Mono- and Trinuclear Nickel(II) Complexes with Sulfur-Containing Oxime Ligands:  Uncommon Templated Coupling of Oxime with Nitrile

Abstract

4,7-Dithiadecane-2,9-dione dioxime forms both violet and purple-black nickel(II) complexes with unexpected structural properties, quite unlike the square-planar chelates formed by its dithiaundecane homologue. Their perchlorate salts were isolated and examined crystallographically. The lilac product [Ni{(Dtox)(CH(3)CNH)(2)}](ClO(4))(2) entails a bis(iminoether) ligand formed by coupling of the dioxime with two moles of acetonitrile. The purple-black complex results from further ligand deprotonation, to yield trinuclear, antiferromagnetic [Ni(3)(Dtox)(DtoxH)(2)](ClO(4))(2).CH(3)CN, which maintains its structure in solution. The first one-electron electrochemical oxidation step is relatively facile for the trimer, yielding a Ni(2)(II)Ni(III) complex, whereas for [Ni{(Dtox)(CH(3)CNH)(2)}](ClO(4))(2) a transient Ni(I) species is accessible. Comment is made on those properties (coordination number, donor type, core charge) of nickel(II) coordination spheres that affect the accessibility of the corresponding nickel(I) and nickel(III) forms. [Ni(3)(Dtox)(DtoxH)(2)](ClO(4))(2).CH(3)CN crystallizes in the monoclinic space group P2(1)/n, with cell parameters a = 12.295(2) Å, b = 17.360(2) Å, c = 20.764(2) Å, alpha = 90 degrees, beta = 94.080(10) degrees, gamma = 90 degrees, V = 4420.7(6) Å(3), Z = 4. [Ni{(Dtox)(CH(3)CNH)(2)}](ClO(4))(2) crystallizes in the rhombohedral space group R&thremacr;, with cell parameters a = 32.954(2) Å, b = 32.954(2) Å, c = 13.477(2) Å, alpha = 90 degrees, beta = 90 degrees, gamma = 120 degrees, Z = 18.

Pentadentate thioether-oxime macrocyclic and quasi-macrocyclic complexes of copper(II) and nickel(II)

“…The transition w 1 is split into a double-humped peak, which can be interpreted as indicated above, but attempts to calculate the Racah B parameter produced values which were physically unrealistic for those reasons. The values obtained for 10 Dq (10 400 -13 500 cm − 1 ) are reasonable for pseudo-octahedral high-spin Ni(II) complexes with strong in-plane fields [7,40,41]. The values of 10 Dq are larger for those compounds which possess an axial thioether relative to those with ether axial donors.…”

“…Acetonitrile for electrochemistry was distilled off P 4 O 10 under N 2 . 3-Chloro-2-propanone oxime and 3-chlorobutanone oxime were prepared according to literature procedures [7,17]. Proton NMR spectra were obtained on a Bruker AM250 spectrometer using CDCl 3 as solvent with TMS as internal standard.…”

“…Three such ether extracts were combined and dried over anhydrous Na 2 (20 ml), the solution was heated to the boil on a steam bath followed by the addition of triethylamine (0.10 g, 0.138 ml, 1 mmol) and boron trifluoride diethyl etherate (0.14 g, 0.125 ml, 1 mmol). The solution volume was reduced to 10 ml (steam bath), the solution was cooled on ice to precipitate a lilac solid, which was filtered off and washed with MeCN (2×3 ml) and Et 2 O (5 ml) and dried over anhydrous CaCl 2 2 were collected on a Siemens P4S diffractometer and refined according to previously published procedures [7].…”

Ferromagnetic Properties of a Trinuclear Nickel(II) Complex with a Trithiocyanurate Bridge

“…[9] [Ni 3 (dtox)-(dtoxH) 2 ](ClO 4 ) 2 (dtoxH 2 = 4,7-dithiadecane-2,9-dione dioxime), [{Ni 3 (medpt) 3 (NCS) 4 }(µ 3 -CO 3 )] [medpt = bis(3-aminopropyl)methylamine], and [{Ni 3 (medpt) 3 (NCSe) 4 }-(µ 3 -CO 3 )] are further examples of irregular triangular nickel(II) complexes, structurally characterized, showing weak and very strong antiferromagnetic interactions, respectively. [10][11][12] We can notice that in all the above-mentioned nickel(II) complexes, except for that containing the Ni-(CN) 4 2-unit, the central atoms are in a deformed octahedral arrangement.…”

Benzene‐1,3,5‐tricarboxylate‐bridged Double‐layered Nickel(II) Complex with Ferromagnetically Coupled Ni3 Units

“…For the aqua pathways, the Ni-O-Ni bond angles are 122.8°, out of the range 80-100° for ferromagnetic coupling. [6][7][8] Hence, the overall ferromagnetic interaction in 1 should be originated from the ferromagnetic contribution (J F ) of carboxylate bridges that is larger than the antiferromagnetic contribution (J AF ) of the aqua bridges. Previous reports 9 have shown that the solely syn-syn carboxylate bridge transmits moderate antiferromagnetic coupling between Ni(II) ions.…”