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Funding Information: This work was supported by Business Finland (grant no. 883/31/2019) and the Academy of Finland (grant nos. 318890 and 318891, Competence Centre for Materials Bioeconomy, FinnCERES). The authors acknowledge Dr. Ville Liljeström for his help in measuring WAXS and Dr. Laleh Solhi for her help in sample preparation and TEM measurements. Publisher Copyright: © 2022 American Chemical Society. All rights reserved. Phosphorylation of cellulose nanocrystals (CNCs) has remained a marginal activity despite the undisputed application potential in flame-retardant materials, sustainable high-capacity ion-exchange materials, or substrates for biomineralization among others. This is largely due to strenuous extraction methods prone to a combination of poor reproducibility, low degrees of substitution, disappointing yields, and impractical reaction sequences. Here, we demonstrate an improved methodology relying on the modification routines for phosphorylated cellulose nanofibers and hydrolysis by gaseous HCl to isolate CNCs. This allows us to overcome the aforementioned shortcomings and to reliably and reproducibly extract phosphorylated CNCs with exceptionally high surface charge (2000 mmol/kg) in a straightforward routine that minimizes water consumption and maximizes yields. The CNCs were characterized by NMR, ζpotential, conductometric titration, thermogravimetry, elemental analysis, wide-angle X-ray scattering, transmissionelectron microscopy, and atomic force microscopy.

Funding Information: Yingfeng Wang and Teemu Airaksinen from Aalto University, School of Chemical Engineering are gratefully acknowledged for measuring the intrinsic viscosity of the cotton bed linens and roll towels. This work was financially supported by the Strategic Research Council of the Academy of Finland under grant agreement no. 327296 – the FINIX project (finix.aalto.fi). The viscoelastic properties of cellulose fibers play an important role in chemical recycling of textiles. Here we discriminated the intrinsic viscosity of cotton roll towels and bed linens using near-infrared imaging spectroscopy and supervised pattern recognition. The classification results showed training and test set accuracies of 84–97% and indicated that the relevant spectral features were related to water, cellulose, and cellulose crystallinity. We hypothesized that the decreasing intrinsic viscosity of cotton was associated with changes in cellulose crystallinity and water adsorption, which was supported by additional X-ray and sorption measurements. These results are important as they indicate the potential to non-invasively estimate the degree of polymerization and the suitability of different cotton materials for chemical recycling. We propose that changes in the degree of polymerization and cellulose crystallinity could be used as an indicator of the chemical quality of cellulose fibers, which would have wider impacts for textile recycling.

Funding Information: The authors acknowledge Sateri International, Singapore, for financial support of the project. Publisher Copyright: © 2021 The Authors. Published by American Chemical Society. Lyocell-type fibers often exhibit a high tendency to fibrillate under wet abrasion conditions, and fibrillation must be diminished for a better quality of the textile product. In this study, we propose a green route for cross-linking regenerated cellulose fibers using citric acid (CA) and 1,2,3,4-butanetetracarboxylic acid (BTCA) to prevent the fibers from fibrillation. We investigated the influence of process conditions and additives on the fibrillation tendency and fiber properties. The fibrillation tendency of the cross-linked fibers highly depended on the concentration of cross-linker solution, curing temperature, and curing time. BTCA showed better cross-linking performance in comparison to CA. CA cross-linked fibers also suffer from yellowing issues due to the formation of unsaturated side products during curing. Thus, glycerol and xylitol were added during cross-linking to avoid the reaction that led to the unsaturated compound. Washing fastness tests confirmed that the cross-linking has high stabilitywhen the cross-linker concentration is 100 g/L and fibers are cured at 180 °C for 5 min. The disadvantage of the CA and BTCA cross-linked fibers was a relatively low mechanical performance. The study demonstrated that adding softener in the cross-linker solution enhanced the mechanical properties and was also able to reduce the curing temperature without deteriorating the fibrillation index of the cross-linked fibers.

