Initiating PeriCBD to probe perinatal influences on neurodevelopment during 3-10 years in China

Adverse perinatal factors can interfere with the normal development of the brain, potentially resulting in long-term effects on the comprehensive development of children. Presently, the understanding of cognitive and neurodevelopmental processes under conditions of adverse perinatal factors is substantially limited. There is a critical need for an open resource that integrates various perinatal factors with the development of the brain and mental health to facilitate a deeper understanding of these developmental trajectories. In this Data Descriptor, we introduce a multicenter database containing information on perinatal factors that can potentially influence children's brain-mind development, namely, periCBD, that combines neuroimaging and behavioural phenotypes with perinatal factors at county/region/central district hospitals. PeriCBD was designed to establish a platform for the investigation of individual differences in brain-mind development associated with perinatal factors among children aged 3-10 years. Ultimately, our goal is to help understand how different adverse perinatal factors specifically impact cognitive development and neurodevelopment. Herein, we provide a systematic overview of the data acquisition/cleaning/quality control/sharing, processes of periCBD.

Rh(III)-Catalyzed C-H Allylation of Aromatic Ketoximes with Vinylaziridines

The Rh(III)-catalyzed reaction of aromatic ketoximes with 2-vinylaziridines affords ortho-allylation products of the phenyl rings of aromatic ketoximes in moderate to excellent yields. The reaction requires 0.5 equiv of NaOAc as a base and occurs under mild conditions. The protocol exhibits ortho-monoallylation selectivity, wide scope of substrates, and good compatibility of functional groups.

A longitudinal resource for population neuroscience of school-age children and adolescents in China

During the past decade, cognitive neuroscience has been calling for population diversity to address the challenge of validity and generalizability, ushering in a new era of population neuroscience. The developing Chinese Color Nest Project (devCCNP, 2013-2022), the first ten-year stage of the lifespan CCNP (2013-2032), is a two-stages project focusing on brain-mind development. The project aims to create and share a large-scale, longitudinal and multimodal dataset of typically developing children and adolescents (ages 6.0-17.9 at enrolment) in the Chinese population. The devCCNP houses not only phenotypes measured by demographic, biophysical, psychological and behavioural, cognitive, affective, and ocular-tracking assessments but also neurotypes measured with magnetic resonance imaging (MRI) of brain morphometry, resting-state function, naturalistic viewing function and diffusion structure. This Data Descriptor introduces the first data release of devCCNP including a total of 864 visits from 479 participants. Herein, we provided details of the experimental design, sampling strategies, and technical validation of the devCCNP resource. We demonstrate and discuss the potential of a multicohort longitudinal design to depict normative brain growth curves from the perspective of developmental population neuroscience. The devCCNP resource is shared as part of the "Chinese Data-sharing Warehouse for In-vivo Imaging Brain" in the Chinese Color Nest Project (CCNP) - Lifespan Brain-Mind Development Data Community ( https://ccnp.scidb.cn ) at the Science Data Bank.

Increased systemic RNA oxidative damage and diagnostic value of RNA oxidative metabolites during Shigella flexneri-induced intestinal infection

BACKGROUND

Shigella flexneri (S. flexneri) is a major pathogen causing acute intestinal infection, but the systematic oxidative damage incurred during the course of infection has not been investigated.

AIM

To investigate the incurred systemic RNA oxidative damage and the diagnostic value of RNA oxidative metabolites during S. flexneri-induced intestinal infection.

METHODS

In this study, a Sprague-Dawley rat model of acute intestinal infection was established by oral gavage with S. flexneri strains. The changes in white blood cells (WBCs) and cytokine levels in blood and the inflammatory response in the colon were investigated. We also detected the RNA and DNA oxidation in urine and tissues.

RESULTS

S. flexneri infection induced an increase in WBCs, C-reactive protein, interleukin (IL)-6, IL-10, IL-1β, IL-4, IL-17a, IL-10, and tumor necrosis factor α (TNF-α) in blood. Of note, a significant increase in urinary 8-oxo-7,8-dihydroguanosine (8-oxo-Gsn), an important marker of total RNA oxidation, was detected after intestinal infection (P = 0.03). The urinary 8-oxo-Gsn level returned to the baseline level after recovery from infection. In addition, the results of a correlation analysis showed that urinary 8-oxo-Gsn was positively correlated with the WBC count and the cytokines IL-6, TNF-α, IL-10, IL-1β, and IL-17α. Further detection of the oxidation in different tissues showed that S. flexneri infection induced RNA oxidative damage in the colon, ileum, liver, spleen, and brain.

CONCLUSION

Acute infection induced by S. flexneri causes increased RNA oxidative damage in various tissues (liver, spleen, and brain) and an increase of 8-oxo-Gsn, a urinary metabolite. Urinary 8-oxo-Gsn may be useful as a biomarker for evaluating the severity and prognosis of infection.

Systemic RNA oxidation can be used as a biomarker of infection in challenged with Vibrio parahaemolyticus

More and more evidence support the concept that RNA oxidation plays a substantial role in the progress of multiple diseases; however, only a few studies have reported RNA oxidation caused by microbial pathogens. Urinary 8-oxo-7,8-dihydroguanosine (8-oxo-Gsn) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dGsn), which are broadly used as indicators of oxidative damage of RNA and DNA, were analyzed in this study to determine which can be used as a biomarker of infection in challenged with Vibrio parahaemolyticus (V. parahaemolyticus). In this work, 24 specific-pathogen-free (SPF) male SD rats were randomly divided into two groups: an infection group and a phosphate-buffered saline (PBS) control group. Our results proved that 8-oxo-Gsn rather than 8-oxo-dGsn was significantly increased after challenged with V. parahaemolyticus in urine and tissue samples of SD rats compared with the PBS control group. Simultaneously, white blood cells (WBCs) counts, intestinal inflammation and inflammatory factors (including CRP, IL-6, IL-1β, TNF-α, IL-10, and IL-17A) were also increased sharply. Which has more clinical value is that the trend of urinary 8-oxo-Gsn was consistent with WBCs, intestinal inflammation and all kinds of inflammatory factors. More importantly is that urinary 8-oxo-Gsn of infection group was positively correlated with WBCs and various inflammatory cytokines. In a word, our results demonstrated that as a systemic RNA oxidation biomarker, we hope 8-oxo-Gsn can be used as a biomarker of the severity of microbial pathogens infection, rather than a specific biomarker of microbial pathogens infection.

