The Democratic Peace Theory and Its Problems

This essay discusses the democratic peace theory from the prespective of both its proponents and opponents. The puzzle of the democratic peace theory has long been debated methodologically and empirically. Both have a strong argument to support their views, however. This essay highlights the debate by focusing on three problems of the democratic peace theory. First, the differences of the definitions of democracy, war, and peace that demonstrates the lack of robustness in the democratic peace theory. Second, democracy by force has often failed to establish peace whether International or domestic peace and therefore the promotion of democarcy around the world have been seen as a justification of democratic intervention to other sovereign states. Third, the democratic peace theory does not always apply in new emerging democratic countries. As a result, it raises a question whether the democratic peace theory or an ideology

(Et₄N)₂[(Mo₂O₂Se₆)_0.20(Mo₂O₂Se₇)_0.18(Mo₂O₂Se₈)_0.62], a New Dimeric Molybdenum Polyselenide Containing a [Mo₂O₂(μ-Se)₂] Core

(Et4N)2[(Mo2O2Se6)0.20(Mo2O2Se7)0.18(Mo2O2Se8)0.62], a New Dimeric Molybdenum Polyselenide Containing a [Mo2O2(μ-Se)2] Cor

Assembly of Polymeric Silver(I) Complexes of Isomeric Phenylenediethynides with the Supramolecular Synthons Ag<i>_n</i>⊂ C₂RC₂ ⊃Ag<i>_n</i> (R = <i>p</i>-, <i>m</i>-, <i>o</i>-C₆H₄; <i>n</i> = 4, 5)

New Agn⊂ C2RC2 ⊃Agn (R = p-, m-, o-C6H4; n = 4, 5) supramolecular synthons have been explored in the coordination network assembly of silver(I) complexes of the isomeric phenylenediethynides. An unprecedented μ5-η-coordination mode for the ethynide moiety and a mixed μ4,μ5-coordination mode for the o-phenylenediethynide group are observed, providing a rationale for the abundant occurrence of C2@Agn (n ≤ 10) polyhedral cages in double and multiple salts of silver acetylenediide

Silver(I) 1,3-Butadiynediide and Two Related Silver(I) Double Salts Containing the C₄^2- Dianion

Ag2C4, the second silver carbide to be fully characterized, has been synthesized as a light-gray powder (contaminated with metallic silver) that is explosive at high temperature (130 °C) and sensitive to mechanical shock, rather like the well-known prototype Ag2C2. In the pair of hydrated double salts Ag2C4·6AgNO3·nH2O (n = 2, 3), the nearly linear, centrosymmetric 1,3-butadiyne-1,4-diyl dianion C42-exhibits an unprecedented μ8-coordination mode, each terminal being capped by four σ-bonded silver(I) atoms with π-interaction to one of them

Assembly of Silver(I) Two- and Three-Dimensional Coordination Networks with Complementary Tridentate Heteroaryl Ethynide Ligands

Three pairs of complementary nitrogen heteroaryl ligands [2,6-(CC)2-py and 2-CC-pym; 2,5-(CC)2-py and 2-CC-pyz; 3,5-(CC)2-py and 5-CC-pym (py = pyridine, pyz = pyrazine, pym = pyrimidine)], wherein a ring nitrogen atom in one is interchanged with a carbon atom bearing an ethynyl substituent in the other, have been used to generate seven silver(I) complexes (1−7), in which silver infinite chains and two-dimensional coordination networks bridged by heteroaryl ethynide ligands were obtained as pre-programmed. The relative positions and bonding preference between the ethynide group and ring nitrogen atom act as controlling factors to produce various structural building units for the formation of multidimensional coordination networks. The fusion of CC⊃Agn (n = 3, 4) building units yields multinuclear silver aggregates in 1−6 whose nuclearities range from seven to twelve. The crystal structure of 7 displays a honeycomb layer composed of Ag4 baskets alternately linked by pyrimidinyl-5-ethynide ligands. In addition, complex 1 features an infinite chain composed of an alternate arrangement of twist-boat water hexamers and bridging silver atoms

Ligand-Induced Disruption of Polyhedral C₂@Ag<i>_n</i> Cage Assembly in Silver Acetylenediide Complexes

The use of pyrazine-2-carboxamide as an ancillary ligand in hydrothermal synthesis yielded two new silver acetylenediide complexes exhibiting novel C2@Agn motifs:  an unprecedented open fishlike Ag6(μ6-C2) aggregate and the first example of two C22- dianions entrapped inside a partially disrupted Ag13 cage

