Trialkylsilylium cation equivalents partnered with halogenated carborane anions (such as Et(3)Si[HCB(11)H(5)Cl(6)]) function as efficient and long-lived catalysts for hydrodehalogenation of C-F, C-Cl, and C-Br bonds with trialkylsilanes as stoichiometric reagents. Only C(sp(3))-halogen bonds undergo this reaction. The range of C-F bond-containing substrates that participate in this reaction is quite broad and includes simple alkyl fluorides, benzotrifluorides, and compounds with perfluoroalkyl groups attached to an aliphatic chain. However, CF(4) has proven immune to this reaction. Hydrodechlorination was carried out with a series of alkyl chlorides and benzotrichlorides, and hydrodebromination was studied only with primary alkyl bromide substrates. Competitive experiments established a pronounced kinetic preference of the catalytic system for activation of a carbon-halogen bond of a lighter halide in primary alkyl halides. On the contrary, hydrodechlorination of C(6)F(5)CCl(3) proceeded much faster than hydrodefluorination of C(6)F(5)CF(3) in one-pot experiments. A solid-state structure of Et(3)Si[HCB(11)H(5)Cl(6)] was determined by X-ray diffraction methods.

Sulfonated graphitic carbon nitride having both Brønsted base and Brønsted acid sites is used as a heterogeneous catalyst for the selective conversion of different biomass-derived saccharides to 5-hydroxymethylfurfural in green solvents.

Four isostructural chiral three-dimensional (3D) porous pillared-layer frameworks based on Co(II) and Ni(II), {[M(l-mal)(azpy)0.5]·2H2O} n (M = Co (1), Ni (2)) and {[M(l-mal)(bpee)0.5]·H2O} n (M = Co (3), Ni (4)); (l-mal = l-malate dianion, azpy = 4,4′-bisazobipyridine, and bpee = 1,2-bis(4-pyridyl)ethylene), have been synthesized using mixed ligand systems and characterized structurally. All the frameworks are homochiral, based on the chiral l-malate dianion. The bridging of l-malate with Co(II) or Ni(II) forms a two-dimensional (2D) layer of {M(l-mal)} n which is further pillared by azpy or bpee to form a 3D pillared-layer porous framework. The large rectangular channels along the crystallographic b direction (7.0 × 6.2 Å2 for 1 and 2; 6.8 × 6.1 Å2 for 3 and 4) are occupied by the guest water molecules. The binding of −OH and −COO groups of l-malate with the Co(II) or Ni(II) render interesting antiferromagnetic and ferrimagnetic type behavior in 1 and 2, respectively. All the frameworks show high thermal stability and guest-induced structural contraction evidenced by the temperature-dependent powder X-ray diffraction patterns. Gas (N2, CO2, H2, O2, and Ar) adsorption studies on the dehydrated frameworks of 1 and 3 show excellent selective CO2 gas uptake at 195 K. The lesser uptake of CO2 in the dehydrated framework of 3 compared to 1 has been rationalized to the different polarity of the pore surface due to the change in the functional group of the pillar module. The more polar azo (−NN−) group in 1 renders strong interaction with CO2 compared to the ethylenic (−CHCH−) group in 3. The difference in polarity in 1 and 3 also is reflected in water sorption studies.

The sunlight-driven fixation of CO 2 into valuable chemicals constitutes a promising approach toward environmental remediation and energy sustainability over traditional thermal-driven fixation. Consequently, in this article, we report a strategic design and utilization of Mg-centered porphyrin-based metal− organic framework (MOFs) having relevance to chlorophyll in green plants as a visible light-promoted highly recyclable catalyst for the effective fixation of CO 2 into value-added cyclic carbonates under ambient conditions. Indeed, the Mg-centered porphyrin MOF showed good CO 2 capture ability with a high heat of adsorption (44.5 kJ/mol) and superior catalytic activity under visible light irradiation in comparison to thermal-driven conditions. The excellent light-promoted catalytic activity of Mg−porphyrin MOF has been attributed to facile ligand-to-metal charge transfer transition from the photoexcited Mg−porphyrin unit (SBU) to the Zr 6 cluster which in turn activates CO 2 , thereby lowering the activation barrier for its cycloaddition with epoxides. The in-depth theoretical studies further unveiled the detailed mechanistic path of the light-promoted conversion of CO 2 into high-value cyclic carbonates. This study represents a rare demonstration of sunlight-promoted sustainable fixation of CO 2 , a greenhouse gas into value-added chemicals.

Highly porous, polyhedral metal−organic frameworks (MOFs) of Co(II)/Ni(II), {[M 6 (TATAB) 4 (DABCO) 3 (H 2 O) 3 ]•12DMF• 9H 2 O} n (where M = Co(II) (1)/Ni(II) ( 2), H 3 TATAB = 4,4′,4″-striazine-1,3,5-triyl-tri-p-aminobenzoic acid, and DABCO = 1,4diazabicyclo[2.2.2]octane) have been synthesized solvothermally. Both MOFs 1 and 2 show a 2-fold interpenetrated 3D framework structure composed of dual-walled cages of dimension ∼ 30 Å functionalized with a high density of Lewis acidic Co(II)/Ni(II) metal sites and basic -NHgroups. Interestingly, MOF 1 shows selective adsorption of CO 2 with high heat of adsorption (Q st ) value of 39.7 kJ/mol that is further supported by theoretical studies with computed binding energy (BE) of 41.17 kJ/mol. The presence of the high density of both Lewis acidic and basic sites make MOFs 1/2 ideal candidate materials to carry out co-catalyst-free cycloaddition of CO 2 to epoxides. Consequently, MOFs 1/2 act as excellent recyclable catalysts for cycloaddition of CO 2 to epoxides for high-yield synthesis of cyclic carbonates under co-catalystfree mild conditions of 1 bar of CO 2 . Further, MOF 1 was recycled for five successive cycles without substantial loss in catalytic activity. Herein, rational design of rare examples of 3D polyhedral MOFs composed of Lewis acidic and basic sites exhibiting efficient co-catalyst-free conversion of CO 2 has been demonstrated.

