Tracking the dissolution–recrystallization structural transformation (DRST) of copper(II) complexes: a combined crystallographic, mass spectrometric and DFT study

Abstract

<jats:p>Methanol- and temperature-induced dissolution–recrystallization structural transformation (DRST) was observed among two novel Cu<jats:sup>II</jats:sup> complexes. This is first time that the combination of X-ray crystallography, mass spectrometry and density functional theory (DFT) theoretical calculations has been used to describe the fragmentation and recombination of a mononuclear Cu<jats:sup>II</jats:sup> complex at 60 °C in methanol to obtain a binuclear copper(II) complex. Combining time-dependent high-resolution electrospray mass spectrometry, we propose a possible mechanism for the conversion of bis(8-methoxyquinoline-κ<jats:sup>2</jats:sup> <jats:italic>N</jats:italic>,<jats:italic>O</jats:italic>)bis(thiocyanato-κ<jats:italic>N</jats:italic>)copper(II), [Cu(NCS)<jats:sub>2</jats:sub>(C<jats:sub>10</jats:sub>H<jats:sub>9</jats:sub>NO)<jats:sub>2</jats:sub>], <jats:bold>Cu1</jats:bold>, to di-μ-methanolato-κ<jats:sup>4</jats:sup> <jats:italic>O</jats:italic>:<jats:italic>O</jats:italic>-bis[(8-methoxyquinoline-κ<jats:sup>2</jats:sup> <jats:italic>N</jats:italic>,<jats:italic>O</jats:italic>)(thiocyanato-κ<jats:italic>N</jats:italic>)copper(II)], [Cu<jats:sub>2</jats:sub>(CH<jats:sub>3</jats:sub>O)<jats:sub>2</jats:sub>(NCS)<jats:sub>2</jats:sub>(C<jats:sub>10</jats:sub>H<jats:sub>9</jats:sub>NO)<jats:sub>2</jats:sub>], <jats:bold>Cu2</jats:bold>, <jats:italic>viz.</jats:italic> [Cu(SCN)<jats:sub>2</jats:sub>(<jats:bold>L</jats:bold>)<jats:sub>2</jats:sub>] (<jats:bold>Cu1</jats:bold>) → [Cu(<jats:bold>L</jats:bold>)<jats:sub>2</jats:sub>] → [Cu(<jats:bold>L</jats:bold>)]/<jats:bold>L</jats:bold> → [Cu<jats:sub>2</jats:sub>(CH<jats:sub>3</jats:sub>O)<jats:sub>2</jats:sub>(NCS)<jats:sub>2</jats:sub>(<jats:bold>L</jats:bold>)<jats:sub>2</jats:sub>] (<jats:bold>Cu2</jats:bold>). We screened the antitumour activities of <jats:bold>L</jats:bold> (8-methoxyquinoline), <jats:bold>Cu1</jats:bold> and <jats:bold>Cu2</jats:bold> and found that the antiproliferative effect of <jats:bold>Cu2</jats:bold> on some tumour cells was much greater than that of <jats:bold>L</jats:bold> and <jats:bold>Cu1</jats:bold>.</jats:p>

Humidity-Induced Structural Transformation in Pseudopolymorph Coordination Polymers

“…It seems that EtOH is not a good solvent for crystals of 3 and just some parts of crystals solved in it and recrystallized as compound 1 . This result showed that transformation from 3 to 1 is possible through the DRST process. ,,− It should be noted that after 1 month a transformation (SC–SC or DRST) from 3 to 2 was not observed.…”

“…Solid-state structural transformations of CPs have been attracting high attention recently. − Also, there are a few reports on the structural transformation of solid samples of CPs and discrete complexes in solution through dissolution–recrystallization structural transformation (DRST). ,,− …”

Water Content-Controlled Formation and Transformation of Concomitant Pseudopolymorph Coordination Polymers

“…Although this event is rather rare, there are some reports about it. In a few interesting cases, supramolecular isomers were formed in the reaction vessel concomitantly. − Although structural transformation of CPs in the solid phase is highly regarded, − there are few studies on the structural transformation in the liquid phase in CPs, especially through dissolution–recrystallization structural transformation (DRST). ,,,− …”

Crystal structure of dimethanolato-k2 O:O-bis(1-((2-methyl-1H-benzo[d]imidazol-1-yl)methyl)-1H-benzo[d][1,2,3]triazole-κN)-bis(thiocyanato-κN)dicopper(II), C34H32Cu2N12O2S2

“…The title compound contains a binuclear complex. As is shown in the Figure, [12,13]. In addition, the benzotriazole rings in adjacent molecules are parallel, with an average interplanar distance of 3.89 Å, thus π-π interaction cannot be ruled out.…”