Heavier Group Research Articles

Structures and bonding of C2X2Yq(X=Si,Ge,Sn,Pb; Y=C,Si,Ge,Sn,Pb; q = +1,0,−1): π-type templates for planar tetracoordinate heavier group 14 atoms

ABSTRACTContrasting the big family of the planar tetracoordinate carbon (ptC), species featuring the planar tetracoordinate heavier group element M (ptM) have been largely limited. Effective structural frameworks to accommodate such ptM centres are thus highly desired. In the present article, we report an extensive computational study on 60 pentatomic systems C2X2Yq (X=Si,Ge,Sn,Pb; Y=C,Si,Ge,Sn,Pb; q = +1,0,−1) covering both the low and high spin states. Up to 34 systems were shown to have the very low-lying singlet planar tetracoordinate heavier group 14 (ptM with M=Si,Ge,Sn,Pb) structures bearing the 19 (q = +1), 20 (q = 0) and 21 (q = −1) valence electrons (ve). Structural and bonding analysis confirmed the effectiveness of the inherent π-type ligand skeleton XCCX or XCCY that each have several sets of π-bonding orbitals to stabilise the ptM centre. The structural and bonding motifs of these ptMs differ greatly from the classic ptMs, which have the σ-type ligand skeleton, smaller number of valence electrons (≤18ve), and the centre → ligand π-delocalisation.

Reduced risk factors of metabolic syndrome in immigrant compared to resident South Asian Indian young men

South Asian Indians are at higher risk for developing metabolic syndrome (MetS) than the general USA population, and at risk of developing diabetes and cardiovascular disease. We hypothesized that USA (immigrant) SA men develop MetS in their early adulthood to a greater extent than men living in India (resident), and this is due to a combination of dietary changes and stress. We examined 73 men (ages of 19–29 y; BMI >23 kg/m2) in the USA and in India. Because a heavier group was recruited in India than in the USA, we used ANCOVA in all analysis, to control for BMI. In contrast to our hypothesis, immigrant compared to resident Indians had lower total cholesterol (165±37 vs 183±31 mg/dl), low density lipoprotein (LDL) (95 ± 33 vs. 122 ± 27 mg/dl) and higher high density lipoprotein (HDL) (49 ±10 vs. 41±6 mg/dl) (p < 0.05). Glucose was 89±6 in immigrants and 93±7 mg/dl in resident Indians (p≤0.06). Systolic blood pressure was lower in immigrant (113±13) than resident Indians (130±11) (p < 0.001), and USA men also had a lower perceived stress score (p<0.05). This was consistent with fewer risk factors for MetS in immigrant than resident Indians (i.e., 10% vs 26% had at least 2 components of MetS). We also found that men in the USA were taller (p <0.001) and that the percent protein intake was greater in immigrant (20 ± 9%) than resident men (12 ±6%; p < 0.001), whereas the lower %fat intake (22±11% vs. 37±9%) did not differ significantly between the groups. Interestingly, men living in the USA > 10 years (vs shorter duration) had higher serum HDL levels (p <0.05), suggesting a possible effect of acculturation. Immigrant Indian young men living in the USA are at lower risk for MetS, possibly due to lower stress compared to their resident Indian counterparts.Support or Funding InformationCenter for Global Advancement and International Affairs (Rutgers GAIA)

Synthesis and properties of stable alumoles

GRAPHICAL ABSTRACT

ChemInform Abstract: Group 14 Inorganic Hydrocarbon Analogues

AbstractReview: [118 refs.

The Route to Phosphabenzene and Beyond

AbstractThis article presents the background of the author's synthesis of phosphabenzene in 1971. It also expands to tell the story behind the syntheses of the heavier group 15 heterobenzenes: arsabenzene, stibabenzene, and bismabenzene, which were prepared nearly at the same time and by a largely similar route.

Same Program, Different Outcomes: Understanding Differential Effects from Access to Free, High-Quality Early Care

The Infant Health and Development Program (IHDP) was designed to promote the development of low-birth weight (up to 2,500 grams) and premature (up to 37 weeks gestational age) infants. There is evidence that the IHDP intervention, a randomly-assigned bundle of services including primarily free, high-quality child care from 12 to 36 months, boosted cognitive and behavioral outcomes by the time participants at the end of the intervention. The literature has established that the intervention was more effective among the subsample of heavier low birth weight (2,000-2,500 grams) than among those born lighter. Among the heavier group, it was more effective for children from lower-income families. Families who participated in the intervention were diverse in key observable characteristics like income, race or ethnicity. In addition, families reallocated their time in different ways when then had the opportunity to use the free services provided by the IHDP. The goal of this paper is to understand the economic decisions and constraints faced by households who gained access to the IHDP and explain their differential behavior. In order to do so, we propose an economic model, construct measures of theoretically-relevant drivers of postnatal investment decisions, and explore patterns of heterogeneity in parental response and child development along these dimensions.

