Premium
Tetranuclear Nickel and Cobalt Complexes with an Incomplete Double‐Cubane Structure – Homo‐ and Heterometallic Complexes and Their 1D Coordination Polymers
Author(s) -
Nakajima Takayuki,
Seto Keiko,
Scheurer Andreas,
Kure Bunsho,
Kajiwara Takashi,
Tanase Tomoaki,
Mikuriya Masahiro,
Sakiyama Hiroshi
Publication year - 2014
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201402536
Subject(s) - chemistry , nickel , cubane , cobalt , stereochemistry , ligand (biochemistry) , pyridine , medicinal chemistry , amine gas treating , metal , crystal structure , crystallography , inorganic chemistry , organic chemistry , biochemistry , receptor
The reactions of M(OAc) 2 · 4H 2 O (M = Ni, Co) with three unsymmetrical amine‐diol ligands RN(CH 2 CH 2 OH)(CH 2 CH 2 CH 2 OH) (H 2 L n : n = 1, R = benzyl; n = 2, R = 4‐methylbenzyl; n = 3, R = 2‐naphthalenylmethyl) in the presence of NEt 3 or pyridine in MeOH or BnOH gave the tetranuclear complexes [M 4 (H L n ) 2 (OAc) 6 (MeOH) 2 ] {M = Ni, n = 1 ( 1a ), 2 ( 1b ), 3 ( 1c ); M = Co, n = 1 ( 4a ), 2 ( 4b ), 3 ( 4c )} and [M 4 (H L n ) 2 (OAc) 6 (BnOH) 2 ] {M = Ni, n = 1 ( 2a ), 2 ( 2b ), 3 ( 2c ); M = Co, n = 1 ( 5a ), 2 ( 5b ), 3 ( 5c )}. When p ‐xylene‐α,α′‐diol was used instead of monoalcohols, the tetranuclear {M 4 O 6 } units were linked by p ‐xylene‐α,α′‐diol to form the 1D coordination polymers [M 4 (H L n ) 2 (OAc) 6 ( p ‐HOCH 2 C 6 H 4 CH 2 OH)] m {M = Ni, n = 1 ( 3a ), 2 ( 3b ); M = Co, n = 1 ( 6a ), 2 ( 6b )}. The structures of 1 – 6 were determined by X‐ray crystallography and consist of centrosymmetrical tetranuclear {M 4 O 6 } face‐shared defective double‐cubane cores supported by two monodeprotonated (H L n ) – ligands. The mixed‐metal tetranuclear complexes [Ni 2.2 Co 1.8 (H L 1 ) 2 (OAc) 6 (MeOH) 2 ] ( 7 ) and [Mn 1.7 Ni 2.3 (H L 1 ) 2 (OAc) 5 (OMe) 2 ] ( 8 ) were also synthesized by using equimolar amounts of Ni 2+ and M 2+ (M = Co, Mn) ions. X‐ray crystallographic and fluorescent analyses revealed that 7 is isomorphous with 1a and 4a and contains nonstoichiometric amounts of disordered Ni 2+ and Co 2+ ions in an average ratio of 2.2:1.8 with different occupancies for the two crystallographically independent metal centers. In contrast, 8 consists of a C 2 ‐symmetrical face‐shared defective double‐cubane {M II 3 Mn III O 6 } core with a Ni/Mn ratio of 2.3:1.7; the amounts of Ni 2+ and Mn 2+ ions vary depending on the metal sites, and one of the C 2 axial positions is exclusively occupied by Mn 3+ ions. Detailed magnetostructural analyses on the nickel ( 1a , 2a , 3a ) and cobalt ( 4a ) complexes with appropriate spin‐Hamiltonian models showed that both ferro‐ and antiferromagnetic spin exchange interactions were involved within the tetranuclear units, and their extent depends on the combination of the metal ions and the ligand systems in a delicate fashion.