Wet Solvents Research Articles

Separating Convective from Diffusive Mass Transport Mechanisms in Ionic Liquids by Redox Pro-fluorescence Microscopy.

The study of electrochemical reactivity requires analytical techniques capable of probing the diffusion of reactants and products to and from electrified interfaces. Information on diffusion coefficients is often obtained indirectly by modeling current transients and cyclic voltammetry data, but such measurements lack spatial resolution and are accurate only if mass transport by convection is negligible. Detecting and accounting for adventitious convection in viscous and wet solvents, such as ionic liquids, is technically challenging. We have developed a direct, spatiotemporally resolved optical tracking of diffusion fronts which can detect and resolve convective disturbances to linear diffusion. By tracking the movement of an electrode-generated fluorophore, we demonstrate that parasitic gas evolving reactions lead to 10-fold overestimates of macroscopic diffusion coefficients. A hypothesis is put forward linking large barriers to inner-sphere redox reactions, such as hydrogen gas evolution, to the formation of cation-rich overscreening and crowding double layer structures in imidazolium-based ionic liquids.

Comparative (magneto)optical, redox, and photophysical properties of phosphorous octacarbazole- and tetra-tert-butyltetrabenzotriazacorroles

The spectroscopy and electronic structure of the novel phosphorous(V) octacarbazole tetrabenzotriazacorrole (TBC(Cz)8P=O) compound were evaluated using a large array of experimental and theoretical methods, and compared to the reference terta-tert-butyl tetrabenzotriaazacorrole (TBC(tBu)4P=O). The first coordination sphere in TBC(Cz)8P(XY) and TBC(tBu)4P(XY) in a solid state and solution was probed by MALDI-TOF mass spectrometry, 31P NMR spectroscopy, XPS, UV–Vis, MCD, and elemental analysis. Based on the 31P NMR, mass spectrometry, UV–Vis, and MCD data, it was demonstrated that the initial pentacoordinated TBC(tBu)4P=O complex can be easily transformed to the hexa-coordinated species in the presence of water and methanol following TBC(tBu)4P=O ⇌ TBC(tBu)4P(OH)2 ⇌ TBC(tBu)4P(OH)(OMe) ⇌ TBC(tBu)4P(OMe)2 equilibrium. In wet solvents, the UV–Vis and MCD spectroscopies revealed that the two structures possess similar absorbance profiles; however, the TBC(Cz)8P(OH)2 compound had a more intense and red-shifted Q-band than the TBC(tBu)4P(OH)2 compound. The first oxidation under spectroelectrochemical conditions was found to be completely reversible for the TBC(Cz)8P(OH)2 compound; conversely, these experiments were completely irreversible for the TBC(tBu)4P(OH)2 compound. DFT and TDDFT calculations were performed using three different exchange-correlation functionals. The DFT results revealed several (16 in total) carbazole-centered MOs at energies in between the classical Gouterman's a1u and a2u frontier orbitals while the four Gouterman's frontier orbitals were found to be energetically sequential for the TBC(tBu)4P(OH)2 compound. The TDDFT calculations provided a very reasonable agreement between theory and experiment and demonstrated the presence of the inter-ligand (carbazole-to-TBC) charge-transfer transitions in TBC(Cz)8P(OH)2 in ∼500 nm region. Steady-state fluorescence spectroscopy data are indicative of the mid-range fluorescence quantum yields in both compounds. Transient absorption spectroscopy was utilized to probe triplet state formation and lifetimes (τT) which were found to be 112 μs for TBC(Cz)8P(OH)2 and 91 μs for TBC(tBu)4P(OH)2.

Metal carbonyl mediated rearrangement of 5-(2-oxoalkyl)-1,2,4-oxadiazoles: synthesis of fully substituted pyrimidines.

