A Two-dimensional Metal-Organic Framework as Promising Cathode for Advanced Lithium Storage.

Anthraquinone electrode materials are promising candidates for lithium-ion batteries (LIBs) due to the abundance of anthraquinone and the high theoretical capacity, and good reversibility of the anthraquinone electrodes. However, the active anthraquinone materials are soluble in organic electrolytes, resulting in a sharp decay of capacity during the charge and discharge processes. Herein, we report on a two-dimensional calcium anthraquinone 2,3-dicarboxy metal-organic framework (2D CaAQDC MOF) fabricated using a simple hydrothermal method. The 2D CaAQDC MOF not only effectively inhibits the dissolution of active electrode substances into the electrolyte, but also promotes the diffusion of lithium ion into the pores of the MOF. When used as a cathode for the LIBs, the resulting CaAQDC electrode delivers a high specific capacity of ~100 mAh g-1 at a current density of 50 mA g-1 after 200 cycles, demonstrating its good cycle stability. Even at a high current density of 200 mA g-1 , the CaAQDC electrode exhibits a specific capacity of ~60 mAh g-1 . The fabricated 2D coordination polymers effectively restrains the dissolution of anthraquinone into the organic electrolyte and enhances the structural stability, which greatly improves the electrochemical performance of anthraquinone. These research results offer a rational molecular design strategy to address the dissolution of this and other active organic electrode materials.

Insight into the Contribution of the Electrolyte Additive LiBF4 in High-Voltage LiCoO2||SiO/C Pouch Cells.

High-voltage pouch cells using an LiCoO2 cathode and SiO/C anode are regarded as promising energy storage devices due to their high energy densities. However, their failure is associated with the unstable, high-impedance cathode electrolyte interphase (CEI) film on the cathode and the solid electrolyte interphase (SEI) film on the anode surface, which hinder their practical use. Here, we report a novel approach to ameliorate the above challenges through the rational construction of a stable, low-impedance cathode and anode interface film. Such films are simultaneously formed on both electrodes via the participation of the traditional salt, lithium tetrafluoroborate (LiBF4), as electrolyte additive. The application of 1.0% LiBF4 enhances the capacity retention of the cell from 26.1 to 82.2% after 150 cycles between 3.0 and 4.4 V at 1 C. Besides, the low-temperature discharge performance is also improved by LiBF4 application: the discharge capacity of the cell with LiBF4 is 794 mAh compared with 637 mAh without LiBF4 at 1 C and -20 °C. The excellent electrochemical performance of pouch cells is ascribed to the contribution of LiBF4. Especially, the low binding energy of LiBF4 with the oxygen on the LiCoO2 surface leads to the enrichment of LiBF4 that forms the protective cathode interface, which fills the blanks of previous research.

Sulfur-Rich Additive-Induced Interphases Enable Highly Stable 4.6†V LiNi0.5 Co0.2 Mn0.3 O2 ||graphite Pouch Cells.

High-voltage lithium-ion batteries (LIBs) have attracted great attention due to their promising high energy density. However, severe capacity degradation is witnessed, which originated from the incompatible and unstable electrolyte-electrode interphase at high voltage. Herein, a robust additive-induced sulfur-rich interphase is constructed by introducing an additive with ultrahigh S-content (34.04 %, methylene methyl disulfonate, MMDS) in 4.6 V LiNi0.5 Co0.2 Mn0.3 O2 (NCM523)||graphite pouch cell. The MMDS does not directly participate the inner Li+ sheath, but the strong interactions between MMDS and PF6 - anions promote the preferential decomposition of MMDS and broaden the oxidation stability, facilitating the formation of an ultrathin but robust sulfur-rich interfacial layer. The electrolyte consumption, gas production, phase transformation and dissolution of transition metal ions were effectively inhibited. As expected, the 4.6 V NCM523||graphite pouch cell delivers a high capacity retention of 87.99 % even after 800 cycles. This work shares new insight into the sulfur-rich additive-induced electrolyte-electrode interphase for stable high-voltage LIBs.

Advanced 1D Metal-Organic Coordination Polymer for Lithium-Ion Batteries: Designing, Synthesis, and Working Mechanism.

