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The reactions between Ni (d10 1S) and CH4 have been carried out at the B3LYP/6-311+G(2d, 2p) and B3LYP/6-311++G(3df,2p) theoretical levels. The reaction path in which the intermediates transfer from one to another via transition state is rationalized by their structures and natural bond orbital analysis. The reactions of Ni+CH4→NiCH2+H2, Ni+CH4→NiCH3⋅+H⋅ and Ni+CH4→NiH⋅+CH3⋅ are predicted to be endothermic, and the reaction Ni+CH4→NiH⋅+CH3⋅ is the easiest to occur. [Copyright &y& Elsevier]

The hydrogenolysis of lignin model compounds (MCs) into high-value chemicals has received increasing attention, but their catalytic reaction mechanisms are not yet very clear. Here, we report the reaction mechanisms of the hydrogenolysis of MC into 4-acetylanisole (AAL) and guaiacol (GAL) catalyzed by LRuCl 3 (L = 4'-(4-methoxyphenyl)-2,2':6',2″-terpyridine) with MC, H 2 , and 1-phenylethan-1-ol (PEO) as the H-sources in aqueous solution with the Bro̷nsted base (NaOH), at the M06/def2-TZVP, 6-311++G (d,p) theoretical level, namely, RS-Self, RS-H 2 , and RS-PEO, respectively. After dissociation in NaOH aqueous solution, the LRuCl 3 compound can form a stable complex LRh (OH) 3 as the initial catalytically active species. Their rate-determining steps are related to the cleavage of the -C α O-H bond in both RS-Self-and RS-PEO, whereas it is associated with the heterolysis of the H-H bond in RS-H 2 . From NaOH aqueous solution, the OH - ligand of LRh(OH) 3 promotes the cleavage of the -C α O-H bond with MC and PEO as H-sources, whereas it advances the heterolysis of the H-H bond with H 2 as the H-source, owing to its strong Bro̷nsted basicity. Furthermore, the Rh center of LRh(OH) 3 mediates the cleavage of the -C α -H bond, because of its Lewis acidity. The reaction activity lowers as RS-Self > RS-PEO ≫ RS-H 2 , which is positively dependent on the protonation degree of the departing H atom. Compounds containing both -C α O-H and -C α -H groups can act as effective donors for H-sources. In the meantime, the stronger the electron-withdrawing groups they contain, the more pronounced the protonation of the -C α O-H group and the higher the reaction activity in providing H-sources. The present results provide insights into utilizing lignin's own functional groups as a hydrogen source for high-value conversion.

Ru/NC shows a good catalytic performance in cellobiose-to-sorbitol hydrogenation. However, the molecular origins of the selective orientation of the reaction pathway remain unclear. Here, we rationally designed the Ru 2 /NC catalyst, for which Ru2@N8 V4 is preferred as the model. The hydrogenation mechanisms for the hydrogenation of β-cellobiose to sorbitol employing H 2 as the H-source in aqueous solution have been investigated over Ru2@N8 V4 at the GGA-PBE/DNP level. For the hydrogenation of β-cellobiose to sorbitol, the optimal reaction pathway involves the ring-opening of cellobiose with H 2 O as a promoter and then the hydroreduction of aldehyde group, followed by the β-1,4-glycosidic bond hydrolysis. The selective orientation of the optimal reaction pathway originates from the dissociation of H 2 O on Ru-sites of Ru2@N8 V4 to form Brønsted acid (Ru-H + ) and Brønsted base (Ru-OH - ), which collaboratively promote the ring-opening. The rate-determining steps are relative to the β-1,4-glycosidic bond cleavage, where an applicable π-π interaction between reactant molecule and Ru2@N8 V4 is of critical importance. Kinetically, the β-1,4-glycosidic bond cleavage from cellubitol is more favorable than that from β-cellobiose. For the hydrogenation of β-cellobiose to cellubitol, the first ring-opening with H 2 O as promoter and then hydrogenation are kinetically superior to the direct hydrogenation and ring opening. This derives from its dissociation over Ru-sites to Ru-H and Ru-OH groups. Predictably, protic solvents (HOR) are readily dissociated into Ru-H and Ru-OR at Ru-sites, which can promote the ring-opening of pyran-ring. The present research outcomes should contribute to the theoretical understanding necessary for the development of novel supported noble metal N-doped carbon catalysts for the hydrogenation of cellulose.

