Complexes of the fac-{Re(CO)3}+ core with tridentate ligands derived from arylpiperazines

Lihui Wei, Sangeeta Ray Banerjee, Murali K. Levadala, John Babich, Jon Zubieta

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Arylpiperazines, XC6H4N(CH2CH 2)2NH, are readily alkylated to give the N-alkylpiperazines of the type XC6H4N(CH 2CH2)2N(CH2)nNH 2. The amine functions of these derivatives are in turn easily subjected to mono- or dialkylation to provide potentially tridentate ligands of the types XC6H4N(CH2CH2) 2N(CH2)nN(H)(CH2Y) and XC 6H4N(CH2CH2)2N(CH 2)nN(CH2Y)(CH2Z), respectively. The latter class of dialkylated derivatives may be symmetrically (Y=Z) or unsymmetrically (Y≠Z) substituted. The donor groups Y and Z of this study include pyridine, imidazole, methyl-imidazole, thiazole, carboxylate and thiolate. The reactions of these ligands with [NEt4] 2[Re(CO)3Br3] yield complexes of the type [Re(CO)3{(YCH2)N(H)(CH2)n(H) xN(CH2CH2)2N(H)yC 6H4X}]n and [Re(CO)3{(ZCH 2)(YCH2)N(CH2)n(H) xN(CH2CH2)2N(H)yC 6H4X}]n where the molecular charge n (0, +1, or +2) depends on the nature of the donor groups Y and Z (whether neutral or anionic or a combination of neutral and anionic) and on the degree of protonation of the piperazine unit (x=0 or 1; y=0 or 1). This variety of tridentate chelators provides complexes with fac-{Re(CO)3N 3}, {Re(CO)3N2O}, {Re(CO)3NO 2}, {Re(CO)3N2S} and {Re(CO)3NS 2} coordination geometries. The structures of the model compound [Re(CO)3{(CH3N2C3H 2CH2)N(H)CH2CH2-piperidine}] Br·H2O, [Re(CO)3{(CH3N2C 3H2CH2)N(H)CH2CH2- Fphenpip}]Br, [Re(CO)3{(NC5H4CH 2)N(H)CH2CH2-Fphenpip}]Br, [Re(CO) 3{(O2CCH2)2NCH2CH 2CH2-CH3OphenpipH}]·xCH3OH (x≈0.875), [Re(CO)3{(NC5H4CH 2)2NCH2CH2CH2-CH 3OphenpipH}]Br2·2CH2Cl 2·H2O and [Re(CO)3{(CH3N 2C3H2CH2)(O2CCH 2)NCH2CH2CH2-CH 3OphenpipH2}]BrCl·1.5CH3OH·H 2O are discussed (phenpip: phenylpiperazine, -C6H 4N(CH2CH2)2N-).

Original languageEnglish (US)
Pages (from-to)1499-1516
Number of pages18
JournalInorganica Chimica Acta
Issue number5
StatePublished - Mar 25 2004

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry


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