Qing-Mei Hu

Excited-state absorption and optical-limiting properties of organometallic fullerene–C60 derivatives

Singlet excited-state absorption properties and optical limiting behaviors of organochromium and organomolybdenum C60 derivatives (C89H24CrO3P2 and C89H24MoO3P2) were studied by using a double frequency ns/ps Nd:YAG pulse laser system at wavelength of 532 nm and pulse width 21 ps. The experimental results demonstrated that the optical limiting behavior of organochromium C60 derivative is better than both organomolybdenum C60 derivative and fullerene–C60 itself. The experimental results agree well with the singlet excited-state absorption theory.

Synthesis of single and double butterfly iron carbonyl complexes by reactions of [(μ-RSe)(μ-CO)Fe2(CO)6]− anions. Crystal structures of (μ-p-MeC6H4Se)[μ-PhCH2N(H)CS]Fe2(CO)6 and [(μ-PhSe)(μ-MeAs)Fe2(CO)6]2

Abstract The in situ reactions of the [Et3NH]+ and [MgBr]+ salts of [(μ-RSe)(μ-CO)Fe2(CO)6]− (1) anions with PhC(Cl)ue605NPh gave single butterfly complexes (μ-RSe)(μ-PhCue605NPh)Fe2(CO)6 (2, R=Ph; 3, R=p-MeC6H4; 4, R=Et), whereas those of the [Et3NH]+ salts of 1 with R′Nue605Cue605S afforded single butterfly complexes (μ-RSe)[μ-R′N(H)Cue605S]Fe2(CO)6 (5, R=Ph, R′=Ph; 6, R=p-MeC6H4 R′=Ph; 7, R=p-MeC6H4, R′=PhCO; 8, R=p-MeC6H4, R′=PhCH2). Compound 8 could also be prepared by reaction of the [MgBr]+ salt of 1 (R=p-MeC6H4) with PhCH2NCS followed by treatment with CF3CO2H. More interestingly, while the [Et3NH]+ salt of 1 (R=Ph) reacted with Et3OBF4 to give a carbyne ligand-bridged single butterfly complex (μ-PhSe)(μ-EtOC)Fe2(CO)6 (9), reaction of the [Et3NH]+ salt of 1 (R=Ph) with MeAsI2 produced a MeAsue5f8AsMe ligand-bridged double butterfly complex [(μ-PhSe)(μ-MeAs)Fe2(CO)6]2 (10). All the new complexes, 2–10, were characterized by elemental analysis and various spectroscopic methods, for complexes 8 and 10, the structures were also confirmed by X-ray diffraction techniques.

Synthesis and structural characterization of the novel tetrahedral MNiFeS clusters containing functionally substituted cyclopentadienyl ligands (η5-RC5H4(η5-C5H5)MNiFeS(CO)5 (M = Mo, W ; R = CHO, CH3CO, CH3O2C, CH2OH, CH(OH)CH3, (NO2)2C6H3NHN). The crystal molecular structure of (η5-CHOC5H4(η5-C5H5)MoNiFeS(CO)5

Abstract A series of functionally substituted cyclopentadienyl MNiFeS clusters (η5-RC5H4(η5-C5H5)MNiFes(CO)5 (1, M = Mo, R = CHO; 2, M = W, R = CHO; 3, M = Mo, R = CH3CO; 4, M = W, R = CH3CO; 5, M = Mo, R = CH3O2C; 6, M = W , R = CH3O2C) were successfully synthesized by isolobal displacement reactions of corresponding functional cyclopentadienyl MCoFeS clusters η5-RC5H4MCoFeS(CO)8 with nickelocene in THF at reflux. Further treatment of clusters 1–4 with reducing NaBH4 at r.t. in MeOH yielded primary and secondary alcohol cluster derivatives (7, M = Mo, R = CH2OH ; 8, M = W , R = CH2OH; 9, M = Mo, R = CH(OH)CH3 ; 10, M = W, R = CH(OH)CH3), which could react with the alkylating reagent Et3OBF4 to give ether cluster derivatives (11, M = Mo, R = CH(OC2H5)CH3; 12, M = W, R = CH(OC2H5)CH3). Although reactions of clusters 1 and 2 with an aqueous acid solution of 2,4-dinitrophenylhydrazine at r.t. led to almost complete decomposition of the starting clusters, the reactions of clusters 3 and 4 under similar conditions afforded phenylhydrazone cluster derivatives (13, M = Mo, R = 2,4-(NO2)2C6H3NHN ; 14, M = W, R = 2,4-(NO2)2C6H3NHN). All these novel cluster products have been characterized by elemental analysis and spectroscopic techniques, as well as for cluster 1 by X-ray crystallographic study.

