Kinetic and mechanistic study on the reaction of alkylcobaloximes with azoles

The kinetics of axial water substitution by azoles (pyrazole and 1,2,4-triazole) in three different cobaloximes, viz.trans-[Co(Hdmg)(2)(R)H(2)O] where Hdmg = dimethylglyoximate, R = PhCH(2), Et and CF(3)CH(2), were studied as a function of azole concentration, temperature and pressure in aqueous solution. The second order rate constants for the substitution of water in trans-[Co(Hdmg)(2)(R)H(2)O] for R = Et at pH 6.0, 25 degrees C and I= 0.1 M (NaClO(4)), were found to be 1309 and 1200 M(-1) s(-1) for pyrazole (Pz) and 1,2,4-triazole (Tz), respectively, and those obtained for R = PhCH(2) were found to be 755 and 691 M(-1) s(-1), respectively. The second order rate constants in the case of R = CF(3)CH(2) were found to be 0.358 and 0.348 M(-1) s(-1) for Pz and Tz, respectively. The relative order of reactivity for the different alkyls being Et > PhCH(2) > CF(3)CH(2). The activation parameters (DeltaH([not equal]), DeltaS([not equal]) and DeltaV([not equal])) obtained for these reactions were found to be in the range of 65-87 kJ mol(-1), 24-47 J mol(-1) K(-1) and 2.5-7.7 cm(3) mol(-1), respectively. These data suggest that an I(d) substitution mechanism operates where the azoles participate in the transition state.     

固-液相转移催化合成V.醛亚胺的michael加成和羰基加成反应合成α-氨基 酸

报道了在以K~2CO~2为固体碱的固-液相转移催化条件下,用醛亚胺与亲电的 烯烃和醛类化合物进行Michael加成,羰基加成反应,合成了一系列醛亚胺亲核加成产物.并通过水解羰基加成产物制备了一系列丝氨酸衍生物.该法简便,温和,反应时间短,产率高,是合成具有取代基的甘氨酸,丙氨酸和丝氨酸及其酯的一种有用方法.     

双羰基双膦合铂(O)配合物的合成及其与卤代烃的氧化加成反应

本文报道一种合成标题配合物Pt(diphos)(CO)2的简便方法及其与碳-卤键的氧化加成反应. 在一氧公碳气氛存在下用NaBH4还原[Pt(diphos)Cl2]可“原位"得到[Pt(diphos)(CO)2]的THF溶液, 能与卤代烃发生氧化加成反应, 并用^1H NMR和^3^1PNMR谱进行了研究. 氧化加成反应按自由基非链式机理进行, 加成产物[Pt(diphos)X2]之一[Pt(d(i-Pr)pe)I2]经过分子结构测定, 反应能力与卤代烃和双膦螯合配体的电子性质有关.     

异-α-姜黄烯及其衍生物的合成

姜科姜黄属是一个重要的药用植物群其根茎和块根分别称为姜黄和郁金。中医中药认为, 郁金具有行气, 纠瘀和通经等功效。动物药理试验表明, 姜科植物温郁金具有抗生育活性, 而其挥发油主要含有姜烯、α-姜黄烯和异-α-姜黄烯等倍半萜类化合物。本文合成了温郁金挥发油的另一个成分异-α-姜黄烯和其衍生物2-甲基-6-对甲苯基-2-庚醇、脱氢异-α-姜黄烯和2-甲基-6-对甲苯基-5-庚烯-2-醇。它们的化学结构得到确证。     

Synthesis and coordination properties of new bis(phosphinomethyl)pyridine N,P,P'-trioxides

