Santosh K. Mandal

The preparation and crystal structure of (dppe) (CO)3Re-OC(O)O-Re(CO)3(dppe)

Abstract The title compound is readily prepared from the rhenium carboxylate, (dppe)(CO)3ReC(O)OCH3, by prolonged stirring of a solution of the carboxylate in benzene/H2O or THF/H2O. The reaction involves the unusual in situ conversion of ReC bonds to ReO bonds. The X-ray structure of the title compound shows that the μ2,η2-carbonato ligand is present in the symmetrical syn, syn conformation in the solid state in contrast to the alternate syn, anti geometry reported for the related complex, (diars)(CO)3ReOC(O)ORe(CO)3(diars).

Conversion of a manganese-carbon-bonded complex to a manganese-oxygen-bonded complex, some reactions of manganese carbonato complexes

Abstract Stirring a solution of the manganese carboxylate, (dppe)(CO) 3 Mn-C(O)OCH 3 , 1 , in dichloromethane saturated with water converts it to the bridging carbonato complex. (dppe)(CO) 3 (dppe), 2 . This multi-step conversion involves the in-situ transformation of a MnC bonded complex to a MnO bonded one. When 2 is stirred with HCl, it is converted quantitatively to the covalent chloride (dppe)(CO) 3 MnCl, 11 , with evolution of carbon dioxide. Similar HCl treatment of the manganese carboxylate 1 gives three compounds: the same covalent chloride, 11 ; the ionic chloride, [(dppe)(CO) 4 Mn] + Cl, 12 , and the hydride, (dppe)(CO) 3 MnH, 5 . Reasonable schemes for these conversions are suggested. Heating the ionic chloride to its melting point converts it to the covalent chloride complex: the same transformation is accomplished by refluxing the ionic chloride in acetonitrile.

Reactions of [(CO)3(P-P)Mn]2 with primary alcohols, where, P-P is dppe {Ph2P(CH2)2PPh2}, dppp {Ph2P(CH2)3PPh2}, dppb {Ph2P(CH2)4PPh2}, dpppe {Ph2P(CH2)5PPh2}, dtpe {(p-tol)2P(CH2)2P(p-tol)2}, or dcpe {(chex)2P(CH2)2P(chex)2}. Synthesis of fac-(CO)3(P-P)MnH and the X-ray structure of fac-(CO)3(dtpe)MnH

Abstract Treatment of the manganese(tricarbonyl)diphosphine dimers [(CO)3(P-P)Mn]2 (where, P-P is dppe {Ph2P(CH2)2PPh2}, dppp {Ph2P(CH2)3PPh2}, dppb {Ph2P(CH2)4PPh2}, dpppe {Ph2P(CH2)5PPh2}, dtpe {(p-tol)2P(CH2)2P(p-tol)2}, and dcpe {(chex)2P(CH2)2P(chex)2}), with 1-propanol, 1-butanol, 1-pentanol, or 1-hexanol yielded fac-(CO)3(dppe)MnH (1), fac-(CO)3(dppp)MnH (2), fac-(CO)3(dppb)MnH (3), fac-(CO)3(dpppe)MnH (4), fac-(CO)3(dtpe)MnH (5), and fac-(CO)3(dcpe)MnH (6), respectively, and the corresponding aldehydes. Also treatment of Mn2(CO)10 with P-P in 1-propanol, 1-butanol, 1-pentanol, or 1-hexanol yielded the corresponding manganese(I) hydrides (1–6) and aldehydes. Structural characterization of 5 demonstrates a manganese–hydrogen (Mn–H(1)) bond length of 1.57(3) A which is in close agreement with the manganese–hydrogen bond length of 1.60(2) A observed in (CO)5MnH by neutron diffraction analysis.

Synthesis and X-ray structures of manganese(I) and rhenium(I) formato complexes, fac-(CO)3(dppp)MOC(H)O

Abstract The mononuclear manganese(I) and rhenium(I) formato complexes, fac-(CO)3(dppp)MOC(H)O (M=Mn, 1; M=Re, 2), have been prepared from fac-(CO)3(dppp)MH and formic acid, and their X-ray structures determined. Compounds 1 and 2 are unusual in that the formato ligands are bound in a terminal, monodentate fashion. For Mn, only multinuclear complexes containing bridging formato ligands have been characterized previously by X-ray diffraction. The MO bond lengths and MOC bond angles are 2.043(2) A and 124.2(2)°, respectively for 1 and 2.167(3) A and 122.3(3)°, respectively for 2. Compounds 1 and 2 can also be decarboxylated at elevated temperatures with quantitative recovery of fac-(CO)3(dppp)MH.