Heavier group 2 metal complexes with a flexible scorpionate ligand based on 2-mercaptopyridine

Synthetic and structural details of flexible scorpionate ligand based on 2-mercaptopyridine (Bmp) supported heavier alkaline earth metal complexes with metal–sulfur bonds (metal = Sr, Ba) have been presented.

2-Adamantylidene and its heavier analogues: hyperconjugation versus lone pair stability and electrophilicity versus nucleophilicity.

The structure, bonding and reactivity of 2-adamantylidene and its heavier group-14 analogues, 2X (X10H14, X = C-Sn), have been studied at the M06/def2-TZVPP//BP86/def2-TZVPP level of theory. 2-Adamantylidene and its heavier analogues, 2X, have a singlet ground state, where the carbene and silylene bridges in 2C and 2Si are bent similarly to the foiled-type carbenes. The bending of the carbene and silylene bridges in 2C and 2Si as well as their stability are mainly attributed to the Cieplak-type hyperconjugative interaction between a pair of vicinal σ-bonds with the empty p-orbital on the carbon and silicon atoms. However, the inertness of the lone pair of the silicon atom also contributes to the stability of 2Si. The extent of hyperconjugative interactions is significantly less in 2Ge and 2Sn and the inertness of the lone pair is the major factor for their stability. The high proton affinity (PA) and hydride affinity (HA) of 2-adamantylidene and its heavier analogues suggest their ambiphilic nature. The high PA and HA of 2X can be attributed to the stabilization of the protonated adduct, 4X, and the hydride adduct, 5X, by the Cieplak-type and Felkin-Anh-type hyperconjugations, respectively. However, the nucleophilicity of 2X decreases and electrophilicity increases when X changes from C to Sn.

Fused metallaborane clusters of group 9 and 8 transition metals

Building on our earlier results, the condensation of rhodium polychlorides with borane reagents (LiBH4·thf, BH3·thf, BHCl2·SMe2 etc.), we continue to explore the chemistry of the same system with metal carbonyl compounds. As a result, the reaction of [(Cp*Rh)2B2H6], generated from fast metathesis of [Cp*RhCl2]2 and LiBH4, with heavier group 8 metal carbonyl compounds, yielded [(Cp*Rh)2B4H4Rh{Cp*RhB3H8}], 1, [(Cp*Rh)B3H7{Ru(CO)2}(Cp*RhCO)2], 2 [(Cp*Rh)2B3H3{Ru(CO)3}2], 3 and [(Cp*Rh)2{Os4(CO)12}(B)H], 4. Further, these reaction also generated two mixed-metal tetrahedral hydrido clusters [(Cp*Rh){Os(CO)3}3(μ-H)4], 5 and [(Cp*Rh)2{Os(CO)3}2(μ-CO) (μ-H)2], 6 as minor products. Compound 1 is an octahedra and a square pyramid fused cluster, whereas for 2 a square pyramid and a triangle are fused through a vertex. Both 1 and 2 follow Mingos's formalism for fused clusters. Cluster 4 is an interstitial boride composed of one boron, two rhodium and four osmium atoms. Based on its compositions, compound 4 is a rare example of heteronuclear borides. All the compounds have been characterized by IR, 1H, 11B, 13C NMR spectroscopy in solution and the solid state structures were established by crystallographic analysis of 1–5.

ChemInform Abstract: N‐Heterocyclic Carbene Supported Heavier Group 14 Elements: Recent Progress and Challenges

AbstractReview: 75 refs.

