Hydrolysis of Coordinated Diazoalkanes To Yield Side-On 1,2-Diazene Derivatives

Diazoalkane complexes [Ru­(η⁵-C₅Me₅)­(N₂CAr1Ar2)­(PPh₃)­{P­(OR)₃}]­BPh₄ [R = Me (<b>1</b>), Et (<b>2</b>); Ar1 = Ar2 = Ph (<b>a</b>); Ar1 = Ph, Ar2 = <i>p</i>-tolyl (<b>b</b>); Ar1Ar2 = C₁₂H₈ (<b>c</b>)] were prepared by allowing chloro complexes RuCl­(η⁵-C₅Me₅)­(PPh₃)­[P­(OR)₃] to react with diazoalkane Ar1Ar2CN₂ in ethanol. The treatment of compounds <b>1</b> and <b>2</b> with H₂O afforded 1,2-diazene derivatives [Ru­(η⁵-C₅Me₅)­(η²-NHNH)­(PPh₃)­{P­(OR)₃}]­BPh₄ (<b>3</b> and <b>4</b>) and ketone Ar1Ar2CO. A reaction path involving nucleophilic attack by H₂O on the coordinated diazoalkane is proposed. The complexes were characterized spectroscopically (IR and NMR) and by X-ray crystal structure determination of [Ru­(η⁵-C₅Me₅)­(η²-NHNH)­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>3</b>)

Preparation and Reactivity of Stannyl Complexes of Ruthenium(II) Stabilized by an Indenyl Ligand

Trichlorostannyl complexes Ru­(SnCl₃)­(η⁵-C₉H₇)­(PPh₃)­L (<b>1</b>; L = P­(OMe)₃, P­(OEt)₃) were prepared by allowing chloro compounds RuCl­(η⁵-C₉H₇)­(PPh₃)­L to react with SnCl₂·2H₂O in ethanol. Treatment of compounds <b>1</b> with NaBH₄ in ethanol yielded the tin trihydride derivatives Ru­(SnH₃)­(η⁵-C₉H₇)­(PPh₃)­L (<b>2</b>). The reaction of trichlorostannyl complexes <b>1</b> with MgBrMe in diethyl ether afforded the chlorodimethylstannyl derivatives Ru­(SnClMe₂)­(η⁵-C₉H₇)­(PPh₃)­L (<b>3</b>), whereas reaction with Li⁺CCPh^– in THF yielded the trialkynylstannyl compounds Ru­[Sn­(CCPh)₃]­(η⁵-C₉H₇)­(PPh₃)­L (<b>4</b>). Treatment of the trihydridostannyl complexes <b>2</b> with the alkyl propiolate HCCCOOR led to the trivinylstannyl derivatives Ru­[Sn­{C­(COOR)CH₂}₃]­(η⁵-C₉H₇)­(PPh₃)­L (<b>5</b>,<b> 6</b>; R = Me, Et). However, the reaction of [Ru]–SnH₃ (<b>2</b>) with the propargylic alcohol HCCCPh₂OH yielded the alkene H₂CC­(H)­CPh₂OH and the hydride RuH­(η⁵-C₉H₇)­(PPh₃)­L (<b>7</b>). Treatment of tin trihydride complexes <b>2</b> with H₂O led to the trihydroxostannyl derivatives Ru­[Sn­(OH)₃]­(η⁵-C₉H₇)­(PPh₃)­L (<b>8</b>). Protonation of [Ru]–SnH₃ (<b>2</b>) with triflic acid (HOTf) produced the very unstable dihydridostannyl compound Ru­[SnH₂(OTf)]­(η⁵-C₉H₇)­(PPh₃)­L (<b>9</b>). Stabilization of SnH₂ species was achieved by protonation with HOTf at −30 °C of the cyclopentadienyl compound Ru­(SnH₃)­(η⁵-C₅H₅)­(PPh₃)­[P­(OMe)₃], which yielded the complex Ru­[SnH₂(OTf)]­(η⁵-C₅H₅)­(PPh₃)­[P­(OMe)₃] (<b>10a</b>). The complexes were characterized by spectroscopy (IR and ¹H, ³¹P, ¹³C, and ¹¹⁹Sn NMR data) and by X-ray crystal structure determinations of Ru­[Sn­(CCPh)₃]­(η⁵-C₉H₇)­(PPh₃)­[P­(OEt)₃] (<b>4b</b>) and Ru­[Sn­(OH)₃]­(η⁵-C₉H₇)­(PPh₃)­[P­(OEt)₃] (<b>8b</b>)