Variously substituted ethyl 6-oxo-1,6-dihydropyrimidine-5-carboxylates can be easily prepared by a metal carbonyl mediated rearrangement of ethyl 3-oxo-2-(1,2,4-oxadiazol-5-yl)propanoates. The irradiation of a mixture of oxadiazoles and Fe(CO)5 in wet solvents with a 365 nm LED at room temperature for 2 h followed by heating at 80 °C for 2 h gives pyrimidines in up to 90% yield. This procedure enables the preparation of 6-oxo-1,6-dihydropyrimidine-5-carboxylates with various aryl substituents at the C2 and alkyl or aryl substituents at the C4 position. 1-(1,2,4-Oxadiazol-5-yl)propan-2-ones analogously give 6-methylpyrimidin-4(3H)-ones, albeit in lower yields. Ethyl 6-oxo-1,6-dihydropyrimidine-5-carboxylates can be easily modified at the C6 position by bromination followed by cross-coupling reactions to give pyrimidine-5-carboxylates with pyridyl, amino and ethynyl substituents.

Ortho-Phosphinoarenesulfonamide-Mediated Staudinger Reduction of Aryl and Alkyl Azides.

Conventional Staudinger reductions of organic azides are sluggish with aryl or bulky aliphatic azides. In addition, Staudinger reduction usually requires a large excess of water to promote the decomposition of the aza-ylide intermediate into phosphine oxide and amine products. To overcome the challenges above, we designed a novel triaryl phosphine reagent 2c with an ortho-SO2NH2 substituent. Herein, we report that such phosphine reagents are able to mediate the Staudinger reduction of both aryl and alkyl azides in either anhydrous or wet solvents. Good to excellent yields were obtained in all cases (even at a diluted concentration of 0.01 M). The formation of B-TAP, a cyclic aza-ylide, instead of phosphine oxide, eliminates the requirement of water in the Staudinger reduction. In addition, computational studies disclose that the intramolecular protonation of the aza-ylide by the ortho-SO2NH2 group is kinetically favorable and responsible for the acceleration of Staudinger reduction of the aryl azides.

Solution‐Processed Chemically Non‐Destructive Filter Transfer of Carbon‐Nanotube Thin Films onto Arbitrary Materials

AbstractFilter‐transfer methods of single‐walled carbon‐nanotube (SWNT) thin films have been widely employed to fabricate state‐of‐the‐art electronics and photonics devices with highly transparent and conductive electrodes; however, a challenge remains for all solution‐processable technologies to overcome substrates’ destruction due to their solvent incompatibility. Here, an advanced method of transferring SWNT thin films onto arbitrary material substrates by adopting chemically stable and flexible polytetrafluoroethylene (PTFE) membranes is reported. Filtrated SWNT thin films on PTFE membranes (PTFE@SWNTs) press‐freely adhere to not only flat but curved substrates by their solvent‐wettability and flexibility natures, and are spontaneously transferred after low‐temperature evaporation of the wet solvents and peeling of the PTFE membrane. SWNT thin films transferred onto polyethylene terephthalate films show sheet resistance values of ≈400 Ω □−1 at ≈90% transmittance, which are drastically decreased to ≈50 Ω □−1 at ≈65% from ≈100 Ω □−1 at ≈80%. The wet solvents are suitably displaced based on solvent‐compatibility experiments with the substrates. Topically, it is demonstrated that the solvent‐wetted PTFE@SWNT can be non‐destructively placed onto a perovskite (CH3NH3PbI3) substrate via the as‐displaced various organic solvents. A pre‐doping process of PTFE@SWNTs is possible by using a HNO3 aqueous solution. The HNO3‐doped SWNT thin film is successfully transferred onto the perovskite substrate.

Naked eye detection of moisture in organic solvents and development of alginate polymer beads and test cassettes as a portable kit

New dabsyl-thiophene based receptor DABT and its mercury complex DABT-Hg is reported as a colorimetric sensor for rapid and sensitive detection of trace amount of water in aprotic solvents. Based on intramolecular charge transfer in the excited state, the receptor dabsyl-thiophene (yellow color) binds with the mercury ions (magenta color) to stimulate a colorimetric response. The mercury complex is used as a moisture sensor in THF, acetone, and acetonitrile due to its instability in moisture containing organic solvents. The probe exhibits higher sensitivity towards water in THF (LOD = 0.0041% w/w), acetone (LOD = 0.0144% w/w) and acetonitrile (LOD = 0.1008% w/w). The dissociation of mercury from probe DABT-Hg in the presence of water is accountable for the colorimetric response as proven by the 1H NMR and ESI-MS studies. DABT-Hg is the first mercury based complex for the detection of moisture in organic solvents. Test paper strip and PVA thin film doped with the probe were successfully used to detect moisture content in organic solvents. DABT-Hg incorporated alginate beads are prepared to determine the water content in triethylamine and ethylene glycol. Portable test cassettes are developed for the on-site detection of distilled and undistilled wet solvents in the chemical laboratory through naked-eye detection.

