Intra- and intermolecular Se...X (X = Se, O) interactions in selenium-containing heterocycles: 3-benzoylimino-5-(morpholin-4-yl)-1,2,4-diselenazole

Abstract

In the selenium-containing heterocyclic title compound {systematic name: N-[5-(morpholin-4-yl)-3H-1,2,4-diselenazol-3-ylidene]benzamide}, C13H13N3O2Se2, the five-membered 1,2,4-diselenazole ring and the amide group form a planar unit, but the phenyl ring plane is twisted by 22.12 (19)° relative to this plane. The five consecutive N-C bond lengths are all of similar lengths [1.316 (6)-1.358 (6) Å], indicating substantial delocalization along these bonds. The Se···O distance of 2.302 (3) Å, combined with a longer than usual amide C=O bond of 2.252 (5) Å, suggest a significant interaction between the amide O atom and its adjacent Se atom. An analysis of related structures containing an Se-Se···X unit (X = Se, S, O) shows a strong correlation between the Se-Se bond length and the strength of the Se···X interaction. When X = O, the strength of the Se···O interaction also correlates with the carbonyl C=O bond length. Weak intermolecular Se···Se, Se···O, C-H···O, C-H···π and π-π interactions each serve to link the molecules into ribbons or chains, with the C-H···O motif being a double helix, while the combination of all interactions generates the overall three-dimensional supramolecular framework.

Zero-, one-, two- and three-dimensional supramolecular architectures sustained by Se…O chalcogen bonding: A crystallographic survey

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Fig. 12 Chemical diagrams for the interacting species, 127 – 159 [80] , [95] , [152] , [159] , [180] , [181] , [182] , [183] , [184] , [185] , [186] , [187] , [188] , [189] , [190] , [191] , [192] , [193] , [194] , [195] , [196] , [197] , [198] , [199] , [200] , [201] , [202] , [203] , [204] , [205] , in multi-nuclear selenium(II) crystals featuring Se … O contacts leading to supramolecular one-dimensional chains.

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Diverse Derivatives of Selenoureas: A Synthetic and Single Crystal Structural Study

“…The crystallographic data and structure refinement details are depicted in Table 1 . There is one molecule of the compound and one molecule of chloroform in the asymmetric unit in 2 , two molecules of the compound and highly disordered dichloromethane (removed using PLATON SQUEEZE [ 24 ]) in 3 , and three symmetry-independent molecules of the compound in the case of 4 in the asymmetric unit. However, there is a single molecule of the compound in the asymmetric unit in 5 and 6 .…”

“…As a result, we suggest that the lone pair electrons on N(1) and N(3) atoms are almost perpendicular to the C=Se group. The similar C–N single bond lengths [N(1)-C(2) 1.318(2) Å, C(2)-N(3) 1.388(2) Å, N(3)-C(4) 1.379(2) Å] in 2 are significantly shorter than the typical single bond length [1.47Å] and the C=O and C=Se double bond distances [C(4)-O(4) 1.217(2) Å, Se(1)-C(2), 1.830(2) Å] indicate a delocalized π-system [ 24 ].…”

Synthesis of side-chain regioregular and main-chain alternating poly(bichalcogenophene)s and an ABC-type periodic poly(terchalcogenophene)

“…[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] However, an intrinsic drawback of P3HT and other thiophene-based polymers is the limited absorption window from approximately 300 to 550 nm, thereby hindering their various optoelectronic applications. Structurally similar to thiophene, two other ve-membered heterocycles in the chalcogenophene family-selenophene and tellurophene, featuring group-16 Se and Te elements, respectively-have attracted considerable interest because (1) Se and Te atoms are larger and have d-orbitals of higher polarizability (relative to S) to induce strong Se/Se and Te/Te attractions, potentially strengthening their interpolymer interactions, [37][38][39][40][41] and (2) as the chalcogen becomes heavier, the p-electrons in selenophene and tellurophene tend to adopt a more quinoidal character with higher coplanarity, giving rise to narrower band gaps and bathochromic shis in their absorption. [42][43][44][45][46][47][48][49][50] The homopolymers 3alkylselenophene (P3AS) 51,52 and 3-alkyltellurophene (P3ATe) 53,54 have also been prepared using the KCTP.…”