One-pot synthesis of manganese(I) and rhenium(I) alkylcarbonato complexes, fac-(CO)3(dppp)MOC(O)OR. Possible trapping of intermediate diphosphine dimers, [(CO)3(dppp)M]2

Abstract The reactions of Mn2(CO)10 and Re2(CO)10 with dppp, where, dppp is 1,3-bis(diphenylphosphino)propane, in primary alcohols, yielded the corresponding hydrides, fac-(CO)3(dppp)MH under argon atmosphere. However, similar reactions of the metal carbonyls with diphosphines in alcohols in the presence of air or carbon dioxide afforded one equivalent of the corresponding hydrides, fac-(CO)3(dppp)MH and one equivalent of the alkylcarbonato complexes, fac-(CO)3(dppp)MOC(O)OCH2R. The rhenium propylcarbonato complex, fac-(CO)3(dppp)ReOC(O)OCH2CH2CH3 is very stable and has been characterized by X-ray crystal structure determination. The manganese-analog, fac-(CO)3(dppp)MnOC(O)OCH2CH2CH3 is moisture-sensitive and converted slowly to the known carbonato-bridged complex, (CO)3(dppp)MnOC(O)OMn(dppp)(CO)3.

Synthesis, spectroscopy, and X-ray structures of fac-(CO)3(dppe)MnSC(S)H, fac-(CO)3(dppe)ReSC(S)H, fac-(CO)3(dppp)ReSC(S)H, and fac-(CO)3(dppb)ReSC(S)H

The monodentate dithioformato complexes, fac-(CO)3(dppe)MnSC(S)H (1), fac- (CO)3(dppe)ReSC(S)H (2), fac-(CO)3(dppp)ReSC(S)H (3), and fac-(CO)3 (dppb)ReSC(S)H (4), where dppe is 1,2-bis(diphenylphosphino)ethane, dppp is 1,3-bis(diphenylphosphino)propane, and dppb is 1,4-bis(diphenylphosphino)butane, were synthesized from the treatment of the corresponding hydrides, fac-(CO)3 (P-P)MSC(S)H with CS2. Compounds 1–4 crystallize in the monoclinic crystal system: for 1, space group = P21/c, a = 15.3139(3) Å, b = 9.7297(4) Å, c = 19.0991(6) Å, β = 105.928(1)○, V = 2736.5 Å3, Z = 4; for 2, space group = P21/c, a = 15.6395(8) Å, b = 9.8182(5) Å, c = 19.4153(11) Å, β = 106.741(1)○, V = 2854.9(3) Å3, Z = 4; for 3, space group = P21/n, a = 11.3570(10) Å, b = 19.465(2) Å, c = 15.5702(14) Å, β = 104.776(2)○, V = 3328.3(5) Å3, Z = 4; and for 4, space group = C2/c, a = 32.078(2) Å, b = 10.4741(6) Å, c = 19.0608(9) Å, β = 94.315(2)○, V = 6386.1(6) Å3, Z = 8.

Quantum dots: a promising tool in molecular biology

Quantum dot is a spatial semiconductor of periodic groups of II-VI, III-V, or IV-VI materials, which generates optically stable fluorophores upon excitations at various wavelengths (from UV-IR). To date, quantum dot technologies are used in various fields and the use in molecular biology has increased dramatically over the past years. In this review article, we would discuss the potential uses of this versatile nano crystal. Quantum dot technology is also used in cell labelling, bio-sensing, in-vivo imaging, bimodal magnetic-luminescent imaging, and diagnostics. We would also discuss toxicity issues surrounding this nano crystal and speculate about the future uses of quantum dot in large areas of biomedical sciences.

Reactions of dirhenium heptoxide with manganese(I) and rhenium(I) hydrido, alkoxo, methylcarbonato, carbonato-bridged, and methoxymethyl complexes. The X-ray structures of fac-(CO)3(dppp)MnOReO3 and fac-(CO)3(dppp)ReOReO3

Abstract Treatment of Re2O7 with manganese(I) and rhenium(I) hydrido {fac-(CO)3(PP)MH}, alkoxo {fac-(CO)3(PP)MOR}, methylcarbonato {fac-(CO)3(PP)MOC(O)OCH3}, carbonato-bridged [(CO)3(PP)M]2{μ-OC(O)O} and methoxymethyl {fac-(CO)3(PP)MCH2OCH3} complexes, where, R is CH3 or CH2CH3, PP is dppe {1,2-bis(diphenylphosphino)ethane} or dppp {1,3-bis(diphenylphosphino)propane}, yielded the corresponding perrhenato complexes, fac-(CO)3(PP)MOReO3 (1, M=Mn, PP=dppe; 2, M=Mn, PP=dppp; 3, M=Re, PP=dppe; 4, M=Re, PP=dppp), in moderate to excellent yield. The perrhenato complexes have been characterized spectroscopically and the molecular structures of fac-(CO)3(dppp)MnOReO3, 2 and fac-(CO)3(dppp)ReOReO3, 4 have been established through X-ray crystallography.

