A crystalline paradise – three substances exhibiting the following crystallization modes: (1) conglomerate, kryptoracemic and unbalanced (2) conglomerate and kryptoracemic

Unbalanced racemates: solid state solutions containing enantiomeric pairs crystallizing in Sohncke space groups with (L:D) ratios other than (1:1) – illustrated with crystals of a Co(III) coordination compound

Herein we describe materials of composition [Co(NH3)4(X-leucinato)]I2·H2O in which the amino acid ligand is either L or D, and in which (a) while in pure enantiomorphic form (L), crystallizes in a Sohncke space group with Z′ = 2.0; but, whose packing closely resembles that of its racemate. Such substances are labeled a Racemic Mimic; and (b) crystals in which the L:D ratio of the amino acid ligand in the asymmetric unit is (71:29), which interestingly crystallize in the same space group and cell constants as those of the former. Moreover, the packing behavior is essentially the same in both—the difference being that the (1:1) species is fully ordered, while that with L:D (71:29) ratio has a partially disordered propyl chain. The (71:29) species we describe herein as an Unbalanced Racemate.

Chirality determination in crystals

This tutorial review article discusses chirality determination in the solid state, both in single crystals and in crystal assemblies, with an emphasis on X-ray diffraction. The main principles of using X-ray diffraction to reliably determine absolute structure are summarized, and the complexity which can be encountered in chiral structures-kryptoracemates, scalemates, and inversion twinning-is illustrated with examples from our laboratories and the literature. We then address the problem of the bulk crystallization and discuss different techniques to determine chirality in a large assembly of crystal structures, with a special prominence given to an X-ray natural circular dichroism mapping technique that we recently reported.

1D Mn(III) coordination polymers exhibiting chiral symmetry breaking and weak ferromagnetism

Mn(iii) complexes with achiral ligands, (E)-N-(2-((2-aminobenzylidene)amino)-2-methylpropyl)-5-X-2-hydroxybenzamide (HLX, X = H, Cl, Br, and I), crystallise as chiral conglomerates containing amide oxygen-bridged one-dimensional coordination polymers that exhibit weak ferromagnetism. The bulk products exhibit symmetry breaking in that they do not contain equal amounts of enantiomers, though which is the dominant species depends on the substituent X.

Kryptoracemic compound hunting and frequency in the Cambridge Structural Database

Determination of kryptoracemic compound frequency in the Cambridge Structural Database using CCDC Python API script.

Chiral and kryptoracemic Dy(iii) complexes with field-induced single molecule magnet behavior

Crystalline mode modulation and magnetic relaxation manipulation can be realized by the introduction of different anions into mononuclear Dy(iii) single molecule magnets (SMMs).

Calix[4]arene-fused phospholes

A calix[4]arene-based biarylphosphine has been synthesised and catalytically converted into two diastereomeric, calixarene-fused phospholes.