Oxidative DNA and RNA damage and their prognostic values during Salmonella enteritidis-induced intestinal infection in rats

Emerging evidence suggests that microbial pathogens may induce oxidative stress in infected hosts. The aim of the present study was to investigate the relationship between changes in oxidative stress and intestinal infection with and without antibiotic treatment in animal models. Sprague-Dawley (SD) rats were divided into three groups: rats infected with Salmonella enterica serovar Enteritidis (S. enteritidis), rats infected with S. enteritidis followed by norfloxacin treatment, and the control group. To evaluate oxidative stress changes, levels of 8-oxo-7,8-dihydroguanosine (8-oxo-Gsn) and 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxo-dGsn), which represented oxidative damage to RNA and DNA, respectively, were analysed in urine and tissue samples. In urine, the level of 8-oxo-Gsn increased significantly after oral exposure to S. enteritidis (p ≤ 0.001) and returned to baseline after recovery. Notably, norfloxacin treatment decreased the level of 8-oxo-Gsn in urine significantly (p = 0.001). Changes of 8-oxo-Gsn measured in tissues from the small intestine, colon, liver and spleen were consistent with 8-oxo-Gsn measured in urine. Our study suggested that 8-oxo-Gsn in urine may serve as a highly sensitive biomarker for evaluating the severity of S. enteritidis infection and the effectiveness of antibiotic treatment against infection.

Effect of oxycodone patient-controlled intravenous analgesia after cesarean section: a randomized controlled study

Background

Oxycodone is a semisynthetic μ-opioid receptor agonist with a potentially good analgesic efficacy in visceral pain. This study aims to compare the efficacy of oxycodone with sufentanil patient-controlled intravenous analgesia (PCIA).

Methods

One hundred and twenty primiparas undergoing elective cesarean section were randomized into four groups by different drugs of PCIA: group S (sufentanil 100 μg), group OS1 (sufentanil 70 μg, oxycodone 30 mg), group OS2 (sufentanil 50 μg, oxycodone 50 mg), and group O (oxycodone 100 mg). Ramosetron 0.3 mg was added to each group. In all groups, drugs were diluted to 100 mL and managed with a continuous infusion of 1 mL·h⁻¹, a bolus dose of 2 mL, and a lockout interval of 15 min. The maximum dose of PCIA per hour was 10 mL. After surgery, pain scores, PCIA doses, and side effects were compared among groups.

Results

At all time points (6, 12, and 24 h after surgery), Numerical Rating Scale (NRS) of uterine cramping pain (NRS-U) scores in group O were lower than those in groups OS1 and S (P<0.008) and NRS-U scores in groups OS2 and OS1 were lower than that in group S (P<0.008). NRS of moving into the sitting position (NRS-S) scores in group O were lower than those in the other groups (P<0.008). NRS-S scores in group OS2 were lower than those in groups OS1 and S (P<0.008). At 12 and 24 h after surgery, NRS of incision pain at rest (NRS-R) scores in group O were lower than those in the other groups (P<0.008). At all time points, NRS-R scores in group OS2 were lower than those in groups OS1 and S (P<0.008). The number of PCIA boluses and amount of opioid consumption in group O were lower than those in groups OS1 and S at all time points (P<0.008).

Conclusion

Oxycodone PCIA may be more effective than sufentanil PCIA for pain relief after cesarean section but the incidence of side effects needs further investigation.

Levels of 8-oxo-dGsn and 8-oxo-Gsn in random urine are consistent with 24 h urine in healthy subjects and patients with renal disease

Oxidatively generated damage to nucleic acids may play an important role in the pathophysiological processes of a variety of diseases. 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dGsn) and 8-oxo-7,8-dihydroguanosine (8-oxo-Gsn) are oxidatively generated products of DNA and RNA, respectively. Our previous studies have suggested that the amounts of 8-oxo-dGsn and 8-oxo-Gsn in urine were considerably higher than other body fluid or tissue. The aim of this study was to investigate whether 8-oxo-dGsn and 8-oxo-Gsn levels in random urine samples are consistent with those in 24 h urine samples in healthy subjects and patients with renal disease. A total of 16 healthy subjects and 104 renal disease patients were enrolled in this study, and their random and 24 h urine samples were collected. The levels of urinary 8-oxo-dGsn and 8-oxo-Gsn were quantified by LC-MS/MS and corrected by creatinine. Regardless of healthy subjects or renal disease patients, the levels of oxidised nucleosides in random urine samples were consistent with 24 h urine samples. Regardless of the age bracket, there is no significant difference between random samples and 24 h urine samples. In conclusion, 8-oxo-dGsn and 8-oxo-Gsn levels in random urine samples could replace those in 24 h urine samples, and were considered as the representative of the level of systemic oxidative stress for the whole day.

Occult HBV Infection in Immunized Neonates Born to HBsAg-Positive Mothers: A Prospective and Follow-Up Study

Objective

Occult HBV infection (OBI) has been reported in infants born to HBsAg-positive mothers despite immunization. This study aims to determine the maintenance of this status in a prospective birth cohort.

Methods

A total of 158 neonates born to HBsAg-positive mothers were enrolled. All received passive-active immunization against HBV according to a 0-1-6 schedule. Sera were collected at 7 months of age. Those diagnosed with OBI were serially followed up at 12, 24 and 36 months of age. HBV serological markers were determined by Abbott i2000 system. HBV DNA was quantitated by Abbott m2000 system. Standard PCR followed by direct sequencing were applied for mother-child HBV pairs. Homology and phylogenetic comparisons were done by BLAST and Mega 5.

Results

All the 158 neonates were HBsAg-negative and anti-HBs-positive at 7 months of age, and 32 (20.3%) of them were diagnosed with OBI, with a median HBV DNA level of 1.97 (1.20–3.71) log IU/mL. Of them, HBV DNA was positive in 25.0%, 21.9% and 7.7% at 12, 24 and 36 months of age, respectively. HBV DNA disappeared at one of the follow-up points in 31 neonates, however, rebounded to low levels in 6 of them thereafter. HBV DNA persisted at low levels during follow-ups in the other one neonate apart from the above 31. All remained negative for HBsAg. Only two (6.3%) neonates were positive for anti-HBc after 24 months of age. HBV showed close homology and phylogenetic relationships for mother-child pairs. S-escape mutant, G145R, was not discovered. The first vaccine dose within 6 hours of birth significantly reduced the occurrence of OBI (59.4% vs. 83.3%, p = 0.003).

