Chloro-form Solvent Mol-ecule Research Articles

Unexpected formation of FeIIFeIIIFeII- and FeIIFeIIFeII-trinuclear hexapyridineoximate helicates: synchrotron single-crystal X-ray structures

Template condensation of 2-acetylpyridineoxime with butyl ester of 1,3-propanediboronic acid in the presence of iron(II) affords a poorly separable mixture of complex products. Similar results were observed when Fe3+ ions were used for cross-linking in place of the diboronic acid. Prolonged crystallization of these mixtures gave crystals of perchlorate salts of a FeIIFeIIIFeII-trinuclear hexapyridineoximate cation and of an analogous FeIIFeIIFeII-intracomplex that crystallize with chloroform and dichloromethane solvent molecules, respectively. Both complexes were characterized by synchrotron single-crystal X-ray diffraction (XRD) experiments. The Fe–N distances of the two ‘terminal’ iron cations are virtually the same between these trinuclear complexes and unambiguously support assignments of oxidation number +2 and low-spin state (S = 0). The centers of the FeN6 -coordination polyhedra adopt geometries resembling trigonal antiprisms with distortion angles φ of approximately 40°. The FeO6 -coordination polyhedra possess an almost ideal Oh geometry with φ close to 60°. Each of these iron(II) or iron(III) µ3 -metallocenters acts as a bifunctional Lewis acid that cross-links two pseudoclathrochelate entities, formed by the ‘terminal’ iron(II) ions, to give an almost linear (the corresponding intramolecular Fe(2)…Fe(1)…Fe(3) angles are close to 180°) helical cation or intracomplex.

Ultrafast dynamics of CN radical reactions with chloroform solvent under vibrational strong coupling.

Polariton chemistry may provide a new means to control molecular reactivity, permitting remote, reversible modification of reaction energetics, kinetics, and product yields. A considerable body of experimental and theoretical work has already demonstrated that strong coupling between a molecular vibrational mode and the confined electromagnetic field of an optical cavity can alter chemical reactivity without external illumination. However, the mechanisms underlying cavity-altered chemistry remain unclear in large part because the experimental systems examined previously are too complex for detailed analysis of their reaction dynamics. Here, we experimentally investigate photolysis-induced reactions of cyanide radicals with strongly-coupled chloroform (CHCl3) solvent molecules and examine the intracavity rates of photofragment recombination, solvent complexation, and hydrogen abstraction. We use a microfluidic optical cavity fitted with dichroic mirrors to facilitate vibrational strong coupling (VSC) of the C-H stretching mode of CHCl3 while simultaneously permitting optical access at visible wavelengths. Ultrafast transient absorption experiments performed with cavities tuned on- and off-resonance reveal that VSC of the CHCl3 C-H stretching transition does not significantly modify any measured rate constants, including those associated with the hydrogen abstraction reaction. This work represents, to the best of our knowledge, the first experimental study of an elementary bimolecular reaction under VSC. We discuss how the conspicuous absence of cavity-altered effects in this system may provide insights into the mechanisms of modified ground state reactivity under VSC and help bridge the divide between experimental results and theoretical predictions in vibrational polariton chemistry.

Elastic Crystalline Fibers Composed of a Nickel(II) Complex

The generation of elastic crystalline fibers from a nonfibrous crystal of metal complex is demonstrated. Applying mechanical stimuli to a platelike crystal of NiII(salophen) [1; H2salophen = N,N'-bis(salicylidene)-o-phenylenediamine] resulted in this complex being transformed into crystal fibers, which could be bent into a loop and demonstrated its high elasticity. Single-crystal X-ray diffraction analyses revealed that the transformation reflects the presence of molecular strands that are composed of a one-dimensional assembly of the slip-stacked arrangement by nearly planar Ni(salophen) molecules. The fiber flexibility was demonstrated to be lost upon the introduction of chloroform solvent molecules into the crystal lattice by recrystallization.