In a search for more hydrocarbon solvent soluble derivatives of the parent ligand, 2,6-[Ph(2)P(O)CH(2)](2)C(5)H(3)NO (1a), a series of new ligands, 2,6-[R(2)P(O)CH(2)](2)C(5)H(3)NO [R = Bz (1b); Tol (1c); Et (1d); Pr (1e); Bu (1f); Pn (1g); Hx (1h); Hp (1i); and Oct (1j)] and 2,6-[RR'P(O)CH(2)](2)C(5)H(3)NO [R = Ph, R' = Bz (2a); R = Ph, R' = Me (2b); R = Ph, R' = Hx (2c); R = Ph, R' = Oct (2d)], have been prepared by either Arbusov or Grignard substitutions on 2,6-bis(chloromethyl)pyridine followed by N-oxidation. The new ligands have been characterized by spectroscopic methods, and their coordination chemistry with selected lanthanide ions has been surveyed. Several 1:1 and 2:1 ligand/metal complexes have been isolated, and single-crystal X-ray diffraction analyses for Nd(2a)(NO(3))(3), Er(2a)(NO(3))(3), Yb(1d)(NO(3))(3), and [Nd(1c)(2)](NO(3))(3) are described. The new structural data are discussed in relation to the structures of complexes formed by 1a.     

Kinetic and mechanistic study of the Pt(II) versus Pt(IV) effect in the platinum-mediated nitrile-hydroxylamine coupling

The metal-mediated coupling between coordinated EtCN in the platinum(II) and platinum(IV) complexes cis- and trans-[PtCl(2)(EtCN)(2)], trans-[PtCl(4)(EtCN)(2)], a mixture of cis/trans-[PtCl(4)(EtCN)(2)] or [Ph(3)PCH(2)Ph][PtCl(n)(EtCN)] (n = 3, 5), and dialkyl- and dibenzylhydroxylamines R(2)NOH (R = Me, Et, CH(2)Ph, CH(2)C(6)H(4)Cl-p) proceeds smoothly in CH(2)Cl(2) at 20-25 degrees C and the subsequent workup allowed the isolation of new imino species [PtCl(n){NH=C(Et)ONR(2)}(2)] (n = 2, R = Me, cis-1 and trans-1; Et, cis-2 and trans-2; CH(2)Ph, cis-3 and trans-3; CH(2)C(6)H(4)Cl-p, cis-4 and trans-4; n = 4, R = Me, trans-9; Et, trans-10; CH(2)Ph, trans-11; CH(2)C(6)H(4)Cl-p, trans-12) or [Ph(3)PCH(2)Ph][PtCl(n){NH=C(Et)ONR(2)}] (n = 3, R = Me, 5; Et, 6; CH(2)Ph, 7; CH(2)C(6)H(4)Cl-p, 8; n = 5, R = Me, 13; Et, 14; CH(2)Ph, 15; CH(2)C(6)H(4)Cl-p, 16) in excellent to good (95-80%) isolated yields. The reduction of the Pt(IV) complexes 9-16 with the ylide Ph(3)P=CHCO(2)Me allows the synthesis of Pt(II) species 1-8. The compounds 1-16 were characterized by elemental analyses (C, H, N), FAB-MS, IR, (1)H, (13)C{(1)H}, and (31)P{(1)H} NMR (the latter for the anionic type complexes 5-8 and 13-16) and by X-ray crystallography for the Pt(II) (cis-1, cis-2, and trans-4) and Pt(IV) (15) species. Kinetic studies of addition of R(2)NOH (R = CH(2)C(6)H(4)Cl-p) to complexes [Ph(3)PCH(2)Ph][Pt(II)Cl(3)(EtCN)] and [Ph(3)PCH(2)Ph][Pt(IV)Cl(5)(EtCN)] by the (1)H NMR technique revealed that both reactions are first order in (p-ClC(6)H(4)CH(2))(2)NOH and Pt(II) or Pt(IV) complex, the second-order rate constant k(2) being three orders of magnitude larger for the Pt(IV) complex. The reactions are intermolecular in nature as proved by the independence of k(2) on the concentrations of added EtC triple bond N and Cl(-). These data and the calculated values of Delta H++ and Delta S++ are consistent with the mechanism involving the rate-limiting nucleophilic attack of the oxygen of (p-ClC(6)H(4)CH(2))(2)NOH at the sp-carbon of the C triple bond N bond followed by a fast proton migration.     