Conclusions

HBV may be controlled in immunized neonates of HBsAg-positive mothers, after being diagnosed with OBI. Timely vaccination against HBV may provide the utmost protection. Long-term and close monitorings are needed.

The effect of HLA on immunological response to hepatitis B vaccine in healthy people: a meta-analysis

BACKGROUND AND AIM

Evidence is accumulating that several markers in the human leukocyte antigen (HLA) region have been associated with decreased or increased antibody response to hepatitis B vaccine in different individuals. This meta-analysis is to assess the associations of HLA class II DRB1 and DQB1 alleles with immunologic response to hepatitis B vaccine in healthy people.

METHODS

A systematic review of cohort studies in healthy people was performed. We searched databases for relevant studies that were published in English or Chinese up to February 17, 2012. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) of HLA alleles response to hepatitis B vaccine were pooled by using of a fixed-effects or random-effects model depending on absence or presence of significant heterogeneity. All statistical tests were two-sided.

RESULTS

Fifteen studies were included in this meta-analysis after scanning 774 potentially relevant articles. A total of 2308 subjects (including 1215 responders, 873 nonresponders and 220 control populations) were included. For DRB1 alleles, pooled ORs showed that three HLA variants, DRB1*01, DRB1*1301 and DRB1*15 were associated with a significant increase antibody response to hepatitis B vaccine, their pooled ORs were 2.73, 5.94 and 2.29 respectively. While DRB1 *03 (DRB1*0301), DRB1*04, DRB1*07 and DRB1*1302 were opposite, their pooled ORs were 0.55(0.42), 0.57, 0.24 and 0.25 respectively. And for DQB1 alleles, pooled ORs showed that DQB1*05 (DQB1*0501), DQB1*06, DQB1*0602 were associated with a significant increase antibody response to hepatitis B vaccine. Their merger ORs were 1.85, 2.35, 2.34 and 3.32 respectively. While DQB1*02 (pooled OR=0.27) was adverse. Sensitivity and specificity analysis of HLA alleles showed that DRB1*1301and DQB1*0602 had high specificity (94.2% and 90.1%) but low sensitivity (25.1% and 26.3%), respectively.

CONCLUSION

It was suggested that specific HLA class II alleles (DRB1 and DQB1) were associated with antibody response to HepB.

A predictive value of quantitative HBsAg for serum HBV DNA level among HBeAg-positive pregnant women

BACKGROUND

The high maternal HBV DNA level is the most important factor contributing to HBV perinatal transmission. This study is to explore whether HBsAg can be used as a surrogate marker of serum HBV DNA for HBsAg-positive pregnant women.

METHODS

A total of 975 HBsAg-positive pregnant women and their infants were enrolled in this study. All infants received three doses of a yeast-derived recombinant Hepatitis B vaccine at 0, 1 and 6 months. They were also given Hepatitis B immunoglobulin (HBIG) at birth. HBsAg and HBeAg were determined using Abbott Architect assays while serum HBV DNA level was detected by the Abbott Real Time HBV DNA assay.

RESULTS

Of the 975 subjects, 367 (37.6%) were HBeAg-positive and 608 (62.4%) were HBeAg-negative. Among the HBeAg-positive group, the samples with HBV DNA levels of ≥7.0 logIU/mL were 76.6% (281/367), and it was only 0.7% (4/608) for the HBeAg-negative group. HBV DNA level was positively correlated with HBsAg in HBeAg-positive group (r=0.786, p<0.001) but not in HBeAg-negative group (r=0.022, p=0.593). Among HBeAg-positive group, the area under the receiver-operator curve (ROC) of HBsAg titer for high HBV DNA level (≥7.0 logIU/mL) was 0.961 (95% CI, 0.940-0.983, p<0.001). The optimum cut-off point HBsAg titer above 4.1 logIU/mL had a sensitivity of 85.1%, specificity of 96.5%, and accuracy of 87.5% to predict HBV DNA levels of ≥7.0 logIU/mL. Of 367 infants born to mothers with HBeAg-positive, perinatal transmission was detected in 24 infants (6.5%, 24/367). Their mothers all had serum HBV DNA levels of ≥7.0 logIU/mL, 23 (95.8%) had HBsAg titers of ≥4.1 logIU/mL and the other mother had HBsAg titer of 3.9 logIU/mL. Of 608 infants born to mothers with HBeAg-negative, only one (0.2%, 1/608) became HBsAg-positive at the age of 7 months, and the mother of the infant had serum HBV DNA level of 3.4 logIU/mL and HBsAg titer of 1.8 logIU/mL, respectively.

CONCLUSION

Serum HBsAg titer may be used as a surrogate marker of serum HBV DNA for HBeAg-positive pregnant women.

A type-specific nested PCR assay established and applied for investigation of HBV genotype and subgenotype in Chinese patients with chronic HBV infection

BACKGROUND

Many studies have suggested that hepatitis B virus (HBV) genotypes show not only geographical distribution and race specificity, but also are associated with disease progression and response to interferon treatment. The objective of this study was to develop a nested polymerase chain reaction (nPCR) assay for genotypes A-D and subgenotypes B1, B2, C1 and C2 of hepatitis B virus (HBV) and to investigate the distribution characteristics of HBV genotypes/subgenotype in China.

METHODS

After redesigning the primers and optimizing the reaction conditions using common Taq polymerase, the sensitivity, specificity and reproducibility of the method were evaluated using plasmids and serum samples. In total, 642 serum samples from patients with chronic HBV infection were applied to investigate the distribution of HBV genotype and subgenotype in China.

RESULTS

The genotype and subgenotype could be identified when the HBV DNA load of a sample was ≥10(2.3) IU/mL. For the 639 successfully genotyped samples, the sequencing results of 130 randomly selected samples (20.3%, 130/639) were consistent with those of the nPCR method. The present study showed that HBV genotype B (11.2%, 72/642), C (68.2%, 438/642) and D (7.2%, 46/642) were circulating in China, while genotype C was the dominant strain except for western region where genotype D was the prevalent strain. The main subgenotypes of genotypes B and C were B2 (87.5%, 63/72) and C2 (92.9%, 407/438), respectively.

CONCLUSIONS

The low-cost nPCR method would be a useful tool for clinical and epidemiological investigation in the regions where genotypes A-D are predominant.