Preparation of Diazoalkane Complexes of Ruthenium and Their Cyclization Reactions with Alkenes and Alkynes

The diazoalkane complexes [Ru­(η⁵-C₅H₅)­(N₂CAr1Ar2)­(PPh₃)­(L)]­BPh₄ (<b>1</b>–<b>5</b>: Ar1 = Ar2 = Ph (<b>a</b>), Ar1 = Ph and Ar2 = <i>p-</i>tolyl (<b>b</b>), Ar1Ar2 = C₁₂H₈ (<b>c</b>), Ar1 = Ph and Ar2 = PhCO (<b>d</b>); L = PPh₃ (<b>1</b>), P­(OMe)₃ (<b>2</b>), P­(OEt)₃ (<b>3</b>), PPh­(OEt)₂ (<b>4</b>), Bu^<i>t</i>NC (<b>5</b>)) were prepared by allowing the chloro compounds RuCl­(η⁵-C₅H₅)­(PPh₃)­(L) to react with the diazoalkanes Ar1Ar2CN₂ in ethanol. Treatment of complexes <b>1</b>–<b>5</b> with ethylene (CH₂CH₂) under mild conditions (1 atm, room temperature) led not only to the η²-ethylene complexes [Ru­(η⁵-C₅H₅)­(η²-CH₂CH₂)­(PPh₃)­(L)]­BPh₄ (<b>10</b>–<b>14</b>) but also to dipolar (3 + 2) cycloaddition, affording the 4,5-dihydro-3<i>H</i>-pyrazole derivatives [Ru­(η⁵-C₅H₅)­{η¹-NNC­(Ar1Ar2)­CH₂CH₂}­(PPh₃)­(L)]­BPh₄ (<b>6</b>–<b>9</b>). Acrylonitrile (CH₂C­(H)­CN) reacted with diazoalkane complexes <b>2</b> and <b>3</b> to give the 1<i>H</i>-pyrazoline derivatives [Ru­(η⁵-C₅H₅)­{η¹-NC­(CN)­CH₂C­(Ar1Ar2)NH}­(PPh₃)­(L)]­BPh₄ (<b>19</b>, <b>20</b>). However, reactions with propylene (CH₂C­(H)­CH₃), maleic anhydride (ma, CHCHCO­(O)CO) and dimethyl maleate (dmm, CH₃OCOCHCHOCOCH₃) led to the η²-alkene complexes [Ru­(η⁵-C₅H₅)­(η²-R1CHCHR2)­(PPh₃)­(L)]­BPh₄ (<b>17</b>–<b>22</b>). Treatment of the diazoalkane complexes <b>1</b> and <b>2</b> with acetylene CHCH under mild conditions (1 atm, room temperature) led to dipolar cycloaddition, affording the 3<i>H</i>-pyrazole complexes [Ru­(η⁵-C₅H₅)­{η¹-NNC­(Ar1Ar2)­CHCH}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>24</b>), whereas reactions with the terminal alkynes PhCCH and Bu^<i>t</i>CCH gave the vinylidene derivatives [Ru­(η⁵-C₅H₅)­{CC­(H)­R}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>25</b>,<b> 26</b>). The alkyl propiolates HCCCOOR1 (R1 = Me, Et) also reacted with complexes <b>2</b> to give the 3<i>H</i>-pyrazole complexes [Ru­(η⁵-C₅H₅)­{η¹-NNC­(Ar1Ar2)­C­(COOR1)CH}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>27</b>,<b> 28</b>). The complexes were characterized by spectroscopy and by X-ray crystal structure determinations of [Ru­(η⁵-C₅H₅)­{η¹-NC­(CN)­CH₂C­(Ph)­(<i>p</i>-tolyl)NH}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>19b</b>), [Ru­(η⁵-C₅H₅)­{η²-CHCHCO­(O)CO}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>21</b>), and [Ru­(η⁵-C₅H₅)­{η¹-NNC­(C₁₂H₈)­CHCH}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>24c</b>)