Laserpitium peucedanoides

Five new silver­(I) double and triple salts containing conformationally flexible 1,5-hexadiyne-1,6-diide (⁻CCCH₂CH₂CC^–, C₆H₄^2–) and nitrate ions, namely Ag₂C₆H₄<b>·</b>7AgNO₃ (<b>1</b>), Ag₂C₆H₄<b>·</b>3AgNO₃<b>·</b>2AgF (<b>2</b>), Ag₂C₆H₄<b>·</b>4AgNO₃<b>·</b>2L1 (<b>3</b>; L1 = imidazole), Ag₂C₆H₄<b>·</b>2AgNO₃<b>·</b>2AgL2 (<b>4</b>; HL2 = pyrazole), and Ag₂C₆H₄<b>·</b>4AgNO₃<b>·</b>2L3 (<b>5</b>; L3 = 3,5-dimethylpyrazole), have been synthesized, in which the C₆H₄^2– species was found to adopt two distinct configurations: anti in <b>1</b> and <b>3</b> and gauche in <b>2</b>, <b>4</b>, and <b>5</b>. Complex <b>1</b> features an unusual Ag₅⊂C₆H₄⊃Ag₄ aggregate as the basic building unit, and such aggregates are interconnected by the nitrate ions to generate a three-dimensional coordination network. Complex <b>2</b> exhibits a three-dimensional coordination network constructed with compact C₆H₄⊃Ag₇ units, nitrate ions, and fluoride ions that assume a μ₃ trigonal-pyramidal coordination mode. In <b>3</b>, the Ag₄⊂C₆H₄⊃Ag₄ aggregates are stabilized by nitrate groups and imidazole ligands to generate a layer structure. In complex <b>4</b>, infinite chains each bearing deprotonated pyrazole ligands attached to the silver backbone are weaved by nitrate groups to form a three-dimensional coordination architecture. In <b>5</b> the 3,5-dimethylpyrazole ligands coordinate to silver atoms at the upper surface of each coordination layer, and the layers are interconnected to form a three-dimensional supramolecular network via hydrogen bonding

Assembly of Polymeric Silver(I) Complexes of Isomeric Phenylenediethynides with the Supramolecular Synthons Ag<i>_n</i>⊂ C₂RC₂ ⊃Ag<i>_n</i> (R = <i>p</i>-, <i>m</i>-, <i>o</i>-C₆H₄; <i>n</i> = 4, 5)

New Agn⊂ C2RC2 ⊃Agn (R = p-, m-, o-C6H4; n = 4, 5) supramolecular synthons have been explored in the coordination network assembly of silver(I) complexes of the isomeric phenylenediethynides. An unprecedented μ5-η-coordination mode for the ethynide moiety and a mixed μ4,μ5-coordination mode for the o-phenylenediethynide group are observed, providing a rationale for the abundant occurrence of C2@Agn (n ≤ 10) polyhedral cages in double and multiple salts of silver acetylenediide

Assembly of Silver(I) Two- and Three-Dimensional Coordination Networks with Complementary Tridentate Heteroaryl Ethynide Ligands

Three pairs of complementary nitrogen heteroaryl ligands [2,6-(CC)2-py and 2-CC-pym; 2,5-(CC)2-py and 2-CC-pyz; 3,5-(CC)2-py and 5-CC-pym (py = pyridine, pyz = pyrazine, pym = pyrimidine)], wherein a ring nitrogen atom in one is interchanged with a carbon atom bearing an ethynyl substituent in the other, have been used to generate seven silver(I) complexes (1−7), in which silver infinite chains and two-dimensional coordination networks bridged by heteroaryl ethynide ligands were obtained as pre-programmed. The relative positions and bonding preference between the ethynide group and ring nitrogen atom act as controlling factors to produce various structural building units for the formation of multidimensional coordination networks. The fusion of CC⊃Agn (n = 3, 4) building units yields multinuclear silver aggregates in 1−6 whose nuclearities range from seven to twelve. The crystal structure of 7 displays a honeycomb layer composed of Ag4 baskets alternately linked by pyrimidinyl-5-ethynide ligands. In addition, complex 1 features an infinite chain composed of an alternate arrangement of twist-boat water hexamers and bridging silver atoms

Structure Diversity of C₂@Ag_<i>n</i> Cages Consolidated by Heteroaromatic N‑Donor Ligands in Silver Ethynediide Complexes

Seven new silver ethynediide complexes containing ancillary heteroaromatic N-donor ligands, namely, Ag2C2·4AgCF3CO2­·(bipyH)­(CF3CO2)­·H2O (1), Ag2C2­·7AgCF3CO2­·(H3O)­(CF3CO2)­·2­(bipyH2)­(CF3CO2)2­·3H2O (2), 2Ag2C2­·8AgCF3CO2·6L1 (L1 = pyrazole) (3), Ag2C2­·4AgCF3CO2­·2L2 (L2 = 3,5-dimethylpyrazole) (4), Ag2C2­·4AgCF3CO2­·2L3 (L3 = 1,2,4-triazole) (5), Ag2C2­·10AgCF3CO2­·2L4 (L4 = 4,5-dihydro-3-(4-pyridinyl)-2H-benz­(g)-indazole) (6), and Ag2C2­·5AgCF3CO2­·2­(H3O)­(CF3CO2)­·3­(AgL52)­(CF3CO2)­·2­(L5H)­(CF3CO2)­·2­(H2O) (L5 = benzimidazole) (7) have been synthesized under hydrothermal conditions and characterized by single crystal X-ray analysis. Directed by N-donor ligands of different bulkiness and disposition of coordinating sites, various silver chain-type architectures (compounds 1 and 3–6) and discrete molecular structures (2 and 7) were assembled. In the case of 1 and 2, the influence of nonincorporated additive agents (NH4)2HPO4 and H2C2O4·H2O on product formation was also investigated