Covalent titanium aryldioxy one-, two-, and three-dimensional networks and their examination as Ziegler-Natta catalysts.

Treatment of ((i)PrO)4Ti with 2,7-dihydroxynaphthalene at 100 degrees C afforded the one-dimensional ladder [cis-Ti(mu(2,7)-OC10H6O)2py2]n (1: C30H22N2O4Ti, orthorhombic, P2(1)2(1)2(1), a = 9.866(2) A, b = 15.962(3) A, c = 16.223(3) A, Z = 4), in pyridine, and the stacked ladder, two-dimensional [Ti(mu(2,7)-OC10H6O)2(4-picoline)2.(4-picoline)(0.5)]n (2: C70H59N5O8Ti2, triclinic, P1, a = 10.814(2) A, b = 16.785(3) A, c = 18.020(4) A, alpha = 93.88(3) degrees, beta = 107.31(3) degrees, gamma = 108.77(3) degrees, Z = 2), in 4-picoline. A disruption of intramolecular edge-to-face and intermolecular face-to-face pi-stacking interactions in 1 by the Me group of the 4-picoline causes the structural change to 2. These derivatives and related two- and three-dimensional covalent metal organic networks (CMON) were assayed for ethylene and propylene polymerization activity via the addition of methylaluminoxane. CMON are mediocre Ziegler-Natta catalysts that generate polydisperse, linear polyethylene and atactic polypropylene. The data are best accommodated by viewing the degradation of CMON into numerous active sites of differing activity.

A covalent vanadium(III) 2-dimensional network and vanadyl chains linked by aryldioxides.

Thermolysis of (iPrO)4V and 2,6-dihydroxynaphthalene in 4-(3-phenylpropyl)pyridine afforded [mer-V(mu 2,6-OC10H6O)1.5(4-(3-phenylpropyl)py)3]n (1; C57H54N3O3V, triclinic, P1, a = 10.450(2) A, b = 14.098(3) A, c = 16.765(3) A, alpha = 100.09(3) degrees, beta = 103.85(3) degrees, gamma = 103.08(3) degrees, Z = 2) and oxidation product bis-2,6-dinaphthol. Paramagnetic (S = 1) 1 adopts a bricklike motif of aryldioxide-connected V(III) centers whose channels are filled with the bound 4-(3-phenylpropyl)py. A similar procedure involving (iPrO)3VO provided the linear chain [(mu 2,6-OC10H6O)(4-(3-phenylpropyl)py)2VO]n (2; C38H36N2O3V, monoclinic, P2(1)/c, a = 10.6172(2) A, b = 9.4477(3) A, c = 31.8129(8) A, beta = 95.20(3) degrees, Z = 4). Interchain pyridine ring-edge to phenyl-face interactions generate a sheet of like-oriented oxos, but adjacent sheets are oriented in opposition so that no net dipole exists. Another 1-dimensional chain, [(mu 1,4-OC6H4O)(py)2VO]n (3; C16H14N2O3V, monoclinic, P2(1)/c, a = 8.377(2) A, b = 16.675(3) A, c = 11.061(2) A, beta = 103.91(3) degrees, Z = 4), was prepared by heating (iPrO)4V and hydroquinone in pyridine. Pyridines of adjacent chains interpenetrate to form a sheet, but oxos in adjacent chains are now in opposition.

Synthesis, structure, and antitumor activity of a novel tetranuclear titanium complex.

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.

Covalent metal-organic networks: pyridines induce 2-dimensional oligomerization of (mu-OC6H4O)2Mpy2 (M = Ti, V, Zr).

Treatment of M(OiPr)4 (M = Ti, V) and [Zr(OEt)4]4 with excess 1,4-HOC6H4OH in THF afforded [M(OC6H4O)a(OC6H4OH)3.34-1.83a(OiPr)0.66-0.17a(THF)0.2]n (M = Ti, 1-Ti; V, 1-V, 0.91 < or = a < or = 1.82) and [Zr(1,4-OC6H4O)2-x(OEt)2x]n (1-Zr, x = 0.9). The combination of of 1-M (M = Ti, V, Zr) or M(OiPr)4 (M = Ti, V), excess 1,4- or 1,3-HOC6H4OH, and pyridine or 4-phenylpyridine at 100 degrees C for 1 d to 2 weeks afforded various 2-dimensional covalent metal-organic networks: [cis-M(mu 1,4-OC6H4O)2py2] infinity (2-M, M = Ti, Zr), [trans-M(mu 1,4-OC6H4O)2py2.py] infinity (3-M, M = Ti, V), solid solutions [trans-TixV1-x(mu 1,4-OC6H4O)2py2.py] infinity (3-TixV1-x, x approximately 0.4, 0.6, 0.9), [trans-M(mu 1,4-OC6H4O)2(4-Ph-py)2] infinity (4-M, M = Ti, V), [trans-Ti(mu 1,3-OC6H4O)2py2] infinity (5-Ti), and [trans-Ti(mu 1,3-OC6H4O)2(4-Ph-py)2] infinity (6-Ti). Single-crystal X-ray diffraction experiments confirmed the pleated sheet structure of 2-Ti, the flat sheet structure of 3-Ti, and the rippled sheet structures of 4-Ti, 5-Ti, and 6-Ti. Through protolytic quenching studies and by correspondence of powder XRD patterns with known titanium species, the remaining complexes were structurally assigned. With py or 4-Ph-py present, aggregation of titanium centers is disrupted, relegating the building block to the cis- or trans-(ArO)4Tipy2 core. The sheet structure types are determined by the size of the metal and the interpenetration of the layers, which occurs primarily through the pyridine residues and inhibits intercalation chemistry.

Use of a mesh for musculoaponeurotic defects of the abdominal wall in cancer surgery and the risk of bowel fistulas.

BACKGROUND: Enterocutaneous fistulas resulting from mesh reconstruction of full-thickness musculoaponeurotic abdominal defects in benign conditions is a relatively infrequent, but serious complication. STUDY DESIGN: In the period 1977 to 1986, 26 patients with abdominal wall defects due to ablative surgery for carcinoma had repair with prosthetic material without any special effort to interpose tissue between bowel loops and the mesh. In the period 1986 to 1992, 30 patients with similar defects had tissue interposition between the bowel loops and the mesh (four patients had a free peritoneal patch). In an experimental study, 11 rabbits had an abdominal wall defect repaired with mesh alone, and 14 other rabbits had the abdominal wall defect repaired with the mesh plus a free peritoneal patch sutured underneath. RESULTS: In the first group of patients, six (23 percent) of 26 had enterocutaneous fistulas develop, in the second group zero (zero percent) of 30 had a fistula develop (p = 0.007). In the experimental study, the first group (ten of 11 rabbits) had dense adhesions develop between bowel loops and the mesh. In the second group, none of the 14 rabbits had adhesions develop (p < 0.0001). CONCLUSIONS: In full-thickness abdominal wall defects, omentum, muscle flap, or a peritoneal patch sewn under a mesh prevent fistula formation.