Funding Information: Open access funding provided by Aalto University. This work was funded by the Academy of Finland's Flagship Programme under Projects No. 318890 and 318891 (Competence Center for Materials Bioeconomy, FinnCERES). Publisher Copyright: © 2021, The Author(s). This study focuses on the investigation of the extent of the γ-valerolactone (GVL) hydrolysis forming an equilibrium with 4-hydroxyvaleric acid (4-HVA) in aqueous solutions over a wide pH range. The hydrolysis of a 50 wt% GVL solution to 4-HVA (3.5 mol%) was observed only at elevated temperatures. The addition of sulfuric acid (0.2 × 10–5 wt% to 6 wt%) at elevated temperatures (150–180 °C) and reaction times between 30 and 180 min caused the formation of 4 mol% 4-HVA. However, with decreasing acidity, the 4-HVA remained constant at about 3 mol%. The hydrolysis reactions in alkaline conditions were conducted at a constant time (30 min) and temperature (180 °C) with the variation of the NaOH concentration (0.2 × 10–6 wt% to 7 wt%). The addition of less than 0.2 wt% of NaOH resulted in the formation of less than 4 mol% of sodium 4-hydroxyvalerate. A maximum amount of 21 mol% of 4-HVA was observed in a 7 wt% NaOH solution. The degree of decomposition after treatment was determined by NMR analysis. To verify the GVL stability under practical conditions, Betula pendula sawdust was fractionated in 50 wt% GVL with and without the addition of H2SO4 or NaOH at 180 °C and a treatment time of 120 min. The spent liquor was analyzed and a 4-HVA content of 5.6 mol% in a high acidic (20 kg H2SO4/t wood) and 6.0 mol% in an alkaline (192 kg NaOH/t wood) environment have been determined.

The hydrolysis kinetics of 7-methyl-1,5,7triazabicyclo[4.4.0]dec-5-enium acetate [mTBDH][OAc] was investigated in a comprehensive study by the utilization of the well-known Schlenk technique to achieve a better understanding of its stability for dry-jet wet spinning applications (e.g., Ioncell) and due to the course of operation for recovery methods like fractional distillation. Decomposition behavior as a function of temperature, time, acid-base stoichiometry, and water content was extensively analyzed and characterized by nuclear magnetic resonance spectroscopy (NMR), capillary electrophoresis (CE), and thermogravimetric analysis (TGA). Furthermore, kinetic models were formulated for the prediction of the stability and the results were compared with the closely related amidine-based analogues 1,5diazabicyclo[4.3.0]non-5-enium acetate [DBNH][OAc] and 1,8-diazabicyclo[5.4.0]undec-7-enium acetate [DBUH][OAc].

Quaternization of common N-functionalized imidazoles (vinyl-, allyl-, propargyl-) with pentafluorobenzyl bromide afforded the respective series of differently substituted imidazolium salts. Likewise, chemospecific S- and N-alkylation of the commercial medicinal drug methimazole (1-methyl-3H-imidazole-2-thione) and its vinylated relative 1-vinyl-3H-imidazole-2-thione yielded N,S-bis(pentafluorobenzyl)-2-mercaptoimidazole derivatives. In order to illustrate the proven feasibility of perfluorophenyl moieties to undergo further nucleophilic aromatic substitution, one member of this newly conceived family of fluorinated salts was converted to the 4-azido derivative, namely 3-(4-azido-2,3,5,6-tetrafluorobenzyl)-1-vinylimidazolium bromide. Staudinger and copper-catalyzed azide-alkyne cycloaddition reactions were performed as well in an initial investigation into azide follow-up chemistry. All target compounds, including new intermediates, were characterized by routine spectroscopy and mass spectrometry. Additionally, X-ray single crystal structure determinations were performed for 14 substances. Surfactant properties were investigated for selected representatives through surface tension measurements. Lastly, the thermal stability of the azido compound was evaluated by thermoanalysis (TGA /DSC).