Anthraquinone (AQ) and its derivatives have been attracting more attention as promising electrode materials for lithium storage because of their high specific capacity, structural diversity, and environmental friendliness. The dissolution and poor electrical conductivity of AQ, however, limit its practical application. Here, a novel metal-organic coordination polymer with a one-dimensional (1D) chain ([C14H6O4Cu]n denoted as Cu-DHAQ; DHAQ, 1,5-dihydroxyl anthraquinone) and its composite with graphene (Cu-DHAQ/G; G, graphene) are developed by the introduction of graphene and copper ion into DHAQ. The fabricated polymer with a 1D chain not only well inhibits the dissolution of DHAQ in organic electrolytes but also facilitates lithium-ion insertion/extraction on carbonyl groups and shortens the migration path of lithium ions. Furthermore, the addition of the conductive network of graphene provides fast transfer rates of electrons. As a result, Cu-DHAQ/G delivers a high discharge capacity, long cycle life, and excellent rate capability. The lithium storage mechanism shows lithium ion insertion/extraction on two carbonyl groups of Cu-DHAQ in the range of 1.6-2.0 V and the redox reaction of Cu+/Cu2+ between 2.8 and 3.0 V, and Cu2+ and Cu+ coexist in the Cu-DHAQ/G electrode during the charge/discharge process. This study provides meaningful guidance to develop metal-organic coordination polymer electrodes for high-performance Li-ion batteries.

Facile Synthesis of a LiC15H7O4/Graphene Nanocomposite as a High-Property Organic Cathode for Lithium-Ion Batteries.

Organic electrode materials face two outstanding issues in the practical applications in lithium-ion batteries (LIBs), dissolution and poor electronic conductivity. Herein, we fabricate a nanocomposite of an anthraquinone carboxylate lithium salt (LiAQC) and graphene to address the two issues. LiAQC is synthesized via a green and facile one-pot reaction and then ball-milled with graphene to obtain a nanocomposite (nr-LiAQC/G). For comparison, single LiAQC is also ball-milled to form a nanorod (nr-LiAQC). Together with pristine LiAQC, the three samples are used as cathodes for LIBs. Results show that good cycling performance can be obtained by introducing the -CO2Li hydrophilic group on anthraquinone. Furthermore, the nr-LiAQC/G demonstrates not only a high initial discharge capacity of 187 mAh g-1 at 0.1 C but also good cycling stability (reversible capacity: ∼165 mAh g-1 at 0.1 C after 200 cycles) and good rate capability (the average discharge capacity of 149 mAh g-1 at 2 C). The superior electrochemical properties of the nr-LiAQC/G profit from graphene with high electronic conductivity, the nanorod structure of LiAQC shortening the transport distance for lithium ions and electrons, and the introduction of the -CO2Li hydrophilic group decreasing the dissolution of LiAQC in the electrolyte. Meanwhile, density functional theory calculations support the roles of graphene and -CO2Li groups. The fabrication is general and facile, ready to be extended to other organic electrode materials.

Graphene-Supported Naphthalene-Based Polyimide Composite as a High-Performance Sodium Storage Cathode.

Electroactive acid anhydride with multicarbonyl is highly promising for electrochemical energy storage because of its high specific capacity and environmental benignity. Its low electrical conductivity and high dissolution in organic electrolyte, however, result in poor cycling and rate capabilities. Here, we report a naphthalene polyimide derivative (NPI) synthesized by using anhydride under condensation polymerization conditions, along with its composite with graphene (NPI-G) fabricated via in situ polymerization. The composite delivers a high reversible capacity and outstanding cycling stability and rate capability as a cathode for sodium-ion batteries (SIBs) owing to the formation of a polymer, the improvement in the electrical conductivity brought about by the highly dispersed graphene sheets, and the enhancement of structural stability resulting from the π-π stacking interaction between the phenyl groups of NPI and the six-member carbon rings of graphene. This investigation sheds light on the development, design, and screening of next-generation organic electrode materials with high performance for SIBs.

Supramolecule-Inspired Fabrication of Carbon Nanoparticles In Situ Anchored Graphene Nanosheets Material for High-Performance Supercapacitors.

