1252 D. W. TIIOMPSON, W. A . SOMEKS, A N D M. 0 . WOKKMAN
single-crystal X-ray study of NbBr(OCHa)z(SpCN(C2HJ2)2is in progress. Acknowledgment.-Mrs. Dot H. Fricks prepared the tantalum derivatives reported in this study and did molecular weight measurements and halide analyses. This research was sponsored by the Air Force Office of Scientific Research, United States Air Force, under Grant AFOSR-68-1355. D. C. P. was an NSF graduate trainee, 1967-1970.
reported are monomers in which the metal is coordinated to seven donor atoms. The nmr studies suggest that the OCH3 ligands are probably equivalent. The environments on opposite ends of the essentially planar carbamate ligands seem to be different. A model which is consistent with these observations and preliminary X-ray data has trans axial OCH3 groups with the carbamate ligands and the halogen in the equatorial positions of a pentagonal bipyramid. A
CONTRIBUTION FROM \vILLIAXSBURG, YIRGINIA 23185,
THE
ASD
lnorganic Chcmistry
DEPARTMENTS OF CHEMISIRY,COLLEGE OF WILLIAMASD MARY, UNIVERSITY O F VIRGISIA, CHARLOTTESVILLE, L-IRGINIA 22901
Complexes of Titanium(1V) Containing the 3-Methyl-2,4-pentanedionate Anion BY D. W. THOMPSON,ia WILLIAM A. SOMERS,Ib A N D M. 0.
Received November 3 , 1969 Seven 3-methyl-2,4-pentanedionatocomplexes of titanium(1V) have beeii prepared and characterized. Thcsc itlclutie ( Y - = FeCld-, SbClo-). The dihalo and X;ri(C6H002)2(X = F, C1, Br), X3Ti(CeHy02) (X = C1, Br), and [Ti(C6H002)3]Y trihalo complexes are monomeric and nonionic; the trisubstituted complexes are 1: 1 electrolytes. Nmr data show that the dihalo complexes have the c i s configuration. All solvents were purified by distillation under nitrogen or Introduction vacuum from suitable dehydrating agents before use. NitroThe past few years have seen an interest in the reacbenzene was purified in a manner similar to that reported.4b tions of titanium tetrahalides with f l - d i k e t o n e ~ . ~ - ~ General Procedures.-All preparations were performed under Complexes most frequently isolated are (1) simple an atmosphere of dry nitrogen by methods previously described.2d All compounds were washed thoroughly with hexane and dried Lewis acid-base adducts of the 6-diketones, ( 2 ) monounder vacuum a t room temperature. Physical measurements substituted X3TiL enolate complexes, and ( 3 ) disubstiwere made on samples prepared in a nitrogen-filled glove bag or a tuted XzTiLzconiplexes. Further, tris-substituted comVacuum Stmospheres Dri-Lab. plexes containing an L3Ti+ cation have been isolated Preparation of Trichloro(3-methyl-2,4-pentanedionato)titamainly by the reaction of ClzTiLz complexes with a nium(IV).-3-Methyl-2,4-pentanedione (2.5 X 10-2 mol) in suitable Lewis acid such as antimony pentachloride or methylene chloride (15 ml) was added dropwise to a solution of mol) in 40 nil of methylene titanium tetrachloride (2.7 X ferric chloride. In this paper we report the preparation A dark solution resulted. dpproximately half the chloride. and characterization of titanium (IV) complexes conmethylene chloride was boiled off under a slow stream of nitrotaining the 3-methyl-2,4-pentanedionate anion. gen. Hexane was then added; a dark red precipitate formed and
Experimental Section Reagents.-Titanium tetrafluoride, titanium tetrabromide (Alfa Inorganics, Inc.), and titanium tetrachloride (Fisher Scientific Co., “purified”) were purchased. Titanium tetrachloride was redistilled under nitrogen just prior to use; the other tetrahalides were used without further purification. 3-Methyl2,4-pentanedione was prepared and characterized by a reported procedure. 2 d , 8 (1) College of William and Mary. Address correspondence t o this author. (b) Undergraduate research participant, College of William and Mary. (c) University of Virginia. (2) (a) K. D. Pande a n d li. C. Mehrotra, Chem. l i d (London), 1198 (1958); (b) D. M. Puri a n d IC. C . Mehrotra, J . Less-Common Metals, 3, 247 (1961); (c) D. 31, Puri, K. C. Pande, and R. C . Mehrotra, i b i d . , 4, 481 (1962); (d) A. L. Allied and D. W. Thompson, I n o v g . C h e m . , 7 , 1196 (1968). (3) M. Cox, J. Lewis, a n d R. S. Nyholm, J . Chem. Soc., 6113 (1964). (4) (a) R. C. F a y a n d I
