Yuh S. Wen

Synthesis, spectroscopy and structure of new push–pull ferrocene complexes containing heteroaromatic rings (thiophene and furan) in the conjugation chain

Abstract Six new ferrocene based donor acceptor complexes containing thiophene and furan in the conjugation chain have been synthesized by conventional methods and characterized by NMR, electronic absorption spectral and electrochemical methods. X-ray single crystal structures of three thiophene derivatives, [(C5H5)–Fe–(C5H4CHCH–C4H3S)] (la), [(C5H5)–Fe–(C5H4–CHCH–C4H2S–CHO)] (2a) and [(C5H5)–Fe(C5H4–CHCH–C4H2S–CHC(CN)2)] (3a) have also been determined. Electronic absorption spectral and electrochemical studies suggest that π-donor acceptor interactions are facile in thiophene derivatives when compared to their benzene analogues.

Phosphido bridged heterodinuclear (Mn/Fe, Mn/Cr, Mn/W) complexes

Abstract Treatment of (MeCp)Mn(CO)2 (Ph2PLi), generated in situ, with M(CO)n(THF) in THF at −60°C followed by cation exchange, provides [Et4N][(MeCp)Mn(CO)2(μ-PPh2)M(CO)n] (3, MFe, n = 4; MCr, n = 5; 6, MW, n = 5). Complex 3 reacts with NO+BF4− to give (MeCp)MnFe(CO)4(NO)(μ-PPh2) (7) which contains a metal-metal (MnFe) bond. Photolysis of 6 also results in formation of a metal-metal bond, and [Et4N][(MeCp)MnW(CO)6(μ-PPh2)] (8) was isolated. Complex 8 reacts with CO and MeNC to afford 6 and [Et4N][(MeCp)Mn(CO)2(μ-PPh2)W(CO)4(MeNC)] (9), respectively. X-ray diffraction studies of [(MeCp)Mn(CO)2](μ-Ph2PPPh2) (4), 6, and 9 were carried out to give data as follows. 4: P21/n, Z = 4, a = 9.6875(9), b = 12.191(1), c = 15.382(2) A , β = 107.20(1)°, V = 1735.4(4) A , R = 0.032, R w = 0.036 . Pbca, Z = 8, a = 13.197(2), b = 20.544(4), c = 24.953(4) A , V = 6765(2) A , R = 0.031, R w = 0.031 . 9: P21/c, Z = 4, a = 14.252(1), b = 12.816(3), c = 19.176(2) A , β = 96.255(9)°, V = 3481.6(9) A , R = 0.035, R w = 0.038 .

Substitution of phosphine for CO ligand in HW2(CO)9(NO). The structures of HW2(CO)8(NO)(η1-(η5-C5H4PPh2)2Fe), HW2(CO)7(NO)(Ph2PH)2, HW2(CO)7(NO)- (η2-Ph2PCH2PPh2), and [HW2(CO)8(NO)]2- (μ-Ph2PCH2CH2PPh2)

Abstract Several binuclear tungsten complexes containing a three-center, two-electron (3c-2e) metal—hydrogen—metal bond, HW 2 (CO) 8 (NO)(L) (L = Ph 2 PH ( 1 ), PPh 3 ( 2 ), PCy 3 ( 3 ), η 1 — (η 5 -C 5 H 4 PPh 2 ) 2 Fe ( 4 )), HW 2 (CO) 7 (NO)(L′) 2 (L′ = Ph 2 PH ( 5 ), PPh 3 ( 6 ), Ph 2 PCH 2 PPh 2 /2 ( 7 ), Ph 2 PCH 2 CH 2 PPh 2 /2 ( 8 )), [HW 2 (CO) 8 (NO)[ 2 (μ-L ∼ L) (L ∼ L = Ph 2 PCH 2 CH 2 PPh 2 ( 9 ), (η 5 -C 5 H 4 PPh 2 ) 2 Fe ( 10 )), are obtained by treatment of HW 2 (CO) 9 (NO) with phosphine ligands. X-ray diffraction studies of 4 , 5 , 7 , 9 were carried out to give the data as follows. 4 : P , Z = 2, a = 9.602(3), b = 11.467(2), c = 22.824(3) A, α = 107.1(1), β = 76.37(2), γ = 109.23(2)°, V = 2240.43 A 3 , R = 0.037, R w = 0.041. 5 : P 2 1 / c , Z = 4, a = 9.344(2), b = 16.514(5), c = 21.525(9) A, β = 92.52(3)°, V = 3318.41 A 3 , R = 0.028, R w = 0.031. 7 : P 2 1 / n , Z = 4, a = 16.372(6), b = 12.868(6), c = 16.654(11) A, β = 107.52(4)°, V = 3346.01 A 3 , R = 0.023, R w = 0.032. 9 : P , Z = 2, a = 10.024(6), b = 10.516(2), c = 12.614(1) A, α = 78.67(1)°, β = 73.74(2)°, γ = 81.05(3)°, V = 1244.39 A 3 , R = 0.023, R w = 0.030.