Chloroform desorption from poly(lactic acid) nanocomposites: a thermal desorption spectroscopy study

Abstract Biopolymer nanocomposites were prepared by solvent casting dispersing lauryl-functionalized cellulose nano-fibrils (CNF) in a poly(lactic acid) matrix (PLA). The release of residual chloroform (CHCl3) solvent molecules was studied by Thermal Desorption Spectroscopy (TDS) analysis. TDS spectra of the PLA matrix show a single desorption peak at T P = 393 K with FWHM ~10 K, compatible with a zero-order desorption kinetics. This narrow TDS peak was accurately reproduced assuming that: (i) the rate limiting step is given by the CHCl3 de-trapping from sites in the PLA matrix where residual solvent molecules form small aggregates and (ii) the activation energy for desorption linearly decreases from 1.19 eV for saturated traps to 1.11 eV when the traps occupancy by solvent molecules approaches zero. The balance energy term ϵ D = −0.08 eV is due to the attractive interactions between trapped CHCl3 molecules. Adding CNF particles to the PLA matrix the zero-order peak shifts to lower temperatures and a second peak with FWHM ~60 K appears at higher temperatures. This second peak is compatible with a first-order desorption kinetics and is attributed to the release of dispersed CHCl3 molecules from trapping sites in PLA-CNF interface region. The obtained information are of interest for applications in food and electronic packaging and for the development of medical materials.

Construction of a supramolecule comprising [2,3,9,10,16,17,23,24-octakis(2,6-dimethylphenoxy)phthalocyaninato]zinc(II) and (5,10,15,20-tetraphenylporphyrinato)zinc(II)

The supramolecular features in the title compound, [2,3,9,10,16,17,23,24-octakis(2,6-dimethylphenoxy)phthalocyaninato]zinc(II) bis[(5,10,15,20-tetraphenylporphyrinato)zinc(II)] chloroform tetrasolvate, [Zn(C96H80N8O8)][Zn(C44H28N4)]2·4CHCl3 or [Zn(Pc)][Zn(TPP)]2·4CHCl3, result from a self-assembly of one molecule of [2,3,9,10,16,17,23,24-octakis(2,6-dimethylphenoxy)phthalocyaninato]zinc(II) (ZnPc) and two molecules of (5,10,15,20-tetraphenylporphyrinato)zinc(II) (ZnTPP). One half ZnPc, one ZnTPP and two chloroform molecules define the asymmetric unit, with the zinc(II) cation of ZnPc situated on an inversion centre. In the supramolecule, the central ZnPc moiety is sandwiched between two ZnTPPs moieties in a co-facial conformation with a π-conjugated system, leading to a nearly H-type aggregate with a distance of 3.4967 (5) Å between adjacent zinc sites. The ZnTPP units are slightly glided away to form a partial ecliptic arrangement. Each phenyl group of the TPP ligand is anchored above the N atom of the isoindole linker of the Pc ligand through weak C—H...N hydrogen bonds and is held into the crevice between the two dimethylphenoxy groups of phthalocyanine via van der Waals interactions. In the crystal, chloroform solvent molecules are situated between the supramolecules. There is another solvent-accessible void of 341 (2) Å3. The contribution of disordered solvent molecules situated in this void was removed from the diffraction data using SQUEEZE in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not consider this unknown solvent molecule(s).

Crystal structure of (methanol-κO)[5,10,15,20-tetra-kis-(2-amino-phen-yl)porphyrinato-κ4N]zinc(II)-chloro-form-methanol (1/1/1).

In the crystal structure of the title compound, [Zn(C44H32N8)(CH3OH)]·CHCl3·CH3OH, the ZnII cation is coordinated by four porphyrin N and one methanol O atom within a slightly distorted square-pyramidal environment and is shifted out of the porphyrin plane towards the direction of the methanol mol-ecule. The methyl group of the coordinating methanol mol-ecule is disordered over two sets of sites. The porphyrin backbone is nearly planar and the phenyl rings are almost perpendicular to the porphyrin plane. As is typical for picket-fence porphyrins, all four ortho substituents of the meso-phenyl groups (here the amino groups) are facing to the same side of the porphyrin mol-ecule. In the crystal structure, two neighbouring porphyrin complexes form centrosymmetric dimers that are connected via O-H⋯N hydrogen bonding. With the aid of additional N-H⋯N and C-H⋯N hydrogen bonding, these dimers are stacked into columns parallel to [010] that are finally arranged into layers parallel to (001). Between these layers channels are formed where chloro-form solvent mol-ecules are located that are connected to the porphyrin complexes by weak C-H⋯Cl hydrogen bonding. There are additional cavities in the structure where some small residual electron density is found, indicating the presence of disordered methanol mol-ecules, but a reasonable model could not be refined. Therefore the contribution of the electron density associated with the methanol solvent mol-ecule was removed with the SQUEEZE procedure [Spek (2015 ▸). Acta Cryst. C71, 9-18] in PLATON. Nevertheless, the given chemical formula and other crystal data take into account the methanol solvent mol-ecule.

