The first series of niobium-tungsten-lanthanide (Nb-W-Ln) heterometallic polyoxometalates {Ln W O (H O) (Nb O ) } (Ln=Y, La, Sm, Eu, Yb) have been obtained, which are comprised of giant cluster-in-cluster-like ({Ln W }-in-{Nb }) structures built from 12 hexaniobate {Nb O } clusters gathered together by a rare 24-nuclearity sodalite-type heterometal-oxide cage {Ln W O (H O) }. The Nb-W-Ln clusters present the largest multi-metal polyoxoniobates and a series of rare high-nuclearity 4d-5d-4f multicomponent clusters. Furthermore, the giant Nb-W-Ln clusters may be isolated as discrete inorganic alkali salts and can be used as building blocks to form high-dimensional inorganic-organic hybrid frameworks.

A series containing the highest nuclearity polyoxoniobate (PONb) nanoclusters, ranging from dimers to tetramers, has been obtained. They include one 114-nuclear {Li ⊂Nb O }, one 81-nuclear {Li K⊂Nb O }, and one 52-nuclear {H Nb O }. The Nb nuclearity of these PONbs is remarkably larger than those of all known high-nuclearity PONbs (≤32). Furthermore, the introduction of 3d Cu ions can lead to the generation of extended inorganic-organic hybrid frameworks built from novel, high-nuclearity, nanoscale heterometallic PONb building blocks {H Cu Nb O } or {H Cu (en)Nb O }. These building blocks also contain the largest number of Nb centers of any heterometallic PONbs reported to date. The synthesis of new-type PONbs has long been a challenging subject in PONb chemistry.

A protein-sized (ca. 4.2×4.2×3.6 nm ) non-biologically derived molecule {Nb O (OH) (CO ) } (Nb ) containing up to 288 niobium atoms has been obtained, which is by far the largest and the highest nuclearity polyoxoniobate (PONb). Particularly, in terms of metal nuclearity number, Nb is the second largest cluster so far reported in classic polyoxometalate chemistry (V, Mo, W, Nb, and Ta). Nb can be described as a giant windmill-like cluster aggregate of six nanoscale high-nuclearity PONb units {Nb O (OH) (CO ) } (Nb ) joined together by six additional Nb ions. Interestingly, the 47-nuclearity Nb units generated in situ can be isolated and bridged by copper complexes to form an inorganic-organic hybrid three-dimensional PONb framework, which exhibits effective catalytic activity for hydrolyzing nerve agent simulant of dimethyl methylphosphonate. The unique Nb cluster also provides a new type of topology to very limited family of Nb-O clusters.

IntroductionChild emotional or behavioral problems and insufficient social development has been a heavy burden on family and society. However, currently large-scale studies on emotional and behavioral problems as well as social competence among school children in China are still lacking. This cross-sectional study analyzed the current status and risk factors of behavioral problems and social competences in Beijing students.MethodA total of 9,295 students, with ages ranging from 6 to 16 years old, were enrolled in the study. The Child Behavior Checklist (CBCL) was used to screen emotional and behavioral problems, social competences of students. We then assessed significant predictors factors associated with children behavioral problems and social competences.ResultsThe total detection rate of behavioral problems of this cohort was 16.7%. All kinds of social competence scores of boys were lower than girls (P <0.05). The scores of social and learning ability in children with behavioral problems were significantly lower than those without behavior problems (P <0.05). Gender, developmental delay, recent life events, negative relationships and negative child-rearing styles were the shared influencing factors for behavioral problems and social competence. In addition, age, macrosomia, threatened abortion, hospitalization for physical illness, physical illness, poor sleep were independent risk factors for children's emotional and behavioral problems, and non-breastfeeding was an independent risk factor for abnormal social competence.ConclusionThe social competence, emotional and behavioral problems are serious among students in Beijing. More attention should be paid to mental health and effective intervention measures should be provided.