Cis-trans isomerism in mononuclear nickel(II). beta. -ketoenamine complexes

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Journal of Coordination Chemistry; (USA)

DOI:https://doi.org/10.1080/00958978909408861· OSTI ID:6946125

Maverick, A W; Fronczek, F R; Martone, D P ^[1]; Bradbury, J R ^[2]

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1. Louisiana State Univ., Baton Rouge (USA)
2. Washington Univ., St. Louis, MO (USA)

Solution NMR and x-ray crystallographic structural studies of square-planar nickel(II) Schiff base complexes are reported. In contrast to recently prepared cofacial binuclear complexes derived from bis({beta}-ketoenamines), which have the cis arrangement of O and NH donors about each metal atom, two representative mononuclear complexes, Ni(acim){sub 2} (acimH = 4-amino-3-penten-2-one) and Ni-(bzacim){sub 2} (bzacimH = 3-amino-1-phenyl-2-buten-1-one), are produced as trans isomers. Ni(acim){sub 2} (NiC{sub 10}H{sub 16}N{sub 2}O{sub 2}) is orthorhombic, space group Ccca, a = 16.770(2), b = 15.054(2), c = 13.494(1) {angstrom}, Z = 12, R = 0.055, R{sub w} = 0.042 for 143 parameters and 1,748 reflectons with I > 1{sigma}(I). Ni(bzacim){sub 2} (NiC{sub 20}H{sub 20}n{sub 2}O{sub 2}) is monoclinic, space group P2{sub 1}/c, a = 5.9186(8), b = 13.694(2), c = 11.944(4) {angstrom}, {beta} = 112.18(2){degree}, Z = 2, R = 0.038, R{sub w} = 0.037 for 156 parameters and 1,589 reflections with I > 2{sigma}(I). Crystals of Ni(bzacim){sub 2} contain centrosymmetric, nearly planar trans molecules. The structure of Ni(acim){sub 2} contains independent molecules with 2 and 222 symmetry, but both of these are disordered, so that whether the cis or trans isomer is present cannot be determined. However, solution {sup 1}H NOE and lanthanide shift measurements indicate that the trans isomer predominates for both compounds.

• OSTI ID: 6946125
• Journal Information: Journal of Coordination Chemistry; (USA), Vol. 20:2; ISSN 0095-8972
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
NICKEL COMPLEXES
STRUCTURAL CHEMICAL ANALYSIS
CRYSTALS
DATA ANALYSIS
EXPERIMENTAL DATA
MEASURING INSTRUMENTS
MEASURING METHODS
NUCLEAR MAGNETIC RESONANCE
STEREOCHEMISTRY
COMPLEXES
DATA
INFORMATION
MAGNETIC RESONANCE
NUMERICAL DATA
RESONANCE
TRANSITION ELEMENT COMPLEXES
400000* - Chemistry
400200 - Inorganic
Organic
& Physical Chemistry
360000 - Materials
400201 - Chemical & Physicochemical Properties