Kevin J. Moriarty

The formation and crystal and molecular structures of (η5-pentamethylcyclopentadienyl)(η5-cyclopentadienyl)dichloro-titanium, -zirconium and -hafnium

Abstract A reaction between (η5-C5Me5)TiCl3 and C5H5Tl in benzene solution has afforded (η5-C5Me5)(η5-C5H5)TiCl2 (I) in quantitative yield. (η5-C5Me5)(η5-C5H5)HfCl2 (III) has been prepared in 83% yield from a reaction between (η5-C5Me5)HfCl3 and C5H5Na·DME in refluxing toluene solution. The crystal and molecular structures of (η5-C5Me5)(η5-C5H5TiCl2 (I), (η5-C5Me5)(η5-C5H5)ZrCl2 (II) and (η5-C5Me5)(η5-C5H5HfCl2 (III) have been determined from X-ray data measured by counter methods. The three compounds are isostructural, crystallizing in the orthorhombic space group Pnma. The cell constants are: (I): a 9.873(1), b 12.989(3), c 11.376(4) A and Dcalc 1.45 g cm−3 for Z = 4; (II): a 9.930(3), b 13.231(9), c 11.628(3) A and Dcalc 1.58 g cm−3 for Z = 4; (III): a 9.938(1), b 13.156(2), c 11.582(2) A and Dcalc 1.97 g cm−3 for Z = 4. In each case the metal atom resides on a crystallographic mirror plane which bisects both cyclopentadienyl rings and the ClMCl bond angle. The MCl bond lengths are 2.3518(9) for I, 2.4421(9) for II and 2.415(1) A for III. The metal—cyclopentadienyl and metal—pentamethylcyclopentadienyl bond distances average 2.38(5) and 2.42(2) A for I, 2.50(4) and 2.53(2) A for II, and 2.48(4) and 2.50(1) A for III respectively.

The formation, crystal and molecular structures of bis(η5-indenyl)dicarbonyltitanium and bis(η5-indenyl)dicarbonylzirconium

Abstract Bis(η5-indenyl)dicarbonyltitanium has been produced in 47% yield by reduction of bis(η5-indenyl)dichlorotitanium with activated aluminum in THF solution under a carbon monoxide atmosphere. Bis(η5-indenyl)dicarbonylzirconium can similarly be prepared in 45% yield by the reductive carbonylation of bis(η5-indenyl)dichlorozirconium using activated magnesium turnings. IR spectral evidence has been obtained for the corresponding hafnium analog, although it could not be isolated. Detailed syntheses for the precursors (η5-indenyl)2MCl2 (M = Ti, Zr, Hf) have been developed. Bis(η5-indenyl)dicarbonyltitanium crystallizes in the monoclinic space group C2/c with unit cell parameters a 30.435(8), b 7.357(5), c 28.279(8) A and β 90.93(5)°. Refinement of 3530 observed reflections lead to final agreement indices of R = 0.052 and Rw = 0.049. Bis(η5-indenyl)dicarbonylzirconium crystallizes in the monoclinic space group P21/n with unit cel parameters of a 7.288(5), b 14.398(8), c 15.273(7) A and β 89.84(5)°. Refinement of 2253 observed reflections lead to final agreement indices of R = 0.049 and R2 = 0.055.

Synthesis and properties of optically active organomolybdenum compounds

Abstract The reaction of an optically active cyclopentadienyl salt, formed from the asymmetric reduction of 6-methyl-6-phenylfulvene, with Mo(CO)6 followed by treatment with N-methyl-N-nitroso-p-toluenesulfonamide, yields an optically active organomolybdenum complex. Thermally induced substitution of a carbon monoxide ligand by trimethyl- or triphenylphosphine produces products with two chiral centers.

High-performance liquid chromatography of homologous titanaindene complexes

The high-performance liquid chromatographic (HPLC) behavior of homologous titanaindene complexes has been investigated. Various polar (silica, cyano-bonded, phenyl-bonded) and non-polar (C18-bonded) adsorbents were employed in this study for normal-phase and reversed-phase HPLC, respectively. Data reported include capacity factors (k′), separation efficiencies (N), tailing factors (T) and compound resolutions (R). Normal-phase separation of a titanaindene structural isomer pair on a phenyl-bonded silica column is demonstrated.