Reactions of metal–metal triply bonded complexes [(η5-RC5H4)2M2(CO)4] (M=Mo, W) with diphenyl ditelluride. Crystal structures of [(η5-MeC5H4)Mo2(CO)4(μ-TePh)3] and [(η5-EtO2CC5H4)2W2(CO)4(μ-TePh)2]

Abstract Reactions of triply bonded complexes [(η5-RC5H4)2M2(CO)4] with Ph2Te2 in solution and solid state were investigated. While [(η5-RC5H4)2M2(CO)4] (M=Mo, R=H, Me3Si, MeCO; M=W, R=MeCO, MeO2C, EtO2C) reacted with Ph2Te2 in toluene at reflux to give a series of doubly bridged complexes [(η5-RC5H4)2M2(CO)4(μ-TePh)2] (1, M=Mo, R=H; 2, Mo, Me3Si; 3, Mo, MeCO; 4, W, MeCO; 5, W, MeO2C; 6, W, EtO2C), the reaction of [(η5-MeC5H4)2Mo2(CO)4] with Ph2Te2 under the same conditions produced not only the corresponding doubly bridged complex [(η5-MeC5H4)2Mo2(CO)4(μ-TePh)2] (7) but also the unexpected triply bridged complex [(η5-MeC5H4)Mo2(CO)4(μ-TePh)3] (8). For these bridged dinuclear complexes structural characterization and conformational analysis were carried out, while the crystal structures of 6 and 8, representing the two types of the structures of complexes 1–8, were successfully determined by single crystal X-ray diffraction techniques.

Unexpected metalmetal bond formation in the MHgM (M = Cr, Mo, W) structural unit. Synthesis and characterization of [η5-RC5H4(CO)3M]2Hg complexes (R = H, M = W; R = CH3CO, M = Cr, Mo, W)

Abstract Trimetallic complexes with the general formula of [η 5 -RC 5 H 4 (CO) 3 M] 2 Hg (R = H, M = W. R = CH 3 CO, M = Cr, Mo, W) were prepared from the reactions of MeHgCl with Nη 5 -C 5 H 5 W(CO) 3 ] or with Na[η 5 -CH 3 COC 5 H 4 M(CO) 3 ] (M = Cr, Mo, W) in diglyme. Structures assigned by combustion analysis and spectroscopy were confirmed by X-ray crystal structure determination of one representative complex, [η 5 -C 5 H 5 (CO) 3 W] 2 Hg. This molecule crystallizes in the monoclinic space group C 2/ c with a = 21.119(2), b = 7.067(1), c = 12.033(1) A; β = 91.10(1)°; V = 1795.5 A 3 ; Z = 4. While the Wue5f8Hgue5f8W skeleton possesses a linear configuration, the geometry around each tungsten atom approximates to a square-based pyramid with the cyclopentadienyl ring occupying the apical position.

Unexpected reactions of anionic intermediates [(μ-RS)(μ-Se)Fe2(CO)6]− with SO2Cl2. Synthesis of [(μ-RS)Fe2(CO)6]2(μ4-Se)(R = Ph, Et, nPr, tBu) and crystal structure of [(μ-PhS)Fe2(CO)6]2(μ4-Se)

Abstract The addition of elemental selenium to CO-bridged anions [(μ-RS)(μ-CO)Fe2(CO)6]− gave new selenido-bridged intermediates [(μ-RS)(μ-Se)Fe2(CO)6]−. Treatment of the intermediates in situ with SO2Cl2, afforded unexpected products [(μ- RS ) Fe 2 ( CO ) 6 ] 2 (μ 4 - Se )( R = Ph, Et, n Pr, t Bu ) , among which the structure of the product with R=Ph was confirmed by X-ray crystallography. It crystallized in the monoclinic space group P21/n(#14) with the lattice constants a=8.971(3), b=12.891(8), c=26.955(7) A , β=98.03(2) and Z=4. The structure was refined to an R value of 0.069.

