Dichloromethane Suspension Research Articles

Synthesis, characterization and application of a highly dispersed and reactive hypervalent iodine(V)/polyvinylpyrrolidone dendrimer nanocomposite: Hetero- vs. homo-intermolecular secondary O---I bonds

Polyvinylpyrrolidone (PVP) assisted aerobic oxidation of bulk iodosylbenzene or hydrolysis/oxidation of iodobenzene diacetate under mild conditions leading to the formation of nanostructured iodylbenzene is reported. AFM and FESEM-EDX analyses confirmed the formation of dendrimer iodylbenzene-polyvinylpyrrolidone nanocomposite (PhIO2-PVP) through the two top-down approaches. The formation of PhIO2 was confirmed by 1H NMR spectroscopy. Strong interactions between iodylbenzene molecules and the polymer through secondary intermolecular O---I bonds was evident from the large difference between the morphology of PVP (cubic) and PhIO2-PVP (dendrimer) nanoparticles. FESEM images showed a maximum width and length of 70 and 1000 nm for the dendrimers, respectively. The dual role played by PVP, i.e., facilitating the oxidation of I(III) to I(V) and stabilization the hypervalent I(V) compound was attributed to the formation of strong secondary hetero-intermolecular O---I bonds, between the polymer and iodine centre. The very fine aqueous and dichloromethane suspensions of PhIO2-PVP were indistinguishable to the naked eye. Efficient direct oxidation of cyclohexene and methylene blue with PhIO2-PVP at room temperature and a short reaction time provided evidence of significantly increased reactivity of PhIO2-PVP compared to that of the bulk oxidant. PhIO2-PVP was also used in the oxidation of methyl phenyl sulfide and styrene in water and dichloroethane, using water soluble and insoluble metalloporphyrins, respectively. The former led to the formation of the corresponding sulfoxide as the sole product in the two solvents. In addition to styrene oxide formed in both solvents, benzaldehyde was also formed with a selectivity of 24% in water. Almost complete oxidation of the organic substrates was observed in dichloroethane. The results of this study show that the nanostructured iodine(V) compound can be used as an efficient terminal oxidant in biomimetic oxidations.

Confinement Effect of Micro- and Mesoporous Materials on the Spectroscopy and Dynamics of a Stilbene Derivative Dye

Micro- and mesoporous silica-based materials are a class of porous supports that can encapsulate different guest molecules. The formation of these hybrid complexes can be associated with significant alteration of the physico-chemical properties of the guests. Here, we report on a photodynamical study of a push–pull molecule, trans-4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM), entrapped within faujasite-type zeolites (HY, NaX, and NaY) and MCM-41 in dichloromethane suspensions. The complex formation gives rise to caged monomers and H- and J-aggregates. Steady-state experiments show that the nanoconfinement provokes net blue shifts of both the absorption and emission spectra, which arise from preferential formation of H-aggregates concomitant with a distortion and/or protonation of the DCM structure. The photodynamics of the hybrid complexes are investigated by nano- to picosecond time-resolved emission experiments. The obtained fluorescence lifetimes are 65–99 ps and 350–400 ps for H- and J-aggregates, respectively, while those of monomers are 2.46–3.87 ns. Evidences for the presence of a charge-transfer (CT) process in trapped DCM molecules (monomers and/or aggregates) are observed. The obtained results are of interest in the interpretation of electron-transfer processes, twisting motions of analogues push–pull systems in confined media and understanding photocatalytic mechanisms using this type of host materials.