Aim: To evaluate the clinical effect of a new surgery technique (covering corneal stromal lenticule, CSL) for macular hole (MH) in pathological myopia., Methods: This was a prospective non-randomized series case study. Fourteen eyes of 14 patients whose axial length were more than 29 mm and suffered from MH and macular hole retinal detachment (MHRD) were included in this study. All cases were treated with 25-gauge pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling, covering CSL and C 3 F 8 gas tamponade. These cases were followed for 6mo, and the best-corrected visual acuity (BCVA), healing status of MH, the reattached rate of retinal detachment (RD), and reoperation rate were analyzed., Results: All cases were successfully performed the surgery and the postoperative follow-up was completed. After surgery, MHs were healed in all 14 eyes (100%, 14/14) after assessed by optical coherence tomography. The reattachment of retina was achieved in all 6 eyes (100%, 6/6) with MHRD. BCVA was improved in 12 eyes (85.71%, 12/14), and had no significant change in 2 eyes (14.29%, 2/14). The overall mean BCVA was improved from 1.80±0.77 to 0.82±0.46 logMAR ( F =10.46, P <0.01). No serious complications occurred in all cases., Conclusion: The new surgery technique (covering CSL) has high reattached rate of RD and high healing rate of MH in pathological myopia in the preliminary study. And it can effectively improve the visual function of patients. This new technique offers meaningful new ideas for treating refractory MH in pathological myopia., Competing Interests: Conflicts of Interest: Tang ZY, None; Qiao G, None; Zhang XJ, None; Xie LJ, None; Zou QX, None; He CM, None; Zhao L, None; Yang HQ, None; Quan Y, None; Cao K, None; Jiang H, None; He YK, None., (International Journal of Ophthalmology Press.)

A Ru-containing complex shows good catalytic performance toward the hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) with the assistance of organic base ligands (OBLs) and CO 2 . Herein, we report the competitive mechanisms for the hydrogenation of LA to GVL, 4-oxopentanal (OT), and 2-methyltetrahydro-2,5-furandiol (MFD) with HCOOH or H 2 as the H source catalyzed by RuCl 3 in aqueous solution at the M06/def2-TZVP, 6-311++G(d,p) theoretical level. Kinetically, the hydrodehydration of LA to GVL is predominant, with OT and MFD as side products. With HCOOH as the H source, initially, the OBL (triethylamine, pyridine, or triphenylphosphine) is responsible for capturing H + from HCOOH, leading to HCOO - and [HL] + . Next, the Ru 3+ site is in charge of sieving H - from HCOO - , yielding [RuH] 2+ hydride and CO 2 . Alternatively, with H 2 as the H source, the OBL stimulates the heterolysis of H-H bond with the aid of Ru 3+ active species, producing [RuH] 2+ and [HL] + . Toward the [RuH] 2+ formation, H 2 as the H source exhibits higher activity than HCOOH as the H source in the presence of an OBL. Thereafter, H - in [RuH] 2+ gets transferred to the unsaturated C site of ketone carbonyl in LA. Afterwards, the Ru 3+ active species is capable of cleaving the C-OH bond in 4-hydroxyvaleric acid, yielding [RuOH] 2+ hydroxide and GVL. Subsequently, CO 2 promotes Ru-OH bond cleavage in [RuOH] 2+ , forming HCO 3 - and regenerating the Ru 3+ -active species owing to its Lewis acidity. Lastly, between the resultant HCO 3 - and [HL] + , a neutralization reaction occurs, generating H 2 O, CO 2 , and OBLs. Thus, the present study provides insights into the promotive roles of additives such as CO 2 and OBLs in Ru-catalyzed hydrogenation.

Al-containing catalysts, e.g., Al(OTf) 3 , show good catalytic performance toward the conversion of cellulose to fructose in methanol solution. Here, we report the catalytic isomerization and alcoholysis mechanisms for the conversion of cellobiose to fructose at the PBE0/6-311++G(d,p), aug-cc-pVTZ theoretical level, combining the relevant experimental verifications of electrospray ionization mass spectrometry (ESI-MS), high-performance liquid chromatography (HPLC), and the attenuated total reflection-infrared (ATR-IR) spectra. From the alcoholysis of Al(OTf) 3 in methanol solution, the catalytically active species involves both the [CH 3 OH 2 ] + Brønsted acid and the [Al(CH 3 O)(OTf)(CH 3 OH) 4 ] + Lewis acid. There are two reaction pathways, i.e., one through glucose (glycosidic bond cleavage followed by isomerization, w-G ) and another through cellobiulose (isomerization followed by glycosidic bond cleavage, w-L ). The Lewis acid ([Al(CH 3 O)(OTf)(CH 3 OH) 4 ] + ) is responsible for the aldose-ketose tautomerization, while the Brønsted acid ([CH 3 OH 2 ] + ) is in charge of ring-opening, ring-closure, and glycosidic bond cleavage. For both w-G and w-L , the rate-determining steps are related to the intramolecular [1,2]-H shift between C1-C2 for the aldose-ketose tautomerization catalyzed by the [Al(CH 3 O)(OTf)(CH 3 OH) 4 ] + species. The Lewis acid ([Al(CH 3 O)(OTf)(CH 3 OH) 4 ] + ) exhibits higher catalytic activity toward the aldose-ketose tautomerization of glycosyl-chain-glucose to glycosyl-chain-fructose than that of chain-glucose to chain-fructose. Besides, the Brønsted acid ([CH 3 OH 2 ] + ) shows higher catalytic activity toward the glycosidic bond cleavage of cellobiulose than that of cellobiose. Kinetically, the w-L pathway is predominant, whereas the w-G pathway is minor. The theoretically proposed mechanism has been experimentally testified. These insights may advance on the novel design of the catalytic system toward the conversion of cellulose to fructose.