Preparation of push-pull type chromophores via nitrothiophene induced Michael type reaction of alkynes

Abstract Nitrothiophene activates a neighboring alkyne to undergo Michael addition with dialkylamines and methanol to afford push-pull type chromophores. These compounds exhibit a large positive solvatochromism. The olefinic moiety in (Z)-(((5-nitrothien-2-yl)methylene)-(ferrocenyl)methyl)diethylamine (14) can be converted to an α-diketone.

Synthesis, structure and electroluminescent properties of cyclometalated iridium complexes possessing sterically hindered ligands

New CN donor ligands incorporating pyridine or benzoimidazole N donors and a sterically hindered cyclometalating aromatic core featuring a polyphenylenephenyl, fluoranthene, or triphenylene segment are prepared and successfully converted into heteroleptic iridium(III) cyclometalated complexes with acetylacetone auxiliary ligands. The X-ray structure of the complex, derived from a ligand containing a fluoranthene fragment, has been solved to unveil the corresponding structure. The results clearly demonstrate that the nature of the sigma-coordinating ligand segment plays a key role in dictating the emission profile and peak position, such that the emission hue has been successfully tuned ranging from green to red. Supplementary support of this viewpoint is also rendered by computational (DFT) approaches. Electroluminescent devices fabricated using a complex as dopant in the PVK matrix were found to exhibit bright greenish yellow emission with promising device characteristics (maximum brightness 26450 cd m(-2) at 30 V and a maximum current efficiency of 40 cd A(-1)).

Synthesis, structure, and reactivity of HMo2(CO)9(NO)

Abstract Treatment of (Na)(HMo 2 (CO) 10 ) with acidic sodium nitrite affords HMo 2 (CO) 9 (NO) ( 1 ) in 32% yield. Several derivatives of 1 , HMo 2 (CO) 8 (L)(NO) ( 2 , L = PCy 3 ; 3 , L  PPh 3 ; 4 , L = P( p -C 6 H 4 OMe) 3 ), HMo 2 (CO) 7 (L) 2 (NO) ( 5 , L  P(OMe) 3 ; 6 , L  Ph 2 PH), HMo 2 (CO) 7 (MeNC) 2 (NO eq ) ( 7 ), HMo 2 (CO) 7 ( i PrNC) 2 (NO ax ) ( 8 ), HMo 2 (CO) 7 (PCy 3 )( n PrNC)(NO) ( 9 ), and (NMe 4 )(HMo 2 (CO) 7 (η 2 -S 2 CNEt 2 )(NO)) ( 10 ), have been synthesized. X-ray crystal structural analyses for 1 , 2 , 6 , and 9 were carried out. 1 : triclinic, P 1 , Z = 1, a 6.810(2), b 6.906(3), c 8.741(2) A, α 103.50(2), β 68.85(2), γ 92.04(2)°, V 372.3(2) A 3 , R = 0.020, R w = 0.025. 2 : monoclinic, P 2 1 / c , Z = 4, a 12.179(1), b 14.983(1), c 17.068(2) A, β 92.126(8)°, V 3112.4(5) A 3 , R = 0.035, R w = 0.041. 6 : monoclinic, P 2 1 / c , Z = 4, a 9.402(2), b 16.614(3), c 21.635(3) A, β 92.58(3)°, V 3376(1) A 3 , R = 0.034, R w = 0.035. 9 : orthorhombic, Pbca , Z = 8, a 17.113(7), b 17.715(2), c 22.954(3) A, V 6959(3) R = 0.036, R w = 0.038.