The common structural feature of the four title IrIII compounds is the octa­hedral coordination of the IrIII atom by a PCP pincer complex, a C atom of a (eth­oxy­oxoethanyl­idene)methane group and two variable ligands X (H, CH2CO2Et, Cl) and Y (Cl, CO)., The common feature of the four iridium(III) salt complexes, (bis­{[(di­phenyl­phosphan­yl)meth­yl]di­phenyl­phosphanyl­idene}(eth­oxy­oxoethanyl­idene)methane-κ4 P,C,C′,P′)chlorido­hydridoiridium(III) chloride methyl­ene chloride 2.75-solvate (4), (bis­{[(di­phenyl­phosphan­yl)meth­yl]di­phenyl­phosphanyl­idene}(eth­oxy­oxoethanyl­idene)methane-κ4 P,C,C′,P′)chlorido­(eth­oxy­oxoethanido)iridium(III) chloride–methanol–water (1/1/0.5) (5), (bis­{[(di­phenyl­phosphan­yl)meth­yl]di­phenyl­phosphanyl­idene}(eth­oxy­oxoethanyl­idene)methane-κ4 P,C,C′,P′)di­chlorido­iridium(III) chloride–methanol–water (1/1/2) (6) and (bis­{[(di­phenyl­phosphan­yl)meth­yl]di­phenyl­phosphanyl­idene}(eth­oxy­oxoethanyl­idene)methane-κ4 P,C,C′,P′)carbon­yl(eth­oxy­oxoethanide)iridium(III) dichloride–meth­yl­ene chloride–water (1/2/1.5) (7) or in terms of their formulae [Ir(C55H50O2P4)ClH]Cl·2.75CH2Cl2 (4), [Ir(C4H7O2)(C55H50O2P4)Cl]Cl·CH3OH·0.5H2O (5), [Ir(C55H50O2P4)Cl2]Cl·CH3OH·2H2O (6) and [Ir(C4H7O2)(C55H50O2P4)(CO)]Cl2·2CH2Cl2·1.5H2O (7) is a central IrIII atom coordin­ated in a distorted octa­hedral fashion by a PCCP ligand system and two additional residues, such as chlorides, a hydride, a carbonyl or an alkyl unit. Thereby, the PCP pincer ligand system and the residue trans to the carbodi­phospho­rane (CDP) C atom surround the iridium(III) transition metal in the equatorial plane under the formation of two five-membered dissimilar chelate rings [C—CCDP—P (4, 5, 6 and 7) for the first ring: 120.2 (3), 121.9 (5), 111.2 (3) and 121.7 (2) °; for the second ring: 112.1 (3), 113.5 (5), 120.5 (3) and 108.3 (2)°]. A cyclo­propane-like heterocycle is positioned approximately orthogonal (84.21–88.85°) to the equatorial plane, including an alkyl­idene bridge connecting the IrIII atom and the coordinating CDP atom of the PCP subunit. In general, the neutral PCCP ligand system coordinates the metal in a tetra­dentate way via three Lewis acid/base bonds and by an alkyl­idene unit presenting strengthened inter­actions. In all the crystal structures, (disordered) solvent mol­ecules are present in the voids of the packed mol­ecules that inter­act with the positively charged complex and its chloride counter-ion(s) through weak hydrogen bonding.

The common feature of the four iridium(III) salt complexes, (bis{[(diphenylphosphanyl)methyl]diphenylphosphanylidene}(ethoxyoxoethanylidene)methane-κ4 P,C,C′,P′)chloridohydridoiridium(III) chloride methylene chloride 2.75-solvate (4), (bis{[(diphenylphosphanyl)methyl]diphenylphosphanylidene}(ethoxyoxoethanylidene)methane-κ4 P,C,C′,P′)chlorido(ethoxyoxoethanido)iridium(III) chloride–methanol–water (1/1/0.5) (5), (bis{[(diphenylphosphanyl)methyl]diphenylphosphanylidene}(ethoxyoxoethanylidene)methane-κ4 P,C,C′,P′)dichloridoiridium(III) chloride–methanol–water (1/1/2) (6) and (bis{[(diphenylphosphanyl)methyl]diphenylphosphanylidene}(ethoxyoxoethanylidene)methane-κ4 P,C,C′,P′)carbonyl(ethoxyoxoethanide)iridium(III) dichloride–methylene chloride–water (1/2/1.5) (7) or in terms of their formulae [Ir(C55H50O2P4)ClH]Cl·2.75CH2Cl2 (4), [Ir(C4H7O2)(C55H50O2P4)Cl]Cl·CH3OH·0.5H2O (5), [Ir(C55H50O2P4)Cl2]Cl·CH3OH·2H2O (6) and [Ir(C4H7O2)(C55H50O2P4)(CO)]Cl2·2CH2Cl2·1.5H2O (7) is a central IrIII atom coordinated in a distorted octahedral fashion by a PCCP ligand system and two additional residues, such as chlorides, a hydride, a carbonyl or an alkyl unit. Thereby, the PCP pincer ligand system and the residue trans to the carbodiphosphorane (CDP) C atom surround the iridium(III) transition metal in the equatorial plane under the formation of two five-membered dissimilar chelate rings [C—CCDP—P (4, 5, 6 and 7) for the first ring: 120.2 (3), 121.9 (5), 111.2 (3) and 121.7 (2) °; for the second ring: 112.1 (3), 113.5 (5), 120.5 (3) and 108.3 (2)°]. A cyclopropane-like heterocycle is positioned approximately orthogonal (84.21–88.85°) to the equatorial plane, including an alkylidene bridge connecting the IrIII atom and the coordinating CDP atom of the PCP subunit. In general, the neutral PCCP ligand system coordinates the metal in a tetradentate way via three Lewis acid/base bonds and by an alkylidene unit presenting strengthened interactions. In all the crystal structures, (disordered) solvent molecules are present in the voids of the packed molecules that interact with the positively charged complex and its chloride counter-ion(s) through weak hydrogen bonding.