Bis(triphenylphosphine)iminium tetrafluoroborate chloroform monosolvate

In the title compound, C36H30NP2 +·BF4 −·CHCl3 or [PPN]BF4·CHCl3, where [PPN] = [(Ph3P)2N]+, two triphenylphosphine units are attached to a central N atom. The P—N—P bond angle is 137.69 (11)°. The two P—N bonds are nearly equivalent, with lengths of 1.5834 (18) and 1.5798 (17) Å. Both the BF4 − anion and the chloroform solvent molecule are disordered over two positions, with occupancy ratios of 0.872 (3):0.128 (3) and 0.9628 (9):0.0372 (9), respectively. In the crystal, C—H...F and C—H...Cl hydrogen bonds link the [PPN]+ cations, the BF4 − anions, and the chloroform solvent molecules into an array which extends along the b-axis direction.

Solvent Effects on Optical Rotation: On the Balance between Hydrogen Bonding and Shifts in Dihedral Angles.

Optical rotations of several conformers of four fluorinated molecules containing the 1-naphthalene or 4-(benzyloxy)phenyl group at the stereocenter have been calculated both in the gas phase and in an aqueous environment. For the compounds containing the 4-(benzyloxy)phenyl group, solvent effects on the optical rotations have also been investigated in chloroform as solvent. Optical rotations have been obtained by time-dependent density functional theory (TDDFT) with the CAM-B3LYP functional and the aug-cc-pVDZ basis set at λ = 589 nm. Implicit and explicit solvent effects were investigated through the polarizable continuum model (PCM) and a microsolvation approach in conjunction with PCM, respectively. In the latter model, solvent molecules are considered as an explicit solvent and their positions are obtained by geometry optimizations for different conformers of the chiral molecule. For molecules containing the 1-naphthalene group, this model gives the same optical rotation signs for all conformers as compared to both gas phase and PCM results and reduces absolute deviations between calculations and experiment. Also, the microsolvation model reproduces the sign of the experimental optical rotations for the molecules containing the 4-(benzyloxy)phenyl group using both water and chloroform as solvent. In a microsolvation model, however, the water and chloroform solvent molecules have similar hydrogen bonds but different effects on the conformation and thereby on the optical rotation since one dihedral angle, having a large effect on the optical rotation, is strongly sensitive to hydrogen bonding to water but not to chloroform. Our investigations demonstrate that a microsolvation approach in conjunction with PCM predicts optical rotations in reasonable agreements with experiments for both sign and magnitude.

Crystal structure of ({(1R,2R)-N,N'-bis-[(quino-lin-2-yl)methyl]cyclo-hexane-1,2-di-amine}-chlorido-iron(III))-μ-oxido-[tri-chlorido-ferrate(III)] chloro-form monosolvate.

The first FeIII atom in the solvated title compound, [Fe2Cl4O(C26H28N4)]·CHCl3, adopts a distorted six-coordinate octa-hedral geometry. It is coordinated by one chloride ligand, four N atoms from the (1R,2R)-N,N'-bis-[(quinolin-2-yl)methyl]cyclo-hexane-1,2-di-amine ligand, and a bridging oxido ligand attached to the second FeIII atom, which is also bonded to three chloride ions. A very weak intra-molecular N-H⋯Cl hydrogen bond occurs. In the crystal, the coordination complexes stack in columns, and a grouping of six such columns create channels, which are populated by disordered chloro-form solvent mol-ecules. Although the Fe-Cl bond lengths for the two metal atoms are comparable to the mean Fe-Cl bond lengths as derived from the Cambridge Structural Database, the Fe-O bond lengths are notably shorter. The solvent chloro-form mol-ecule exhibits 'flip' disorder of the C-H moiety in a 0.544 (3):0.456 (3) ratio. The only directional inter-action noted is a weak C-H⋯Cl hydrogen bond.