Femto-to nanosecond photodynamics of Nile Red in metal-ion exchanged faujasites

We report on the photodynamics of Nile Red (NR) interacting with faujasite (NaY)-type zeolites having different Na/Al ratios and charge balancing metals (Li+, Mg2+, and Cs+) in dichloromethane (DCM) suspensions. The encapsulation of NR in these materials leads to the formation of different populations, reflected in H- and J-aggregates, monomers, and surface adsorbed species. Due to the interaction of the dye with both the Brønsted and Lewis sites of the zeolite, a bathochromic shift is observed in the steady-state diffuse transmittance and emission spectra. The relative contribution of each population is affected by the Na/Al ratio and the nature of the doping metal ion. These findings are further explored by femto-to nanosecond time-resolved emission experiments, where a multi-exponential behaviour is observed for the excited samples. The fluorescence lifetimes range from ∼100 ps to ∼2 ns. They are assigned to the emission from H- and J-aggregates and monomers. At low Na/Al ratios, we observed an increase in the fluorescence time constants which is explained in terms of H-bonds formation between NR and the zeolite framework, while the change in the emission lifetimes for the metal ion exchanged zeolites is due to the variation of the properties (size and polarization ability) of the exchanged cation. An ultrafast formation (∼200 fs) of a charge-separated state (CS) followed by a vibrational cooling (∼1–2 ps) are observed in the fluorescence up-conversion transients. These results indicate a strong interaction between NR and the studied zeolites and may help for the design of metal ion sensors and for a better understanding of nanocatalysis.

Preparation of Capped Octahedral OsHC6 Complexes by Sequential Carbon-Directed C–H Bond Activation Reactions

A synthetic procedure based on sequential C-directed C–H bond activation reactions is reported for the preparation of capped octahedral OsHC6 complexes. Reactions of the dimer [OsCl2(η6-p-cymene)]2 (1) with PhMeLAgI (PhMeL = 1-phenyl-3-methyl-1H-benzimidazolylidene (PhMeBIm), 1-phenyl-3,5,6-trimethyl-1H-benzimidazolylidene (PhMeBIm*)) afford OsCl2(η6-p-cymene)(PhMeL) (L = BIm (2), BIm* (3)), which undergo cyclization to give OsCl{κ2-C,C-(MeL-C6H4)}(η6-p-cymene) (L = BIm (4), BIm* (5)) by stirring in dichloromethane suspensions of Al2O3. Complexes 4 and 5 exchange the anion with AgOTf (OTf = CF3SO3). In acetonitrile, at 75 °C, the resulting OTf derivatives Os(OTf){κ2-C,C-(MeL-C6H4)}(η6-p-cymene) (L = BIm (6), BIm* (7)) release the arene to yield the tetra(solvento) compounds [Os{κ2-C,C-(MeL-C6H4)(CH3CN)4]OTf (L = BIm (8), BIm* (9)). Complexes 8 and 9 react with PhMeLAgI to coordinate a second NHC ligand. The generated species Os{κ2-C,C-(MeL-C6H4)(PhMeL)(CH3CN)3]OTf (L = BIm (10), BIm* (11)), containing a C...

Competitive Excimer Formation and Energy Transfer in Zr-Based Heterolinker Metal-Organic Frameworks.

The spectroscopy and dynamics of a series of Zr-based MOFs in dichloromethane suspension are reported. These Zr-NADC MOFs were constructed by using different mixtures of 2,6-naphthalenedicarboxylate (NDC) and 4-amino-2,6-naphthalenedicarboxylate (NADC) as organic linkers. The fraction of NADC relative to NDC in these heterolinker MOFs ranges from 2 to 35 %. The results indicate two competitive photoprocesses: NDC excimer formation and an energy transfer (ET) from excited NDC linkers to NADC linkers. Increasing the fraction of NADC linkers in the Zr-NADC nanostructure decreases the mean time constant of NDC excimer formation, while the NADC emission intensity experiences a drop at the highest fraction of this linker in the MOF. The first observation is explained by an increase in the energy-transfer probability between the two linkers, and the second by emission quenching in the NADC linkers due to ultrafast charge transfer assisted by the amino group. Femtosecond time-resolved emission studies showed that the ET process (recorded as decaying and rising components) from excited NDC to NADC takes place in 1.2 ps. Direct excitation of the NADC linkers (at 410 nm) shows a decaying, but not rising, component of 250-480 fs, which could reflect the formation of a nonemissive charge-separation state. The results show that by using MOFs having heterolinkers it is possible to trigger and tune excimer formation and ET processes.