Aqua-bis-(4-chloro-2-hy-droxy-benzoato-κO)(1,10-phenanthroline-κN,N')zinc(II)

In the title compound, [Zn(C(7)H(4)ClO(3))(2)(C(12)H(8)N(2))(H(2)O)], the Zn(II) cation is coordinated by two 4-chloro-2-salicylate anions, one 1,10-phenanthroline ligand and one water mol-ecule in a square-pyramidal coordination geometry; the Zn cation lies 0.4591 (11) Å from the basal plane. The benzene rings of the anions are involved in π-π stacking. The centroid-centroid distance between parallel benzene rings of adjacent mol-ecules is 3.9017 (17) Å, and the centroid-centroid distance between benzene and pyridine rings of adjacent mol-ecules is 3.584 (2) Å. Intra-molecular O-H⋯O hydrogen bonding is present.

Dichloridobis(isoquinoline-κN)zinc(II)

In the title compound, [ZnCl₂(C₉H₇N)₂], the Zn^II cation is coordinated by two Cl⁻ anions and two isoquinoline ligands in a distorted ZnCl₂N₂ tetra­hedral geometry; the two isoquinoline ring systems are twisted with respect to each other at a dihedral angle of 45.72 (8)°. The parallel isoqiunoline ring systems of adjacent mol­ecules are partially overlapped, with the shorter face-to-face distance of 3.438 (19) Å indicating the existence of weak π–π stacking in the crystal structure.

catena-Poly[[diaqua-bis-(isoquinoline-κN)cobalt(II)]-μ-succinato-κO:O]

In the title compound, [Co(C₄H₄O₄)(C₉H₇N)₂(H₂O)₂]_n, the Co^II cation, located on an inversion center, is coordinated by two succinate anions, two isoquinoline ligands and two water mol­ecules in a distorted octa­hedral geometry. The succinate anion, located across another inversion center, bridges the Co cations, forming polymeric chains running along the b axis. The partially overlapped arrangement of parallel isoquinoline ring systems of adjacent polymeric chains and the shorter face-to-face distance of 3.402 (6) Å indicates the existence of weak π–π stacking in the crystal structure. Classical intra- and inter­molecular O—H⋯O hydrogen bonding and weak non-classical inter­molecular C—H⋯O hydrogen bonding help to stabilize the crystal structure.

Bis(μ-2,4-dihy-droxy-benzoato-κO:O')bis-[aqua-(2,4-dihy-droxy-benzoato-κO)(1,10-phenanthroline-κN,N')cadmium(II)]

In the title centrosymmetric dimeric Cd^II complex, [Cd₂(C₇H₅O₄)₄(C₁₂H₈N₂)₂(H₂O)₂], the Cd^II cation is coord­inated by a bidentate phenanthroline (phen) ligand, three dihy­droxy­benzoate (dhba) anions and one water mol­ecule in a distorted CdN₂O₄ octa­hedral geometry. Among the dhba anions, two anions bridge two Cd^II cations to form the dimeric complex with significant different Cd—O bond distances of 2.2215 (19) and 2.406 (2) Å. The centroid–centroid distance of 3.4615 (19) Å between two nearly parallel benzene rings of the dhba and phen ligands coordinating to the same Cd^II cation indicates the existence of intra­molecular π–π stacking in the complex. Extensive O—H⋯O hydrogen bonding and inter­molecular weak C—H⋯O hydrogen bonding help to stabilize the crystal structure. One hy­droxy group of the monodentate dhba ligand is disordered over two sites with a site-occupancy ratio of 0.9:0.1.

Bis(μ-4-chloro-2-oxidobenzoato)bis-[(1,10-phenanthroline)copper(II)] dihydrate

The structure of the the title compound, [Cu₂(C₇H₃ClO₃)₂(C₁₂H₈N₂)₂]·2H₂O, consists of a dimeric unit involving a planar Cu₂O₂ group arranged around an inversion center. The coordination sphere of the Cu^II atom can be described as an elongated distorted square pyramid where the basal plane is formed by the two N atoms of the 1,10-phenanthroline mol­ecule and the two O atoms of the hydroxy­chloro­benzoate (hcbe) anion. The long apical Cu—O distance of 2.569 (2) Å involves the O atom of a symmetry-related hcbe anion, building up the dinuclear unit. Each dinuclear unit is connected through O—H⋯O hydrogen bonds involving two water mol­ecules, resulting in an R₄²(8) graph-set motif and building up an infinite chain parallel to (10). C—H⋯O inter­actions further stabilize the chain.

Bis(μ-imino-diacetato)bis-[(2,2'-diamino-4,4'-bi-1,3-thia-zole)lead(II)] tetra-hydrate

In the crystal structure of the title compound, [Pb(2)(C(4)H(5)NO(4))(2)(C(6)H(6)N(4)S(2))(2)]·4H(2)O, the dinuclear Pb(II) complex mol-ecule is centrosymmetric. The Pb atom is chelated by a tridentate imino-diacetate anion (IDA) and a diamino-bithia-zole (DABT) ligand, while a carboxyl-ate O atom from an adjacent IDA anion further bridges the Pb atom with a longer Pb-O bond [2.892 (3) Å]. The lone-pair electrons of the Pb atom occupy an axial site in the Ψ-penta-gonal-bipyramidal coordination polyhedron. The IDA anion displays a facial configuration: its chelating five-membered rings assume an envelope configuration. Within the DABT ligand, the two thia-zole rings are twisted relative to each other, making a dihedral angle of 9.51 (17)°. Extensive N-H⋯O, O-H⋯O and weak C-H⋯O hydrogen bonding helps to stabilize the crystal structure.

Poly[[tris-(μ(3)-2-oxidopyridinium-3-carboxyl-ato)manganese(II)sodium(I)] monohydrate]

In the crystal structure of the title compound, {[MnNa(C₆H₄NO₃)₃]·H₂O}_n, the Mn^II cation is located on a threefold rotation axis and is chelated by three 2-oxidopyridinium-3-carboxyl­ate (opc) anions in an octa­hedal coordination. The Na^I cation is located on a threefold rotation axis and is surrounded by six O atoms from three opc anions. The opc anions link the Mn and Na cations, forming a three-dimensional polymeric structure. The uncoordinated water mol­ecule, located on a threefold rotation axis, is equally disordered over two sites. The three-dimensional network is consolidated by N—H⋯O hydrogen bonds.

