full heating−cooling cycle. The maximum energy density is observed for the fully loaded composite 1⊃AB1.0, which releases 28.9 J g−1. In addition, the cis-AB guests in this composite showed negligible thermal reconversion during 4 months at ambient temperature, with an estimated energy storage half-life of 4.5 years. Further development of MOF-based STF-ss-PCMs could lead to applications for solar energy conversion and storage, and thermal management

4-π-Photocyclization of 1,2-Dihydropyridazines: An Approach to Bicyclic 1,2-Diazetidines with Rich Synthetic Potential.

The 4-π-photocyclization of a range of 1,2-dihydropyridazines is described, generating bicyclic 1,2-diazetidines in high yields on multigram scale. The key bicyclic 1,2-diazetidines are versatile synthetic intermediates and were easily converted into a range of novel derivatives, including functionalized 1,2-diazetidines, cyclobutenes, cyclobutanes, and 1,3-dienes

Crystal structure of chlorido-methanol-(N-(2-(oxy)-3-methoxy-benzylidene)pyridine-4-carbohydrazonato-kappa O-3,N,O ')-(4-methylphenyl)methyl-tin(IV), C23H24ClN3O4Sn

C23H24ClN3O4Sn, triclinic, P (1) over bar (no. 2), a = 9.7536(2) angstrom, b = 10.0755(2) angstrom, c = 12.4215(3) angstrom, alpha = 84.928(2)degrees, beta = 72.544(2)degrees, gamma = 74.382(2)degrees, V = 1121.44(4) angstrom(3), Z = 2, R-gt(F) = 0.021, wR(ref)(F-2) = 0.054, T = 100(2) K

Preparation, characterization and in vitro antioxidant and cytotoxicity studies of some 2,4-dichloro-N-[di(alkyl/aryl)carbamothioyl]benzamide derivatives

Abstract In the present study, three biologically active, substituted acyl thiourea compounds (1–3) have been synthesized from 2,4-dichlorobenzoyl chloride, potassium thiocyanate and the corresponding secondary amine in dry acetone. As analytical and spectral data of 1 and 3 have already been discussed in the literature, only the compound 2 was characterized by elemental analyses, UV–Visible, FT–IR, 1H & 13C NMR spectroscopic techniques. The molecular structures of 1–3 were determined by single crystal X-ray crystallography which shows twists of up to 70° about the (S=)C–NC(=O) bonds. All the synthesized compounds show good antioxidant property and cytotoxic potential against Ehrlich Ascites Carcinoma (EAC) cancer cell line

A Tripodal Ruthenium(II) Polypyridyl Complex with pH Controlled Emissive Quenching

A tripodal podand has been prepared and complexed to ruthenium(II) creating a metal complex with C3-symmetry and an enclosed cavity. The complex shows the anticipated enhanced emission when compared to [Ru(bipy)3]2+ in acetonitrile. The emission from this cryptand like structure is invariant to the introduction of monovalent cations in aqueous solution, but a significant drop in the emission was observed with increasing pH over a very broad pH range (3 to 12). This is attributed to an N to t2g electron transfer in the excited-state in the unprotonated form with a transfer rate of the order of 4.2 x 105 s-1. The crystal structure indicates the inclusion of water within the cavity suggesting that the protonation of a tertiary amine can be effectively moderated by a water molecule held in close proximity within a rigid cavit

Hydrodinamic Aspects of a High-Speed SWATH and New Hull Form

The main problems of high-speed ships operating in open seas are their insufficient seaworthiness and speed loss in high sea states. Small Water-plane Area Twin-Hulls (SWATH) are characterised by excellent seaworthiness, but the hull forms of a traditional SWATH are not suited for higher speeds. A new shape of underwater gondola has been developed for a semi-planing (S/P) SWATH. Additionally, hydrofoils can be applied to this ship to provide the optimal dynamic draught and trim, to mitigate motions in rough seas, and even to carry a part of the ship weight. The relative speed of this SWATH can be beneficially increased up to the displacement Froude number 3. Several concept designs addressing naval and civil transportation needs are outlined in this paper