3-(2-Chloropyridin-3-yl)quinazoline-2,4(1H,3H)-dione chloroform monosolvate

The solvated title compound, C13H8ClN3O2·CHCl3, is a product of a condensation reaction between 2-amino-N-(2-chloropyridin-3-yl)benzamide and phosgene. The presence of the chlorine substituent in the pyridine ring forces the latter to adopt a nearly perpendicular orientation relative to the planar quinazoline ring (r.m.s. deviation = 0.04 Å), the two ring systems being inclined to one another by 84.28 (9)°. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers with anR22(8) ring motif. The dimers are linked by C—H...O hydrogen bonds, forming ribbons propagating along thea-axis direction. The chloroform solvent molecules are linked to the organic molecule by C—H...N hydrogen bonds.

Aquabis(2,2′-bipyridine-κ2N,N′)chloridonickel(II) chloride chloroform monosolvate hemihydrate

The title solvated salt, [NiCl(C10H8N2)2(H2O)]Cl·CHCl3·0.5H2O, contains a mononuclear NiIIcomplex cation with 2,2′-bipyridine, chloride and aqua ligands forming a slightly distorted ClN4O octahedral coordination set. The charge of the cation is balanced by a chloride anion. In the crystal, half a water molecule and a chloroform solvent molecule are present per formula unit. Individual components are held together by O—H...Cl hydrogen bonding and π–π interactions.

Crystal structure of an HgII coordination polymer with an unsymmetrical dipyridyl ligand: catena-poly[[[di-chlorido-mercury(II)]-μ-N-(pyridin-4-ylmeth-yl)pyridin-3-amine-κ2N:N'] chloro-form hemisolvate

The asymmetric unit of the title compound, {[HgLCl2]·0.5CHCl3} n (L = N-(pyridin-4-ylmeth-yl)pyridin-3-amine, C11H11N3), contains one HgII ion, one bridging L ligand, two chloride ligands and a chloro-form solvent mol-ecule with half-occupancy that is disordered about a crystallographic twofold rotation axis. Each HgII ion is coordinated by two pyridine N atoms from two symmetry-related L ligands and two chloride anions in a highly distorted tetra-hedral geometry with bond angles falling in the range 99.05 (17)-142.96 (7)°. Each L ligand bridges two HgII ions, forming polymeric zigzag chains propagating in [010]. In the crystal, the chains are linked by inter-molecular N/C-H⋯Cl hydrogen bonds together with weak C-H⋯π inter-actions, resulting in the formation of a three-dimensional supra-molecular network, which is further stabilized by C-Cl⋯π inter-actions between the solvent chloro-form mol-ecules and the pyridine rings of L [chloride-to-centroid distances = 3.442 (11) and 3.626 (13) Å]. In addition, weak Cl⋯Cl contacts [3.320 (5) Å] between the chloro-form solvent mol-ecules and the coordinating chloride anions are also observed.

Structure and Phase Transition of 4,7-Bis-(4′-cyano-biphenyl-4-yl)-[1, 10]phenanthroline

4,7-Bis-(4′-cyano-biphenyl-4-yl)-[1, 10]phenanthroline (cnbiphphen) is synthesized from a palladium mediated coupling between 4-cyanobenzene boronic acid and 4,7-bis(4-bromophenyl)-[1,10]phenanthroline. The single crystal X-ray structure was measured at both 298(2) K and 90(2) K. The asymmetric unit of the title compound in the low-temperature phase, C38H22N 4 . HCCl3, is comprised of one cnbiphphen molecule and one chloroform solvent molecule. Additional symmetry relates one-half of the title compound to the other at room temperature. During cooling the structure experiences a reversible phase transition from A 2/a (different setting of C 2/c, with a and c exchanged to match lattice parameters of both phases) to P 21/c. The crystal packing of the title compound consists primarily of electronic charge interactions between the cyano moieties. The chloroform solvent mol-ecule is situated in a cavity between two phenanthroline systems and is associated to two nitrogen atoms of cnbiphphen molecules through Cl3C–H⋯Nphen van der Waals interaction. The synthesis, structure, analytical characterization, optical properties and phase transition of 4,7-bis-(4’-cyano-biphenyl-4-yl)-[1,10]phenanthroline is presented.

