CLASS No.

of f i v e c r y s t a l structures, one using photographic data, and four using diffractometer data. (1) Glycyi-L-tryptophanatocopper(II) t r i h y d r a t e, i s orthorhombic with u n i t- c e l l dimensions a- 7.74, b = 13.78, c = 14.81 2, space group P2^2j^2j ^ and Z = 4. Least-squares refinement, using 1119, v i s u a l l y estimated, independent r e f l e c t i o n s gave a f i n a l R of 0.106. In t h i s complex the peptide molecule behaves as a tr i d e n t a t e chelate via i t s terminal amino group, peptide nitrogen atom and carbonyl group. The single peptide nitrogen i s deprotonated. The C u ( l l) atom has a coordination number of 4. The peptide donor atoms and one H ̂ O molecule form an approximate square. (2) CN-N '-Diacetyldiimine-N-0]bis(dimethylphenylphcsphlne)plaxinum(IX), crystals are monoclinic with u n i t- c e l l dimensions a = 11.450, b = 22.120, c = 9.013 8, 6 = 103.01°, space group P2^/a and Z = 4. Least-squares refinement, using 2644 independent r e f l e c t i o n s gave a f i n a l R of 0.128, The central platinum atom i s square planar coordinated by tv/o phosphorus atoms, and an oxygen atom and a nitrogen atom of the azodiacetyl group. The two phosphorus atoms are cis to each other.. (3) OxodichloroCacetone N-benzoylhydrazonato(l-)-N',0]-tri-phenylphosphine-rhenium.(V), crystals are mpnoclinic with u n i t- c e l l dimensions a = 15.610, b = 18.510, c = 10.550 6 = 114.68°, space group P2^/a and Z = 4. Least-squares refinement, using 2678 independent r e f l e c t i o n s gave a f i n a l R of 0.052. The rhenium atom has distorted octahedral coordination. The chlorine atoms are cis to each other, and trans to these two atoms are the phosphorus atom and the nitrogen atom from the ketone hydrazonato group. The remaining two positions which are trans, are occupied by the single oxygen atom and the oxygen from the keto hydrazonato chelate r i n g