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001-es BibID:	BIBFORM085974
Első szerző:	Espenson, James H.
Cím:	Synthesis and characterization of dimetallic oxorhenium(V) and dioxorhenium(VII) compounds, and a study of stoichiometric and catalytic reactions / James H. Espenson, Xiaopeng Shan, Ying Wang, Ruili Huang, David W. Lahti, JaNeille Dixon, Gábor Lente, Arkady Ellern, Ilia A. Guzei
Dátum:	2002
ISSN:	0020-1669 1520-510X
Megjegyzések:	Chelating dithiolate ligands-e.g., mtp from 2-(mercaptomethyl)thlophenol, edt from 1,2-ethanedithiol, and pdt from 1,3-propanedithiol-stabilize high-valent oxorhenium(V) against hydrolytic and oxidative decomposition. In addition to the dithiolate chelating to a single rhenium, one sulfur forms a coordinate bond to the other rhenium. In one arrangement this gives a dimer with a nearly planar diamond core with different internal Re-S distances. The new compounds are {MeReO(edt)}(2) (2) and {MeReO(pdt)}(2) (3), which can be compared to the previously known {MeReO(mtp)}(2) (1), Another mode of synthesis leads to {ReO}(2)(mtp)(3) (5) and {ReO}(2)(edt)(3) (6). They, too, have similar Re2S2 cores that involve donor atoms from two of the dithiolate ligands; the third dithiolate chelates one of the rhenium atoms. Gentle hydrolysis of 1 affords [Bu(n)4][{MeReO(mtp)}(2)(mu-OH)] (7) in low yield, It appears to be the first example of this structural type for rhenium. The use of dithioerythritol as a starting material allowed the synthesis of a dioxorhenium(VII) compound, {MeReO2}(2)(dte) (8). Its importance lies in understanding the role such compounds are believed to play as intermediates in oxygen atom catalysis. Ligation of the dimers 1-3 converts them into monomeric compounds, MeReO(dithiolate)L. These reactions go essentially to completion for L = PPh3, but reach an equilibrium for L = NC5H4R. With R = 4-Ph, the values of K/10(3) L mol(-1) for the reactions (1-3) + 2L = 2MeReO(dithiolate)L are identical within 3sigma: 1.15(3) (1), 1.24(4) (2), and 1.03(16) (3), The rates of monomer formation follow the rate law -d In [dimer]/dt = k(a)[L] + k(b)[L](2). These trends were found: (1) phosphines are slow to react compared to pyridines, (2) the edt dimer 2 reacts much more rapidly than 1 and 3. Dimer 1 and MeReO(mtp)PPh3 both catalyze oxygen atom transfer: PicO + PPh3 - Pic + Ph3PO. Compound 1 is ca. 90 times more reactive, which can be attributed to its lability toward small ligands as opposed to the low rate of displacement of PPh3 from the mononuclear catalyst, The kinetics of this reaction follows the rate law -d[PicO]/dt = k[PicO][1]/{1 + kappa[PPh3]}, with k = 5.8 x 10(6) L mol(-1) s(-1) and kappa = 3.5 x 10(2) L mol(-1) at 23 degreesC in benzene. A mechanism has been proposed to account for these findings.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Inorganic Chemistry. - 41 : 9 (2002), p. 2583-2591. -
További szerzők:	Shan, Xiaopeng Wang, Ying Huang, Ruili Lahti, David W. Dixon, JaNeille Lente Gábor (1973-) (vegyész) Ellern, Arkady Guzei, Ilia A.
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001-es BibID:	bibEBI00009668
Első szerző:	Jacob, Joseman
Cím:	Monomerization of a rhenium(V) dimer by ligation / J. Jacob, G. Lente, I. A. Guzei, J. H. Espenson
Dátum:	1999
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Inorganic chemistry. - 38 : 17 (1999), p. 3762-3763. -
További szerzők:	Lente Gábor (1973-) (vegyész) Guzei, Ilia A. Espenson, James H.
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001-es BibID:	BIBFORM087712
Első szerző:	Lente Gábor (vegyész)
Cím:	Kinetics and mechanism of the monomerization of a Re(IV) dithiolato dimer with monodentate ligands. Electronic and steric effects / Gábor Lente, Ilia A. Guzei, James H. Espenson
Dátum:	2000
ISSN:	0020-1669 1520-510X
Megjegyzések:	The sulfur-bridged dimeric dithiolato rhenium(V) chelate (D), derived from 2-mercaptothiophenol, was monomerized to give (M?L) in benzene upon reaction with various neutral and anionic monodentate ligands (L) such as pyridine and its substituted derivatives, triarylphosphines, dimethyl sulfoxide, 4-picoline-N-oxide, and halide ions. The kinetic observations can readily be interpreted for all ligands by a unified mechanism in which the initial fast formation of a 1:1 (DL) and 1:2 (DL2) adduct is followed by the slow monomerization of each species so formed. The use of different ligands gave insight into different steps of the same multistep mechanism. The kinetics of ligand exchange between free L and the monomeric complexes was also studied; an associative pathway has been proposed to interpret the results. The crystal structures of two new monomeric ML complexes (with L = 4-acetylpyridine and 1,3-diethylthiourea) are reported.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Inorganic Chemistry. - 39 : 6 (2000), p. 1311-1319. -
További szerzők:	Guzei, Ilia A. Espenson, James H.
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001-es BibID:	BIBFORM087692
Első szerző:	Lente Gábor (vegyész)
Cím:	Syntheses and structures of rhenium(IV) and rhenium(V) complexes with ethanedithiolato ligands / Gábor Lente, Xiaopeng Shan, Ilia A. Guzei, James H. Espenson
Dátum:	2000
ISSN:	0020-1669 1520-510X
Megjegyzések:	A novel dimeric rhenium(IV) complex, [Re-2(SCH2CH2S)(4)], and a monomeric methyloxorhenium(V) complex, [CH3ReO(SCH2CH2S)PPh3], were synthesized from methyloxorhenium(V) complexes and characterized crystallographically. The structure of [Re-2(SCH2CH2S)(4)], the formation reaction of which showed surprising demethylation conceivably through the homolytic cleaveage of the rhenium-carbon bond, features distorted trigonal prismatic coordination of sulfurs around the metal center and a rhenium-rhenium triple bond. A revised structure, [Tc-2(SCH2CH2S)(4)], is proposed for a related technetium complex, originally identified as [Tc-2(SCR2CH2S)(2)(SCH=CHS)(2)] (Tisato et al. Inorg. Chem. 1993, 32, 2042). Additionally, a new compound, CH3Re(O)(SPh)(2)PPh3, was prepared.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Inorganic Chemistry. - 39 : 16 (2000), p. 3572-3576. -
További szerzők:	Shan, Xiaopeng Guzei, Ilia A. Espenson, James H.
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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