Chemical pressure effects of deuteration of long alkyl chains in counteranions on the charge state of platinum–iodine quasi-one-dimensional MX-chains

Quasi-one-dimensional halogen-bridged metal complexes (MX-chains) have structures in which metal ions, such as Pt, Pd, and Ni, are alternately linked with bridging halogen atoms. The distance between the metal ions and the halogen atoms is a reliable indicator for assessing their electronic states. In this study, we report a new Pt-I MX-chain with an anion possessing long alkyl chains, in which all hydrogen atoms are replaced by deuterium. We elucidated the effects of deuteration of the alkyl chains in the assembled anions on the chemical pressure effect. Deuteration of long alkyl chains in the anions resulted in a shortened Pt-I distance. Consequently, the cell volume was reduced by approximately 2.8%. Furthermore, improved crystallization during compound synthesis led to larger and more stable crystals.