Highly thermal and chemically stable, 20-connected lanthanide metal–organic frameworks (MOFs) [{Ln­(BTB)­(H2O)}­·H2O] n (where Ln = Sm (MOF1)/Gd (MOF2), BTB = 1,3,5-tris (4-carboxy phenyl) benzene) have been synthesized solvothermally and characterized by single-crystal X-ray diffraction analysis and other physicochemical methods. MOF1 and 2 are isostructural and feature three-dimensional honeycomb-like structure with large one-dimensional hexagonal channels of dimension ∼10.20 × 10.11 Å2. Gas uptake studies of the samples revealed selective adsorption properties of MOF1 for CO2 over other (N2, Ar, and H2) gases. The activated samples of the MOF1/2 act as efficient recyclable catalysts for heterogeneous cycloaddition of CO2 with styrene oxide, resulting in cyclic carbonate with high yield and selectivity. Interestingly, the pore size-dependent catalytic conversion of epoxides has been observed, suggesting the potential utility of MOF1 as a promising heterogeneous catalyst for cycloaddition of carbon dioxide. Furthermore, the MOF1 catalyst can be easily recycled for several cycles without significant loss of catalytic activity as well as structural rigidity. MOF1 and 2 represent rare examples of 20-c lanthanide MOFs exhibiting selective capture and efficient cycloaddition of CO2 with epoxides at mild conditions.

Febuxostat exhibits unprecedented solid forms with a total of 40 polymorphs and pseudopolymorphs reported. Polymorphs differ in molecular arrangement and conformation, intermolecular interactions, and various physicochemical properties, including mechanical properties. Febuxostat Form Q (FXT Q) and Form H1 (FXT H1) were investigated for crystal structure, nanomechanical parameters, and bulk deformation behavior. FXT Q showed greater compressibility, densification, and plastic deformation as compared to FXT H1 at a given compaction pressure. Lower mechanical hardness of FXT Q (0.214 GPa) as compared to FXT H1 (0.310 GPa) was found to be consistent with greater compressibility and lower mean yield pressure (38 MPa) of FXT Q. Superior compaction behavior of FXT Q was attributed to the presence of active slip systems in crystals which offered greater plastic deformation. By virtue of greater compressibility and densification, FXT Q showed higher tabletability over FXT H1. Significant correlation was found with anticipation that the preferred orientation of molecular planes into a crystal lattice translated nanomechanical parameters to a bulk compaction process. Moreover, prediction of compactibility of materials based on true density or molecular packing should be carefully evaluated, as slip-planes may cause deviation in the structure-property relationship. This study supported how molecular level crystal structure confers a bridge between particle level nanomechanical parameters and bulk level deformation behavior.

Non-steroidal anti-inflammatory drugs (NSAIDs) are a group of molecules which have been found to be active against cancer cells with chemopreventive properties by targeting cyclooxygenase (COX-1 and COX-2) and lipoxygenase (LOX), commonly upregulated (particularly COX-2) in malignant tumors. Arene ruthenium(ii) complexes with a pseudo-octahedral coordination environment containing different ancillary ligands have shown remarkable activity against primary and metastatic tumors as reported earlier. This work describes the synthesis of four novel ruthenium(ii)-arene complexes viz. [Ru(η-p-cymene)(nap)Cl] 1 [Hnap = naproxen or (S)-2-(6-methoxy-2-naphthyl)propionic acid], [Ru(η-p-cymene)(diclo)Cl] 2 [Hdiclo = diclofenac or 2-[(2,6-dichlorophenyl)amino] benzeneacetic acid, [Ru(η-p-cymene)(ibu)Cl] 3 [Hibu = ibuprofen or 2-(4-isobutylphenyl)propanoic acid] and [Ru(η-p-cymene)(asp)Cl] 4 [Hasp = aspirin or 2-acetoxy benzoic acid] using different NSAIDs as chelating ligands. Complexes 1-3 have shown promising antiproliferative activity against three different cell lines with GI (concentration of drug causing 50% inhibition of cell growth) values comparable to adriamycin. At the concentration of 50 μM, complex 3 is more effective in the inhibition of cyclooxygenase and lipooxygenase enzymes, followed by complex 2 and complex 1 in comparison to their respective free NSAID ligands indicating a possible correlation between the inhibition of COX and/or LOX and anticancer properties. Molecular docking studies with COX-2 reveal that complexes 1 and 2 having naproxen and diclofenac ligands exhibit stronger interactions with COX-2 than their respective free NSAIDs and these results are in good agreement with their relative experimentally observed COX inhibition as well as anti-proliferative activities.