Complexes of technetium(V) and rhenium(V) with 2,3-bis(2-pyridyl)pyrazine (DPP) and 2,3-bis(2-pyridyl)quinoxaline (DPQ). Evidence for seven-membered chelate ring formation in DPQ complexes

Journal Article · Sat Dec 31 04:00:00 EST 1994 · Journal of Coordination Chemistry

DOI:https://doi.org/10.1080/00958979408024273· OSTI ID:430430

Du Preez, J G.H.; Gerber, T I.A.; Jacobs, R ^[1]

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1. Univ. of Port Elizabeth (South Africa)

Complexes formed by the reaction of (n-Bu{sub 4}N)[MOCl{sub 4}] (M = Re, Tc) with the diamines 2,3-bis(2-pyridyl)pyrazine (DPP) and 2,3-bis(2--pyridyl)quinoxaline (DPQ) in ethanol were studied. With DPP as ligand, the monometallic complexes [MOCl{sub 2}(X)(DPP)] (M = Tc, Re; X = Cl, OEt) and the bimetallic compounds [MOCl{sub 2}(X)]({mu}-DPP)[MOCl{sub 2}(OEt)] (X = Cl for M = Tc; X = OEt for M = Re) were isolated. Infrared and {sup 1}H NMR data suggest that coordination of DPP to the metals occurs in a bidentate manner through one pyrazine and one pyrazine and one pyridine nitrogen atom to form a five-membered metallocycle. Only monometallic complexes of formulation [MOCL{sub 2}(X)(DPQ)] (X = Cl, OEt) could be isolated with DPQ as ligand, irrespective of the mol ratio of reactants. Experimental evidence suggests bidentate coordination of DPQ to the metals through the two pyridinic nitrogen atoms, with the two quinoxaline nitrogens not participating in bonding to the metals, to form a single seven-membered chelate ring.

• Sponsoring Organization: USDOE
• OSTI ID: 430430
• Journal Information: Journal of Coordination Chemistry, Journal Name: Journal of Coordination Chemistry Journal Issue: 2 Vol. 33; ISSN JCCMBQ; ISSN 0095-8972
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CHEMICAL PREPARATION
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
ORGANIC NITROGEN COMPOUNDS
PYRAZINES
RHENIUM COMPLEXES
TECHNETIUM COMPLEXES