Tetra-kis(μ(2)-phenyl-acetato-κO:O')bis-[(isoquinoline-κN)copper(II)]

In the title centrosymmetric binuclear Cu(II) complex, [Cu(2)(C(8)H(7)O(2))(4)(C(9)H(7)N)(2)], the two Cu cations are bridged by four carboxyl-ate groups of the phenyl-acetate anions; each Cu cation is further coordinated by an isoquinoline ligand to complete the distorted CuO(4)N square-pyramidal geometry. The Cu cation is displaced by 0.2092 (8) Å from the basal plane formed by the four O atoms. Within the dinuclear mol-ecule, the Cu⋯Cu separation is 2.6453 (6) Å. Although a parallel, overlapped arrangement of isoquinoline ligands exists in the crystal structure; the longer face-to-face distance of 3.667 (5) Å suggests there is no π-π stacking between isoquinoline ring systems.

Bis(1H-imidazole-κN)bis-(2-oxidopyridinium-3-carboxyl-ato-κO,O)cobalt(II)

In the mol-ecule of the title Co(II) complex, [Co(C(6)H(4)NO(3))(2)(C(3)H(4)N(2))(2)], the Co(II) atom is located on a twofold rotation axis and chelated by two oxidopyridiniumcarboxyl-ate anions and further cis-coordinated by two imidazole ligands in a distorted octa-hedral geometry. The shorter C-O bond distance of 1.260 (2) Å suggests electron delocalization between the oxido group and the pyridinium ring. The uncoordinated carboxyl-ate O atom links with the imidazole and pyridinium rings of adjacent mol-ecules via N-H⋯O hydrogen bonding. Weak C-H⋯O hydrogen bonding is also present in the crystal structure.

Bis[4-(4-pyridyl)pyridinium] μ-4,4'-bipyridine-bis-[tetra-aqua-(4,4'-bipyridine)manganese(II)] bis-(5-sulfonatobenzene-1,3-dicarboxyl-ate) 4,4'-bipyridine solvate penta-deca-hydrate

The crystal structure of the title compound, (C₁₀H₉N₂)₂[Mn₂(C₁₀H₈N₂)₃(H₂O)₈](C₈H₃O₇S)₂·C₁₀H₈N₂·15H₂O, consists of dinuclear Mn^II complex cations, sulfonato­benzene­dicarboxyl­ate trianions, 4-(4-pyridyl)pyridinium cations, uncoordin­ated 4,4′-bipyridine and uncoordinated water mol­ecules. One 4,4′-bipyridine mol­ecule bridges two Mn atoms, forming a centrosymmetric dinuclear complex; the mid-point of the C—C bond linking the pyridine rings of the bridging ligand is located on an inversion center. Each Mn^II atom is coordinated by four water and two 4,4′-bipyridine mol­ecules in a distorted octa­hedral geometry. The Mn^II atom deviates by 0.591 (5) and 0.209 (2) Å from the mean planes of the coordinated pyridine rings. In the 4-(4-pyridyl)pyridinium cation, the two pyridine rings are twisted with respect to each other, making dihedral angle of 34.78 (17)°. The uncoordinated bipyridine mol­ecule is also centrosymmetric. One of uncoordinated water mol­ecules has site symmetry 2, and the other uncoordinated water mol­ecule is located close to an inversion center and its one H atom is disordered equally over two sites. Extensive π–π stacking between pyridine rings is observed and an extensive hydrogen-bonding network of the types N—H⋯N, O—H⋯N and O—H⋯O is present.

Bis(1H-imidazole-κN)bis-(2-oxidopyridinium-3-carboxyl-ato-κO,O)nickel(II)

In the crystal structure of the title Ni^II complex, [Ni(C₆H₄NO₃)₂(C₃H₄N₂)₂], the Ni^II atom is located on a twofold rotation axis and is chelated by two oxidopyridiniumcarboxyl­ate anions and further cis-coordinated by two imidazole ligands in a distorted cis-N₂O₄ octa­hedral geometry. The C—O bond distance of 1.2573 (19) Å found for the non-coordinating O atom of the carboxyl­ate group indicates significant delocalization of π-electron density over this residue. Similarly, the C—O bond distance of 1.260 (2) Å in the heteroaromatic ring indicates delocalization between the deprotonated hydr­oxy group and the pyridinium ring. The uncoordinated carboxyl­ate O atom links with the imidazole and pyridinium rings of adjacent mol­ecules via N—H⋯O and C—H⋯O hydrogen bonding, leading to a two-dimensional array parallel to (100).

Bis(3-hydroxy-pyridine-κN)bis-(3-nitro-benzoato-κO)zinc(II)

The title complex, [Zn(C(7)H(4)NO(4))(2)(C(5)H(5)NO)(2)], has site symmetry 2. The Zn(II) ion is located on a crystallographic twofold rotation axis and assumes a distorted tetra-hedral ZnN(2)O(2) coordination geometry. Mol-ecules are linked by an inter-molecular O-H⋯O hydrogen bond and π-π stacking inter-actions between pyridine rings [centroid-centroid speparation 3.594 (1) Å].

Tetra-μ(2)-acetato-κO:O'-bis-[(isoquinoline-κN)copper(II)]

In the crystal structure of the title compound, [Cu(2)(CH(3)COO)(4)(C(9)H(7)N)(2)], the Cu(II) cation is coordinated by four acetate anions and one isoquinoline mol-ecule in a distorted square-pyramidal geometry; the Cu(II) cation is 0.1681 (6) Å from the basal coordination plane formed by the four O atoms. Each acetate anion bridges two Cu(II) cations to form the centrosymmetric dinuclear complex. Within the dinuclear mol-ecule, the Cu⋯Cu separation is 2.6459 (4) Å. A parallel arrangement of isoquinoline ligands of adjacent complexes is observed in the crystal structure; the face-to-face distance of 3.610 (10) Å suggests there is no π-π stacking between isoquinoline ring systems.

Poly[bis-(μ(2)-pyrimidine-2-carboxyl-ato-κO,N:O',N')calcium]

In the crystal structure of the title polymeric complex, [Ca(C(5)H(3)N(2)O(2))(2)](n), the Ca(II) cation has site symmetry m2 and is N,O-chelated by four pyrimidine-2-carboxyl-ate anions in a square-anti-prismatic geometry. The planar pyrimidine-2-carboxyl-ate anion is located on a crystallographic special position, three C atoms have site symmetry 2mm, while the carboxyl O atom, the pyrimidine N atom and the other C atom have site symmetry m. Each pyrimidine-2--carboxyl-ate anion bridges two Ca(II) cations, forming polymeric sheets extending parallel to (001). π-π stacking exists between parallel pyrimidine rings [centroid-centroid distance = 3.6436 (6) Å] of adjacent polymeric sheets. Weak C-H⋯O hydrogen bonding is also observed between these sheets.

