Unexpected solids from enantiopure cationic palladium complexes and racemic anions: A structural study of chiral non-discrimination

A robust conglomerate structure type in salts of cationic organopalladium complexes and non-coordinating anions

“…Although cyclopalladation can be considered a classical reaction, 25 the Cambridge Structural Database 26 contains only 15 examples of cyclopalladated amines and N,N9-chelating ligands, 27 six of them reported in our recent communication about partially racemic solids. 9 All complex cations described here are essentially square planar; the distance of the metal center to the best plane through the coordinating atoms is most pronounced in the cation of 1b and amounts to 0.0718(4) A ˚. Bond lengths between palladium and the tmeda nitrogen atoms differ significantly: The Pd-N distance trans to carbon, with values ranging from 2.1523(19) to 2.180(4), is consistently longer than the bond to the nitrogen atom trans to the amino group (2.085(2)-2.122(8) A ˚).…”

“…We note that the above-mentioned robustness of the conglomerate structure type is not trivial: for comparison with the tmeda complexes reported in this work, a series of 2-aminomethylpyridine derivatives have been synthesized. 34 The aminomethyl ligand as well as ethylenediamine 9 exhibit potential hydrogen bond donors. Hydrogen bonding in these donor-rich derivatives plays a much more dominant role than in the complexes discussed here-does an extended network of hydrogen bonds preclude conglomerate formation in these cases?…”

“…7 Extensive work on conglomerate formation in coordination compounds is due to Bernal and coworkers. 8 We have decided to dedicate a systematic study to the comparison of conglomerates and racemates of organopalladium compounds, and we have recently communicated 9 our results on partially racemic solids, i.e. salts containing an enantiopure ion and the racemate of a counteranion in the same unit cell.…”

Mesoxalate as Cu(ii)–Ln(iii) linker in the construction of MOFs in DMSO/water medium

“…3) resulting in a cubic (10,3)-a network which is known as the default network of the combination of triangles. 17,22,[36][37][38][39][40][41][42][43][44][45][46] The crystallization of LaCu 3 , CeCu 3 , PrCu 3 , and NdCu 3 proceeds enantioselectively to give chiral crystals with either right-handed (P) or left-handed (M) (10,3)-a nets. 3).…”

“…3). 17,22,[36][37][38][39][40][41][42][43][44][45][46] The crystallization of LaCu 3 , CeCu 3 , PrCu 3 , and NdCu 3 proceeds enantioselectively to give chiral crystals with either right-handed (P) or left-handed (M) (10,3)-a nets. Nevertheless, the batch of crystals contains both enantiomorphs and the overall crystal mixture is expected to be racemic.…”