Ultrafast Dynamics of Nile Red Interacting with Metal Doped Mesoporous Materials

We report on ultrafast studies of Nile Red (NR) interacting with MCM41 mesoporous materials doped by Al, Ga, Zr, and Ti in dichloromethane suspensions. The steady-state results showed a significant red shift and broadening of the diffuse transmittance and the emission spectra upon interaction with the MCM41-based materials. These findings are explained in terms of H-bonds with the host, different Brønsted/Lewis interactions with the matrix and formation of H- and J-aggregates, in addition to weakly and strongly adsorbed monomers. The pico- to nanosecond time-resolved data support this explanation, showing a significant shortening in the emission lifetimes where NR is interacting with metal-doped MCM41. The femtosecond dynamics of NR loaded into X-MCM41 (X = Si, Al, Ga) indicate that the charge-separated state (CS) is formed at the S1 state in ∼350 fs. For Zr- and Ti- MCM41 hosts the intramolecular charge transfer (ICT) occurs in less than 200 fs, and a subsequent electron injection to Ti or Zr trap states happens in ∼250 fs. Our studies reveal a strong interaction between the NR species and the framework of MCM41 materials at both the S0 and S1 states.

Exploring the Photobehavior of Nanocaged Monomers and H- and J-Aggregates of a Proton-Transfer Dye within NaX and NaY Zeolites

We report on steady-state absorption and emission and time-resolved emission studies of (E)-2-(2-hydroxybenzyliden)amino-4-nitrophenol (HBA-4NP) interacting within NaX and NaY zeolites in dichloromethane (DCM) suspensions. In pure DCM, the enol (E) structure, which is the only one at S0, undergoes an excited-state intramolecular proton-transfer (ESIPT) reaction at S1 to produce a keto (K) type phototautomer emitting a largely Stokes shifted emission band with a short lifetime (14 ps) due to a twisting motion enhancing the radiationless decay. Upon interaction with NaX and NaY frameworks, different loading yields (NaX: 20%, NaY: 90%) were obtained due to the different amounts of aluminum atoms in the related frameworks and different amounts of sodium cations within their cages. The composites contain caged HBA-4NP E structures in the forms of monomers and H- and J-aggregates. The spectral broadening and shift reflect the emissions of the tautomers of the different electronic species which reflect the confinement effect of the zeolite supercages on their relaxation. The fluorescence lifetimes of K produced from caged monomers within NaX and NaY are remarkably very long (about 6 ns) when compared to that in solution (14 ps) due to the confinement effect on the radiationless pathways. For the composites made from diluted DCM solutions, those of H-aggregates are around 100 ps, while those of J-types are around 1 ns, respectively. Increasing the loading leads to a strong shortening in the K monomers and aggregate emission lifetimes due to enhanced guest:guest interactions within the same cage or between guests located in neighboring cages. Our results show the first observation of three absorbing and emitting structures (monomers and H- and J-aggregates) of intramolecular H-bonded molecules within zeolites, able to undergo ESIPT reactions to produce a broad emission with lifetimes ranging from tens of picoseconds to several nanoseconds. The data give new insights into the zeolite:dye complexes nature and thus can help in the design of new nanophotonics devices (nanosensors, nanolasers) based on this kind of material and in a better understanding of nanocatalysis and drug delivery using zeolites as supports and vehicles.

Interfacial Electron Transfer Dynamics in a Solar Cell Organic Dye Anchored to Semiconductor Particle and Aluminum-Doped Mesoporous Materials

We report on femto- to nanosecond emission studies of the interaction of an organic dye (TPC1) for solar cells, of (electron-donor)–(π-spacer)–(electron-acceptor) structure, with different semiconductor particles and aluminum-doped MCM-41 silicate mesoporous material, in a dichloromethane (DCM) suspension. We used ZnO, ZrO2, and Al2O3 nanoparticles employed in dye-sensitized solar cells as active electron collection materials or insulating layers. Steady-state absorption and emission spectra reflect strong complex formation between TPC1 and the used materials. The femto- to nanosecond emission transients of the interfacial systems show a nonexponential behavior with an averaged half lifetime of 4, 11, and 150 ps for ZnO, ZrO2, and Al2O3, respectively. For the latter, we observed the effect of the dye’s concentration indicating the action of a fluorescence self-quenching mechanism. For ZnO and ZrO2 samples, the lifetime of the complexes is determined by an electron injection rate to the conduction band and...