Structural and Energetic Analysis of Group V Impurities in p-Type HgCdTe: The Case of As and Sb

Although molecular beam epitaxy technology-based arsenic-doped Hg1−x Cd x Te has been extensively studied, according to the newly proposed framework of the defect-complex-based p-type doping mechanism, heavier group V elements such as antimony (Sb) should have a different doping behavior because of their larger radius which can cause larger lattice distortion. In this work, we performed first-principles calculations and took As and Sb as examples to study this issue. The substitutional doping, interstitial doping (including split, tetrahedral, and hexagonal interstitial sites), and defect complex doping forms for arsenic and antimony are all investigated. A significant lattice distortion is found in hexagonal and split-site interstitial-Sb-doped Hg0.75Cd0.25Te due to the larger covalent radius of Sb. Compared with As, Sb can lead to a more complicated configuration change in the case of SbHg-V Hg-SbHg tridoping, and the interstitial Sb is found to be stable even with the coupling of Hg vacancies through detailed energetic calculations, indicating that the interstitial Sb has greater ability to form stable defect complexes, and thus great potential to be a more appropriate p-type dopant. This study provides more complementary understanding of the behaviors of group V impurities in HgCdTe.

Carcass quality, physico-chemical parameters, muscle fibre traits and myosin heavy chain composition of m. longissimus lumborum from Puławska and Polish Large White pigs

In 54 Puławska pigs and 60 Polish Large White pigs (PLW), slaughtered at 30 and 100kg body weight, carcass and meat quality of m. longissimus lumborum were studied. Analysis revealed that in both examined body weight groups, hot carcass weight, carcass yield percentage, meat content, and weight of ham and carcass ham percentage were significantly lower and backfat thickness higher for Puławska pigs compared to PLW pigs, while PLW pigs exhibited significantly longer carcasses, greater loin eye area, and, in the case of lighter pigs, smaller proportion of loin in the carcass. Muscles of Puławska pigs, in the lighter group, had higher IMF content and a* value, while in the heavier group they exhibited higher pH45, pH24 and a* values, lower L*, drip loss, WHC, and thermal loss compared with PLW pigs. PLW pigs had higher WB and hardness values and more glycolytic muscles characterised by higher TNF.

Complexes of SiH\(_2^{2+}\) with Carbodiphosphorane and Analogues {E(PPh\(_3\))\(_2\)} (E = C – Pb) in Unusual Bonding Mode

Quantum chemical calculations at the BP86 level with various basis sets (SVP, TZVPP) were carried out for complexes of carbodiphosphorane analogues E(PPh3)2 with E = C–Pb. The equilibrium geometries of the complexes [SiH22+–{E(PPh3)2}] (Si2+-1E) possess the carbodiphosphorane ligand 1C is slightly bonded in a tilted way to SiH22+ in the complex Si2+-1C, whereas the heavier group-14 ligands E(PPh3)2 (E = Si – Pb) in the complexes Si2+-1Si – Si2+-1Pb are strongly bonded in side-on fashions. The surprising structures SiH22+-tetrylone complexes possess a strong Si-C1 bond between the Si atom of the SiH22+ fragment and atom C1 of the phenyl group. The trend of the BDEs for the Si-E bond in the Si2+-1E complexes is Si2+-1C ~ Si2+-1Si < Si2+-1Ge < Si2+-1Sn < Si2+-1Pb. Bonding analysis of the complexes shows that the Si-E bonds have a significant contribution from H2Si2+←E(PPh3)2 π-donation.

ChemInform Abstract: A New Family of Multiple‐Bond Compounds Between Heavier Group 14 Elements

AbstractReview: 93 refs.

Bespoke synthesis of unsymmetrical diaminoboranes by alkaline earth catalysis

Heavier group 2 (Mg, Ca) bis(trimethylsilyl)amides are catalysts for the formation of unsymmetrical diaminoboranes, [(R(2)N)BH(NR'(2))], by dehydrocoupling of amine boranes and protic amines; a process which is proposed to occur by a sequential metal-centred elimination-insertion-elimination mechanism.

The solid-state, solution and gas–phase interactions of diphosphane monooxide spacers with heavier group 8,9 transition metals and gallium in novel organometallic assemblies: An experimental and computational study