Robust Alkyne Metathesis Catalyzed by Air Stable d2 Re(V) Alkylidyne Complexes.

We report in this communication the first example of catalytic alkyne metathesis reactions mediated by well-defined non-d0 alkylidyne complexes. The air-stable d2 Re(V) alkylidyne complex Re4, bearing two PO-chelating ligands and a labile pyridine ligand, could catalyze homometathesis of internal alkynes with a broad substrate scope, including alcohols, amines, and even carboxylic acids. The catalyst can tolerate heating, air, and moisture in both solid and solution states, and the catalytic metathesis reactions could proceed normally in wet solvents.

Gas-solvent and water-solvent partition of trans-stilbene at 298 K

We start with literature data on gas to solvent partition of trans-stilbene, as log K, for 52 solvents. The log K values can be converted into corresponding water to solvent partitions, as log P, through the stilbene gas to water partition coefficient, and lead, with four additional equations, to a set of 108 simultaneous equations that can be solved to yield descriptors for stilbene with a standard deviation of no more than 0.096 log units. This represents statistically the best analysis of stilbene solubility to date. The stilbene descriptors can be combined with equation coefficients to give predictions of stilbene gas to solvent partition and water to solvent partition for numerous dry solvents, wet (water saturated) solvents and ionic liquid solvents, as well as predictions of environmental and biological processes involving styrene.

An Atom‐Economic Approach for Vinylation of Indoles and Phenols Using Calcium Carbide as Acetylene Surrogate

An efficient N‐vinylation of indoles and O‐vinylation of phenols to give N‐vinyl indoles and phenyl vinyl ethers is reported. The vinylated products can be produced in satisfactory to excellent yields (65–92 %) upon treatment of indoles or phenols with calcium carbide in wet solvents in a standard laboratory setup. Key features of this reaction include the use of calcium carbide as a safe and inexpensive slow released acetylene source for N‐ and O‐vinylation under simple reaction conditions without the need for metal catalyst or halogenated substrates.

B(C6F5)3-Catalyzed Reductive Amination using Hydrosilanes

In contrast to the established dogma that B(C6F5)3 is irreversibly poisoned by excess H2O/amine (or imine) bases, B(C6F5)3 is actually a water-tolerant catalyst for the reductive amination of primary and secondary arylamines with aldehydes and ketones in “wet solvents” at raised temperatures and using only 1.2 equiv of Me2PhSiH as reductant. Arylamines/N-arylimines do not result in the irreversible deprotonation of H2O–B(C6F5)3, allowing sufficient B(C6F5)3 to be evolved at raised temperatures to effect catalytic reductions. Stronger Bronsted basic amines such as tBuNH2 (and derived imines) result in irreversible formation of [HO–B(C6F5)3]− from H2O–B(C6F5)3, precluding the formation of B(C6F5)3 at raised temperatures and thus preventing any imine reduction. A substrate scope exploration using 1 mol % nonpurified B(C6F5)3 and “wet solvents” demonstrates that this is an operationally simple and effective methodology for the production of secondary and tertiary arylamines in high yield, with imine reduction...

Structure and stoichiometry of resorcinarene solvates as host–guest complexes – NMR, X-ray and thermoanalytical studies

Controlled release of a guest from inclusion host–guest complexes is an important aspect of design and synthesis of advanced materials for sensing, purification, chromatography, and storage of wide variety of molecules. In this work, host–guest complexes of C-methylcalix[4]resorcinarene (RES1) and C-undecylcalix[4]resorcinarene (RES2) with four solvents were examined by NMR, X-ray and thermoanalytical techniques in order to compare their stoichiometries, solvent effects, the role of water during solubilization/complexation process. The phenomena of poor solubility of some resorcinarenes in dry solvents versus their good solubility in wet solvents is explained on example of resorcinarene/dioxane/water complex. An asymmetric unit contains RES1 macrocycle in C2v symmetry which adopts a boat-like conformation and RES1 is a rccc isomer with four axial methyl groups. Water is a molecular linker that organizes the whole network in RES1·2dioxane·3H2O solvate.