The remarkable electrochemical performance of graphene-based materials has drawn a tremendous amount of attention for their application in supercapacitors. Inspired by supramolecular chemistry, the supramolecular hydrogel is prepared by linking ß-cyclodextrin to graphene oxide (GO). The carbon nanoparticles-anchored graphene nanosheets are then assembled after the hydrothermal reduction and carbonization of the supramolecular hydrogels; here, the ß-cyclodextrin is carbonized to carbon nanoparticles that are uniformly anchored on the graphene nanosheets. Transmission electron microscopy reveals that carbon nanoparticles with several nanometers are uniformly anchored on both sides of graphene nanosheets, and X-ray diffraction spectra demonstrate that the interlayer spacing of graphene is enlarged due to the anchored nanoparticles among the graphene nanosheets. The as-prepared carbon nanoparticles-anchored graphene nanosheets material (C/r-GO-1:3) possesses a high specific capacitance (310.8 F g-1, 0.5 A g-1), superior rate capability (242.5 F g-1, 10 A g-1), and excellent cycle stability (almost 100% after 10 000 cycles, at the scan rate of 50 mV s-1). The outstanding electrochemical performance of the resulting C/r-GO-1:3 is mainly attributed to (i) the presence of the carbon nanoparticles, (ii) the enlarged interlayer spacing of the graphene sheets, and (iii) the accelerated ion transport rates toward the interior of the electrode material. The supramolecule-inspired approach for the synthesis of high-performance carbon nanoparticles-modified graphene sheets material is promising for future application in graphene-based energy storage devices.

[Expression of p53, p21, PCNA and COX-2 and its relationship with recurrence in the early-stage laryngeal cancer with negative surgical margin].

OBJECTIVE: To explore the relation between the expression of p53, p21, PCNA and COX-2 and local recurrence in resection margins of laryngeal carcinoma operation. METHOD: SElect 98 patients with laryngeal carcinoma, who came to our hospital from Nov, 2005 to Dec, 2010. Diagnosed with early laryngeal squamous cell carcinoma by a pathological examination, all these patients received CO2 laser surgery to cut the entire tumors. Keep the primary lesion and resection margin tissues after that and take 5 mm peritumoral tissue as a sample of operation resection margin. With the chemical method of SP, record in detail the local recurrence condition by clinical diagnosis every 3-6 months or telephone follow-up for 2 years. RESULT: (1)The positive rate of p53, p21, PCNA and COX-2 in the tumor tissues of the 98 patients with laryngeal carcinoma are 65. 3%, 52. 0%, 70. 4% and 69. 4%. The positive rate of p53, p21, PCNA and COX-2 in their resection margin tissues are 23. 5%, 39. 8%, 32. 7% and 30. 6%. So there is no relation between the expression of p53, p21, PCNA and COX-2 in tumor tissue and tumorous grading and TNM staging. (2)There appeared 17 cases of local recurrence in two years, with a recurrence rate of 17. 3%. The recurrence rate of patients with a positive expression of p53, p21, PCNA and COX-2 in resection margin tissue is higher than those with a negative expression(P<0. 05). Among positive cases, the recurrence rate of patients with double positive results is obviously higher than those with single positive results(P< 0. 05). (3)The expression of p21 in p53 positive resection margin tissue is greatly higher than that in negative tissue. The expression of PCNA in p53 positive resection margin tissue is greatly higher than that in negative tissue (P<0. 01); however, the PCNA positive expression in p53 positive cut edge organization rather than in the expression of negative cut edge groups(P>0. 05). CONCLUSION: Through the discussion on the effect of p53, p21, PC- NA and COX-2 in the process of laryngeal carcinoma cell proliferation and local recurrence, the study proposes that biochemical metabolism and molecular structure level abnormal expression occur before the change of cell morphology apparent, and suggests that positive index should be examined regularly and effective foreseeability intervention can be applied to patients with positive expression.

Heteroaromatic organic compound with conjugated multi-carbonyl as cathode material for rechargeable lithium batteries.

The heteroaromatic organic compound, N,N'-diphenyl-1,4,5,8-naphthalenetetra- carboxylic diimide (DP-NTCDI-250) as the cathode material of lithium batteries is prepared through a simple one-pot N-acylation reaction of 1,4,5,8-naphthalenetetra-carboxylic dianhydride (NTCDA) with phenylamine (PA) in DMF solution followed by heat treatment in 250 °C. The as prepared sample is characterized by the combination of elemental analysis, NMR, FT-IR, TGA, XRD, SEM and TEM. The electrochemical measurements show that DP-NTCDI-250 can deliver an initial discharge capacity of 170 mAh g(-1) at the current density of 25 mA g(-1). The capacity of 119 mAh g(-1) can be retained after 100 cycles. Even at the high current density of 500 mA g(-1), its capacity still reaches 105 mAh g(-1), indicating its high rate capability. Therefore, the as-prepared DP-NTCDI-250 could be a promising candidate as low cost cathode materials for lithium batteries.