Aqua-(2,2'-bipyridine)bis-(4-hydroxy-benzoato)zinc(II)

In the title complex, [Zn(C₇H₅O₃)₂(C₁₀H₈N₂)(H₂O)], the Zn^II ion is coordinated by two 4-hydroxy­benzoate anions, one 2,2′-bipyridine mol­ecule and one water mol­ecule and displays a distorted octa­hedral geometry. One Zn—O bond [2.5300 (15) Å] is much longer than the others in the mol­ecule. In the crystal structure, the face-to-face separation of 3.547 (9) Å suggests no π–π stacking between parallel bipyridine ring systems, and an extensive O—H⋯O hydrogen-bonding network between the coordinated water molecule, the phenol group and carboxylate O atoms is present.

Hexakis(1H-imidazole-κN)cobalt(II) triaqua-tris(1H-imidazole-κN)cobalt(II) bis-(naphthalene-1,4-dicarboxyl-ate)

The asymmetric unit of the title compound, [Co(C₃H₄N₂)₆][Co(C₃H₄N₂)₃(H₂O)₃](C₁₂H₆O₄)₂, contains two halves of crystallographically independent Co^II complex cations, each assuming a distorted octa­hedral geometry, and one uncoordinated naphthalene-1,4-dicarboxyl­ate dianion. One Co^II cation is located on an inversion center and is coordinated by six imidazole mol­ecules, while the other Co^II cation is located on a twofold rotation axis and is coordinated by three water and three imidazole mol­ecules. The uncoordinated naphthalene-1,4-dicarboxyl­ate dianion links both Co^II complex cations via O—H⋯O and N—H⋯O hydrogen bonding. One imidazole ligand is equally disordered over two sites about a twofold rotation axis, while the coordinated N atom of the imidazole is located on the twofold rotation axis. One water O atom has site symmetry 2.

Bis(3-hydroxy-pyridinium) fumarate

The crystal structure of the title compound, 2C(5)H(6)NO(2) (+)·C(4)H(2)O(4) (2-), consists of 3-hydroxy-pyridinium cations and fumarate dianions. The dianion is located on an inversion center and the cation is linked to it by O-H⋯O and N-H⋯O hydrogen bonds. The cation is twisted with respect to the anion by 24.83 (5)°.

4-Acetyl-pyridine-fumaric acid (2/1)

In the crystal structure of the title cocrystal, 2C(7)H(7)NO·C(4)H(4)O(4), the complete fumaric acid mol-ecule is generated by a crystallographic inversion centre. The two components of the cocrystal are linked by an O-H⋯N hydrogen bond.

Poly[octa-μ-aqua-tetraaquabis(μ-5-sulfonatobenzene-1,3-dicarboxylato)cobalt(II)tetrasodium]

The title compound, [CoNa₄(C₈H₃O₇S)₂(H₂O)₁₂]_n, is a three-dimensional coordination polymer bridged by sulfoisophthalate trianions and water mol­ecules. The Co^II atom, located on an inversion centre, is coordinated by two carboxyl­ate groups of the sulfoisophthalate trianions and by four water mol­ecules in a distorted CoO₆ octa­hedral geometry. Two independent Na^I atoms also have a distorted octa­hedral coordination geometry formed by water, carboxyl­ate O and sulfonate O atoms. An extensive O—H⋯O and C—H⋯O hydrogen-bonding network is present in the crystal structure, as well as weak π-π stacking [centroid–centroid distance = 3.9553 (11) Å].

Poly[octa-μ-aqua-tetra-aqua-bis(μ(4)-5-sulfonatobenzene-1,3-dicarboxyl-ato)nickel(II)tetra-sodium]

In the crystal structure of the title compound, [Na(4)Ni(C(8)H(3)O(7)S)(2)(H(2)O)(12)](n), the Ni(II) cation occupies an inversion centre and is coordinated by the carboxyl groups of the sulfoisophthalate trianions and water mol-ecules in a distorted octa-hedral geometry. Two independent Na(I) atoms are connected by the carboxyl and sulfonate groups of the sulfoisophthalate ligands anions and water mol-ecules in a distorted octa-hedral geometry. The sulfoisophthalate ligands and coordinated water mol-ecules bridge the Ni(II) and Na(I) cations, forming a three-dimensional polymeric structure. Weak π-π stacking is present between parallel benzene rings [centroid-centroid distance = 3.9349 (10) Å]. Extensive O-H⋯O and C-H⋯O hydrogen bonding helps to stabilize the crystal structure.

Tetraaqua(2,2′-bipyridine-κ2N,N′)manganese(II) di-μ-aqua-bis[aqua(2,2′-bipyridine-κ2N,N′)(5-sulfonatoisophthalato-κO)manganate(II)] tetrahydrate

The crystal structure of the title salt, [Mn(C₁₀H₈N₂)(H₂O)₄][Mn₂(C₈H₃O₇S)₂(C₁₀H₈N₂)₂(H₂O)₄]·4H₂O, consists of mononuclear manganese(II) cations, dinuclear manganate(II) dianions and uncoordinated water mol­ecules. The dianion is located about an inversion center; the Mn^II atom is coordinated by a 2,2′-bipyridine ligand, a sulfonatoisophthalate group, a water mol­ecule along with two bridging water mol­ecules in an octa­hedral geometry. The cation lies on a twofold rotation axis; the Mn^II atom is coordinated by four water mol­ecules and a chelating 2,2′-bipyridine ligand in a distorted octa­hedral geometry. A partially overlapped arrangement between the bipyridine ligands and the aromatic ring of the sulfoisophthalate group of adjacent anions is observed; the distance (3.357 Å) indicates π–π stacking. Hydrogen bonds, with the water mol­ecules serving as hydrogen-bond donors, lead to a three-dimensional network architecture.