SYNTHESIS OF SOME MANGANESE AND RHENIUM TRIFLUOROACETOXYMETHYL AND IODOMETHYL COMPLEXES. X-RAY STRUCTURES OF CIS-RE(CO)4(PPH3)CH2OC(O)CF3, FAC-RE(CO)3 (DPPP)CH2OC(O)CF3 AND CIS-RE(CO)4(PPH3)CH2I

Abstract The manganese and rhenium trifluoroacetoxymethyl complexes, cis -Re(CO) 4 (PPh 3 )CH 2 OC(O)CF 3 ( 1 ), fac -Mn(CO) 3 (dppe)CH 2 OC(O)CF 3 ( 2 ), fac -Mn(CO) 3 (dppp)CH 2 OC(O)CF 3 ( 3 ), fac -Re(CO) 3 (dppe)CH 2 OC(O)CF 3 ( 4 ), fac -Re(CO) 3 (dppp)CH 2 OC(O)CF 3 ( 5 ) and the manganese iodomethyl complex fac -Mn(CO) 3 (dppp)CH 2 I ( 6 ), have been prepared by treating the corresponding methoxymethyl complexes with CF 3 COOH and (CH 3 ) 3 SiI, respectively. Structural characterizations of 1 , 5 and cis -Re(CO) 4 (PPh 3 )CH 2 I ( 7 ) show rhenium–carbon (ReCH 2 ) bond lengths of 2.267(8), 2.242(3) and 2.38(8) A, respectively. The ReCCH 2 I bond angle of 118.8(3)° in 7 indicates that the methylene carbon is severely distorted from tetrahedral geometry.

Abstract 4485: Anticancer properties of novel rhenium compounds against human cancer cell lines.

Cisplatin, carboplatin, oxaliplatin, and related metallodrugs are extensively being used in the treatment of a variety of cancers. Unfortunately these drugs are highly toxic and tumor becomes drug-resistance. These circumstances have led researchers to look for new cytotoxic agents that may exhibit less toxicity and devoid of drug resistance. It is believed that cisplatin and related drugs directly bind to genomic DNA through purine bases. Synthesis of new metallodrugs which does not follow the above mechanism of action might yield better drugs with less toxicity and devoid of drug resistance. Recently we have demonstrated that several anticancer rhenium compounds do not directly bind to DNA. We have synthesized numerous rhenium pentylcarbonato and acetylsalicylato complexes which include (CO)3(2,2’-Bipyridyl)ReOC(O)OC5H11 (PC-1), (CO)3(1,10-Phenanthroline)ReOC(O)OC5H11 (PC-2), (CO)3(5-Methyl-1,10-Phenanthroline)Re ReOC(O)OC5H11 (PC-3), (CO)3(2,9-Dimethyl-1,10-Phenanthroline)ReOC(O)OC5H11 (PC-4), (CO)3(5,6-Dimethyl-1,10-Phenanthroline)ReOC(O)OC5H11 (PC-5), (CO)3(4,7-Diphenyl-1,10-Phenanthroline)ReOC(O)OC5H11 (PC-6), (CO)3(2,9-Dimethyl-4,7-Diphenyl-1,10-Phenanthroline)Re ReOC(O)OC5H11 (PC-7), (CO)3(2,2’-Bipyridyl)ReOC(O)C6H4·C(O)OCH3 (ASP-1), (CO)3(1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3, (ASP-2), (CO)3(5-Methyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-3), (CO)3(2,9-Dimethyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-4), (CO)3(5,6-Dimethyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-5), (CO)3(4,7-Diphenyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-6), (CO)3(2,9-Dimethyl-4,7-Diphenyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-7). The anticancer properties of the compounds were evaluated using human prostate, alveolar lung, brain, colon, and leukemia cancer cell lines and normal bone marrow cell lines. The results of this study demonstrate that these complexes have significant anticancer properties. Therefore, these complexes can potentially find applications in the treatment of these cancers. Acknowledgment. The work at MSU was partially supported by grants from the National Institutes of Health (Grant No. G11HD038439) and Nuclear Regulatory Commission (Grant No. NRC-HQ-12-G-27-0086). The work at ECSU-UNC was partially supported by grant from the Department of Energy (TMCF/DOE grant). Citation Format: Hirendra N. Banerjee, Deidre Vaughan, Jewe Medley, Gwyn Hyman, Christopher Krauss, Carl Parson, Santosh Mandal, Pola Olczak, Michael Mbagu, Divine Kebulu, Saroj Pramanik, Fazlul Sarkar. Anticancer properties of novel rhenium compounds against human cancer cell lines. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4485. doi:10.1158/1538-7445.AM2013-4485