Synthesis and characterization of organomolybdenum and organotungsten halides containing the η5-pentabenzylcyyclopentadienyl ligand η5-Bz5C5M(CO)3X (M Mo, W; X Cl, Br, I). The X-ray molecular structure of η5-Bz5C5Mo(CO)3I

Abstract An improved synthetic procedure for pentabenzylcyclopentadiene Bz5C5H was developed. Six new organomolybdenum and organotungsten halides η5-Bz5C5M(CO)3X(M ue5fb Mo, W; X ue5fb Cl, Br, I) were syntesized through the reaction of η5-Bz5C5M(CO)3Li (derived from Bz5C5H, n-BuLi and M(CO)6) with PCl3, PBr3 or I2 and characterized by elemental analysis, IR and 1H NMR spectroscopy. The structure of η5-Bz5C5Mo(CO)3I was determined by single-crystal X-ray diffraction techniques. It crystallized in the monoclinic space groupp P2/c with cell parameters a = 13.294(4), b = 15.147(4), c = 19.027(3) A , β = 108.32(2)°, V = 3637(2) A 3 , Z = 4 and D x = 1.50 g cm −3 . The final R value was 0.035 for 4564 observed reflections.

Selective CO oxidation of heterometallic carbonyl clusters with the oxygen transfer reagent (p-CH3OC6H4)2TeO. Crystal structures of (μ3-S)FeCoMo(CO)7(η5-C5H4COCH3)(PPh3) and (μ3-Se)FeCoMo(CO)7(η5-C5H4COCH3)(PPh3)

The oxygen transfer reaction of the heterometallic carbonyl cluster (μ 3 -S)FeCo 2 (CO) 9 with bis( p -methoxyphenyl)telluroxide (BMPTO) gives bis( p -methoxyphenyl)telluride (BMPT) coordinated metal cluster products (μ 3 -S)FeCo 2 (CO) 8 (BMPT) ( 1a ) and (μ 3 -S)FeCo 2 (CO) 7 (BMPT) 2 ( 1b ), which react further with PPh 3 to afford Ph 3 P-substituted derivatives (μ 3 -S)FeCo 2 (CO) 8 (PPh 3 ) ( 1c ) and (μ 3 -S)FeCo 2 (CO) 7 (PPh 3 ) 2 ( 1d ), respectively. Similarly, the reactions of heterometallic clusters (μ 3 -S)FeCoM(CO) 8 (η 5 -C 5 H 4 R) or (μ 3 -Se)FeCoM(CO) 8 (η 5 -C 5 H 4 R) with BMPTO afford (μ 3 -S)FeCoM(CO) 7 (η 5 -C 5 H 4 R)(BMPT) ( 2a , M=Mo, R=H; 2b , M=Mo, R=COCH 3 ; 2c , M=Mo, R=CO 2 CH 3 ; 2d , M=Mo, R=C(CH 3 )NNHC 6 H 3 (NO 2 ) 2 -2,4; 2e , M=W, R=H; 2f , M=W, R=COCH 3 ) and (μ 3 -Se)FeCoM(CO) 7 (η 5 -C 5 H 4 R)(BMPT) ( 2g , M=Mo, R=COCH 3 ; 2h , M=W, R=C(CH 3 )NNHC 6 H 3 (NO 2 ) 2 -2,4), whereas 2a – 2d and 2g react with PPh 3 to produce (μ 3 -S)FeCoMo(CO) 7 (η 5 -C 5 H 4 R)(PPh 3 ) ( 3a , R=H; 3b , R=COCH 3 ; 3c , R=CO 2 CH 3 ; 3d , R=C(CH 3 )NNHC 6 H 3 (NO 2 ) 2 -2,4) and (μ 3 -Se)FeCoMo(CO) 7 (η 5 -C 5 H 4 COCH 3 )(PPh 3 ) ( 3e ). The products have been characterized by elemental analyses, IR, 1 H-NMR 125 Te-NMR and FAB-MS spectroscopies. The X-ray diffraction analyses for 3b and 3e have not only confirmed their structures, but also proved such oxygen transfer reactions to be highly selective towards Co atoms in those heterometallic carbonyl cluster substrates.