Poly[diaquabis-(µ(4)-fumarato-κO:O:O:O)(µ(4)-fumarato-κO:O,O:O:O,O)(µ(2)-fumaric acid-κO:O)dipraseodymium(III)].

The title complex, [Pr(2)(C(4)H(2)O(4))(3)(C(4)H(4)O(4))(H(2)O)(2)](n), was synthesized by reaction of praseodymium(III) nitrate hexa-hydrate with fumaric acid in a water-ethanol (4:1) solution. The asymmetric unit comprises a Pr(3+) cation, one and a half fumarate dianions (L(2-)), one half-mol-ecule of fumaric acid (H(2)L) and one coordinated water mol-ecule. The carboxyl-ate groups of the fumarate dianion and fumaric acid exhibit different coordination modes. In one fumarate dianion, two carboxyl-ate groups are chelating with two Pr(3+) cations, and the other two O atoms each coordinate a Pr(3+) cation. Each O atom of the second fumarate dianion binds to a different Pr(3+) cation. The fumaric acid employs one O atom at each end to bridge two Pr(3+) cations. The Pr(3+) cation is coordinated in a distorted tricapped trigonal-prismatic environment by eight O atoms of fumarate dianion or fumaric acid ligands and one water O atom. The PrO(9) coordination polyhedra are edge-shared through one carboxyl-ate O atom and two carboxyl-ate groups, generating infinite praseodymium-oxygen chains, which are further connected by the ligands into a three-dimensional framework. The crystal structure is stabilized by O-H⋯O hydrogen-bond inter-actions between the coordin-ated water mol-ecule and the carboxyl-ate O atoms.

catena-Poly[[[triaqua-europium(III)]-µ-(1H-benzimidazole-5,6-dicarboxyl-ato-κO:O)-µ-(1H,3H-benzimidazol-3-ium-5,6-dicarboxyl-ato-κO:O,O)] dihydrate].

In the title one-dimensional coordination polymer, {[Eu(C(9)H(4)N(2)O(4))(C(9)H(5)N(2)O(4))(H(2)O)(3)]·2H(2)O}(n), one of the 1H-benzimidazole-5,6-dicarboxyl-ate (Hbdc) ligands is protonated at the imidazole group (H(2)bdc). The Eu(III) ion is eight-coordinated by two O atoms from two Hbdc ligands, three O atoms from two H(2)bdc ligands and three water mol-ecules, showing a distorted square-anti-prismatic geometry. The Eu(III) ions are bridged by the carboxyl-ate groups of the Hbdc and H(2)bdc ligands, forming a chain along [110], with an Eu⋯Eu separation of 5.4594 (3) Å. These chains are further connected by inter-molecular O-H⋯O, N-H⋯O and N-H⋯N hydrogen bonds, as well as π-π inter-actions between the imidazole and benzene rings [centroid-centroid distances = 3.558 (3), 3.906 (2), 3.397 (3), 3.796 (2) and 3.898 (2) Å], into a three-dimensional supra-molecular network.

A one-dimensional triaqua-europium(III)-1H,3H-benzimidazol-3-ium-5,6-dicarboxyl-ate-sulfate polymeric structure.

In the title coordination polymer, catena-poly[[[triaqua-europium(III)]-bis-(µ-1H,3H-benzimidazol-3-ium-5,6-dicarb-oxyl-ato-κ(3)O(5),O(5'):O(6))-[triaqua-europium(III)]-di-µ-sulfato-κ(3)O:O,O';κ(3)O,O':O'] hexahydrate], [Eu(2)(C(9)H(5)N(2)O(4))(2)(SO(4))(2)(H(2)O)(6)]·6H(2)O}(n), the 1H,3H-benzimidazol-3-ium-5,6-dicarb-oxy-l-ate ligand is protonated at the imidazole group (H(2)bdc). The Eu(III) ion is coordinated by nine O atoms from two H(2)bdc ligands, two sulfate anions and three water mol-ecules, displaying a bicapped trigonal prismatic geometry. The carboxyl-ate groups of the H(2)bdc ligands and the sulfate anions link the Eu(III) ions, forming a chain along [010]. These chains are further connected by N-H⋯O and O-H⋯O hydrogen bonds and π-π inter-actions between the imidazole and benzene rings [centroid-centroid distances = 3.997 (4), 3.829 (4) and 3.573 (4) Å] into a three-dimensional supra-molecular network.