Preparation of Diazoalkane Complexes of Ruthenium and Their Cyclization Reactions with Alkenes and Alkynes

The diazoalkane complexes [Ru­(η⁵-C₅H₅)­(N₂CAr1Ar2)­(PPh₃)­(L)]­BPh₄ (<b>1</b>–<b>5</b>: Ar1 = Ar2 = Ph (<b>a</b>), Ar1 = Ph and Ar2 = <i>p-</i>tolyl (<b>b</b>), Ar1Ar2 = C₁₂H₈ (<b>c</b>), Ar1 = Ph and Ar2 = PhCO (<b>d</b>); L = PPh₃ (<b>1</b>), P­(OMe)₃ (<b>2</b>), P­(OEt)₃ (<b>3</b>), PPh­(OEt)₂ (<b>4</b>), Bu^<i>t</i>NC (<b>5</b>)) were prepared by allowing the chloro compounds RuCl­(η⁵-C₅H₅)­(PPh₃)­(L) to react with the diazoalkanes Ar1Ar2CN₂ in ethanol. Treatment of complexes <b>1</b>–<b>5</b> with ethylene (CH₂CH₂) under mild conditions (1 atm, room temperature) led not only to the η²-ethylene complexes [Ru­(η⁵-C₅H₅)­(η²-CH₂CH₂)­(PPh₃)­(L)]­BPh₄ (<b>10</b>–<b>14</b>) but also to dipolar (3 + 2) cycloaddition, affording the 4,5-dihydro-3<i>H</i>-pyrazole derivatives [Ru­(η⁵-C₅H₅)­{η¹-NNC­(Ar1Ar2)­CH₂CH₂}­(PPh₃)­(L)]­BPh₄ (<b>6</b>–<b>9</b>). Acrylonitrile (CH₂C­(H)­CN) reacted with diazoalkane complexes <b>2</b> and <b>3</b> to give the 1<i>H</i>-pyrazoline derivatives [Ru­(η⁵-C₅H₅)­{η¹-NC­(CN)­CH₂C­(Ar1Ar2)NH}­(PPh₃)­(L)]­BPh₄ (<b>19</b>, <b>20</b>). However, reactions with propylene (CH₂C­(H)­CH₃), maleic anhydride (ma, CHCHCO­(O)CO) and dimethyl maleate (dmm, CH₃OCOCHCHOCOCH₃) led to the η²-alkene complexes [Ru­(η⁵-C₅H₅)­(η²-R1CHCHR2)­(PPh₃)­(L)]­BPh₄ (<b>17</b>–<b>22</b>). Treatment of the diazoalkane complexes <b>1</b> and <b>2</b> with acetylene CHCH under mild conditions (1 atm, room temperature) led to dipolar cycloaddition, affording the 3<i>H</i>-pyrazole complexes [Ru­(η⁵-C₅H₅)­{η¹-NNC­(Ar1Ar2)­CHCH}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>24</b>), whereas reactions with the terminal alkynes PhCCH and Bu^<i>t</i>CCH gave the vinylidene derivatives [Ru­(η⁵-C₅H₅)­{CC­(H)­R}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>25</b>,<b> 26</b>). The alkyl propiolates HCCCOOR1 (R1 = Me, Et) also reacted with complexes <b>2</b> to give the 3<i>H</i>-pyrazole complexes [Ru­(η⁵-C₅H₅)­{η¹-NNC­(Ar1Ar2)­C­(COOR1)CH}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>27</b>,<b> 28</b>). The complexes were characterized by spectroscopy and by X-ray crystal structure determinations of [Ru­(η⁵-C₅H₅)­{η¹-NC­(CN)­CH₂C­(Ph)­(<i>p</i>-tolyl)NH}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>19b</b>), [Ru­(η⁵-C₅H₅)­{η²-CHCHCO­(O)CO}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>21</b>), and [Ru­(η⁵-C₅H₅)­{η¹-NNC­(C₁₂H₈)­CHCH}­(PPh₃)­{P­(OMe)₃}]­BPh₄ (<b>24c</b>)