Hexakis(1H-imidazole-κN)nickel(II) triaqua-tris(1H-imidazole-κN)nickel(II) bis-(naphthalene-1,4-dicarboxyl-ate)

The crystal structure of the title compound, [Ni(C₃H₄N₂)₆][Ni(C₃H₄N₂)₃(H₂O)₃](C₁₂H₆O₄)₂, contains uncoordinated naphthalene­dicarboxyl­ate dianions and two kinds of Ni^II complex cations, both assuming distorted octa­hedral geometries. One Ni^II ion is located on an inversion center and is coordinated by six imidazole mol­ecules, while the other Ni^II ion is located on a twofold rotation axis and is coordinated by three water mol­ecules and three imidazole mol­ecules in a mer-NiN₃O₃ arrangement. The naphthalene­dicarboxyl­ate dianion links both Ni^II complex cations via O—H⋯O and N—H⋯O hydrogen bonding, but no π–π stacking is observed between aromatic rings in the crystal structure. One imidazole ligand is equally disordered over two sites about a twofold rotation axis; one N atom and one water O atom have site symmetry 2.

Triaqua-(3-carb-oxy-5-sulfonatobenzoato-κO)(1,10-phenanthroline-κN,N')cobalt(II) monohydrate

In the title compound, [Co(C₈H₄O₇S)(C₁₂H₈N₂)(H₂O)₃]·H₂O, the Co^II cation is coordinated by one sulfoisophthalate dianion, one bidentate phenathroline (phen) mol­ecule and three water mol­ecules in a distorted cis-CoN₂O₄ octa­hedral geometry. In the crystal structure, aromatic π–π stacking occurs [centroid–centroid distances 3.7630 (14) and 3.7269 (15) Å], as well as an extensive O—H⋯O and C—H⋯O hydrogen-bonding network

catena-Poly[[[aqua-bis(1H-imidazole-κN)copper(II)]-μ-naphthalene-1,4-dicarboxyl-ato-κO:O] dihydrate]

In the title compound, {[Cu(C₁₂H₆O₄)(C₃H₄N₂)₂(H₂O)]·2H₂O}_n, the Cu^II cation is coordinated by two naphthalene-1,4-dicarboxyl­ate (naph) dianions, two imidazole mol­ecules and one water mol­ecule in a distorted square-pyramidal geometry. The Cu—O bond distance in the apical direction is 0.509 (3) Å longer than the mean Cu—O bond distance in the basal plane. The naph dianion bridges two Cu^II cations, forming a one-dimensional polymeric chain. The coordinated water mol­ecule is hydrogen-bonded to the carboxylate groups and imidazole ligands of adjacent polymeric chains, forming a three-dimensional supra­molecular structure. No π–π stacking is observed in the crystal structure. One solvent water molecule is disordered equally over two positions.

Bis(2,5-dihydroxy-benzoato-κO)bis-(1,10-phenathroline-κN,N')cadmium(II) 1.25-hydrate

In the crystal structure of the title compound, [Cd(C(7)H(5)O(4))(2)(C(12)H(8)N(2))(2)]·1.25H(2)O, the Cd(2+) cation is coordinated by two phenanthroline (phen) mol-ecules and two 2,5-dihydroxy-benzoate (dhba) anions in a distorted octa-hedral geometry. The centroid-centroid distances of 3.809 (2) and 3.680 (2) Å between nearly parallel pyridine rings of the phen ligands and the benzene rings of dhba anions indicate that the dhba anions are involved in π-π stacking in the crystal structure. The face-to-face separation of 3.35 (3) Å between parallel phen ring systems also suggests π-π stacking between adjacent complex mol-ecules. The crystal structure contains extensive O-H⋯O and C-H⋯O hydrogen bonding.

cis-Dichloridobis(1,10-phenanthroline-κ2N,N′)manganese(II)–2,6-dihydroxybenzoic acid–water (2/1/4)

In the crystal structure of the title compound, [MnCl₂(C₁₂H₈N₂)₂]·0.5C₇H₆O₄·2H₂O, the Mn^II complex assumes a distorted octa­hedral geometry formed by two chloride anions and two phenanthroline (phen) ligands. The 2,6-dihydroxy­benzoic acid mol­ecule is disordered about an inversion center. The face-to-face separations of 3.540 (11) and 3.429 (8) Å between parallel phen ligands indicate the existence of π–π stacking between adjacent Mn^II complexes. Uncoordinated water mol­ecules are linked with complex and dihydroxy­benzoic acid mol­ecules via O—H⋯Cl and O—H⋯O hydrogen bonds.

1,10-Phenanthrolinium 4-chloro-2-hydroxy-benzoate-1,10-phenanthroline-4-chloro-2-hydroxy-benzoic acid (1/1/1)

The title compound, C(12)H(9)N(2) (+)·C(7)H(4)ClO(3) (-)·C(12)H(8)N(2)·C(7)H(5)ClO(3), contains one phenanthrolinium (Hphen) cation, one phenanthroline (phen) mol-ecule, one 4-chloro-2-hydroxy-benzoate anion (hcba) and one 4-chloro-2-hydroxy-benzoic acid (Hhcba) mol-ecule in the asymmetric unit. The phen mol-ecule is approximately parallel to Hphen, making a dihedral angle of 1.98 (6)°. The centroid-centroid distance between pyridine rings of adjacent phen and Hphen species is 3.7718 (15) Å, and that between the benzene and pyridine rings of adjacent phen and Hphen species is 3.7922 (16) Å, indicative of π-π stacking inter-actions. The crystal structure contains an extensive network of classical (O-H⋯O, N-H⋯N and O-H⋯Cl) and weak (C-H⋯O and C-H⋯N) hydrogen bonds. Finally, C-H⋯π inter-actions are seen between Hphen and hcba and between phen and Hhcba in the crystal structure. The hydroxy group of the anion is disordered over the two sites ortho to the carboxylate group in a 0.75:0.25 ratio.

2-Amino-4-methyl-pyridinium 4-amino-benzoate

In the structure of the title salt, C₆H₉N₂⁺·C₇H₆NO₂⁻, the 4-amino­benzoate anions are linked to adjacent anions and 2-amino-4-methyl­pyridinium cations via N—H⋯O hydrogen bonds, forming a three-dimensional supra­molecular structure. The crystal structure also shows a weak C—H⋯O hydrogen bond between adjacent anions. Within the 4-amino­benzoate anion, the carboxyl­ate group is twisted by 14.0 (4)° with respect to the benz­ene ring.