Synthesis of novel quadruply bridged M2Se4 clusters trans/anti and trans/syn-[(η5-RC5H4)2M2(μ-Se)2(μ-SeCH2Ph)2] (M=Mo, W) via an unexpected reaction of MM triply bonded complexes [(η5-RC5H4)2M2(CO)4] with dibenzyl diselenide. Crystal structures of a pair of isomers trans/anti- and trans/syn-[(η5-EtO2CC5H4)2Mo2(μ-Se)2(μ-SeCH2Ph)2]

Abstract The unexpected reaction of triply bonded complexes [(η5-RC5H4)2M2(CO)4] with dibenzyl diselenide (PhCH2)2Se2 in toluene at reflux gave a series of isomeric M2Se4 clusters trans/anti-[(η5-RC5H4)2M2(μ-Se)2(μ-SeCH2Ph)2] (1a, M=Mo, R=MeCO; 2a, Mo, MeO2C; 3a, Mo, EtO2C; 4a, W, MeCO; 5a, W, MeO2C; 6a, W, EtO2C) and trans/syn-[(η5-RC5H4)2M2(μ-Se)2(μ-SeCH2Ph)2] (1b, M=Mo, R=MeCO; 2b, Mo, MeO2C; 3b, Mo, EtO2C; 4b, W, MeCO; 5b, W, MeO2C; 6b, W, EtO2C) in combined 20–41% yields. In addition, the reaction of [(η5-MeO2CC5H4)2W2(CO)4] with (PhCH2)2Se2 in solid state at 90°C also afforded 5a and 5b in a total of 32% yield. The structures of these new clusters were fully characterized by elemental analysis and spectroscopy; those for 3a and 3b were confirmed by single-crystal X-ray diffraction techniques.

Syntheses, spectroscopic characterization and electrochemical properties of organometallic crown ethers containing tetrahedral W2Fe(μ3-S) cluster cores [W2Fe(μ3-S)(CO)7][η5-C5H4CH2(CH2OCH2)nCH2C5H4-η5] (n=1–3). Crystal structures of [W2Fe(μ3-S)(CO)7][η5-C5H4CH2(CH2OCH2)nCH2C5H4-η5] (n=2,3)

Abstract The self-assembly cyclization reactions of the ether chain-bridged dicyclopentadienyl W/Na salts Na2[{W(CO)3}2{η5-C5H4CH2(CH2OCH2)nCH2C5H4-η5}] (Ia–c, n=1–3) with the same chain-bridged dicyclopentadienyl double clusters [WCoFe(μ3-S)(CO)8]2[η5-C5H4CH2(CH2OCH2)nCH2C5H4-η5] (IIa–c, n=1–3) have been shown to give organometallic crown ethers [W2Fe(μ3-S)(CO)7][η5-C5H4CH2 (CH2OCH2)nCH2C5H4-η5] (IIIa–c, n=1–3). While structures of these new W2Fe(μ3-S) cluster crown ethers were fully characterized by elemental analyses, IR, 1H-NMR and FAB-MS spectroscopies, those of IIIb,c were unambiguously confirmed by X-ray diffraction techniques. In the study of possible pathway for the formation of IIIa–c, the new cluster crown ether IIIc and its known Mo analog [Mo2Fe(μ3-S)(CO)7][η5-C5H4CH2(CH2OCH2)3CH2C5H4-η5] (IV) were also found to be formed through self-assembly cyclization reaction of the W/Na salt Na2[{W(CO)3}2{η5-C5H4CH2(CH2OCH2)3CH2C5H4-η5}] and the corresponding Mo-containing double cluster [MoCoFe(μ3-S)(CO)8]2[η5-C5H4CH2(CH2OCH2)3CH2C5H4-η5]. In addition, the electrochemical properties of IIIa–c have been studied by cyclic voltammetric techniques.