Recurrent abdominal pain, headache and limb pains in children and adolescents

Ligand-Directed Metalation of a Gold Pyrazolate Cluster

Solid "[AuL]" (HL = 3-[pyrid-2-yl]-5-tertbutyl-1H-pyrazole) can be crystallized as cyclic [Au₃(μ-L)₃] and [Au₄(μ-L)₄] clusters from different solvents. The crystalline tetramer contains a square Au₄ core with an HT:TH:TH:HT arrangement of ligand substituents, which preorganizes the cluster to chelate to additional metal ions via its pendant pyridyl groups. The addition of 0.5 equiv of AgBF₄ to [AuL] yields [Ag₂Au₄(μ₃-L)₄][BF₄]₂, where two edges of the Au₄ square are spanned by Ag⁺ ions via metallophilic Ag···Au contacts. Treatment of [AuL] with [Cu(NCMe)₄]PF₆ affords the metalloligand helicate [Cu₂Au₂(μ-L)₄][PF₆]₂, via oxidation of the copper and partial fragmentation of the cluster.

A heterometallic Cd/Ag/Se complex incorporating 3-ferrocenyl-5-(2-pyridyl)pyrazolato (fcpp) ligands: synthesis and structure of [Cd2{Ag(SePh)}2(μ3-OH2)2(μ2,η3-fcpp)4]·2C3H6O

A self-assembly reaction of Cd(NO3)2 · 4H2O, 3-ferrocenyl-5-(2-pyridyl)-pyrazole (Hfcpp), [Ag(SePh)] n , and Et3N in a mixed acetone-water solvent resulted in the formation of a heterometallic complex [Cd2{Ag(SePh)}2 (μ 3-OH2)2(μ 2,η 3-fcpp)4] · 2C3H6O (1) with a phenylselenolate ligand. The two cadmium and two silver centers are linked by four [μ 2,η 3-fcpp]− ligands and two μ 3-OH2 water molecules. Each Cd atom is in a slightly distorted octahedral coordination environment, while each Ag atom shows a distorted tetrahedral coordination geometry, which is composed of two pyrazolyl nitrogen atoms, one selenium atom, and one oxygen atom.

Growing pains: What do we know about etiology? A systematic review

BACKGROUND

Growing pains is the most common cause of musculoskeletal pain in early childhood and was first described in 1823 by French physician Marcel Duchamp. Although it has been researched extensively, the etiology is still unknown. Several theories have been proposed throughout the years.

AIM

Analyze the available scientific literature to provide an update on the latest evidence on the etiology.

METHODS

According to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, the scientific literature on the etiology of growing pains was systematically reviewed using the following inclusion criteria: studies of any level of evidence reporting clinical or preclinical results and dealing with the etiology of growing pains. The medical electronic databases PubMed and Web of Science were searched by two independent authors on October 20, 2018. The search string used was “(growing pains OR benign nocturnal limb pains OR musculoskeletal pains) AND (etiology OR pathogenesis) AND (pediatrics)”.

RESULTS

A total of 32 articles were included. The etiology of growing pains still remains poorly understood. Many theories have been proposed, but none of them are decisive. A lower pain threshold has been found among patients suffering from growing pains in comparison to healthy controls. Furthermore, evidence suggests an association between growing pains and reduced bone strength in young patients, although this finding still remains controversial. Changes in the vascular perfusion pattern have also been studied. However, the etiology of growing pains does not seem related to a vascular component. The anatomical/mechanical theory has not been supported, but the role of vitamin D deficiency has been investigated many times. Strong recent evidence indicates a genetic susceptibility in the pathogenesis of growing pains. Furthermore, psychological factors also seem to play a strong role in the onset.

CONCLUSION

The scientific literature about the etiology of growing pains presents heterogeneity and lack of consensus; more studies are needed to understand the genesis of benign musculoskeletal pain syndrome of childhood.

Turning a "useless" ligand into a "useful" ligand: a magneto-structural study of an unusual family of Cu(II) wheels derived from functionalised phenolic oximes

While the phenolic oximes (R-saoH2) are well known for producing monometallic complexes of the type [M(II)(R-saoH)2] with Cu(II) ions in near quantitative yield, their derivatisation opens the door to much more varied and interesting coordination chemistry. Here we show that combining the complimentary diethanolamine and phenolic oxime moieties into one organic framework (H4L1 and H4L2) allows for the preparation and isolation of an unusual family of [Cu(II)]n wheels, including saddle-shaped, single-stranded [Cu(II)8] wheels of general formula [Cu8(HL1)4(X)4](n)[Y] (when n = 0, X = Cl(-), NO3(-), AcO(-), N3(-); when n = 2+ X = (OAc)2/(2,2'-bpy)2 and Y = [BF4]2) and [Cu8(HL2)4(X)4] (X = Cl(-), Br(-)), a rectangular [Cu6(HL1)4] wheel, and a heterometallic [Cu4Na2(HL1)2(H2L1)2] hexagon. Magnetic studies show very strong antiferromagnetic exchange between neighbouring metal ions, leading to diamagnetic ground states in all cases. DFT studies reveal that the magnitude of the exchange constants are correlated to the Cu-N-O-Cu dihedral angles, which in turn are correlated to the planarity/puckering of the [Cu(II)]n rings.

Pyrazoles and pyrazolides-flexible synthons in self-assembly

This Perspective summarises the chemistry of the pyrazole ring, and reviews the metal coordination modes adopted by 1H-pyrazoles and their anions. Pyrazolide anions are probably the most versatile ligands in coordination chemistry, with 20 different terminal or bridging coordination modes having been identified so far. Metal cluster compounds supported by pyrazolido ligation are surveyed, concentrating on those reported during the past ten years. Highlights include the wide structural diversity in apparently simple main group pyrazolides; luminescence and charge-transfer complexes in coinage metal pyrazolide clusters; the use of robust metal pyrazolide clusters to construct liquid crystals, supramolecular materials and metal-organic frameworks; and supramolecular complexes formed by pyrazolide-supported metallacrowns.