Tetraaquabis(pyridine-3-sulfonato-κN)nickel(II)

In the mol­ecule of the title compound, [Ni(C₅H₄NO₃S)₂(H₂O)₄], the Ni^II cation is located on an inversion center and is coordinated by four water mol­ecules and two pyridine-3-sulfonate anions with an NiN₂O₄ distorted octa­hedral geometry. The face-to-face separation of 3.561 (5) Å between parallel pyridine rings indicates the existence of weak π–π stacking between the pyridine rings. The structure also contains inter­molecular O—H⋯O hydrogen bonding and weak C—H⋯O hydrogen bonding.

Hexakis(1H-imidazole-κN)mangan-ese(II) triaqua-tris(1H-imidazole-κN)manganese(II) bis-(naphthalene-1,4-dicarboxyl-ate)

In the crystal structure of the title compound, [Mn(C₃H₄N₂)₆][Mn(C₃H₄N₂)₃(H₂O)₃](C₁₂H₆O₄)₂, there are uncoordinated naphthalene­dicarboxyl­ate dianions and two kinds of Mn^II complex cations, both assuming a distorted octa­hedral geometry. One Mn^II cation is located on an inversion center and is coordinated by six imidazole mol­ecules, while the other Mn^II cation is located on a twofold rotation axis and is coordinated by three water mol­ecules and three imidazole units. The naphthalene­dicarboxyl­ate dianions are linked to both Mn^II complex cations via O—H⋯O and N—H⋯O hydrogen bonding, but no π–π stacking is observed between aromatic rings in the crystal structure.

Eplerenone ethanol solvate

Eplerenone [systematic name: 7α-(methoxy­carbon­yl)-3-oxo-9α,11-ep­oxy-17α-pregn-4-ene-21,17-carbolactone], an aldo­sterone receptor antagonist, crystallizes from ethanol as a monosolvate, C₂₄H₃₀O₆·C₂H₆O. The eplerenone mol­ecule has two five-membered rings, three six-membered rings and one three-membered ring. Both five-membered rings display envelope conformations, while the three six-membered rings assume envelope (cyclohexene), half-chair (cyclohexane sharing one edge with epoxy) and chair (other cyclohexane) conformations. The solvent mol­ecule is disordered equally over two sites. It is linked to the eplerenone mol­ecule by hydrogen bonds.

cyclo-Tetra-μ-malato-κO,O',O'':O'''-tetra-kis[bis-(1H-benzimidazole-κN)cobalt(II)] eicosa-hydrate

The title compound, [Co₄(C₄H₄O₅)₄(C₇H₆N₂)₈]·20H₂O, consists of tetra­nuclear Co^II complexes and disordered uncoordinated water mol­ecules. The tetra­meric complex mol­ecule has symmetry. While two benzimidazole mol­ecules and a tridentate malate dianion coordinate a Co^II ion, the carboxylate O atom from an adjacent malate dianion bridges the Co^II ions to complete a distorted octa­hedral coordination geometry. The tridentate malate dianion chelates the Co^II ion, and the chelate six- and five-membered rings show half-chair and envelope configurations, respectively. A face-to-face separation of 3.494 (9) Å between parallel benzimidazole ligands indicates the existence of π–π stacking between adjacent complexes. The crystal structure also involves N—H⋯O and O—H⋯O hydrogen bonds.

Bis(μ-3-hydroxy-benzoato)-κO:O;κO:O-bis-[bis-(1H-benzimidazole-κN)(3-hydroxy-benzoato-κO)nickel(II)] bis-(1H-benzimidazole-κN)bis-(3-hy-droxy-benzoato-κO)nickel(II) hexa-hydrate

The title compound, [Ni(2)(C(7)H(5)O(3))(4)(C(7)H(6)N(2))(4)][Ni(C(7)H(5)O(3))(2)(C(7)H(6)N(2))(2)]·6H(2)O, is a mononuclear/dinuclear nickel(II) cocrystal, the two mol-ecular species inter-acting through hydrogen bonds that involve the uncoordinated water mol-ecules. In the mononuclear species, the Ni(II) ion, located on an inversion center, is coordinated by two 1H-benzimidazole (bzim) ligands and two 3-hydroxy-benzoate (hba) anions in a square-planar geometry. In the centrosymmetric dinuclear species, the Ni(II) ion is coordinated by two bzim ligands and three hba anions in a square-pyramidal geometry; of the two independent hba anions, one bridges two Ni(II) ions with both carboxylate and hydroxyl groups whereas the other coordin-ates in a unidentate manner to the Ni(II) ion. The apical Ni-O(hydrox-yl) bond is 0.39 Å longer than the basal Ni-O(carbox-yl) bonds. The face-to-face separation of 3.326 (9) Å indicates the existence of π-π stacking between parallel bzim ligands of adjacent dinuclear entities. Extensive N-H⋯O and O-H⋯O hydrogen bonds help to stabilize the crystal structure.

Aqua-(3-hydroxy-benzoato-κO)bis-(1,10-phenanthroline-κN,N')cobalt(II) 3-hydroxy-benzoate penta-hydrate

The crystal structure of the title compound, [Co(C₇H₅O₃)(C₁₂H₈N₂)₂(H₂O)](C₇H₅O₃)·5H₂O, consists of Co^II complex cations, uncoordinated hydroxy­benzoate anions and uncoord­inated water mol­ecules. The Co^II ion is coordinated by two phenanthroline ligands, a water mol­ecule and a 3-hydroxy­benzoate anion, and displays a distorted octa­hedral geometry. π–π stacking is observed between parallel phenanthroline ligands, the face-to-face separations being 3.454 (19) and 3.435 (7) Å. An extensive hydrogen-bonding network helps to stabilize the crystal structure. The hydroxybenzoate ligand is disordered over two positions, with site occupancy factors 0.6 and 0.4. One solvent water molecule is also disordered over two positions, with site occupancy factors 0.6 and 0.4.

Diaqua-bis(pyrimidine-2-carboxylic acid-κN,O)cobalt(II) dichloride

In the title salt, [Co(C(5)H(4)N(2)O(2))(2)(H(2)O)(2)]Cl(2), the Co(II) ion is located on an inversion center. It is chelated by two neutral pyrimidine-2-carboxylic acid molecules and is coordinated by two water mol-ecules in an octa-hedral coordination geometry. The cations and anions are linked via O-H⋯Cl hydrogen bonds into a layer structure; an intra-molecular O-H⋯N hydrogen bond connects the carboxylic acid group to the pyrimidine N atom.