Dinuclear molybdenum carbonyls bridged by hydride ligands

Abstract Complexes (μ-H)(μ-Ph2P(CH2)nPPh2)Mo2(CO)7(NO) (n = 1–4, designated, respectively, as 1, 2, 3, and 4), (μ-H)Mo2-(CO)8(L)(NO) (5, L = PPh3; 6, L = P(p-C6H4F)3; 7, L = P(p-C6H4Me)3; 8, L = P(p-C6H4OMe)3), and (μ-H)Mo2(CO)7-(L)2(NO) (9,L = P(OMe)3; 10, L = PMe2Ph) are synthesized from nitrosylation of (Et4N)((μ-H)(μ-Ph2P(CH2)PPh2)Mo2(CO)8) (n = 1–4), (Et4N)((μ-H)Mo2(CO)9(P(p- C6H4X)3)) (X = H, F, Me, OMe), and (Et4N)(μ-H)Mo2 (CO)8(L)2) (L=P(OMe)3, PMe2Ph) with one equivalent of NO+ BF4− in CH2Cl2 at −60°C. Treatment of 1–4 with Ph3P=NnPr provides (μ-H)(μ-Ph2P(CH2)nPPh 2)Mo2(CO)6(CNnPr)(NO) (11–14, n=1–4). X-ray crystal structure analyses for complexes 3, 12, and (μ-H) W2(CO)7(PMe2Ph)2(NO) (16) were carried out to give data as follows. 3: triclinic, P 1 , Z = 4, a 11.698 (2), b 13.926(2), c 21.605(4) A, α 93.72(2), β 92.89(3), γ 91.85(3)°, V 3505.5 A3, R = 0.034, Rw3= 0.036. 12: triclinic, P 1, Z = 2, a 10.100(3), b 12.982(4), c 15.453(4) A, α 102.60(2), β 83.29(2), γ 105.75(2)°, V 1899.6A3, R = 0.054, Rw = 0.055. 16: monoclinic, C2/c, Z 8, a 15.668(1), b 12.892(2), c 28.764(3)A, β 98.883(8)°, V 5740.4 A3, R = 0.032, Rw= 0.034.

Reactivity of dinuclear tungsten carbonyls bridged both by hydride and by bidentate phosphine ligands, (μ-H)(μ-Ph2P(CH2)nPPh2)W2(CO)7(NO) (n = 1–3)

The ligand substitution of (μ-H)(μ-Ph2P(CH2nPPh2)W2(CO)7(NO) (n = 1–3, designated as 1, 2 and 3) provides complexes (μ-H)(μ-Ph2P(CH2)nPPh2)W2(CO)6(L)(NO) (L = PhPH2, n = 1–3, designated as 4, 5 and 6: L = nPrNC, n = 1–3, designated as 7, 8 and 9). Michael addition towards several conjugate olefins following the deprotonation of PhPH2 in 4 results in the formation of the complexes (μ-H)(μ-dppm)W2(CO)6(PhPH(CH2CH2X))(NO) (10, X = CN; 11, X = C(O)H; 12, X = C(O)Me). Diastereomers are found in complexes 10-12 and the interconversion of the isomers is established for 10. The isomerization involves the dissociation of PhPH(CH2CH2CN). X-ray crystal structure analyses for complexes (μ-H)(μ-dppm)W2(CO)6(Ph2PH)(NO) (13) and 10 were carried out. 13: orthorhombic, Pbca, Z = 8, a 19.428(5), b 36.100(8), c 12.025(1) A, V 8438 (3) A3, R = 0.041, Rw = 0.059. 10: triclinic, P1, Z = 4, a 9.883(2), b 20.429(4), c 21.137(3) A, α 91.24(1), β 91.87(1), γ 99.86(2)°, V 4200(1) A3, R = 0.042, Rw = 0.044.

Ligand substitution in [Fe2(CO)6(NO)(µ-PPh2)] and the isomerism of [Fe2(CO)4(PMe3)2(NO)(µ-PPh2)]

Treatment of [NEt4][Fe2(CO)6(µ-CO)(µ-PPh2)] with NO+BF4– provided [Fe2(CO)6(NO)(µ-PPh2)]1. Several phosphide-bridged diiron complexes, [Fe2(CO)5(PR3)(NO)(µ-PPh2)](R = Me 2, OMe 3 or Ph 4), [Fe2(CO)4L2(NO)(µ-PPh2)][L = PMe35, PEt36, PPh37, P(C6H4OMe-p)38, P(OMe)39, P(OEt)310, P(OPh)311, ½Ph2PCH2PPh212, ½Ph2PP(CH2)3PPh213 or ½(η5-C5H4PPh2)2Fe 14] and [Fe2(CO)3{P(OMe)3}3(NO)(µ-PPh2)]15, have been derived from ligand substitution in 1. These complexes exhibit structural versatility. Interconversion between two isomers of 5, 5b and 5c, has been established by variable-temperature 31P-{H} NMR, two-dimensional exchange spectroscopy and single-crystal structure determination.