Editorial (Thematic Issue: An Overview on the Recent Achievements in Nonmetal Asymmetric Catalysis)

It is our great pleasure as Guest Editors of the journal ‘Mini-Reviews in Organic Chemistry’ to present you with a ‘mini-hot topic issue’ on nonmetal asymmetric catalysis. Asymmetric catalysis entails the catalytic, selective, and reproducible generation of a given enantiomer of a chiral product from achiral reactants. Leading the quest of asymmetric catalysis is the need of the pharmaceutical, flavors and fragrances, and agrochemical industries for enantiopure molecules because the different enantiomers or diastereomers of a molecule often have different biological activity. Nearly 85% of new drugs in the market are chiral. Organocatalysis can be used as environmentally-friendly alternatives to transition-metal catalysts as no toxic metals are required. The principle interactions of organocatalyst are non-covalent, such as hydrophobic, hydrogen bonding, van der Waals and electrostatic as in enzymes. These catalysts are often inexpensive to prepare and reaction can be performed under aerobic environments and in wet solvents. The beneficial impact of organocatalytic reactions on a large scale production of chiral intermediates has been demonstrated. Therefore, this special issue aims to review the advances in nonmetal asymmetric catalysis during the last decade, specified in organocatalysis. The first review related to the above mentioned topic is written by Drs. Leow, Shen and their colleagues, who explore organocatalytic enantioselective protonation of enol derivatives. As they mentioned, the proton is the smallest functional group in organic synthesis and it is extremely challenging to control it in terms of enantioselectivity. Traditional methods are using pre-formed enolates obtained from the direct deprotonation of carbonyl compounds by strong bases. The newer strategies involve the usage of silyl enol ethers, tautomerization of enols or in situ generation of transient enolates. They can be generated through either additions to ketenes, conjugate additions to Michael acceptors, rearrangements, or isomerization of double/triple bonds. In the following article, as an alternative of the most popular asymmetric sulfur-Michael addition, Dr. Zhiyong Jiang and his colleagues summarized the advance on asymmetric α-sulfenylation. Two asymmetric protocols were discussed respectively, including transition-metal catalysis and organocatalysis. It was noted that the unprecedented substrate scopes still exist which represents developing rooms, although asymmetric α-sulfenylation has obtained remarkable progress in recent years; and novel and easily prepared sulfenylated reagents are still highly desirable. In the last article in this issue, Dr. Hansen and his colleagues gave an overview over the major advances in asymmetric enamine catalysis since, and including, 2008 with focus on strategic transformations and catalyst development. As they noted, enamine-catalysis has become a powerful enabling technology for enantioselective chemical synthesis, which could be attributed to a rapid evolution of novel catalyst architectures and strategies, combined with the design and discovery of strategically important, asymmetric transformations. This exciting field will continue to expand, fuelled by its unique ability to generate novel and stereodefined structural complexity in the synthesis of organic molecules. We would like to sincerely thank all the reviewers for their valuable contributions that ensured the quality of articles to be published in this special issue. It was a great opportunity for us to cooperate with researchers from all over the world including United States, Norway, Taiwan and Mainland China. We hope that readers will enjoy this issue, obtain useful information, and be inspired with new ideas for future research on nonmetal asymmetric catalysis.

Conversion of a monodentate amidinate-germylene ligand into chelating imine-germanate ligands (on mononuclear manganese complexes).