Poly[µ-aqua-diaqua(µ(3)-1H-benzimid-azole-5-carboxylato-κN:O,O')(µ(2)-1H-benzimidazole-5-carboxylato-κN:O:O')-µ(5)-sulfato-µ(4)-sulfato-tri-cadmium].

The asymmetric unit of the title compound, [Cd(3)(C(8)H(5)N(2)O(2))(2)(SO(4))(2)(H(2)O)(3)](n), contains three Cd(II) ions, two sulfate anions, two 1H-benzimidazole-5-carboxyl-ate (H(2)bic) ligands and three coordinated water mol-ecules. One Cd(II) ion is six-coordinated and exhibits a distorted octa-hedral geometry, while the other two Cd(II) ions are seven-coordinated, displaying a distorted penta-gonal-bipyramidal geometry. The Cd(II) ions are bridged by two types of sulfate anions, producing inorganic chains along [100]. These chains are further connected by the H(2)bic ligands, leading to a three-dimensional framework. N-H⋯O and O-H⋯O hydrogen bonds and π-π inter-actions between the imidazole and benzene rings [centroid-centroid distances = 3.953 (2), 3.507 (2), 3.407 (2) and 3.561 (2) Å] further stabilize the crystal structure.

catena-Poly[silver(I)-µ-acridine-9-carboxyl-ato-κN:O,O'].

In the title coordination polymer, [Ag(C(14)H(8)NO(2))](n), the Ag(I) cation is coordinated by two O atoms and one N atom from two symmetry-related acridine-9-carboxyl-ate ligands in a distorted trigonal-planar geometry. The metal atoms are connected by the ligands to form chains running parallel to the b axis. π-π stacking inter-actions [centroid-to-centroid distances 3.757 (2)-3.820 (2) Å] and weak Ag⋯O inter-actions further link the chains to form a layer network parallel to the ab plane. The Ag(I) cation is disordered over two positions, with refined site-occupancy factors of 0.73 (3):0.27 (3).

Poly[[hemi-µ(4)-oxalato-hemi-µ(2)-oxalato-bis-(µ(3)-pyrazine-2-carboxyl-ato)erbium(III)silver(I)] monohydrate].

The asymmetric unit of the title complex, {[AgEr(C(5)H(3)N(2)O(2))(2)(C(2)O(4))]·H(2)O}(n), contains one Er(III) atom, one Ag(I) atom, two pyrazine-2-carboxyl-ate (pyc) ligands, two half oxalate ligands (each lying on an inversion center) and one uncoordinated water mol-ecule. The Er(III) atom is coordinated by two O atoms and two N atoms from two pyc ligands, one O atom from a third pyc ligand and four O atoms from two oxalate ligands in a distorted monocapped square-anti-prismatic geometry. The Ag(I) atom is coordinated by two N atoms from two pyc ligands, one O atom from a third pyc ligand and one O atom from one oxalate ligand. The crystal structure exhibits a three-dimensional heterometallic polymeric network. O-H⋯O hydrogen bonding between the uncoordinated water mol-ecule and carboxyl-ate O atoms is observed.

Poly[diaqua-(µ(2)-oxalato-κO,O:O,O)(µ(2)-pyrazine-2-carboxyl-ato-κN,O:O,O')neodymium(III)].

In the title complex, [Nd(C(5)H(3)N(2)O(2))(C(2)O(4))(H(2)O)(2)](n), the Nd(III) atom is ten-coordinated by one N atom and three O atoms from two pyrazine-2-carboxyl-ate ligands, four O atoms from two oxalate ligands and two water mol-ecules in a distorted bicapped square-anti-prismatic geometry. The two crystallographically independent oxalate ligands, each lying on an inversion center, act as bridging ligands, linking Nd atoms into an extended zigzag chain. Neighboring chains are linked by the pyrazine-2-carboxyl-ate ligands into a two-dimensional layerlike network in the (10) plane. The layers are further connected by O-H⋯O and O-H⋯N hydrogen bonds, forming a three-dimensional supra-molecular network.