This study investigates the extent of the g-valerolactone (GVL) hydrolysis forming an equilibrium with 4-hydroxyvaleric acid (4-HVA) in aqueous solutions over a wide pH range. The hydrolysis of pure 50 wt% GVL to 4-HVA (3.5 mol%) was observed only at elevated temperatures. The addition of sulfuric acid (0.2×10-5 wt% to 6 wt%) at elevated temperatures (150 – 180°C) and reaction times between 30-180 min caused the formation of 4 mol% 4-HVA but with decreasing acidity, the 4-HVA remained constant at about 3 mol%. The hydrolysis reactions in alkaline conditions were conducted at constant time (30 min) and temperature (180 °C) with variation of the NaOH concentration (0.2×10-6 wt% to 7 wt%). The addition of less than 0.2 wt % of NaOH resulted in the formation of less than 4 mol% of sodium 4-hydroxyvalerate. A maximum amount of 21 mol% of 4-HVA was observed in a 7 wt% NaOH solution. The stability after synthesis was determined by NMR analysis. To verify the GVL stability results obtained under practical conditions, Betula pendula sawdust was fractionated in 50% GVL with and without addition of H2SO4 or NaOH at 180°C and 120 min, and spent liquor was analyzed. The spent liquor contained 5.6 mol% and 6.0 mol% of 4-HVA in a highly acidic (20 kg H2SO4/t wood) and alkaline (192 kg NaOH/ t wood) environment, respectively.

In this article the extension of the grid-based Numerov approach to probe two coupled, localised vibrational modes is assessed. The theoretically obtained wave numbers are compared to experimental results for five increasingly complex organic molecules carrying two OH groups measured in gas-phase as well as carbon tetrachloride. By using an appropriate spacing of the associated potential energy grid a deviation of the predicted wave numbers with experiment of ≤1% is achieved for both the fundamental and the first overtone bands. In particular the calculated wave numbers of aliphatic species in vacuum underline the versatility of this approach. In addition, it is demonstrated that bicubic interpolation is a viable strategy to greatly reduce the required data points and thus, the computational effort. Comparison of predicted wave numbers obtained for different conformers with experimental data enables the identification of the most relevant conformer present in solution. Since especially the accurate calculation of overtone vibrations is known to be challenging in case of strongly anharmonic potentials such as OH bonds, the presented approach provides a particularly efficient route to study the properties of the associated overtone contribution under the influence of inter-mode coupling. This is due to the fact that the Numerov approach requires no assumption about form and composition of the vibrational wave functions. In addition, the presented method also provides one of the simplest routes to access combined excitations of the considered vibrational modes.

