The structures of two new ten-membered ring compounds, 3,4,5,8,9,10-hexamethyl-1,2,5,8-dithiadiazecine-6,7(5H,8H)-dione (I) and ll,14-dimethyldibenzo[c,f]-Acta Crystallographica Section C

All-trans- and trans(CN),cis(N)-[Co(CN)2(l-ala)2]− and trans(CN)-[Co(CN)2(tmdda)]− were newly prepared; here, tmdda denotes trimethylenediamine-N,N′-diacetate. These complexes were characterized from their electronic absorption, NMR, and Raman spectra. The CD spectra of two trans(CN) isomers of the bis(l-alaninato) complex are also presented.

Key indicatorsSingle-crystal X-ray study T = 296 K Mean '(C±C) = 0.014 A Ê Disorder in main residue R factor = 0.033 wR factor = 0.082 Data-to-parameter ratio = 12.7For details of how these key indicators were automatically derived from the article, see

Vanadium(III) complexes with the hexadentate ligand, tetramethylenediamine-N,N,N′,N′-tetraacetate (tmdta), N,N′-bis(2-pyridylmethyl)-1,2-ethanediamine-N,N′-diacetate (bpedda), and N,N′-bis(2-pyridylmethyl)-1,3-propanediamine-N,N′-diacetate (bppdda), have been prepared. The structures of the tmdta (1) and bpedda (3) complexes have been determined by X-ray crystallography. The stereochemical property of complex 1 was compared with that of the corresponding Cr(III) complex (2), whose structure was also determined by X-ray crystallography. The tmdta complexes adopt a distorted octahedral structure, including a seven-membered chelate ring formed by the tetramethylenediamine moiety of the tmdta ligand. The bpedda complex has been determined to be a heptacoordinate complex with a distorted pentagonal bipyramidal geometry. The isolated bppdda complex has been characterized to be a μ-oxo dinuclear vanadium(III) complex on the basis of its spectral features. The tmdta and bpedda complexes do not yield a corresponding μ-oxo dinuclear vanadium(III) complex on base hydrolysis.

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