Variable modes of nickel(II) coordination with macrocyclic ligands based on 1,5-bis(2-mercaptoethyl)-1,5-diazacyclooctane (BME-DACO)

Journal Article · Wed Nov 25 00:00:00 EST 1992 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00050a012· OSTI ID:6900640

Darensbourg, M Y; Font, I; Mills, D K; Pala, M; Reibenspies, J H ^[1]

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1. Texas A M Univ., College Station (United States)

The synthesis, structural characterization, and spectroscopic and magnetic properties of the Ni[sup II] complexes containing macrocyclic ligands derived from 1,5-bis(2-mercaptoethyl)-1,5-diazacyclooctane are described. The cis orientation of thiolate sulfurs rigidly held in (BME-DACO)Ni[sup II] (1) permits high-yield template syntheses of macrocycle ligands. Thus reaction of 1 with 1,3-dibromopropane gives a four-coordinate N[sub 2]S[sub 2]Ni complex, (4,8-dithia-1,11-diazabicyclo-[9.3.3]heptadecane)nickel(II) bromide, [Ni(bicycle)]Br[sub 2] (3A). Alkylation of 1 with bis(2-iodoethyl) ether results in a six-coordinate complex, containing a pentadentate, N[sub 2]S[sub 2]O donor macrocyclic ligand, (7-oxa-4,10-dithia-1,13-diazabicyclo[11.3.3]nonadecane)iodonickel(II) iodide, [Ni(ether)I]I. Complex 3a crystallizes in the monoclinic P2[sub 1]/c (No. 14) space group. Complex 4b [Ni(ether)I]BPh[sub 4], crystallizes in the orthorhombic P2[sub 1]2[sub 1]2[sub 1] (No. 18) space group. In pseudo-square-planar 3a (a 2.947 (2) [Angstrom] bromide interaction with Ni[sup II] creates a virtual square pyramid), the metalladiazacyclohexane rings are in the chair/boat configurations. However, in pseudooctahedral 4b, the folding back of the eight-membered NiS[sub 2]C[sub 4]O ring to accommodate Ni-O bonding and the presence of an iodide ligand trans to the oxygen enforce the uncommon chair/chair configuration of the fused metalla rings. The larger macrocycle of 4 creates a larger N[sub 2]S[sub 2] cavity, with Ni-S distances in 4b of 2.405 (2) and 2.362 (2) [Angstrom] and in 3a of 2.188 (3) and 2.201 (3) [Angstrom]. The relative accessibility of the Ni[sup I] oxidation state determined by cyclic voltammetry reflects this cavity size, with the larger yielding more positive values of the Ni[sup II/I] couple.

• OSTI ID: 6900640
• Journal Information: Inorganic Chemistry; (United States), Vol. 31:24; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
NICKEL COMPLEXES
MOLECULAR STRUCTURE
CHEMICAL PREPARATION
CRYSTAL STRUCTURE
EXPERIMENTAL DATA
LATTICE PARAMETERS
LIGANDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
VOLTAMETRY
X-RAY DIFFRACTION
COHERENT SCATTERING
COMPLEXES
DATA
DIFFRACTION
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
SCATTERING
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties