The Os(CO)(PiPr3)2 Unit as a Support for the Transformation of Two Alkyne Molecules into New Organometallic Ligands

Osmaindenes: Synthesis and Reversible Mechanochromism Characteristics

A series of novel osmaindenes 1 - 6 bearing different substituents (CF 3 , H, I, Br, OCH 3 , N(Ph) 2 ) has been synthesized by nucleophilic reaction of water with the corresponding aromatic osmanaphthalyne complexes. All osmaindenes 1 - 6 have been characterized by elemental analysis (EA) and nuclear magnetic resonance (NMR) spectroscopy, although the low solubilities of 3 and 4 precluded the accumulation of their 13 C NMR spectra. Osmaindenes 2 , 3 and 5 have also been characterized by single-crystal X-ray diffraction analysis. Subsequently, through solid-state fluorescence spectroscopy, mechanochromic studies, and powder X-ray diffraction (XRD) analysis, we found that osmaindenes 1 - 6 fluoresce at wavelengths in the range 500-800 nm, while also displaying reversible mechanochromic properties. The solid-state fluorescence emission of 1 after grinding extends into the near-infrared region. This research provides new insight into the design and synthesis of metallic materials with excellent mechanochromic properties.

Pentamethylcyclopentadienyl osmium complexes that contain diazoalkane, dioxygen and allenylidene ligands: preparation and reactivity

Diazoalkane complexes [Os(η5-C5Me5)(N2CAr1Ar2)(PPh3){P(OR)3}]BPh4 (1, 2) [R = Me (1), Et (2); Ar1 = Ar2 = Ph (a); Ar1 = Ph, Ar2 = p-tolyl (b); Ar1Ar2 = C12H8 (fluorenyl) (c)] were prepared by reacting bromo-compounds OsBr(η5-C5Me5)(PPh3){P(OR)3} with an excess of diazoalkane in ethanol. The treatment of diazoalkane complexes 1 and 2 with acetylene under mild conditions (1 atm, RT) led to dipolar (3 + 2) cycloaddition affording 3H-pyrazole derivatives [Os(η5-C5Me5)(η1-[upper bond 1 start]N[double bond, length as m-dash]NC(C12H8)CH[double bond, length as m-dash]C[upper bond 1 end]H)(PPh3){P(OR)3}]BPh4 (6, 7) [R = Me (6), Et (7)] whereas reactions with terminal alkynes R1C[triple bond, length as m-dash]CH (R1 = Ph, p-tolyl, COOMe) gave vinylidene derivatives [Os(η5-C5Me5){[double bond, length as m-dash]C[double bond, length as m-dash]C(H)R1}(PPh3){P(OR)3}]BPh4 (8b-d, 9b-d) [R = Me (8), Et (9); R1 = Ph (b), p-tolyl (c), COOMe (d)]. Exposure to air of dichloromethane solutions of complexes 1 and 2 produced dioxygen derivatives [Os(η5-C5Me5)(η2-O2)(PPh3){P(OR)3}]BPh4 (10, 11) [R = Me (10), Et (11)]. Allenylidene [Os][double bond, length as m-dash]C[double bond, length as m-dash]C[double bond, length as m-dash]CR1R2 (12-14) [R1 = R2 = Ph (12, 13); R1 = Ph, R2 = Me (14)], vinylvinylidene [Os][double bond, length as m-dash]C[double bond, length as m-dash]C(H)C(Ph)[double bond, length as m-dash]CH2 (15) and 3-hydroxyvinylidene [Os][double bond, length as m-dash]C[double bond, length as m-dash]C(H)C(H)R2(OH) (16, 17) [R2 = Ph (16), H (17)] derivatives were also prepared. The vinylidene complex [Os(η5-C5Me5)([double bond, length as m-dash]C[double bond, length as m-dash]CH2)(PPh3){P(OMe)3}]BPh4 (8a) reacted with PPh3 to afford the alkenylphosphonium derivative [Os(η5-C5Me5){η1-C(H)[double bond, length as m-dash]C(H)PPh3}(PPh3){P(OMe)3}]BPh4 (18) whereas vinylidene complexes 8 and 9 reacted with water leading to the hydrolysis of the alkyne and the formation of carbonyl complexes [Os(η5-C5Me5)(CO)(PPh3){P(OR)3}]BPh4 (19, 20). The complexes were characterised by spectroscopic data (IR and NMR) and by X-ray crystal structure determination of [Os(η5-C5Me5){[double bond, length as m-dash]C[double bond, length as m-dash]C(H)p-tolyl}(PPh3){P(OEt)3}]BPh4 (9c), [Os(η5-C5Me5)(η2-O2)(PPh3){P(OMe)3}]BPh4 (10) and [Os(η5-C5Me5)(CO)(PPh3){P(OMe)3}]BPh4 (19).