Azo Complexes of Osmium(II): Preparation and Reactivity of Organic Azide and Hydrazine Derivatives

Mixed-ligand hydride complexes OsHCl­(CO)­(PPh₃)₂L (<b>2</b>) [L = P­(OMe)₃, P­(OEt)₃] were prepared by allowing OsHCl­(CO)­(PPh₃)₃ (<b>1</b>) to react with an excess of phosphite P­(OR)₃ in refluxing toluene. Dichloro compounds OsCl₂(CO)­(PPh₃)₂L (<b>3</b>,<b> 4</b>) were also prepared by reacting <b>1</b>, <b>2</b> with HCl. Treatment of hydrides OsHCl­(CO)­(PPh₃)₂L (<b>2</b>), first with triflic acid and then with an excess of RN₃ afforded organic azide complexes [OsCl­(η¹-N₃R)­(CO)­(PPh₃)₂L]­BPh₄ (<b>5</b>–<b>7</b>) [R = 4-CH₃C₆H₄CH₂, C₆H₅CH₂, C₆H₅; L = P­(OEt)₃]. Benzylazide complexes react in CH₂Cl₂/ethanol solution, leading to the imine derivative [OsCl­(CO)­{η¹-NHC­(H)­C₆H₄-4-CH₃}­(PPh₃)₂{P­(OEt)₃}]­BPh₄ (<b>8b</b>). Hydrazine complexes [OsCl­(CO)­(RNHNH₂)­(PPh₃)₂L]­BPh₄ (<b>9</b>–<b>11</b>) [R = H, CH₃, C₆H₅; L = P­(OMe)₃, P­(OEt)₃] were prepared by allowing hydride species OsHCl­(CO)­(PPh₃)₂L (<b>2</b>) to react first with triflic acid and then with an excess of hydrazine. Aryldiazene derivatives [OsCl­(CO)­(ArNNH)­(PPh₃)₂L]­BPh₄ (<b>12</b>,<b> 13</b>) were also prepared following two different methods: (i) by oxidizing arylhydrazine [OsCl­(C₆H₅NHNH₂)­(CO)­(PPh₃)₂L]­BPh₄ (<b>11</b>) with Pb­(OAc)₄ in CH₂Cl₂ at −30 °C; (ii) by allowing hydride species OsHCl­(CO)­(PPh₃)₂L (<b>2</b>) to react with aryldiazonium cations ArN₂⁺ (Ar = C₆H₅, 4-CH₃C₆H₄) in CH₂Cl₂. The complexes were characterized spectroscopically and by X-ray crystal structure determination of OsHCl­(CO)­(PPh₃)₂[P­(OEt)₃] (<b>2b</b>) and [OsCl­{η¹-NHC­(H)­C₆H₄-4-CH₃}­(CO)­(PPh₃)₂{P­(OEt)₃}]­BPh₄ (<b>8b</b>)

Cycloaddition of Coordinated Diazoalkanes to Ethene To Yield 3<i>H</i>‑Pyrazole Derivatives