(BeCl2)2(18‐Krone‐6)] und sein Hydrolyseprodukt [{Be3(μ‐OH)3(H2O)6}‐(18‐Krone‐6)]Cl3·3H2O: Kristallstrukturen und DFT‐Rechnungen

AbstractBeryllium dichloride reacts in dichloromethane suspension with 18‐crown‐6 to give the molecular centrosymmetric complex [(BeCl2)2(18‐crown‐6)] (1), which was characterized by single‐crystal X‐ray diffraction, by vibrational spectroscopy (IR, Raman), and by DFT calculations. 1 crystallizes monoclinically in the space group P21/n with Z = 2. Lattice dimensions at 100(2) K: a = 747.5(1), b = 1373.9(1), c = 899.1(1) pm, β = 94.84(1)°, R1 = 0.0233., Exposition of 1 to moist atmosphere leads to single crystals of [{Be3(μ‐OH)3(H2O)6}(18‐crown‐6)]Cl3·3H2O (2·3H2O), which are characterized by X‐ray diffraction. 2 crystallizes in the triclinic space group P$\rm P\bar1$ with Z = 2. Lattice dimensions at 100(2) K: a = 1046.04(9), b = 1236.12(11), c = 1275.72(13) pm, α = 80.233(8)°, β = 66.439(7)°, γ = 80.053(7)°, R1 = 0.0476.

BeCl2(Ph2PCH2PPh2)2] – ein Donor‐Akzeptorkomplex des Berylliums mit dem Bis(diphenylphosphanyl)methan‐Liganden

AbstractThe donor‐acceptor complex [BeCl2(Ph2PCH2PPh2)2] (1·2CH2Cl2) was prepared from beryllium dichloride and bis(diphenylphosphanyl)methane in dichloromethane suspension to give colorless single crystals, which were characterized by X‐ray diffraction, IR spectroscopy, and DFT calculations. Compound 1·2CH2Cl2 crystallizes monoclinically in space group C2/c with four formula units per unit cell. Lattice dimensions at 193(2) K: a = 2339.5(2), b = 916.7(1), c = 2415.4(2) pm, β = 97.15(1)°, R1 = 0.0386. The structure of 1 consists of distorted tetrahedral molecules with site symmetry C2 and bond lengths Be–Cl of 196.8(2) pm and Be–P of 220.6(3) pm. Quantum chemical calculations at the RI‐BP86/SV(P) level give a structure of 1, which is in very good agreement with the experimental one. The calculations predict that the bond dissociation energies of the first and second Ph2PCH2PPh2 ligand from 1 are De = 16.8 kcal·mol–1 and 24.3 kcal·mol–1, respectively.

Fast to Ultrafast Dynamics of Palladium Phthalocyanine Covalently Bonded to MCM-41 Mesoporous Material

Palladium phthalocyanine (PdPc) covalently bonded to the internal framework of MCM-41 mesoporous structured silicates has been synthesized and studied by UV−vis steady-state absorption and fluorescence spectroscopy, and by pico- and femtosecond time-resolved emission spectroscopy in dichloromethane suspensions. We compare the results obtained for covalently bonded (MO-PdPc) and diffusion-formed (PdPc_MCM41) samples. A significant broadening of the diffuse transmittance spectra of both materials is observed. The effect is due to electrostatic and specific (through H-bonds) interactions of the guest with the host, but to some extent, formation of dimers also contributes to this broadening. However, only the MO-PdPc shows an additional absorption band around 708 nm. The static emission spectrum of MO-PdPc is different from that of PdPc, but it is similar to that of the metal-free phthalocyanine one. The results are explained in terms of confinement effect of the mesoporous material inducing deformation of th...

