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Individuals are consistently observed to be risk-averse over gains and risk-seeking over losses. This study examined whether increased social distance would change these behavioral patterns. To test our hypothesis, social distance was manipulated by asking the participants to make decisions either for themselves or for another person (Experiment 1), either for a known person or for an unknown person (Experiment 2), and either for a close friend or for a distant friend (Experiment 3). The results of Experiments 1 and 3 showed that increased social distance made people more risk-neutral, and such an effect was stronger in the gain domain than in the loss domain. However, the effect of social distance was not observed in Experiment 2. These findings suggest that risk preferences are influenced by the social distance between decision makers and beneficiaries.

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A series of transition metal coordination polymers with azide and flexible zwitterionic dicarboxylate ligands was synthesized and structurally and magnetically characterized. These compounds are formulated as [M(2)(L(1))(N(3))(4)] (L(1) = 4,4'-trimethylenedipyridinio-N,N'-diacetate and M = Mn, 1; Co, 2; and Ni, 3) and [ML(2)(N(3))(6)(H(2)O)(2)] (L(2) = 4,4'-dipyridinio-N,N'-diacetate and M = Mn, 4; Co, 5). The isomorphous compounds 1-3 consist of two-dimensional coordination layers in which the anionic uniform chains with mixed triple bridges (two end-on (EO) azides and a syn-syn carboxylate) are cross-linked by the flexible cationic 4,4'-trimethylenedipyridinium spacers, while the isomorphous compounds 4 and 5 consist of alternating chains with triple (two EO azides plus a carboxylate) and double (two end-to-end azides) bridges, the 4,4'-dipyridinium spacers serving as side bridges along the chain. Magnetic studies demonstrated that the triple bridge transmits antiferromagnetic coupling in the Mn(II) compounds (1 and 4) but ferromagnetic coupling in the Co(II) and Ni(II) species (2, 3, and 5). The differences have been discussed in terms of the collaboration or competition between the carboxylate and azide pathways. Compound 4 exhibits alternating antiferromagnetic interactions, while alternating ferromagnetic-ferromagnetic-antiferromagnetic interactions with spin canting are suggested for 5.

A new two-dimensional (2D) coordination polymer with mixed pyrimidine-2-carboxylate (pymca) and oxalate (ox) bridges, [Mn(2)(pymca)(2)(ox)(H(2)O)(2)](n) (1), was synthesized by a hydrothermal reaction involving the in situ formation of the pymca and ox ligands from 2-cyanopyrimidine (pymCN), and its structure and magnetic properties were characterized. The dianionic ox and monoanionic pymca ligands are both potentially bis(chelating) and have been used to construct anionic and cationic 2D honeycomb networks [(6,3) net], respectively. In the present compound, ox assumes the usual bis(chelating) bridging mode, but pymca serves as a tridentate bridge with one of the pyrimidyl nitrogens uncoordinated. The two different bridges collaborate to generate a highly undulated 2D layer with the (6,3) net topology, and the layers are closely packed in parallel through pi-pi interactions between pyrimidyl rings and hydrogen bonds involving coordinated water molecules, oxalate oxygens, and uncoordinated pyrimidyl nitrogens. Magnetic measurements reveal that the compound is a spin-canted antiferromagnet with weak ferromagnetic transition below T(c) = 2.4 K.

Four novel metal−organic coordination polymers, [Zn2(ppda)(phen)2(HCOO)2] (1), [Mn(ppda)(phen)(H2O)2]·DMF (2), [Zn(mpda)(phen)]·1.5H2O (3), and [Mn2(mpda)2(phen)2] (4), (H2ppda = p-phenylenediacrylic acid, H2mpda = m-phenylenediacrylic acid, and phen = 1,10-phenanthroline) have been synthesized under hydrothermal conditions. Compound 1 consists of two-dimensional (2D) bilayers in which formate-bridged chains are cross-linked by ppda ligands, and the bilayers are sustained by infinite zipper-like π−π stacking of the phen ligands. Compounds 2 and 3 are both one-dimensional (1D) coordination polymers, but exhibit different chain shapes due to the different geometry of ppda and mpda. Via O−H···O hydrogen bonding and pairwise phen···phen π−π stacking, the zigzag chains in 2 are assembled into a three-dimensional (3D) diamond network with 3-fold interpenetration, while the helical chains in 3 are packed into a 3D structure through quadruple π−π stacking arrays. Compound 4 is composed of double twist chains of binuclear units sustained by double carboxylate bridges and phen···phen π−π stacking. Magnetic investigations on 2 and 4 have been carried out. Compound 4 exhibits weak intradimer antiferromagnetic exchange mediated through the carboxylate bridges and the possible π−π stacking pathway, while much weaker antiferromagnetic exchange is operative through the interchain hydrogen bonding motif in 2.

A novel sensor for the determination of parathion based on coupled grafting of the functional macromolecule polyethyleneimine on surfaces of silica gel particles via a surface imprinting method using molecular imprinting technology was fabricated. The electrochemical behavior of parathion at the imprinted sensor was characterized by cyclic voltammetry and linear sweeping voltammetry. The imprinted films showed high selectivity toward parathion in comparison to similar organophosphates. A linear response over parathion concentration in the range of 0.015-15 mg kg(-1) was exhibited with a detection limit of 0.003 mg kg(-1) (S/N = 3). The imprinted film sensor has been applied to the determination of parathion in spiked vegetable samples and shows promise for fast and selective determination of trace levels of parathion in real samples.