The first metallo‐scorpionate ligands, closely related to Trofimenko's scorpionates, are obtained by formal replacement of the hydrido‐boron moiety of hydrido‐tris(pyrazolyl)borate by an (arene)RuII fragment. Coordination to divalent and trivalent 3d‐transition metals (Fe, Co, Ni, Cu) gives access to a series of homoleptic, heterotrimetallic complexes containing linear metal chains bridged by pyrazole ligands. Synthetic aspects, spectroscopic, structural and electrochemical properties are reported and compared to those of standard scorpionate complexes. published

A series of alkylated 2,3-dihydroxybiphenyls has been prepared on the gram scale by using an effective Directed ortho Metalation-Suzuki-Miyaura cross-coupling strategy. These compounds have been used to investigate the substrate specificity of the meta-cleavage dioxygenase BphC, a key enzyme in the microbial catabolism of biphenyl. Isolation and characterization of the meta-cleavage products will allow further study of related processes, including the catabolism of lignin-derived biphenyls.

The synthesis and crystal structures of four iridium–PCP pincer complexes, each containing a highly flexible carbodi­phospho­rane PCP pincer ligand, are discussed., Compound [Ir(C8H12)(C51H45P4)]Cl2 or [Ir(cod)(CH(dppm)2-κ3 P,C,P)]Cl2 (1a), was obtained from [IrCl(cod)]2 and the carbodi­phospho­rane (CDP) salt [CH(dppm)2]Cl [where cod = cyclo­octa-1,5-diene and dppm = bis­(di­phenyl­phosphino)methane]. Treatment of 1a with thallium(I) tri­fluoro­methane­sulfonate [Tl(OTf)] and subsequent crystallization gave complex [Ir(C8H12)(C51H45P4)](OTf)2·CH3CO2C2H5·CH2Cl2 or [Ir(cod)(CH(dppm)2-κ3 P,C,P)](OTf)2·CH3CO2C2H5·CH2Cl2 (1b) [systematic name: (cyclo­octa-1,5-diene)(1,1,3,3,5,5,7,7-octa­phenyl-1,7-diphospha-3,5-di­phospho­niaheptan-4-yl)iridium(I) bis­(tri­fluoro­methane­sulfonate)–ethyl acetate–di­chloro­methane (1/1/1)]. This five-coordinate iridium(I) complex cation adopts a trigonal–bipyramidal geometry with the CDP carbon and one cod double bond in axial sites. Compound 1b represents the first example of a non-meridional coordination of the PCP pincer ligand [CH(dppm)2]+ with a P—Ir—P angle of 98.08 (2)°. Compound 2, [IrCl2H(C51H44P4)]·(CH3)2CO or [IrCl2H(C(dppm)2-κ3 P,C,P)]·(CH3)2CO [systematic name: di­chlorido­hydrido(1,1,3,3,5,5,7,7-octa­phenyl-1,5λ5,7-triphospha-3-phospho­niahept-4-en-4-yl)iridium(III) acetone monosolvate], crystallizes as an acetone monosolvate. It is a six-coordinate IrIII coordination compound. Here, the PCP pincer ligand is coordinated in a meridional manner; one chlorido ligand is positioned trans to the carbon donor, the remaining two coordination sites being occupied by the second chlorido and a hydrido ligand trans to each other. Complex 3, [IrCl2H(C51H45P4)]Cl·5H2O or [IrCl2H(CH(dppm)2-κ3 P,C,P)]Cl·5H2O [systematic name: di­chlorido­hydrido(1,1,3,3,5,5,7,7-octa­phenyl-1,7-diphospha-3,5-di­phospho­niaheptan-4-yl)iridium(III) chloride penta­hydrate], represents the conjugate CH acid of 2. The ligand [CH(dppm)2]+ is coordinated in a meridional manner. In the cationic six-coordinate IrIII complex 4, [IrClH(CO)(C51H44P4)]Cl·2CH3OH·H2O or [IrClH(CO)(C(dppm)2-κ3 P,C,P)]Cl·2CH3OH·H2O [systematic name: carbonyl­chlorido­hydrido(1,1,3,3,5,5,7,7-octa­phenyl-1,5λ5,7-triphospha-3-phos­pho­niahept-4-en-4-yl)iridium(III) chloride–methanol–water (1/2/1)], the chlorido ligand is found in the plane defined by the Ir center and the meridional PCP ligand; the H and CO ligands are positioned axially to this plane and trans to each other.