Synthesis and Crystal Structure of Ca(en)₄Ca(en)₃[Sn₂Se₆] and Ca(en)₄Se₄ in Superheated and Supercritical Ethylenediamine

Abstract

Two new compounds Ca(en) 4 Ca(en) 3 [Sn 2 Se 6 ] (1) and Ca(en) 4 Se 4 (2) were synthesized under superheated and supercritical solvothermal conditions in ethylenediamine. Compound 1 crystallizes in triclinic space group P1 (No. 2) with a = 10.2708(4) Å, b = 12.2739(5) Å, c = 16.3103(6) Å, α = 93.576(3)°, β = 90.609(3)°, γ = 109.269(4)°, Z = 1 and V = 1936.09(13) Å 3 . The crystal structure of 1 comprises of isolated [Sn 2 Se 6 ] 4anion as well as Ca(en) 4 2+ and Ca(en) 3 2+ cations. Compound 2 crystallizes in the orthorhombic space

Synthesis of Terminal Monochalcogenide and Dichalcogenide Complexes of Uranium Using Polychalcogenides, [En]2– (E = Te, n = 2; E = Se, n = 4), as Chalcogen Atom Transfer Reagents

“…Complex 4 features asymmetric K–Se bond lengths (K1–Se1 = 3.208(2), K1–Se2 = 3.486(2) Å), which is indicative of a weak dative interaction between K1 and Se2. Finally, 4 exhibits Se–Se bond lengths (Se1–Se2 = 2.333(1), Se2–Se2* = 2.332(2), Å) comparable to other structurally characterized [Se 4 ] 2– complexes. − …”

Organic Cation and Complex Cation‐Stabilized (Poly‐)Selenides, [Cation]x(Sey)z: Diversity in Structures and Properties

“…[33] In combination with an only threefold coordination of the Li + ion, this compound would probably be classified as a selenidolithiate. [34] We were [37] (c), [Ni(tren) 2 ](Se 3 ) (c) (tren = diethylene triamine), [38] [Mn(en) 3 ](Se 3 ) [39] [42] [Ba(en) 4 ](Se 4 )·en (c), [43] and [Ca(en) 4 ](Se 4 ) [44] (c) clearly belong to organic cation-stabilized selenides, although Fässler and Menezes discuss a 3D network due to interconnecting hydrogen bridges. Dimorpholine and dipiperidine tetraselanes should be excluded from this list, although they are sometimes quoted in literature as (NC 4 H 8 O) 2 (Se 4 ), (NC 5 H 10 ) 2 (Se 4 ).…”

“…[Sr 2 Sn(OH) 6 (H 2 O) 6 ](Se 4 ) (c),36 [Ba 2 (OH) 2 (H 2 O) 10 ] 2 (Se) 4 (c),41 [Ba([2.2.2] crypt )](Se 4 ) · en (c),42 [Ba( en ) 4 ](Se 4 ) · en (c),43 and [Ca( en ) 4 ](Se 4 )44 (c) clearly belong to organic cation‐stabilized selenides, although Fässler and Menezes discuss a 3D network due to interconnecting hydrogen bridges. Dimorpholine and dipiperidine tetraselanes should be excluded from this list, although they are sometimes quoted in literature as (NC 4 H 8 O) 2 (Se 4 ), (NC 5 H 10 ) 2 (Se 4 ) 45.…”

The Origin of Isotope Effects in Sonoluminescence Spectra of Heavy and Light Water

“…In less common cases, one or both ends of a polyselenide anion can be terminating, usually because of presence of strong competition from other types of ligands 7. In particular, the latter cases are found in compounds such as [Sr(15‐crown‐5)]Se 9 8, [Mn(NH 2 CH 3 ) 6 ]Se 5 ,9 and Ca(en) 4 Se 4 ,10 where the metal cations are wrapped by organic ligands, and the molecular polyselenide anions form a well‐defined lattice of “quantum dots”. Such compounds bear similarities to the well‐studied zeolite/selenium nanocomposites, where various types of selenium species are inserted inside the channels of insulating zeolite frameworks by vapor encapsulation 11–13…”