Bond length of perchlorate at different temperatures: X-ray and neutron comparison

Abstract

The averages (average deviations from the mean are given in square brackets) of uncorrected Cl-O bond distances in a perchlorate anion from an X-ray diffraction analysis of (N-{2-[bis(pyridin-2-ylmethyl)amino]ethyl}pyridine-2-carboxamidato)(nitric oxide)manganese perchlorate acetonitrile disolvate, [Mn(C 20 H 20 N 5 O)(NO)]ClO 4 Á2CH 3 CN or [Mn(PaPy 3 )(NO)]ClO 4 Á-2CH 3 CN, decrease from 1.447 [4] Å at 10 K to 1.428 [4] Å at 170 K. The 10 K value is close to the neutron value (1.441 [1] Å ) at 18 K. Comparisons are made with a second X-ray study at 30 K [1.444 (8) Å ] and to libration-corrected, density functional theory (DFT), and Cambridge Structural Database (CSD) values.

Octahedral to Tetrahedral Conversion upon a Ligand-Substitution-Induced Single-Crystal to Single-Crystal Transformation in a Rectangular Zn(II) Metal–Organic Framework and Its Photocatalysis

“…The greater number of C–H···O bonds for each perchlorate oxygen could also cause the elongations of Cl–O bonds due to the change in charge distribution . As observed in the X-ray structure, the Cl1–O2 bond (1.470 Å), as the acceptor of three C–H···O bonds, is significantly longer than the Cl1–O1 (1.431 Å, acceptor for two C–H···O bonds), Cl1–O3 (1.405 Å, acceptor for one C–H···O bond), and Cl1 – O4 bonds (1.404 Å, acceptor for one C–H···O bonds) …”

“…Two crystallographically related and disordered perchlorate anions are trapped in a cationic rectangular cage that is formed 38 The three crystallographically independent 4,4′-bipy ligands are allocated by almost-superimposed stacking accomplished by the double face to face π−π interactions with centroid to centroid distances of 3.794 and 3.828 Å with shift distances of 0.988 and 0.488 Å, respectively (see Figure 2b). The double face to face π−π interactions are energetically disfavored in comparison to parallel and offset or T-shaped interactions due to the strong repulsion between the π-electron clouds.…”