Six new mono-substituted carbonyl clusters [M3(CO)11(DPMO)] (M = Os, Ru; 1–4) and [Rh6(CO)15(DPMO)] (5, 6) were obtained from the reactions of non-symmetrical bifunctional diphosphane monoxides (DPMOs, Ph2P(CH2)nP(O)Ph2, n = 2, 3) with triangular clusters [Os3(CO)12] and [Ru3(CO)12], and octahedral cluster [Rh6(CO)15(NCMe)] under mild conditions. 1–6 were then subjected to electrophilic reactions with GaCl3, which resulted in coordination-based molecular assemblies [M3(CO)11(DPMO)(GaCl3)] (M = Ru, Os; 7–10) and [Rh6(CO)15(DPMO)(GaCl3)] (11, 12). 1–12 were characterised by 31P{1H} NMR, IR spectroscopy, and FAB mass spectrometry. The crystal structures of 1, 2 and 7 were determined by single-crystal X-ray analysis. 7 is the first solid-state characterised Os–Ga bridged complex. The latter and its constitutive fragment, 1, were studied by density functional calculations in the gas phase and in solution in order to better understand their structural features. Two different rotameric structures related by rotation about the P–C–C–P linkage of the DPMO ligand were established for 1 and 7. The bonding properties of 7 were analysed by means of a quantitative energy decomposition analysis (EDA). The EDA revealed a predominant electrostatic character for the interactions between the three units (carbonyl cluster, gallium halide and spacer) constitutive of 7.

Heavier Alkaline Earth Catalysts for the Intermolecular Hydroamination of Vinylarenes, Dienes, and Alkynes

The heavier group 2 complexes [M{N(SiMe(3))(2)}(2)](2)(1, M = Ca; 2, M = Sr) and [M{CH(SiMe(3))(2)}(2)(THF)(2)] (3, M = Ca; 4, M = Sr) are shown to be effective precatalysts for the intermolecular hydroamination of vinyl arenes and dienes under mild conditions. Initial studies revealed that the amide precatalysts, 1 and 2, while compromised in terms of absolute activity by a tendency toward transaminative behavior, offer greater stability toward polymerization/oligomerization side reactions. In every case the strontium species, 2 and 4, were found to outperform their calcium congeners. Reactions of piperidine with para-substituted styrenes are indicative of rate-determining alkene insertion in the catalytic cycle while the ease of addition of secondary cyclic amines was found to be dependent on ring size and reasoned to be a consequence of varying amine nucleophilicity. Hydroamination of conjugated dienes yielded isomeric products via η(3)-allyl intermediates and their relative distributions were explained through stereoelectronic considerations. The ability to carry out the hydroamination of internal alkynes was found to be dramatically dependent upon the identity of the alkyne substituents while reactions employing terminal alkynes resulted in the precipitation of insoluble and unreactive group 2 acetylides. The rate law for styrene hydroamination with piperidine catalyzed by [Sr{N(SiMe(3))(2)}(2)](2) was deduced to be first order in [amine] and [alkene] and second order in [catalyst], while large kinetic isotope effects and group 2 element-dependent ΔS(++) values implicated the formation of an amine-assisted rate-determining alkene insertion transition state in which there is a considerable entropic advantage associated with use of the larger strontium center.

ChemInform Abstract: Chemistry of Aromatic Compounds Containing a Heavier Group 14 Element

AbstractReview: ca. 50 refs.

Executive dysfunction and influencing factors in convalescent patients with traumatic brain injury

Objective To explore and analyze the executive function of patients with traumatic brain injury in recovery phase and reveal its influential factors.Methods Behavioral Assessment of Dysexecutive Syndrome (BADS) was conducted in 104 patients with brain injury at 5 ～ 6 months after discharging and matched healthy comparison subjects in this study.Basic information in patients with the clinical data were collected by self-designed questionnaire to analyze the relevant factors.Results BADS findings showed that the individual scores and total standard scores of brain injury patients( 12.05 ± 2.54 ) were significantly lower than those of health population ( 19.02 ± 3.77 ) (P ＜ 0.05 ).Action program test, temporal judgment test, modified six elements test and total sub-standard scores ( 14.83 ±3.86)in junior high school education level and below group were significantly lower than that in high school and higher education group ( 17.67 ± 4.10 ).The individual scores and total standard scores ( 10.13 ± 3.86 )in heavier group were significantly lower than that in the lighter group ( 15.68 ± 4.10 ).The group without complication' action program test, key search test, zoo map test, modified six elements test were significantly lower than the group with complication.The BADS scores were related to education, illness condition,and complication (hypertension, hyperglykemia, hyperlipemia) (P＜0.05).Conclusion There is executive dysfunction in traumatic brain injury patients.The executive dysfunction is mainly correlated with education, illnesscondition and complication.Medical staff should provide pertinent intervention and treatment according to the above aspects, in order to obtain better effects of rehabilitation therapy . Key words: Traumatic brain injury; Recovery phase; Executive dysfunction; Factors

ChemInform Abstract: Homocatenation of Metal and Metalloid Main Group Elements

AbstractReview: 204 refs.