Diazoalkane complexes [Ru­(η⁵-C₅H₅)­(N₂CAr1Ar2)­(PPh₃)­L]­BPh₄ (<b>1</b>,<b> 2</b>; Ar1 = Ph, Ar2 = <i>p-</i>tolyl; Ar1Ar2 = C₁₂H₈; L = P­(OMe)₃, P­(OEt)₃) were prepared by allowing compounds RuCl­(η⁵-C₅H₅)­(PPh₃)­L to react with diazoalkane in ethanol. Treatment of complexes <b>1</b> and <b>2</b> with ethylene under mild conditions (1 atm, room temperature) led not only to the ethylene complexes [Ru­(η⁵-C₅H₅)­(η²-CH₂CH₂)­(PPh₃)­L]­BPh₄ (<b>5</b>,<b> 6</b>) but also to dipolar (3 + 2) cycloaddition, affording the 3<i>H</i>-pyrazole derivatives [Ru­(η⁵-C₅H₅)­{η¹-NNC­(Ar1Ar2)­CH₂CH₂}­(PPh₃)­L]­BPh₄ (<b>3</b>,<b> 4</b>). The propylene complexes [Ru­(η⁵-C₅H₅)­(η²-CH₃CHCH₂)­(PPh₃)­L]­BPh₄ (<b>7</b>,<b> 8</b>) were also prepared. The compounds were characterized by spectroscopy and by X-ray crystal structure determinations of <b>2a</b>, <b>3b</b>, and <b>7</b>

Azo Complexes of Osmium(II): Preparation and Reactivity of Organic Azide and Hydrazine Derivatives

Mixed-ligand hydride complexes OsHCl­(CO)­(PPh₃)₂L (<b>2</b>) [L = P­(OMe)₃, P­(OEt)₃] were prepared by allowing OsHCl­(CO)­(PPh₃)₃ (<b>1</b>) to react with an excess of phosphite P­(OR)₃ in refluxing toluene. Dichloro compounds OsCl₂(CO)­(PPh₃)₂L (<b>3</b>,<b> 4</b>) were also prepared by reacting <b>1</b>, <b>2</b> with HCl. Treatment of hydrides OsHCl­(CO)­(PPh₃)₂L (<b>2</b>), first with triflic acid and then with an excess of RN₃ afforded organic azide complexes [OsCl­(η¹-N₃R)­(CO)­(PPh₃)₂L]­BPh₄ (<b>5</b>–<b>7</b>) [R = 4-CH₃C₆H₄CH₂, C₆H₅CH₂, C₆H₅; L = P­(OEt)₃]. Benzylazide complexes react in CH₂Cl₂/ethanol solution, leading to the imine derivative [OsCl­(CO)­{η¹-NHC­(H)­C₆H₄-4-CH₃}­(PPh₃)₂{P­(OEt)₃}]­BPh₄ (<b>8b</b>). Hydrazine complexes [OsCl­(CO)­(RNHNH₂)­(PPh₃)₂L]­BPh₄ (<b>9</b>–<b>11</b>) [R = H, CH₃, C₆H₅; L = P­(OMe)₃, P­(OEt)₃] were prepared by allowing hydride species OsHCl­(CO)­(PPh₃)₂L (<b>2</b>) to react first with triflic acid and then with an excess of hydrazine. Aryldiazene derivatives [OsCl­(CO)­(ArNNH)­(PPh₃)₂L]­BPh₄ (<b>12</b>,<b> 13</b>) were also prepared following two different methods: (i) by oxidizing arylhydrazine [OsCl­(C₆H₅NHNH₂)­(CO)­(PPh₃)₂L]­BPh₄ (<b>11</b>) with Pb­(OAc)₄ in CH₂Cl₂ at −30 °C; (ii) by allowing hydride species OsHCl­(CO)­(PPh₃)₂L (<b>2</b>) to react with aryldiazonium cations ArN₂⁺ (Ar = C₆H₅, 4-CH₃C₆H₄) in CH₂Cl₂. The complexes were characterized spectroscopically and by X-ray crystal structure determination of OsHCl­(CO)­(PPh₃)₂[P­(OEt)₃] (<b>2b</b>) and [OsCl­{η¹-NHC­(H)­C₆H₄-4-CH₃}­(CO)­(PPh₃)₂{P­(OEt)₃}]­BPh₄ (<b>8b</b>)