Coordination complexes of isoquinoline with cobalt and nickel halides

Abstract

Reaction of isoquinoline (iQuin) with cobalt(II) and nickel(II) chloride and bromide produced a family of neutral coordination complexes: (iQuin)₂CoX₂ [X = Cl (1), Br (2)], (iQuin)₄CoX₂ (X = Cl (3), X = Br (4)], (iQuin)₄NiX₂ [X = Cl, (5), X = Br, (6)], and (iQuin)₂NiBr₂(CH₃CN)₂ (7). The crystal structures of 1–5 and 7 are reported. The majority of the compounds crystallize with some of the iQuin ligands undergoing a ∼2-fold rotational disorder, likely caused by the nearly equivalent space occupied by the two positions. The disorder is temperature independent and ∼50:50 in all cases but one. Magnetic measurements for all seven compounds indicate that their behavior is dominated by single-ion anisotropy effects with indications of antiferromagnetic exchange also present in 1 and 2.

Keywords:

• Cobalt(II)
• nickel(II)
• magnetism
• X-ray structures
• isoquinoline

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors gratefully acknowledge financial assistance from the National Science Foundation for a grant to purchase the SQUID magnetometer (IMR-0314773). DAD is grateful for MRI grant CHE-2018870 from the NSF toward the purchase of the single crystal diffractometer. Contributions from SEQENS toward the purchase of the powder X-ray diffractometer and from the Kresge Foundation for the purchase of both the SQUID and X-ray diffractometer are also greatly appreciated.