The synthesis of five novel Ni(II) complexes with N donor and/or thiolate S donor ligands and the structure of each compound are reported. Reaction of dichloro[tris(2-aminoethyl)amine]nickel(II), [Ni(tren)Cl2], with sodium maleonitriledithiolate, Na2(mnt), yields a salt composed of the novel complex cation bis[tris(2-aminoethyl)amine]nickel(2+), [Ni(tren)2]2+, and bis(maleonitrile-dithiolato)nickelate(2−), [Ni(mnt)2]2−. Crystals of a DMF disolvate of this salt, 1·2DMF, crystallize in monoclinic space group P21/n with cell dimensions a = 13.086 (2) Å, b = 11.260 (3) Å, c = 14.083 (2) Å, β = 106.69 (1)°, V= 1988 (1) Å3, and Z = 2. The cation contains two tridentate tren ligands in a facial arrangement. The anion is the familiar planar Ni(II) complex with four S donor atoms. An independent synthesis of bis[tris(2-aminoethyl)amine]nickel(2+) tetrafluoroborate, [Ni(tren)2](BF4)2(2), confirms that the structure of the cation is not dependent on the anion in any way, and allows the electronic absorption spectroscopy of the cation to be examined in detail. Crystals of 2 form in the triclinic space group Pl with cell dimensions a = 7.909 (1) Å,b = 8.788 (1) Å, c = 8.919 (1) Å, α = 108.45 (1)°, β = 96.32 (1)°,γ = 104.03 (1)°, V= 558.6 (3) Å3, and Z = 1. The structure of the cation in 2 is essentially the same as was found in 1·2DMF. Reaction of chloro[tris(2-(dimethyl-amino)ethyl)amine]nickel(II) chloride, [Ni(Me6tren)Cl]Cl, with tetraethylammonium (p-chlorothio)phenolate leads to a salt containing two [Ni(Me6tren)Cl]+cations and a dimeric anion, tetrakis(p-chlorothiophenolato)bis(/u-p-chlorothiophenolato)di-nickelate, [Ni2(S-p-C6H4Cl)6]2−. Crystals of a diacetonitrile solvate, 3-2CH3CN, form in the triclinic space group Pl with cell dimensions a = 11.778 (4) Å, b = 13.799 (3) Å, c = 14.774 (3) Å, α = 65.65 (2)°, β = 77.86 (2)°, γ = 64.94 (2)°, V= 1979.8 (9) Å3, and Z = 1. The dianion is the first example of an arenethiolate complex with essentially planar Ni coordination geometry. The cation has approximate trigonal-bipyramidal geometry with an axial chloride ligand. The factors involved in stabilizing this structure are discussed. In solution, the planar structure persists and is not easily converted to the known tetrahedral [Ni(S-p-C6H4CI)42−anion upon addition of more thiolate ligand. However, addition of methanol to solutions of the tetrahedral anion will convert it to the diamagnetic, planar, dimeric anion in 3. Cyclic voltammetric studies of the dianion reveal two irreversible oxidations with anodic peak potentials near the Fc/Fc+couple. When the ligand bis(2-mercaptoethyl)(2-(methylthio)ethyl)amine (NS2SMe) is reacted with anhydrous nickel(II) acetate in methanol, a neutral dimeric complex, [Ni(NS2SMe)]2(4), is obtained. Crystals of 4 from DMF/methanol solution form in the monoclinic space group C2/c with cell dimensions a = 32.391 (9) Å, b = 8.473 (3) Å, c = 16.500 (4) Å, β = 107.17 (2)°, V= 4327 (4) Å3, and Z = 8. The structure is best described as containing two planar Ni(II) centers in NS3coordination environments that share an edge formed by two bridging thiolates. The molecule is folded along the shared edge, and each Ni(NS3) unit has an unbound arm containing the thioether. This structure is compared with a number of other dimeric Ni complexes with similar structures. Evidence is presented that supports an analogous structure (with a pendant thiol) for the dimeric complex formed with the trithiol ligand tris(2-mercaptoethyl)amine. A monomeric complex, 5, is obtained from the reaction of the ligand N,N′-dimethyl-N,N′-bis(2-mercaptoethyl)-l,3-propanediamine with 1 equiv of Ni(O-Ac)2·4H2O in methanol. Crystals of 5 were obtained that formed in monoclinic space group P21/n with cell dimensions a = 8.865 (1) Å,b= 12.172(2) Å, c = 11.729 (2) Å, β = 103.71 (1)°, V= 1229.6 (6) Å3, and Z = 4. The neutral complex is best described as containing planar Ni(N2S2) units with cis geometry. Two of these monomeric units react with additional Ni(II) ions to form a trinuclear species. Cyclic voltammetric studies of 5 reveal an irreversible oxidation with Epa= −25 mV (vs Fc/Fc+). This oxidation is not observed in the trinuclear complex, which instead exhibits a pseudoreversible reduction (E1/2= −1110 mV). © 1990, American Chemical Society. All rights reserved.