The unprecedented transformation of a terminal two-electron-donor amidinate-germylene ligand into a chelating three-electron-donor κ(2)-N,Ge-imine-germanate ligand has been achieved by treating the manganese amidinate-germylene complex [MnBr{Ge((i)Pr2bzam)(t)Bu}(CO)4] (1; (i)Pr2bzam = N,N'-bis(isopropyl)benzamidinate) with LiMe or Ag[BF4]. In these reactions, which afford [Mn{κ(2)Ge,N-GeMe((i)Pr2bzam)(t)Bu}(CO)4] (2) and [Mn{κ(2)Ge,N-GeF((i)Pr2bzam)(t)Bu}(CO)4] (3), respectively, the anionic nucleophile, Me(-) or F(-), ends on the Ge atom while an arm of the amidinate fragment migrates from the Ge atom to the Mn atom. In contrast, the reaction of 1 with AgOTf (OTf = triflate) leads to [Mn(OTf){Ge((i)Pr2bzam)(t)Bu}(CO)4] (4), which maintains intact the amidinate-germylene ligand. Complex 4 is very moisture-sensitive, leading to [Mn2{μ-κ(4)Ge2,O2-Ge2(t)Bu2(OH)2O}(CO)8] (5) and [(i)Pr2bzamH2]OTf (6) in wet solvents. In 5, a novel digermanate(II) ligand, [(t)Bu(OH)GeOGe(OH)(t)Bu](2-), doubly bridges two Mn(CO)4 units. The structures of 1-6 have been characterized by spectroscopic (IR, NMR) and single-crystal X-ray diffraction methods.

Triple associates based on (oxime)Pt(II) species, 18-crown-6, and water: Synthesis, structural characterization, and DFT study

The associates 2(cis-[PtCl2(acetoxime)2])⋅18-crown-6⋅2H2O (1), 2(cis-[PtBr2(acetoxime)2])⋅18-crown-6⋅2H2O (2), and trans-[PtCl2(acetaldoxime)2]⋅(18-crown-6)⋅2H2O (3) were synthesized by co-crystallization of free corresponding platinum species and 18-crown-6 from wet solvents and characterized by 1H NMR and IR spectroscopies, high-resolution mass-spectrometry (ESI), TG/DTA, and X-ray crystallography. The (oxime)Pt(II) species are assembled with 18-crown-6 and water by hydrogen bonding between the hydroxylic hydrogen atoms of the oxime ligands and the oxygen atom of water and between the hydrogen atoms of water and the oxygen atoms of 18-crown-6. In 2(cis-[PtX2(acetoxime)2])⋅18-crown-6⋅2H2O (where X=Cl (1), Br (2)), the molecule of the crown ether is located between the two cis-[PtX2(acetoxime)2] species. The associate trans-[PtCl2(acetaldoxime)2]⋅(18-crown-6)⋅2H2O (3) crystallizes into a 1D array structure. Water molecules play the role of linkers between the (oxime)Pt(II) species and the crown ether molecules. The electronic structures and vibrational frequencies of the triple associates were studied by density functional theory (DFT/B3LYP).

A theoretical study of the nornicotine-catalyzed Mannich reaction in wet solvents and water

Quantum calculations lead the way to a green version of the versatile Mannich reaction in water catalysed by nornicotine.

Allylation of aldehydes with potassium allyltrifluoroborate catalyzed by lanthanide-based metal-organic framework

The use of the framework [Eu2(fum)3(H2O)4]·(3H2O), Eu-MOF, as catalyst for allylation of aldehydes by potassium allyltrifluoroborate is described. The method features the use of small catalyst loads and wet solvents, and the products were obtained in high yields, short reaction times, at room temperature with no further purification. The catalyst was recovered and reused up to six times in further allylation reactions without significant loss in the yields.

Rhenium tricarbonyl chloro of di-2-pyridylketone 4-aminobenzoyl hydrazone (dpk4abh), fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl]: Synthesis, spectroscopic and electrochemical properties

