17 research outputs found
High Rectification Ratio at Room Temperature in Rhenium(I) Compound
Electrical current rectification is an interesting electronic feature,
popularly known as a diode. Achieving a high rectification ratio in a molecular
junction has been a long-standing goal in molecular electronics. The present
work describes mimicking electrical current rectification with pi-stacked
rhenium(I) compound sandwiched between two electrical contacts. Among the two
mononuclear rhenium compounds studied here, [Re(CO)4(PPh3){(N)-saccharinate}]
(1) and [Re(CO)3(phen){(N)-saccharinate}] (2), the latter show strong pi-pi
interactions-induced high rectification ratio of ~ 4000 at 2.0 V at room
temperature. Alternating current (AC)-based electrical measurements ensuring AC
to DC electrical signal conversion at a frequency f of 1 KHz showing 2 can act
as an excellent half-wave rectifier. Asymmetric charge injection barrier height
at the electrode/Re(I) interfaces of the devices with a stacking configuration
of p++-Si/Re compound31nm(2)/ITO originates the flow of electrical current
unidirectionally. The charge transport mechanism governed by thermally
activated hopping phenomena, and charge carrier propagation is explained
through an energy profile considering the Fermi levels of two electrodes, and
the energy of frontier molecular orbitals, HOMO, and LUMO, confirming
rectification is of a molecular origin. The present work paves the way to
combine different organometallic compounds as circuit elements in
nanoelectronic devices to achieve numerous exciting electronic features.Comment: 16 pages, 5 figure
Oxidative-addition of the N-H bond of saccharin (sacH) to a triosmium centre:Synthesis, structure and reactivity of Os<sub>3</sub>(CO)<sub>10</sub>(μ-H)(μ-sac)
Synthetic Studies of Pyrene Oligomers and Their Functionalization Aiming at Circularly Polarized Luminescence
Backbone Modified Small Bite-Angle Diphosphines:Synthesis, Structure, Fluxionality and Regioselective Thermally-Induced Transformations of Ru<sub>3</sub>(CO)<sub>10</sub>{µ-Ph<sub>2</sub>PCH(Me)PPh<sub>2</sub>}
<span style="font-size:13.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;letter-spacing:-.3pt;mso-ansi-language:EN-GB;mso-fareast-language:EN-US; mso-bidi-language:HI" lang="EN-GB">Reaction of electron-deficient triosmium cluster Os<sub>3</sub>(CO)<sub>8</sub>{μ<sub>3</sub>-Ph<sub>2</sub>PCH(CH<sub>3</sub>)P(Ph)C<sub>6</sub>H<sub>4</sub>}(μ-H) with HCl: X-ray structure of two isomers of Os<sub>3</sub>(CO)<sub>8</sub>{μ-Ph<sub>2</sub>PCH(CH<sub>3</sub>)PPh<sub>2</sub>}(μ-Cl)(μ-H)</span>
1104-1108Treatment of electron-deficient Os3(CO)8{μ3-Ph2PCH(CH3)-P(Ph)C6H4}(μ-H)
(1) with HCl at room temperature furnishes
the adduct Os3(CO)8{μ-Ph2PCH(CH3)PPh2}(μ-Cl)(μ-H)
(2)
in almost quantitative yield via oxidative addition of H‒Cl
bond. Cluster (2) is electron-precise and contains bridging chloride and
hydride ligands which rearranges upon heating
at 110 °C to form isomeric (3). Both clusters have been characterized by
a combination of elemental analyses, IR and NMR spectroscopic data together
with single crystal X-ray diffraction studies.
</span
<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Synthesis, structure and reactivity of triosmium clusters derived from the reactions of [Os<sub>3</sub>(CO)<sub>10</sub>(µ-dppm)] and <span style="font-size:11.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-bidi-font-family:Mangal;mso-ansi-language:PT-BR; mso-fareast-language:EN-US;mso-bidi-language:HI" lang="PT-BR">[(<span style="font-size:11.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-bidi-font-family:Mangal;mso-ansi-language:EN-GB; mso-fareast-language:EN-US;mso-bidi-language:HI" lang="EN-GB">µ<span style="font-size:11.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-bidi-font-family:Mangal;mso-ansi-language:PT-BR; mso-fareast-language:EN-US;mso-bidi-language:HI" lang="PT-BR">-H)Os<sub>3</sub>(CO)<sub>8</sub>{<span style="font-size:11.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-bidi-font-family:Mangal;mso-ansi-language:EN-GB; mso-fareast-language:EN-US;mso-bidi-language:HI" lang="EN-GB">µ<sub><span style="font-size:11.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-bidi-font-family:Mangal;mso-ansi-language:PT-BR; mso-fareast-language:EN-US;mso-bidi-language:HI" lang="PT-BR">3</span></sub><span style="font-size:11.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-bidi-font-family:Mangal;mso-ansi-language:PT-BR; mso-fareast-language:EN-US;mso-bidi-language:HI" lang="PT-BR">-Ph<sub>2</sub>PCH<sub>2</sub>P(Ph)C<sub>6</sub>H<sub>4</sub>}] <span style="font-size:11.0pt;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";mso-bidi-font-family:Mangal; mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language:HI" lang="EN-GB">with tris(<span style="font-size:12.0pt;mso-fareast-font-family: "Times New Roman";mso-bidi-font-family:"Times New Roman";mso-ansi-language: EN-GB;mso-fareast-language:EN-US;mso-bidi-language:HI;font-style:normal; mso-bidi-font-style:italic" lang="EN-GB">4<span style="font-size: 11.0pt;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US; mso-bidi-language:HI" lang="EN-GB">-fluorophenyl)phosphine and tris(cyanoethyl)phosphine</span></span></span></span></span></span></span></span></span>
