Lactonic sophorolipids (LSL) are glycolipid biosurfactants produced in large quantity by yeast fermentation. Chemical or enzymatic modification of naturally produced sophorolipids is an effective route to improve their functional properties. For the first time, ring-opening cross metathesis (RO/CM) was used to convert natural LSL to a unique family of modified sophorolipids. Reaction conditions for RO/CM of LSL with n-alkyl acrylates, trans-3-hexene, 1-hexene and ethylene were investigated. For the RO/CM of n-alkyl acrylates with LSL, %-conversions greater than 95% within 1 h resulted from conducting reactions in THF at 60°C using 5 mol% of Grubbs second generation ruthenium based catalyst (M2). The RO/CM reaction of LSL with ethylene performed at 3 bar under an ethylene atmosphere using Grubbs first generation (G1) (10 mol%) as the catalyst in dichloromethane (room temperature, 5 h) gave complete conversion of LSL to the corresponding ring-opened product. Ethanolysis of LSL RO/CM products generated a series of medium chain (C10-C14) SL-surfactants and fatty acid co-products. Values of surface tension reduction at the air-water interface versus Log (C) for modified SLs were measured by the Wilhelmy plate method. Minimum surface tension values varied as a function of the hydrophobic character of modified SLs. The modified SL from RO/CM with 1-hexene (SL-14) gave the largest surface tension reduction and lowest CMC (to 34 mN/m and 0.15 mM, respectively) and showed a similar surface tension reduction behavior as n-dodecyl-b-D-maltoside (Mal-C12). Increasing the number of carbons in the hydrophobic segment for the homologous series of n-alkyl sophorosides results in an almost linear decrease in log(CMC), with B ¼ 0.18 AE 0.03. This number is smaller than that of other related surfactants such as alkyl-b-D-glycosides and alkyl-b-D-maltosides.Practical applications: Modified sophorolipids can be used in a wide variety of applications such as stabilization of oil-in-water dispersions, antimicrobials and various cleaning operations.

Structural diversity and luminescent properties of lanthanide 2,2-and 2,3-dimethylsuccinate frameworks3

The structures of seven new transition metal frameworks featuring Mn, Co, or Zn and either the meso or chiral D and L isomers of the 2,3-dimethylsuccinate ligand are reported. Frameworks that exhibit two-dimensional covalently bonded layers with weak interlayer interactions can be made with all three cations by incorporation of the chiral isomers of the 2,3-dimethylsuccinate ligand. The formation of such structures, suitable for the creation of nanosheets via exfoliation, is, however, not as ubiquitous as is the case with the 2,2-dimethylsuccinate frameworks since frameworks that incorporate the meso-2,3-dimethylsuccinate ligand form three-dimensional structures. This clear distinction between the formation of structures with covalent connectivity in two and three dimensions, depending on the choice of 2,3-dimethylsuccinate isomer, is due to the different conformations adopted by the backbone of the ligand. The chiral isomer prefers to adopt an arrangement with its methyl and carboxylate groups gauche to the neighboring functional groups of the same type, while the meso-ligand prefers to adopt trans geometry. A gauche-arrangement of the methyl groups places them on the same side of the ligand, making this geometry ideal for the formation of layered structures; a trans-relationship leads to the methyl groups being further apart, reducing their steric hindrance and making it easier to accommodate them within a three-dimensional structure. The ease of exfoliation of the layered frameworks is examined and compared to those of known transition metal 2,2-dimethylsuccinate frameworks by means of UV-vis spectroscopy. It is suggested that layered frameworks with more corrugated surfaces exfoliate more rapidly. The size, structure, and morphology of the exfoliated nanosheets are also characterized. The magnetic properties of the paramagnetic frameworks reveal that only the three dimensionally covalently bonded phases containing meso-2,3-DMS in trans-arrangements order magnetically. These frameworks are antiferromagnets at low temperatures, although the Co compound undergoes an unusual antiferromagnetic to ferromagnetic transition with increasing applied magnetic field.

Reactive poly(phosphoester)s (PPEs) have been prepared via the acyclic diene metathesis polymerization of the monomers di(buten-3-yl) chlorophosphate and di(undecen-10-yl) chlorophosphate. Molecular weights can be adjusted from 3000 to ca. 50 000 g/mol and have been prepared and characterized in detail. This is the first report on olefin metathesis polymerization of highly electrophilic phosphochlorides, which were postmodified with different nucleophiles, i.e., alcohols, amines, and water, thus allowing the synthesis of side chain polyphosphoamidates, poly(phosphoester)s, and free acids from the same starting polymer. High side-chain functionality was found in all cases.

Poly(phosphoester)s (PPEs) are interesting degradable multi-functional polymers. Here, we present the first synthesis of poly(phosphoramidate)s (PPAs) via acyclic diene metathesis (ADMET) polycondensation with amidate linkages in side chains. In contrast to conventional polyamides, the P-N-bond in phosphoramidates is more labile than the corresponding esters. Unsaturated PPAs were compared with structural analogues of PPEs: two novel α,ω-dienes, i.e. bis-(undecen-10-yl)-n-butyl-phosphoramidate (1) and bis-(undecen-10-yl)-n-butyl-phosphate (2) have been polymerized by Grubbs-type catalysts to polymers with molecular weights up to ca. 20 000 g mol −1 . After hydrogenation polyethylene-like structures were obtained with the phosphoramidate or -ester representing a precisely placed defect. PPAs were compared to their PPE analogues with respect to their thermal behavior and stability by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), showing similar crystallization behavior for the saturated materials, but significant differences for unsaturated PPA vs. PPE. This synthesis of PPAs via ADMET polymerization offers an interesting approach to various PPAs. The hydrolytically labile pendant phosphoramidate further offers the possibility for the development of hydrolytically degradable materials or as processable intermediates for poly(phosphodiester)s which often show limited solubility. † Electronic supplementary information (ESI) available. See