(Ph4P)2[Be3(μ‐OH)3(H2O)6]Cl5: Crystal Structure and DFT Calculations

AbstractBis(tetraphenylphosphonium)‐tris(μ‐hydroxo)hexaaquatriberylliumpentachloride, (Ph4P)2[Be3(μ‐OH)3(H2O)6]Cl5 (1), was surprisingly obtained by reaction of (Ph4P)N3·n H2O with BeCl2 in dichloromethane suspension and subsequent crystallization from acetonitrile to give single crystals of composition 1·5.25CH3CN. According to the crystal structure determination space group P$\bar{1}$, Z = 2, lattice dimensions at 100 K: a = 1354.8(2), b = 1708.7(2), c = 1753.2(2) pm, α = 114.28(1)°, β = 94.80(1)°, γ = 104.51(1)°, R1 = 0.0586] the [Be3(μ‐OH)3(H2O)6]3+ cations form six‐mem‐bered Be3O3 rings with boat conformation and distorted tetrahedrally coordinated beryllium atoms with the terminally coordinated H2O molecules. The structure ist characterized by a complicated three dimensional hydrogen‐bridging network including O–H···O, O–H···Cl, and O–H···NCCH3 contacts. DFT calculations result in nearly planar [Be3(OH)3] six‐membered ring conformations.

Reaktion von (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamin mit Berylliumchlorid. Kristallstrukturen von (R,R,SN,SN′)‐[(C12H26N2)BeCl2] und (R,R,SN,SN′)‐[(C12H26N2)BeCl(N3)

AbstractReaction of (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamine with Beryllium Chloride. Crystal Structures of (R,R,SN,SN′)‐[(C12H26N2)BeCl2] and (R,R,SN,SN′)‐[(C12H26N2)BeCl(N3)](R,R)‐(N,N′)‐diisopropylcyclohexyl‐1,2‐diamine reacts with equimolar amounts of BeCl2 in dichloromethane suspension to give the donor acceptor complex (R,R,SN,SN′)‐[(C12H26N2)BeCl2] (1). The reaction of 1 with excess trimethylsilylazide in dichloromethane solution leads to the formation of the azido derivative (R,R,SN,SN′)‐[(C12H26N2)BeCl(N3)] (2). Both complexes are characterized by X‐ray diffraction and by IR spectroscopy.1 · 0.5CH2Cl2: Space group P6122, Z = 6, lattice dimensions at 193 K: a = b = 1390.3(1), c = 1624.8(1) pm, R1 = 0.0509. In the chiral complex 1 the BeCl2 unit forms a BeN2C2 chelate ring with Be–N distances of 199.8(4) pm. The molecules are associated via Cl···H–N hydrogen bridges along [001].2: Space group P21, Z = 6, lattice dimensions at 193 K: a = 1501.7(2), b = 968.6(2), c = 1629.2(4) pm, β = 90.03(3)°, R1 = 0.0981. The structure of 2 consists of three independent chiral units (R,R,SN,SN′)‐[(C12H26N2)BeCl(N3)], which are associated via Cl···H–N and Nα···H–N hydrogen bridges along [100], Nα being Nα atoms of the azido groups.

Mesoporous silica films as catalyst support for microstructured reactors: Preparation and characterization

Abstract Mesoporous silica thin films with hexagonal and cubic mesostructure have been deposited by the evaporation induced self-assembly assisted sol–gel route on microchannels etched in a Pyrex® 7740 borosilicate glass substrate. Prior to the synthesis, a 50 nm TiO2 film has been deposited on the substrate by atomic layer deposition from titanium tetrachloride and water to increase adhesion of the mesoporous films to the walls of the substrate. The mesoporous films were produced by templating a silica precursor (TEOS) with the non-ionic surfactant Pluronic F127 (EOxPOyEOx, EO, ethylene oxide; PO, propylene oxide; x = 106; y = 70). The effect of the channel aspect ratio on the uniformity of the silica films was investigated in the channels with a depth of 50 μm and with a width of 100–250 μm. Depending on the microchannel geometry, the thickness along the channels varies in the range of 0.3–1.0 μm. The most uniform films across the whole channel cross-section were obtained at the width-to-depth ratio of 3. Afterwards, the mesoporous films were impregnated with an ether–dichloromethane suspension of [PPN]2[Ru10Pt2C2(CO)28] mixed-metal cluster precursor to obtain well-dispersed, isolated and anchored bimetallic nanoparticles of 3–4 nm in diameter.

