Kristallstruktur des Cadmiumthiocyanat-Hexamethylentetramin-Addukts Cd(SCN)₂·C₆H₁₂N₄ · 2H₂O/ Crystal Structure of the Cadmium Thiocyanate Hexamethylenetetramine Adduct Cd(SCN )₂· C₆H₁₂N₄ · 2H₂O

Abstract

Crystals of the adduct Cd(SCN )2 ·C6H12N4 · 2H2O were obtained by diffusion of an aqueous solution of hexamethylenetetramine into an aqueous solution of cadmium thiocyanate. The crystals are triclinic, space group P 1̄, Z = 2, a = 600.4(2), b = 1005.1(3), c = 1283.9(4) pm , α= 105.79(9), β = 102.63(7), γ = 103.65(3)°. Each cadmium atom is bonded to one hexamethylenetetramine ligand, one water molecule, and, via the N atoms, to two NCS groups, which act as bridging ligands and form bonds, via the S atoms, to adjacent cadmium atoms. Thus a polymeric chain structure is formed. There is an other water molecule present per formula unit, which is not coordinated to cadmium but is located in channels between the chains. Between the oxygen atoms of this water molecule and the oxygen atom of the coordination water molecule, as well as the nitrogen atom of the hexamethylenentetramine ligand, a system of hydrogen bonds is formed. The coordination of the cadmium atoms is approximately octahedral.

Hexamethylenetetramine: An old new building block for design of coordination polymers

“…In spite of having up to four available sites for the coordination, hmt typically adopts a 2 -mode (51 structures), whereas 3 -and 4 -modes are much less common (13 and 6 examples, respectively). Although in the majority of cases (74) [57] was, however, observed within one of the hmt-supported polymers [57,58,62,70].…”

“…In the following two decades, this chemistry developped rather slowly, since only 12 and 15 structures were published in 1980s [50][51][52][53][54][55][56][57] and 1990s [58][59][60][61][62][63][64][65][66][67][68], respectively. However, the flourishing progress of crystal engineering yielded ca.…”

“…The structure of [Cd( 2 -NCS) 2 (hmt)(H 2 O)] n ·nH 2 O (73) [36,62] reveals the linear NCS-driven 1D chains that are similar to the legs encountered in 25 (Fig. 1b) which, however, are not connected in 73.…”

“…1b) which, however, are not connected in 73. Nevertheless, the extension of these chains is achieved via H-bonds between crystallization water and hmt, giving rise to a 2D supramolecular network [36,62]. A compound {[hmtH] 2 [Pb 3 I 2 ( 3 -I) 2 ( 2 -I) 4 (hmt) 2 ]} n (74) [57] features the 1D helical chains constructed from repeating Pb 2 and Pb 4 iodide rings that are supported by terminal iodide and hmt ligands.…”

Kristallstruktur zweier Zinkthiocyanat-Hexamethylentetramin-Addukte, Zn(SCN)2 · (C6H12N4)2 und {Zn(SCN)2 · C6H12N4 · 2H2O}n, mit unterschiedlich koordinierten Zinkionen / Crystal Structure of Two Zinc Thiocyanate Hexamethylenetetramine Adducts, Zn(SCN)2 · (C6H12N4)2 and {Zn(SCN)2 · C6H12N4

“…In vielen Fällen weisen diese Komplexe im Kristall Ketten-oder Raumnetzstrukturen auf, die als "supramolekulare Strukturen" [1] aufgefaßt werden können, z. B. die Verbindungen Cd(CN)2• 2/3 C6H 12N4 [2] und Cd(SCN)2 • C6H 12N4 • 2 H20 [3]. So Dem Fonds der Chemischen Industrie danken wir für die finanzielle U nterstützung dieser Arbeit.…”