scholarly journals Synthesis and structures of ruthenium di- and tricarbonyl complexes derived from 4,5-diazafluoren-9-one

2015 ◽  
Vol 71 (11) ◽  
pp. 965-968 ◽  
Author(s):  
Jorge Jimenez ◽  
Indranil Chakraborty ◽  
Pradip Mascharak

Carbon monoxide (CO) has recently been shown to impart beneficial effects in mammalian physiology and considerable research attention is now being directed toward metal–carbonyl complexes as a means of delivering CO to biological targets. Two ruthenium carbonyl complexes, namelytrans-dicarbonyldichlorido(4,5-diazafluoren-9-one-κ2N,N′)ruthenium(II), [RuCl2(C11H6N2O)(CO)2], (1), andfac-tricarbonyldichlorido(4,5-diazafluoren-9-one-κN)ruthenium(II), [RuCl2(C11H6N2O)(CO)3], (2), have been isolated and structurally characterized. In the case of complex (1), thetrans-directing effect of the CO ligands allows bidentate coordination of the 4,5-diazafluoren-9-one (dafo) ligand despite a larger bite distance between the N-donor atoms. In complex (2), thecisdisposition of two chloride ligands restricts the ability of the dafo molecule to bind ruthenium in a bidentate fashion. Both complexes exhibit well defined1H NMR spectra confirming the diamagnetic ground state of RuIIand display a strong absorption band around 300 nm in the UV.

2012 ◽  
Vol 9 (2) ◽  
pp. 807-817 ◽  
Author(s):  
Mohd Saleem ◽  
Mohita Sharma ◽  
Simpy Mahajan ◽  
H. N. Sheikh ◽  
B. L. Kalsotra

Carbonyl complexes of Chromium, molybdenum and tungsten of composition, [M(CO)4L-L], (where M= Cr, Mo or W and L-L= benzoic acid[1-(Furan-2-yl)methylene]hydrazide (BFMH), benzoic acid[(thiophene-2-yl)methylene]hydrazide (BTMH), benzoic acid[1-(thiophene-2-yl)ethylidene] hydrazide (BTEH), benzoic acid (phenylmethylene)hydrazide (BPMH) and benzoic acid[1-(anisol-3-yl)methylene] hydrazide (BAMH) are reported. These have been prepared by refluxing metal carbonyls and the ligands in 1:1molar ratio. The complexes were characterized by elemental analysis, IR spectra, UV-vis spectra,1H NMR, TGA/DTA, conductivity and magnetic susceptibility measurements. The IR bands suggest that in all the complexes the ligands behave as neutral bidentate chelating type coordinating metal through carbonyl oxygen and azomethine nitrogen. The CO force constants and CO-CO interaction constants for these derivatives have been calculated using Cotton-Kraihanzel secular equations, which indicate poorπ-bonding ability of the coordinated ligands.


2017 ◽  
Vol 73 (11) ◽  
pp. 923-929 ◽  
Author(s):  
Miguel Pinto ◽  
Indranil Chakraborty ◽  
Jorge Martinez-Gonzalez ◽  
Pradip Mascharak

Carbon monoxide (CO) has recently been identified as a gaseous signaling molecule that exerts various salutary effects in mammalian pathophysiology. Photoactive metal carbonyl complexes (photoCORMs) are ideal exogenous candidates for more controllable and site-specific CO delivery compared to gaseous CO. Along this line, our group has been engaged for the past few years in developing group-7-based photoCORMs towards the efficient eradication of various malignant cells. Moreover, several such complexes can be tracked within cancerous cells by virtue of their luminescence. The inherent luminecscent nature of some photoCORMs and the change in emission wavelength upon CO release also provide a covenient means to track the entry of the prodrug and, in some cases, both the entry and CO release from the prodrug. In continuation of the research circumscribing the development of trackable photoCORMs and also to graft such molecules covalently to conventional delivery vehicles, we report herein the synthesis and structures of three rhenium carbonyl complexes, namely, fac-tricarbonyl[2-(pyridin-2-yl)-1,3-benzothiazole-κ2 N,N′](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C12H8N2S)(CO)3](CF3SO3), (1), fac-tricarbonyl[2-(quinolin-2-yl)-1,3-benzothiazole-κ2 N,N′](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C16H10N2S)(CO)3](CF3SO3), (2), and fac-tricarbonyl[1,10-phenanthroline-κ2 N,N′](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C12H8N2)(CO)3](CF3SO3), (3). In all three complexes, the ReI center resides in a distorted octahedral coordination environment. These complexes exhibit CO release upon exposure to low-power UV light. The apparent CO release rates of the complexes have been measured to assess their comparative CO-donating capacity. The three complexes are highly luminescent and this in turn provides a convenient way to track the entry of the prodrug molecules within biological targets.


2019 ◽  
Vol 91 (5) ◽  
pp. 785-796 ◽  
Author(s):  
Divine Mbom Yufanyi ◽  
Toni Grell ◽  
Menyhárt-Botond Sárosi ◽  
Peter Lönnecke ◽  
Evamarie Hey-Hawkins

Abstract Group 6 metal (Cr, Mo, W) carbonyl complexes react with cyclo-(P5Ph5) to afford the phosphorus-rich complexes [Cr(CO)5{cyclo-(P5Ph5)-κP1}] (1), [{Cr(CO)5}2{μ-cyclo-(P5Ph5)-κP1,P3}] (2), [M(CO)4{cyclo-(P5Ph5)-κP1,P3}] (with M=Cr (3), Mo (4), W (exo-5, endo-5)) depending on the reaction conditions. Complexes 1–5 were characterised by 31P{1H} NMR and IR spectroscopy, elemental analysis, and X-ray crystallography. The cyclopentaphosphane remains intact and acts as monodentate (1), bridging (2) or bidentate (3–5) ligand. Compounds exo-5 and endo-5 are configurational isomers and essentially differ in the orientations adopted by the phenyl rings attached to the uncoordinated phosphorus atoms. The 31P{1H} NMR spectra show five multiplets for an ABCDE spin system. Theoretical calculations showed that exo-5 and endo-5 are practically isoenergetic, which is in good agreement with the observed equilibrium in solution between exo-5 and endo-5. The thermal properties of the complexes have also been evaluated.


1986 ◽  
Vol 47 (C8) ◽  
pp. C8-589-C8-592
Author(s):  
N. BINSTED ◽  
S. L. COOK ◽  
J. EVANS ◽  
R. J. PRICE ◽  
G. N. GREAVES

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