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

Journal Article · Tue Nov 24 23:00:00 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), Journal Name: Inorganic Chemistry; (United States) Vol. 31:24; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

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