Geminal poly(1-pyrazolyl)alkanes and their coordination chemistry
01 Aug 1970-Journal of the American Chemical Society (American Chemical Society)-Vol. 92, Iss: 17, pp 5118-5126
About: This article is published in Journal of the American Chemical Society.The article was published on 1970-08-01. It has received 300 citations till now. The article focuses on the topics: Geminal & Coordination complex.
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TL;DR: In this article, the stereochemical properties of over 120 pyrazole-based chelating ligands, studied by single-crystal X-ray crystallography were analyzed.
426 citations
TL;DR: In this paper, a comprehensive surwey of the tris(pyrazolyl)alkanes coordination chemistry, based on the nature of the metal, is presented, together with the main synthetic methods and spectroscopic and structural features of this important class of ligands.
371 citations
TL;DR: The known ligands HC(pz)3, HC(3,5-Me2pz), HC( 3,3-Me 2pz, 3,5,Me 3 pz), and HC(Phpz 2py)3 were prepared in CHCl3-H2O using pyrazole, an excess of Na2CO3, and tetra-n-butylammonium bromide as the phase transfer catalyst as discussed by the authors.
298 citations
TL;DR: In this paper, the authors showed an improvement in the laser power efficiency of pyrromethene-8-ethylpyrromethne-2,6-disulfonate-BF2 complex in the presence of a filter for light <300 nm.
Abstract: Condensations between 3-X-2,4-dimethylpyrroles (X = H, CH3, C2H5, and CO2C2H5) and acyl chlorides gave derivatives of 3,5,3′,5′-tetramethylpyrromethene (isolated as their hydrochloride salts): 6-methyl, 6-ethyl, 4,4′,6-trimethyl, 4,4′-diethyl-6-methyl, and 4,4′-dicarboethoxy-6-ethyl derivatives for conversion on treatment with boron trifluoride to 1,3,5,7-tetramethylpyrromethene–BF2 complex (TMP–BF2) and its 8-methyl (PMP–BF2), 8-ethyl, 2,6,8-trimethyl (HMP–BF2),2,6,-diethyl-8-methyl (PMDEP–BF2), and 2,6-dicarboethoxy-8-ethyl derivatives. Chlorosulfonation converted, 1,3,5,7,8-pentamethylpyrromethene–BF2 complex to its 2,6-disulfonic acid isolated as the lithium, sodium (PMPDS–BF2), potassium, rubidium, cesium, ammonium, and tetramethylammonium disulfonate salts and the methyl disulfonate ester. Sodium 1,3,5,7-tetramethyl-8-ethylpyrromethene-2,6-disulfonate–BF2 complex was obtained from the 8-ethyl derivative of TMP–BF2. Nitration and bromination converted PMP–BF2 to its 2,6-dinitro-(PMDNP–BF2) and 2,6-dibromo- derivatives. The time required for loss of fluorescence by irradiation from a sunlamp showed the following order for P–BF2 compounds (10−3 to 10−4 M) in ethanol: PMPDS–BF2, 7 weeks; PMP–BF2, 5 days; PMDNP–BF2, 72 h; HMP–BF2, 70 h; and PMDEP–BF2, 65 h. Under similar irradiation PMPDS–BF2 in water lost fluorescence after 55 h. The dibromo derivative was inactive, but each of the other pyrromethene–BF2 complexes under flashlamp excitation showed broadband laser activity in the region λ 530–580 nm. In methanol PMPDS–BF2 was six times more resistant to degradation by flashlamp pulses than was observed for Rhodamine-6G (R-6G). An improvement (up to 66%) in the laser power efficiency of PMPDS–BF2 (10−4 M in methanol) in the presence of caffeine (a filter for light <300 nm) was dependent on flashlamp pulse width (2.0 to 7.0 μsec).
261 citations
TL;DR: Cell viability studies of HT29 colon cancer cells treated with the CO-releasing compound [Mn(CO)(3)(tpm)]PF(6) revealed a significant photoinduced cytotoxicity comparable to that of established agent 5-fluorouracil (5-FU).
248 citations