581-587The reactions of [Os3(CO)10(µ-dppm)]
(1) with tris(4-fluorophenyl)phosphine,
P(4-FC6H4)3, and tris(cyanoethyl)
phosphine, P(CH2CH2CN)3, in the presence of Me3NO
in refluxing dichloromethane give the mono-substituted
clusters [Os3(CO)9(µ-dppm){P(4-FC6H4)3)}]
(2) and [Os3(CO)9(µ-dppm){P(CH2CH2CN)3)}]
(3), respectively, in which
the phosphine is bound to the non-dppm-substituted osmium center. The
46-electron compound [(µ-H)Os3(CO)8-
{µ<span style="mso-ansi-language:
PT-BR" lang="PT-BR">3-Ph2PCH2P(Ph)C6H4}]
(6) reacts with an excess of P(4-FC6H4)3 and
P(CH2CH2CN)3 at ambient temperature to yield (2)
and (3), respectively. Heating (2)
or (3)<b style="mso-bidi-font-weight:
normal"> in refluxing toluene at
110 oC afforded the electron-deficient clusters [(µ-H)-
Os3(CO)7{µ3-Ph2PCH2PPh(C6H4)}{P(4-FC6H4)3)}]
(4) and [(µ-H)Os3(CO)7{µ3-Ph2PCH2PPh(C6H4)}{P(CH2CH2CN)3}]
(5) resulting from C-H bond scission
of the coordinated dppm and metal hydride bond formation. The molecular
structures of (2), (3) and (<b style="mso-bidi-font-weight:
normal">4) have been determined by single- crystal X-ray diffraction
studies.
</span
Synthesis and characterization of tungsten carbonyl complexes containing thioamides
274-280Tungsten pentacarbonyl complexes are
isolated from the reactions between [W(CO)5(NCMe)] and thioamides,
the former being generated in situ
upon addition of equimolar amount of Me3NO
into an acetonitrile solution of W(CO)6. Room temperature reactions
between [W(CO)5(NCMe)] and acyclic thioamides such as thioacetamide
and benzamide afford [W(CO)5{к1-(S)-RCSNH2}]
in which the thioamides are coordinated to tungsten through sulfur. Similar
S-coordinated complexes, namely, [W(CO)5{к1-(S)-thiolactam}]
are also isolated from the reactions with cyclic thioamides or thiolactams
under the same reaction conditions. All the new complexes have been adequately
characterized by spectroscopic data together with single crystal X-ray
diffraction studies for four complexes
<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;color:black;mso-ansi-language:EN-GB;mso-fareast-language:EN-US; mso-bidi-language:HI" lang="EN-GB">New tertiary phosphine derivatives of Os<sub>3</sub>(CO)<sub>12</sub>: X-ray structures of 1,2-[Os<sub>3</sub>(CO)<sub>10</sub>{PhP(<i style="mso-bidi-font-style:normal">o</i>-Tol)<sub>2</sub>}<sub>2</sub>], 1,2,3-[Os<sub>3</sub>(CO)<sub>9</sub>{(4-FC<sub>6</sub>H<sub>4</sub>)<sub>3</sub>P}<sub>3</sub>], 1,2,3-[Os<sub>3</sub>(CO)<sub>9</sub>{PhP(Cy)<sub>2</sub>}<sub>3</sub>] and [Os<sub>3</sub>(µ-OH)<sub>2</sub>(CO)<sub>8</sub>{(4-FC<sub>6</sub>H<sub>4</sub>)<sub>3</sub>P}<sub>2</sub>]</span>
161-169Reactions of 1,2-[Os3(CO)10(NCMe)2]
(1) with tertiary phosphines such as
tris(4-fluorophenyl)phosphine
(4-FC6H4)3P, bis(<i style="mso-bidi-font-style:
normal">o-tolyl)(phenyl)phosphine PhP(o-Tol)2
and dicyclohexyl(phenyl)phosphine PhP(Cy)2 have been examined at
room temperature and found to yield the di- and tri-substituted products 1,2-[Os3(CO)10(PR3)2]
{(2<span style="mso-bidi-font-weight:
bold">), PR3 = (4-FC6H4)3P;
(3<span style="mso-bidi-font-weight:
bold">),
PR3 = PhP(o-Tol)2;
(4<span style="mso-bidi-font-weight:
bold">), PR3 = PhP(Cy)2} and 1,2,3-[Os3(CO)9(PR3)3] {(5), PR3 = (4-FC6H4)3P;
(6<span style="mso-bidi-font-weight:
bold">), PR3 = PhP(o-Tol)2;
7, PR3 = PhP(Cy)2}
as the major products, in addition to the dihydroxyl-bridged complexes 1,2-[Os3(CO)8(PR3)2(µ-OH)2]
{(8<span style="mso-bidi-font-weight:
bold">), PR3 = (4-FC6H4)3P;
(9<span style="mso-bidi-font-weight:
bold">), PR3 = PhP(o-Tol)2;
(10<span style="mso-bidi-font-weight:
bold">), PR3 = PhP(Cy)2} in trace amounts. Compounds (<b style="mso-bidi-font-weight:
normal">2)-(10<span style="mso-bidi-font-weight:
bold">) have been characterized by a combination of elemental analyses,
infrared, NMR and mass spectral data together with single crystal
X-ray diffraction studies for (3), (<b style="mso-bidi-font-weight:
normal">5), (7<span style="mso-bidi-font-weight:
bold">) and (8<span style="mso-bidi-font-weight:
bold">).
</span