Structural and spectroscopic comparisons of the square-planar four-coordinate [o-phenylenebis(biuretato)]cobaltate(III) complex and the five-coordinate mono- and six-coordinate dicyano adducts

Takashi Yagi, Hiroshi Hanai, Takashi Komorita, Takayoshi Suzuki, Sumio Kaizaki

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11 Citations (Scopus)

Abstract

The addition of cyanide ion to the paramagnetic four-coordinate square-planar cobalt(III) complex, [Co(bbphen)]- {H4bbphen = o-phenylenebis(biuret), [1]-}, afforded the diamagnetic mono- and dicyano complexes [Co(bbphen)(CN)]2- ([2]2-) and [Co(bbphen)(CN)2]3- ([3]3-). The X-ray crystal structure analyses of [K(crypt)][1]) and (crypt = cryptand[2,2,2]), (PPh4)2[2]·2CH3CN·H 2O, and K3[3]·5.5H2O show them to be a four-coordinate square plane, a five-coordinate square pyramid and a six-coordinate octahedron, respectively. The four-coordinate N atoms of the bbphen ligand in the three complexes were located in a basal plane around the central cobalt atom. The average Co-N bond lengths become longer with increasing coordination number. A novel interactive contact between one of the potassium ions and both the cyano ligand and the phenyl ring of the bbphen ligand is found in K3[3]·5.5H2O. Complex [2]2- exhibits characteristic intense CT absorption bands at 14.0 × 103 (ε = 1380) and 22.7 × 103 cm-1 (ε = 1480 dm3 mol-1 cm-1) together with the distinctively high field 13C NMR chemical shift of the coordinated cyanide ion at 81.5 ppm, as compared with 143.0 ppm for [3]3- in DMSO.

Original languageEnglish
Pages (from-to)1126-1131
Number of pages6
JournalJournal of the Chemical Society, Dalton Transactions
Issue number6
Publication statusPublished - Apr 6 2002
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)

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