The reaction between di-2-pyridyl ketone 4-aminobenzoylhydrazone hydrate (dpk4abh.H 2O) and [Re(CO) 5Cl] in refluxing toluene gave fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl]. Hydrolysis of fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl] to form fac-[Re(CO) 3(κ 3-N,O,N-dpkO,OH)] occurs in wet solvents. The identity of fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl] was established from the results of its elemental analysis, spectroscopic measurements, and electrochemical properties. The infrared spectra of fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl] show the facial coordination of the carbonyl (C O) groups, the coordination of dpkabh and none coordination of the carbonyl (C O) group. 1H-NMR measurements on fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl] in d 6-dmso and d 7-dmf confirmed the coordination of dpkabh, and demonstrate sensitivity of fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl] to its surroundings as manifested by the chemical shift variations observed in different solvents. Variable temperature 1H-NMR studies showed stronger interaction between d 7-dmf and fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl] compared to d 6-dmso and the amine protons of coordinated dpk4abh undergo faster exchanges with solvated water protons compared to the amide proton. The electronic absorption spectra of fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl] showed significant solvent dependence. In CH 3CN, a single intra-ligand charge transfer (ILCT) transition appeared at 332 nm and assigned to π → π * of dpk followed by dpk → hydrazone charge transfer. In a protophilic solvent, such as dmf, two intra-ligand charge transfer (ILCT) transitions assigned to fac-[Re(CO) 3(κ 2-N,N-dpk4abh-H)Cl] and fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl] appeared at 464 and 350 nm, respectively. Reversible interconversion between fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl] and its conjugate base fac-[Re(CO) 3(κ 2-N,N-dpk4abh-H)Cl] was established in protophilic solvents by using a base to shift the equilibrium to the conjugate base and an acid to shift the equilibrium or conjugate base to the neutral form. Acid–base titrations of fac-[Re(CO) 3(κ 2-N,N-dpk4abh-H)Cl] or fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl] show acids or bases in concentrations as low as 1x10 −6 M can be detected and determined using protophilic solutions of fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl]. Electrochemical measurements on fac-[Re(CO) 3(κ 2-N,N-dpk4abh)Cl] in CH 3CN and CH 2Cl 2 showed sequential irreversible redox processes consistent with the electrochemical reduction or oxidation of the hydrazone backbone.

Reactivity of [Os3(μ-H)2(CO)10] with N-Heterocyclic Carbenes: A Combined Experimental and DFT Computational Study

The unsaturated triosmium dihydrido cluster [Os3(μ-H)2(CO)10] (1) reacts at room temperature with N-heterocyclic carbenes (NHCs) of the 1,3-disubstituted imidazol-2-ylidene type (R1R2Im). While the addition product [Os3H(μ-H)(NHC)(CO)10] has been obtained only for NHC = Mes2Im, CO-substitution derivatives of the type [Os3(μ-H)2(NHC)(CO)9] have been obtained for NHC = Me2Im, MePhIm, Ph2Im, and Mes2Im. Small amounts of the hydroxo-bridged derivatives [Os3(μ-H)(μ-OH)(NHC)(CO)9] (NHC = Me2Im, MePhIm) are also formed in wet solvents. DFT mechanistic studies on the reactions of compound 1 with the small Me2Im and the very bulky Mes2Im have revealed that the substitution reactions follow an associative reaction pathway that starts with the addition of the NHC to compound 1 (in one elementary step that gives [Os3H(μ-H)(NHC)(CO)10]) and ends with the elimination of a CO ligand (in three steps from [Os3H(μ-H)(NHC)(CO)10]) to give the final substitution product [Os3(μ-H)(μ-OH)(NHC)(CO)9]. The relative energy of each...

ChemInform Abstract: Polymer-Bound TBTU as a New Solid-Supported Reagent for Peptide Synthesis.

Abstract A new polymer-supported TBTU (P-TBTU) has been prepared from polystyrene-bound 1-hydroxybenzotriazole (P-HOBT) and used efficiently as a solid-supported reagent for peptide-coupling reactions, and is even effective with wet solvents. The P-HOBT can be recovered by simple filtration and reused for the preparation of new P-TBTU.

Partition of compounds from water and from air into the wet and dry monohalobenzenes

Values of the partition coefficient from the gas phase (Ks) and from water (Ps) to the monohalobenzene solvents have been collected for fluorobenzene (21 solutes), chlorobenzene (212 solutes), bromobenzene (126 solutes) and iodobenzene (65 solutes). It is shown that for the wide range of solutes studied, partitions into the dry and wet (water-saturated) solvents are essentially the same, and that equations can be constructed that include data on both dry and wet solvents. Using the Abraham equations, that contain a maximum of five descriptors, statistically satisfactory equations are obtained for log Ks and log Ps with estimated predictive standard deviations of around 0.20 log units. The coefficients in the Abraham equations for the four halobenzene solvents are surprisingly similar and except for the s-coefficient, which reflects the solvent dipolarity/polarisability, are also similar to the coefficients for partition into toluene.