Crystal structure of Boc-(S)-ABOC-(S)-Ala-(S)-ABOC-(S)-Phe-OBn chloro-form monosolvate.

In the title compound, phenyl (S)-2-[(S)-(1-{2-[(S)-(1-{[(tert-but-oxy)carbon-yl]amino}-bicyclo-[2.2.2]octan-2-yl)formamido]-propanamido}-bicyclo-[2.2.2]octan-2-yl)formamido]-3-phenyl-propano-ate chloro-form monosolvate, C42H56N4O7·CHCl3, the α,β-hybrid peptide contains two non-proteinogenic amino acid residues of (S)-1-amino-bicyclo-[2.2.2]octane-2-carb-oxy-lic acid [(S)-ABOC], two amino acid residues of (S)-2-amino-propanoic acid [(S)-Ala] and (S)-2-amino-3-phenyl-propanoic acid [(S)-Phe], and protecting groups of tert-but-oxy-carbonyl (Boc) and benzyl ester (OBn). The tetra-mer folds into a right-handed mixed 11/9 helix stabilized by intra-molecular i,i+3 and i,i-1 C=O⋯H-N hydrogen bonds. In the crystal, the oligomers are linked by N-H⋯O=C hydrogen bonds into chains along the a-axis direction. The chloro-form solvent mol-ecules are inter-calated between the folded chains via C-H⋯O=C inter-actions.

Crystal structure of bis-(3,3-dimethyl-2-oxobut-yl)di-phenyl-phospho-nium bromide chloro-form monosolvate.

In the title salt solvate, C24H32O2P+·Br−·CHCl3, the P atom has a distorted tetra­hedral geometry, and the planes of the phenyl rings form a dihedral angle of 71.86 (14)° with one another. The bromide anion is disordered and was modelled over three positions (occupancy ratio 0.50:0.35:0.15). The crystal also contains one disordered chloro­form solvent mol­ecule that was modeled over three positions (occupancy ratio 0.50:0.35:0.15). Weak inter­molecular inter­actions (C—H⋯Br and C—H⋯O) exist between the complex cation and the bromide anion fragments. The resulting supramolecular structure is an oval-shaped arrangement of phosphonium salt molecules that surround the disordered bromide anion.

(η(6)-Benzene)(carbonato-κ(2) O,O')[di-cyclohex-yl(naphthalen-1-ylmeth-yl)phosphane-κP]ruthenium(II) chloro-form tris-olvate.

The title compound, [Ru(CO3)(η6-C6H6){(C6H11)2P(CH2C10H7)}]·3CHCl3, was synthesized by carbonation of [RuCl2(η6-C6H6){(C6H11)2P(CH2C10H7)}] with NaHCO3 in methanol at room temperature. The RuII atom is surrounded by a benzene ligand, a chelating carbonate group and a phosphane ligand in a piano-stool configuration. The crystal packing is consolidated by C—H⋯O and C—H⋯Cl hydrogen-bonding inter­actions between adjacent metal complexes and between the complexes and the solvent mol­ecules. The asymmetric unit contains one metal complex and three chloro­form solvent mol­ecules of which only one was modelled. The estimated diffraction contributions of the other two strongly disordered chloro­form solvent mol­ecules were substracted from the observed diffraction data using the SQUEEZE procedure in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155].

(η(6)-Benzene)-dichlorido-(chloro-dicyclo-hexyl-phosphane-κP)ruthenium(II) chloro-form monosolvate.