BeCl(12‐Krone‐4)][SbCl4]: Ein neuer kationischer Berylliumkomplex

Abstract[BeCl(12‐Crown‐4)][SbCl4]: A Novel Cationic Beryllium ComplexBeryllium chloride reacts in dichloromethane suspension in the presence of the equimolar amount of 12‐crown‐4 with antimony pentachloride exothermically to give [BeCl(12‐crown‐4)][SbCl4] (1), which is characterized by IR spectroscopy and by single crystal structure determination. Space group P21/c, Z = 8, lattice dimensions at 193 K: a = 1116.4(2), b = 1735.4(2), c = 1709.8(3) pm, β = 91.31(1)°, R1 = 0.0301. 1 contains cations [BeCl(12‐crown‐4)]+ with coordination number five at the beryllium atom, and polymeric anions $\rm [SbCl_{4}^{\phantom{\infty}-}]{\infty}$, forming zigzag chains along [001] with coordination number five at the antimony atoms, thus showing the steric effect of the lone pair.1 can also be obtained by using the twofold amounts of 12‐crown‐4 and antimony pentachloride, however, accompanied by forming [SbCl3(12‐crown‐4)] (2). With respect to the wrong crystal structure determinations previously reported in the literature, we solved the X‐ray structure of 2 in the space group P21/c, Z = 4, lattice dimensions at 173 K: a = 1191.4(1), b = 783.7(1), c = 1489.7(2) pm, β = 90.83(1)°, R1 = 0.0243.

Synthese, Schwingungsspektren und Kristallstrukturen der Nitratoargentate (Ph4P)[Ag(NO3)2(CH3CN)]·CH3CN und (Ph4P)[Ag2(NO3)3

AbstractSynthesis, Vibrational Spectra, and Crystal Structures of the Nitrato Argentates (Ph4P)[Ag(NO3)2(CH3CN)]·CH3CN and (Ph4P)[Ag2(NO3)3]Tetraphenylphosphonium bromide reacts in acetonitril suspension with excess silver nitrate to give (Ph4P)[Ag(NO3)2(CH3CN)]·CH3CN (1), whereas (Ph4P)[Ag2(NO3)3] (2) is obtained in a long‐time reaction from (Ph4P)Br and excess AgNO3 in dichloromethane suspension. Both complexes were characterized by vibrational spectroscopy (IR, Raman) and by single crystal structure determinations.1: Space group P21/c, Z = 4, lattice dimensions at 193 K: a = 1781.5(3), b = 724.8(1), c = 2224.2(3) pm, β = 96.83(1)°, R1 = 0.0348. 1 contains isolated complex units [Ag(NO3)2(CH3CN)]−, in which the silver atom is coordinated by the chelating nitrate groups and by the nitrogen atom of the solvated CH3CN molecule with a short Ag—N distance of 220.7(4) pm.2: Space group I2, Z = 4, lattice dimensions at 193 K: a = 1753.4(4), b = 701.7(1), c = 2105.5(4) pm, R1 = 0.072. In the polymeric anions [Ag2(NO3)3]− each silver atom is coordinated in a chelating manner by one nitrate group and by two oxygen atoms of two bridging nitrate ions. In addition, each silver atom forms a weak π‐bonding contact with a phenyl group of the (Ph4P)+ ions with shortest Ag···C separations of 266 and 299 pm, respectively, indicating a (4+1) coordination of silver atoms.