Poly[[aqua-(µ(2)-oxalato)(µ(2)-2-oxido-pyridinium-3-carboxylato)holmium(III)] monohydrate].

In the title complex, {[Ho(C(2)O(4))(C(6)H(4)NO(3))(H(2)O)]·(H(2)O)}(n), the Ho(III) ion is coordinated by three O atoms from two 2-oxidopyridinium-3-carboxylate ligands, four O atoms from two oxalate ligands and one water mol-ecule in a distorted bicapped trigonal-prismatic geometry. The 2-oxidopyridin-ium-3-carboxylate and oxalate ligands link the Ho(III) ions into a layer in (100). These layers are further connected by inter-molecular O-H⋯O hydrogen bonds involving the coordinated water mol-ecules to assemble a three-dimensional supra-molecular network. The uncoordin-ated water mol-ecule is involved in N-H⋯O and O-H⋯O hydrogen bonds within the layer.

Poly[(6-carboxy-picolinato-κO,N,O)(µ(3)-pyridine-2,6-dicarboxyl-ato-κO,N,O:O:O)dysprosium(III)].

In the title complex, [Dy(C(7)H(3)NO(4))(C(7)H(4)NO(4))](n), one of the ligands is fully deprotonated while the second has lost only one H atom. Each Dy(III) ion is coordinated by six O atoms and two N atoms from two pyridine-2,6-dicarboxyl-ate and two 6-carboxy-picolinate ligands, displaying a bicapped trigonal-prismatic geometry. The average Dy-O bond distance is 2.40 Å, some 0.1Å longer than the corresponding Ho-O distance in the isotypic holmium complex. Adjacent Dy(III) ions are linked by the pyridine-2,6-dicarboxyl-ate ligands, forming a layer in (100). These layers are further connected by π-π stacking inter-actions between neighboring pyridyl rings [centroid-centroid distance = 3.827 (3) Å] and C-H⋯O hydrogen-bonding inter-actions, assembling a three-dimensional supra-molecular network. Within each layer, there are other π-π stacking inter-actions between neighboring pyridyl rings [centroid-centroid distance = 3.501 (2) Å] and O-H⋯O and C-H⋯O hydrogen-bonding inter-actions, which further stabilize the structure.

Poly[[diaqua-bis(µ(2)-isonicotinato-κN:O)bis-(µ(3)-isonicotinato-κN:O:O')neodymium(III)disilver(I)] nitrate monohydrate].

In the title complex, {[Ag(2)Nd(C(6)H(4)NO(2))(4)(H(2)O)(2)]NO(3)·H(2)O}(n), the Nd(III) ion is coordinated by eight O atoms from six isonicotinate ligands and two water mol-ecules in a distorted square anti-prismatic geometry. Each Ag(I) ion is coordinated by two N atoms from two different isonicotinate ligands. The crystal structure exhibits a two-dimensional heterometallic polymeric layer. O-H⋯O hydrogen bonds involving the coordinated and uncoordinated water mol-ecules and intra-layer π-π inter-actions between the pyridine rings [centroid-centroid distances = 3.571 (2) and 3.569 (2) Å] are observed. Each layer inter-acts with two neighboring ones via Ag⋯O(H(2)O) contacts and inter-layer π-π inter-actions [centroid-centroid distances = 3.479 (3) to 3.530 (3) Å], leading to a three-dimensional supra-molecular network.

Poly[bis-(4,4'-bipyridine)(µ(3)-4,4'-dicarboxybiphenyl-3,3'-di-carboxyl-ato)iron(II)].

In the polymeric title complex, [Fe(C(16)H(8)O(8))(C(10)H(8)N(2))(2)](n), the iron(II) cation is coordinated by four O atoms from three different 4,4'-dicarboxybiphenyl-3,3'-di-carboxyl-ate ligands and two N atoms from two 4,4'-bipyridine ligands in a distorted octa-hedral geometry. The 4,4'-dicarboxybiphenyl-3,3'-di-carboxyl-ate ligands bridge adjacent cations, forming chains parallel to the c axis. The chains are further connected by inter-molecular O-H⋯N hydrogen bonds, forming two-dimensional supra-molecular layers parallel to (010).