Preparation and reactivity of diazoalkane complexes of ruthenium stabilised by an indenyl ligand

Diazoalkane complexes [Ru(η(5)-C9H7)(N2CAr1Ar2)(PPh3)L]BPh4 (1-3) [L = PPh3, P(OMe)3, P(OEt)3; Ar1 = Ar2 = Ph; Ar1 = Ph, Ar2 = p-tolyl; Ar1Ar2 = C12H8 fluorenyl] were prepared by allowing chloro-complexes [RuCl(η(5)-C9H7)(PPh3)L] to react with an excess of diazoalkane in ethanol. Complexes 1-3 reacted with ethylene CH2=CH2 (1 atm) and maleic anhydride [ma, CH=CHCO(O)CO] to afford η(2)-alkene complexes [Ru(η(5)-C9H7)(η(2)-CH2=CH2)(PPh3)L]BPh4 (4, 5) and [Ru(η(5)-C9H7){η(2)-CH=CHCO(O)CO}(PPh3)L]BPh4 (7). Further, complexes 1-3 underwent cycloaddition with acrylonitrile CH2=C(H)CN, giving 1H-pyrazoline derivatives [Ru(η(5)-C9H7){η(1)-N=C(CN)CH2C(Ar1Ar2)NH}(PPh3)L]BPh4 (6). Treatment of diazoalkane complexes 1-3 with acetylene CH[triple bond, length as m-dash]CH under mild conditions (1 atm, room temperature) led to dipolar cycloaddition, affording 3H-pyrazole complexes [Ru(η(5)-C9H7)-{η(1)-N=NC(Ar1Ar2)CH=CH}(PPh3)L]BPh4 (8), whereas reaction with terminal alkynes RC≡CH (R = Ph, p-tolyl, Bu(t)) gave vinylidene derivatives [Ru(η(5)-C9H7){=C=C(H)R}(PPh3)L]BPh4 (9). The latter reacted with nucleophiles such as amines and alcohols to give amino- and alkoxy-carbene derivatives [Ru(η(5)-C9H7){=C(NHPr(n))(CH2Ph)}(PPh3)L]BPh4 (11) and [Ru(η(5)-C9H7){=C(CH3)(OEt)}(PPh3)L]BPh4 (10), respectively. In addition, complexes 9 reacted with phenylhydrazine to afford nitrile derivatives [Ru(η(5)-C9H7)(N[triple bond, length as m-dash]CCH2R)(PPh3)L]BPh4 (12) and phenylamine, whereas the reaction with water led to hydrolysis of the alkyne and formation of carbonyl complexes [Ru(η(5)-C9H7)(CO)(PPh3)L]BPh4 (13). Lastly, treatment of vinylidene complexes with the phosphines PPh3 and P(OMe)3 afforded alkenylphosphonium derivatives [Ru(η(5)-C9H7){C(H)=C(R)PPh3}(PPh3)L]BPh4 (14) and [Ru(η(5)-C9H7){C(R)=C(H)P(OMe)3}(PPh3)L]BPh4 (15), respectively. Compound [Ru(η(5)-C9H7){C(H)=C(H)PPh3}(PPh3)L]BPh4 (16) was also prepared. The complexes were characterised by spectroscopy (IR and NMR) and X-ray crystal structure determinations of [Ru(η(5)-C9H7){N2C(C12H8)}(PPh3){P(OEt)3}]BPh4 (3c), [Ru(η(5)-C9H7){=C=C(H)Ph}(PPh3){P(OEt)3}]BPh4 (9d) and [Ru(η(5)-C9H7){C(H)=C(Ph)PPh3}(PPh3){P(OEt)3}]BPh4 (14d).

New iridacyclohexadienes and iridabenzenes by [2+2+1] cyclotrimerization of alkynes and facile interconversion between iridacyclohexadienes and iridabenzenes

Iridabenzenes [Ir[=CHCH=CHCH=C(CH2R)](CH3CN)2(PPh3)2]2+ (R=Ph 4 a, R=p-C6H4CH3 4 b) are obtained from the reactions of H+ with iridacyclohexadienes [Ir[-CH=CHCH=CHC(=CH-p-C6H4R')](CO)(PPh3)2]+ (R'=H 3 a, R'=CH3 3 b), which are prepared from [2+2+1] cyclotrimerization of alkynes in the reactions of [Ir(CH3CN)(CO)(PPh3)2]+ with HC[triple chemical bond]CH and HC[triple chemical bond]CR. Iridabenzenes 4 react with CO and CH3CN in the presence of NEt3 to give iridacyclohexadienes [Ir[-CH=CHCH=CHC(=CHR)](CO)2(PPh3)2]+ (6) and [Ir[-CH=CHCH=CHC(=CHR)](CH3CN)2(PPh3)2]+ (7), respectively. Iridacyclohexadienes 6 and 7 also convert to iridabenzenes 4 by the reactions with H+ in the presence of CH3CN. Alkynyl iridacyclohexadienes [Ir[-CH=CHCH=CHC(=CH-p-C6H4R')](-C[triple chemical bond]CH)(PPh3)2] (8) undergo a cleavage of C[triple chemical bond]C bond by H+/H2O to produce [Ir[-CH=CHCH=CHC(=CH-p-C6H4R')](-CH3)(CO)(PPh3)2] (10) via facile inter-conversion between iridacyclohexadienes and iridabenzenes.