Solid state conformational classification of eight-membered rings in copper complexes double bridged by phosphate, phosphonate or phosphinate ligands

Dinuclear Five‐Coordinate Copper(II) Complexes with Chelating Diphosphonic Acid Ligands: Hydrothermal Synthesis, Structure, and Thermal Properties

“…It is interesting that the molecules are centrosymmetric and have a dimeric structure, where two copper ions are doubly bridged by OPO groups forming an eight‐membered dinuclear ring. The arrangement of the chair like, eight membered ring (Figure 3) (Cu–O1–P1–O6–Cui–O1i–P1i–O6i) is very similar to that of the previously reported metal diphosphonate compounds 16,27–28. Each copper atom in the dinuclear complex displays a five‐coordinate distorted square‐pyramidal coordination, though there is appreciable distortion towards trigonal bipyramid with trigonality index, τ = 0.22 for A and 0.21 for B [ τ is the parameter describing the degree of trigonal distortion and is defined as τ = ( θ 1– θ 2)/60, where θ 1 and θ 2 are two largest ligand–metal–ligand angles, τ = 0 for ideal square‐pyramid (SP) and τ = 1 for ideal trigonal bipyramid (TBP)] 29.…”

Structural Motifs in Aryl Organogermanium Ge-O Derivatives for Material Design

“…The eight-membered [GeO] 4 ring in molecule 3 is in a distorted boat-chair [47] conformation, which enables the reduction in the intracyclic tensions between the Ar rings. It should be noted that Bent's rule was satisfied (angles O(1)-Ge(1)-O(1) 109.0 • vs. C(11)-Ge(1)-C( 21) 112.5 • , respectively), but this small difference may be indicative of the similarity in the electron acceptor properties of the O and p-F 3 CC 6 H 4 groups on the Ge atoms.…”

Probabilistic model-based methodology for the conformational study of cyclic systems: application to copper complexes double-bridged by phosphate and related ligands

“…The classification method. As described in the paper by Pé rez, García, Kessler, Nolsøe, Pé rez, Serrano, Martínez & Carrascosa (2005), if the user specifies the 'preferred' conformations by providing the values of the parameters l k (typically the canonical conformations) and sets the value of k and p k , it is possible to perform an individual classification of the given structure. Based on the m values of the torsion angles for a structure, we are able, through the Bayes rule, to compute the posterior probability that the structure comes from each of the preferred conformations.…”

“…An individual checking of the posterior probabilities assigned to each canonical conformation for a given fragment is also possible. In particular, the appearance of a significant probability for more than one ideal conformation can be used to identify a structure as intermediate between two or more theoretical conformations (Pé rez, García, Kessler, Nolsøe, Pé rez, Serrano, Martínez & Carrascosa, 2005). When setting = 20 in the classification method, the most frequent conformation (C 1 ) turned out to show three kinds of distortions: towards TBC 1 , TC 1 or TC 2 conformations.…”