In a solution of sorbitol (SBT) and Ga(OTf) 3 compounds, the coordination of sorbitol (SBT) to [Ga(OTf) n ] 3- n ( n = 0-3) has been investigated, using both ESI-MS spectra and density functional theory (DFT) calculations at the M06/6-311++g(d,p), aug-cc-pvtz level using a polarized continuum model (PCM-SMD). In sorbitol solution, the most stable conformer of sorbitol includes three intramolecular H-bonds, i.e. , O2H⋯O4, O4H⋯O6, and O5H⋯O3. Through ESI-MS spectra, in a tetrahydrofuran solution of both SBT and Ga(OTf) 3 compounds, five main species are observed, i.e. , [Ga(SBT)] 3+ , [Ga(OTf)] 2+ , [Ga(SBT) 2 ] 3+ , [Ga(OTf)(SBT)] 2+ , and [Ga(OTf)(SBT) 2 ] 2+ . Through DFT calculations, in a solution of sorbitol (SBT) and Ga(OTf) 3 compounds, the Ga 3+ cation tends to form five six-coordination complexes, i.e. , [Ga(η2O,O-OTf) 3 ], [Ga(η3O2-O4-SBT) 2 ] 3+ , [(η2O,O-OTf)Ga(η4O2-O5-SBT)] 2+ , [(η1O-OTf)(η2O2,O4-SBT)Ga(η3O3-O5-SBT)] 2+ , and [(η1O-OTf)(η2O,O-OTf)Ga(η3O3-O5-SBT)] + , which are in good agreement with the experimental observation of the ESI-MS spectra. For both [Ga(OTf) n ] 3- n ( n = 1-3) and [Ga(SBT) m ] 3+ ( m = 1, 2) complexes, the negative charge transfer from ligands to the Ga 3+ -center plays an important role in their stability, because of the strong polarization of the Ga 3+ cation. For [Ga(OTf) n (SBT) m ] 3- n ( n = 1, 2; m = 1, 2) complexes, the negative charge transfer from ligands to the Ga 3+ -center plays an essential role in their stability, accompanied by an electrostatic interaction between the Ga 3+ -center and ligands and/or spatial inclusion of ligands toward the Ga 3+ -center.

Objective: To investigate the clinical effect of NRD assisted Ilizarov technique in the treatment of infected bone and soft tissue defect of tibia., Methods: All 48 patients with infected bone and soft tissue defect of tibia were randomly divided into study group and control group from March 2013 to December 2020. There were 34 males and 14 females, aged from 24 to 55 years old with an average of (40.54±11.64) years old. There were 25 patients in the study group, including 17 males and 8 females, aged from 31 to 55 years old with an average of (41.36±9.69) years old. The study group were treated with NRD assisted with Ilizarov bone transport technique. There were 23 patients in control group, including 17 males and 6 females, aged from 24 to 53 years old with an average of(38.61±8.76) years old. The control group were treated with traditional bone transport technique. The curative rate, recurrence rate, incidence rate of pin track infection, time of using antibiotics, time of wound healing, time of carrying external fixation, time of bone transport, time of bone healing and postoperative function were used to evaluate the therapeutic effect of the two groups., Results: The follow-up period was from 12 to 62 months with an average of (33.0±7.2) months. At the final follow-up, there was no significant difference in the curative rate between the two groups ( P >0.05). The recurrence rate in the study group was lower than that in the control group( P <0.05). The incidence of pin track infection in the study group was lower than that in the control group ( P <0.05). The time of using antibiotics and wound healing in the study group was shorter than that in the control group( P <0.05). There was no significant difference in the time of bone transport and carrying of external fixation between the two groups( P >0.05). There was no significant difference in bone healing and postoperative function between the two groups( P >0.05)., Conclusion: NRD assisted Ilizarov technique can achieve satisfactory results in the treatment of infected bone and soft tissue defect of tibia and shorten the treatment period and the time of using antibiotics. It is worthy of development in clinic.

Aim: To evaluate the therapeutic effect of amniotic membrane (AM) for covering high myopic macular hole associated with retinal detachment following failed primary surgery., Methods: Seventeen eyes of 17 patients whose axial length was more than 29 mm suffered from macular hole (MH) or MH associated with retinal detachment (RD), and had previously surgery of pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling and silicone oil (SO) tamponade. Half a year after the surgery, optical coherence tomography (OCT) showed that MH did not heal in all 17 eyes and RD was still maintained in 13 eyes of these 17 eyes. We performed SO removal combined with AM covering on macular area and C 3 F 8 tamponade, and phacoemulsification combined with intraocular lens implantation simultaneously cataract eyes. We followed up these patients for one year., Results: In all 17 eyes, SO was removed successfully, MHs were healed and RDs were reattached. One eye (5.89%, 1/17) had AM shifted half a month after surgery and underwent a second surgery to adjust the position of the AM and supplement C 3 F 8 . After surgery, the visual acuity (VA) improved in 15 eyes (88.24%, 15/17), no change in two eyes (11.76%, 2/17). No serious complications occurred in all eyes., Conclusion: AM covering is helpful to rescue the previous failure surgery of high myopic MH., (International Journal of Ophthalmology Press.)