The unusual oxygen-linked double cubane-like cluster compound {[Mo(3)PbOS(3)](OAc)(2)(py)(3)(dtp)(2)O}(2) (A) (dtp = S(2)P(OEt(2))(-), OAc = CH(3)COO(-), py = C(5)H(5)N) was obtained for the first time by the reaction of the mixed S/O-bridged cluster [Mo(3)(&mgr;(3)-O)(&mgr;-S)(3)(dtp)(4)H(2)O] (B) with Pb(OAc)(2).3H(2)O in the presence of excess CH(3)COOH and pyridine. It has been characterized by IR, Raman, UV-vis, and X-ray structure analysis. The molecule contains a crystallographic center of inversion and can be viewed as consisting of two [Mo(3)PbOS(3)](6+) cubane-like cores linked through a pair of oxygen bridges with Mo-(&mgr;-O) bond lengths of ca. 1.89 Å. The cell dimensions are a = 11.705(8) Å, b = 19.527(8) Å, c = 20.670(9) Å, beta = 98.14(4) degrees, V = 4677(8) Å(3), Z = 2 in the space group P2(1)/n. The final R = 0.056, R(w) = 0.068 for 5424 reflections with I >/= 3sigma(I). The average Mo-Mo bond distance is 2.613(1) Å and the nonbonding Mo-Pb distances lie in the range from 3.997(1) to 4.090(1) Å. The spectra of IR, Raman, and UV-vis spectra are also shown in this paper.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ic9703890 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
sSPhos: A General Ligand for Enantioselective Arylative Phenol Dearomatization via Electrostatically-Directed Palladium Catalysis.
J Am Chem Soc
November 2023
Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom.
Arylative phenol dearomatization affords complex, cyclohexanone-based scaffolds from simple starting materials, and asymmetric versions allow access to valuable enantioenriched structures. However, bespoke chiral ligands must typically be identified for each new scaffold variation. We have addressed this limitation by applying the concept of electrostatically-directed palladium catalysis whereby the chiral sulfonated ligand sSPhos engages in electrostatic interactions with a phenolate substrate via its associated alkali metal cation.
View Article and Find Full Text PDFConformational analysis of 2-substituted piperazines.
Bioorg Med Chem Lett
July 2016
Retrophin, Inc, 301 Binney Street, Cambridge, MA 02142, United States.
The unusual activity differences of carbon linked versus oxygen linked 2-substituted piperazines as α7 nicotinic acetylcholine receptor agonists led to a conformational study of several examples. The conformational preferences of which are absent from the literature. We report the first study and explanation of the conformational preference of 2-substiturted piperazines and show an example of how this preference controls binding in a pharmaceutically relevant case.
View Article and Find Full Text PDFLack of conventional oxygen-linked proton and anion binding sites does not impair allosteric regulation of oxygen binding in dwarf caiman hemoglobin.
Am J Physiol Regul Integr Comp Physiol
August 2013
Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.
In contrast to other vertebrate hemoglobins (Hbs) whose high intrinsic O2 affinities are reduced by red cell allosteric effectors (mainly protons, CO2, organic phosphates, and chloride ions), crocodilian Hbs exhibit low sensitivity to organic phosphates and high sensitivity to bicarbonate (HCO3(-)), which is believed to augment Hb-O2 unloading during diving and postprandial alkaline tides when blood HCO3(-) levels and metabolic rates increase. Examination of α- and β-globin amino acid sequences of dwarf caiman (Paleosuchus palpebrosus) revealed a unique combination of substitutions at key effector binding sites compared with other vertebrate and crocodilian Hbs: β82Lys→Gln, β143His→Val, and β146His→Tyr. These substitutions delete positive charges and, along with other distinctive changes in residue charge and polarity, may be expected to disrupt allosteric regulation of Hb-O2 affinity.
View Article and Find Full Text PDFSynthesis and Structural Characterization of an Unusual Oxygen-Linked Double Cubane-Like Cluster {[Mo(3)PbOS(3)](OAc)(2)(py)(3)(dtp)(2)O}(2).
Inorg Chem
July 1999
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.
The unusual oxygen-linked double cubane-like cluster compound {[Mo(3)PbOS(3)](OAc)(2)(py)(3)(dtp)(2)O}(2) (A) (dtp = S(2)P(OEt(2))(-), OAc = CH(3)COO(-), py = C(5)H(5)N) was obtained for the first time by the reaction of the mixed S/O-bridged cluster [Mo(3)(&mgr;(3)-O)(&mgr;-S)(3)(dtp)(4)H(2)O] (B) with Pb(OAc)(2).3H(2)O in the presence of excess CH(3)COOH and pyridine. It has been characterized by IR, Raman, UV-vis, and X-ray structure analysis.
View Article and Find Full Text PDFBicarbonate binding to hemoglobin links oxygen and carbon dioxide transport in hagfish.
Respir Physiol
May 1999
Danish Centre for Respiratory Adaptation, Zoophysiology Department, Institute of Biological Sciences, Aarhus University.
Hagfish are unusual among vertebrates in having red cells that almost completely lack the anion-exchanger membrane protein band III and hemoglobins that are highly sensitive to CO2 but only weakly affected by protons. This suggests a different linkage between oxygen and CO2 transport from that of the majority of vertebrates, which is characterized by oxygen-linked proton binding to hemoglobin and chloride-bicarbonate exchange across band III protein. We here report that the hemoglobin of the hagfish Myxtne glutinosa shows oxygen-linked binding of bicarbonate, which decreases the oxygen affinity and thereby enhances oxygen unloading to the tissues.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!