The coordination complex cyclo-tetrakis[bis(1-phenyl-3-methyl-4-benzoylpyrazolon-5-ato++ +)mu-o xotitanium(IV)] has been synthesized and characterized with IR and NMR spectroscopies and X-ray diffraction. The core of this species consists of an eight-membered Ti-mu-oxo ring with alternate short-long Ti-O bond lengths. Besides these two O ligands, each metal is bound octahedrally to four O atoms from two chelating 1-phenyl-3-methyl-4-benzoylpyrazolon-5-ato anions. Several sets of Ti-O bond lengths are present: the shortest are the two Ti-O(oxo) (which are cis to each other), the longest are the two Ti-O(acyl) (cis to each other), and the two Ti-O(pyrazolonato) (trans to each other) are intermediate. The beta-diketonate ligand asymmetry, a feature considered essential in other antitumor Ti compounds, induces the short-long Ti-O(oxo) sequence of bond lengths. The antitumor activity of this compound, encapsulated in a dipalmitoylphosphatidylcholine liposome, has been studied in vitro using TA-3 (mouse mammary adenocarcinoma), HEP-2 (human epithelial larynx carcinoma), and VERO (African green monkey kidney) cell lines and in vivo in CF-1 and AJ female mice ip inoculated with TA-3. In vitro cytotoxicity is greater for TA-3 than for HEP-2 and null for VERO cell lines. In vivo results show a marked increase in survival time (T/C = 293% for AJ and 208% for CF-1), whereas tumor weight decrease was observed for CF-1-treated mice. These results suggest the Ti complex-liposome system may be promising as an antitumor drug.

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For ultrathin copper films of various morphology we studied adsorbate-induced changes in broadband infrared transmission at normal incidence of light. Smooth Cu films on Si(111) and mesoscopically rough Cu films on KBr(001) were exposed to CO and to C 2 H 4 . We observed significant broadband changes for each of these gases and for both surfaces. Applying a Drude-type model we calculated the optical spectra in accord with the experiment. We find that the effects related to a change in the electronic relaxation rate are weakly influenced by the mesoscopic roughness of the film, while the effects related to charge transfer are strongly enhanced due to such roughness. This paper shows that the real adsorbate-induced changes can be determined for both the homogeneous films and the inhomogeneous films beyond percolation. The increased surface area owing to mesoscopic roughness is merely one contribution to larger adsorbate-induced effects of inhomogeneous films. The other more interesting contribution is due to depolarization in rough metal films that is responsible for strong enhancement of charge transfer effects.