The title compound, [RuCl2(η6-C6H6)(C12H22ClP)]·CHCl3, was prepared by reaction of [RuCl2(η6-C6H6)]2 with chloro­dicyclo­hexyl­phosphane in CHCl3 at 323 K under argon. The RuII atom is surrounded by one arene ligand, two Cl atoms and a phosphane ligand in a piano-stool geometry. The phosphane ligand is linked by the P atom, with an Ru—P bond length of 2.3247 (4) Å. Both cyclo­hexyl rings at the P atom adopt a chair conformation. In the crystal, the RuII complex mol­ecule and the chloro­form solvent mol­ecule are linked by a bifurcated C—H⋯(Cl,Cl) hydrogen bond. Intra­molecular C—H⋯Cl hydrogen bonds are also observed.

MIL-53 frameworks in mixed-matrix membranes

The MIL-53 metal–organic framework (MOF) is known to change reversibly from an open-pore framework (MIL-53-ht) to a closed-pore framework (MIL-53-lt) depending on the temperature, pressure, or guest molecules absorbed. Three frameworks of the additive, MIL-53-as synthesized (MIL-53-as), MIL-53-ht, and MIL-53-lt, were prepared, characterized, and combined with Matrimid® to form mixed-matrix membranes (MMMs) for gas separations. The MIL-53-ht/Matrimid® MMMs exhibited higher values of permeability compared to Matrimid® as well as an increased CO2/CH4 selectivity suggesting that the open-pore MIL-53 framework was maintained in the polymer matrix. In addition to higher permeability values, MIL-53-as/Matrimid® MMMs showed higher selectivity for gas pairs with kinetic diameters differing by ⩾0.5Å, including H2/O2, CO2/CH4, H2/CH4, and H2/N2, suggesting the presence of excess benzene dicarboxylic acid molecules within the pores that reduced its diameter enabling the material to discriminate between smaller and larger gases. MIL-53-lt did not retain its closed-pore form in the MMM. Rather, it irreversibly converted to the open-pore form (MIL-53-ht) due to the exchange of water present in the MIL-53 pores with chloroform solvent molecules during membrane casting and to pore penetration and confinement by Matrimid® polymer chains. This finding, that a polymer matrix stabilizes a MOF pore architecture within an MMM, is significant in that the desired selectivity of a MOF-MMM system may be achievable.

Methyl 3'-(2,5-di-methyl-benz-yl)-1'-methyl-2-oxo-4'-phenyl-spiro-[indoline-3,2'-pyrrolidine]-3'-carboxyl-ate chloro-form monosolvate.

In the title solvate, C29H30N2O3·CHCl3, the dihedral angle between the indole ring system (r.m.s. deviation = 0.050 Å) and the 4-methyl­pyrrolidine ring is 88.88 (8)°. The latter ring adopts an envelope conformation with the N atom as the flap. Its mean plane makes dihedral angles of 86.94 (11) and 42.08 (9)° with the phenyl and di­methyl­benzene rings, respectively. The mol­ecular conformation is stabilized by intra­molecular C—H⋯O hydrogen bonds, which generate S(6) and S(9) ring motifs. The chloro­form solvent mol­ecule is linked to the organic mol­ecule by a C—H⋯O hydrogen bond involving the carbonyl O atom of the carboxyl­ate group. In the crystal, mol­ecules are linked via bifurcated N—H⋯(N,O) and C—H⋯O hydrogen bonds, forming chains propagating along [001].

(5-Methyl-pyrazine-2-carboxyl-ato-κ(2) N (1),O)bis-[2-(4-methyl-pyridin-2-yl-κN)-3,5-bis-(tri-fluoro-meth-yl)phenyl-κC (1)]iridium(III) chloro-form hemisolvate.

In the title complex, [Ir(C14H8F6N)2(C6H5N2O2)]·0.5CHCl3, the IrIII atom adopts a distorted octa­hedral geometry, being coordinated by three N atoms (arranged meridionally), two C atoms and one O atom of three bidentate ligands. The complex mol­ecules pack with no specific inter­molecular inter­actions between them. The SQUEEZE procedure in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155] was used to model a disordered chloro­form solvent mol­ecule; the calculated unit-cell data allow for the presence of half of this mol­ecule in the asymmetric unit.