Spray-Dried Amorphous Solid Dispersions of Simvastatin, a Low Tg Drug: In Vitro and in Vivo Evaluations

To obtain free flowing, stable, amorphous solid dispersions (SDs) of simvastatin (SIM), a drug with relatively lower glass transition temperature (T(g)) by spray drying technique, and to perform comparative in vivo study in rats, which could justify the improvement in rate and extent of in vitro drug release. Dichloromethane suspensions of SIM either alone or in combination with PVP (1:1 or 1:2 parts by weight) were spray dried with proposed quantity of Aerosil 200 (1:1, 1:1:1, 1:2:2 parts by weight of SIM, Aerosil 200 and PVP, respectively). SDs were characterized initially in comparison with pure drug and corresponding physical mixtures in same ratios by drug content, saturation solubility, SEM, DSC, XRPD, IR, and in vitro drug release. SD 1:2:2 was further subjected to accelerated stability testing and checked for in vitro drug release and presence of crystallinity using DSC and XRPD. In addition, improvement in rate and extent of in vitro drug release from SD 1:2:2 was justified by in vivo study in rats. Combination of SD and surface adsorption techniques has been attempted to overcome the limitations of spray drying technique for amorphization of low T(g) drugs. Based on powder characteristics, drug content, saturation solubility, and feasibility of processing into tablets; SD 1:2:2 was selected as the optimized formulation. During initial characterization, SEM, DSC, and XRPD analyses confirmed the presence of amorphous form in SD 1:2:2. IR spectroscopy revealed possibility of hydrogen bonding interaction between SIM and PVP in SDs. Also, there was dramatical improvement in rate and extent of in vitro drug release of SD 1:2:2. Insignificant decrease in dissolution was observed with no evidence of crystallinity during accelerated stability studies of SD 1:2:2. Moreover in vivo study in rats also justified the improvement in therapeutic efficacy of SD 1:2:2 over pure SIM. Thus, present study demonstrates high potential of spray drying technique for obtaining stable amorphous SDs of low T(g) drugs.

ClBe{MeN(CH2CH2NMe2)2}]+Cl− ‐ ein kationischer Berylliumkomplex

Abstract[ClBe{MeN(CH2CH2NMe2)2}]+Cl− ‐ a Cationic Beryllium ComplexBeryllium(II)chloride reacts with N,N,N′,N″,N″‐pentamethyldiethylentriamine (PMDETA) in dichloromethane suspension to give the cationic complex [ClBe{MeN(CH2CH2NMe2)2}]+Cl− (1), which crystallizes with one equivalent of CH2Cl2. 1 is characterized by IR spectroscopy and by X‐ray single crystal structure analysis. 1·CH2Cl2: Space group P21, Z = 2, lattice dimensions at 193 K: a = 696.2(1), b = 1107.7(2), c = 1113.4(1) pm, β = 98.20(1)°, R1 = 0.0355.

(Et3PNI)2I]Cl — ein Donor‐Akzeptorkomplex von N‐Iod(triethylphosphan)imin an Iodmonochlorid

[Et3PNI)2I]Cl — a Donor‐Acceptor Complex of N‐Iodo(triethylphosphane)imine with Iodine Monochloride[(Et3PNI)2I]Cl (1) has been obtained by the reaction of the silylated phosphorane imine Me3SiNPEt3 with iodine monochloride in dichloromethane suspension in the presence of cesium fluoride. 1 is characterized by IR spectroscopy and by a crystal structure determination. Space group P21/n, Z = 4, lattice dimensions at —50 °C: a = 717.0(2), b = 1244.7(6), c = 1278.0(8) pm, β = 91.30(5)°, R1 = 0.0654. In the ionic structure of 1 the cation [(Et3PNI)2I]+ consists of two N‐iodo(triethylphosphane)imine molecules INPEt3, which are centrosymmetrically connected by I+ via their nitrogen atoms.

Photocatalysed reaction of meso-tetraphenylporphyrin on mesoporous TiMCM-41 molecular sieves

A preliminary study involving 254 nm irradiation of dichloromethane suspension containing TiMCM-41 catalyst and meso-tetraphenylporphyrin (TPP) was carried out at pH 5.0. The rate of the photoreaction was considerably increased in the presence of the catalyst. Increasing the amount of the catalyst at a fixed TPP concentration enhances the rate, indicating its catalytic role in the reaction. The effect of pH, TPP concentration and calcination temperature of the catalyst on the photoreaction was also investigated.