PtII-mediated 1,3-dipolar cycloaddition of oxazoline N-oxides to nitriles as a key step to dihydrooxazolo-1,2,4-oxadiazoles

A novel type of heterocycle, viz., 2,3a-disubstituted 5,6-dihydro-3aH-[1,3]oxazolo[3,2-b][1,2,4]oxadiazoles, was generated by an intermolecular PtII-mediated 1,3-dipolar cycloaddition (1,3-DCA) between the oxazoline N-oxide C(Me)2CH2OC(R)=N+(O-) (R = Me, Et) and coordinated nitriles in the complexes trans/cis-[PtCl2(R'CN)2] [R' = Me, Et, CH2Ph, Ph, N(C5H10)]. The reaction is unknown for free RCN and oxazoline N-oxides, but under PtII-mediated conditions, it proceeds smoothly (CH2Cl2, 20-25 degrees C, 18-20 h) and gives pure complexes [PtCl2{N=C(R')ONC(R)OCH2CMe2}2] [R/R' = Me/Me, 1; Me/Et, 2; Me/CH2Ph, 3; Me/Ph, 4; Me/N(C5H10), 5; Et/Me, 6; Et/Et, 7; Et/CH2Ph, 8; Et/Ph, 9; Et/N(C5H10), 10] in 42-84% yields after column chromatography. Compounds 1-10 were characterized by elemental analyses (C, H, N), FAB+-MS, IR, and 1H and 13C{1H} NMR spectroscopies, and X-ray diffraction (for 1, 2, 5, and 9). With the exception of benzonitrile complexes, 1,3-DCA of oxazoline N-oxides to the PtII-ligated nitriles occurred diastereoselectively and afforded mixtures of enantiomers. Depending on the substituents on nitriles, asymmetric atoms in both of the formed heterocyclic ligands have the same (SS/RR) or different (SR/RS) configurations. The heterocyclic ligands were liberated from 1-4 and 6-9 by treatment with excess ethane-1,2-diamine (en) in CH2Cl2 for 1 day at 20-25 degrees C (for R' = Me, Et, CH2Ph) and at 50 degrees C (for R' = Ph) to achieve the free organic species and the well-known [Pt(en)2](Cl)2; the products were separated, and 2,3a-disubstituted 5,6-dihydro-3aH-[1,3]oxazolo[3,2-b][1,2,4]oxadiazoles (11-18) were characterized by ESI+-MS and 1H and 13C{1H} NMR spectroscopies.     

Diketo compounds with (trifluoromethyl)trimethylsilane: double nucleophilic trifluoromethylation reactions

Reactions of various diketo compounds with (trifluoromethyl)trimethylsilane (Me3SiCF3) in the presence of catalytic amounts of cesium fluoride have been studied. gamma-Ketoesters, CH3COCH2CH2CO2R (R = Et, Bu), were reacted with 2 equiv of Me3SiCF3 at room temperature to give CH3C(OH)(CF3)CH2CH2COCF3 in good yield after hydrolysis. alpha-Diketones, R1COCOR2 (R1 = R2 = Ph; R1 = Ph, R2 = Me; R1 = R2 = Me; R1 = Me, R2 = Et), when reacted with Me3SiCF3, formed 1:1 or 1:2 addition products depending on the reaction conditions and stoichiometry used. Reactions of diones CH3COXCOCH3 (X = -CH2CH2-, -C6H4C6H4-, -CH2-) with Me3SiCF3 also led to the formation of the mono- or diaddition products depending on reaction conditions. With various kinds of substituted arylglyoxals, 2 equiv of Me3SiCF3 produced monoaddition products in 70-75% yield and diaddition products in 5-10% yield. One of the monoalcohols and two of the diols have been characterized by single-crystal X-ray analysis, and the presence of inter- and intramolecular hydrogen bonding has been confirmed.     

1,3-二碘六氟丙烷的电子转移反应

在四醋酸铅的催化下,二氟二碘甲烷(CF2I2,1)与四氟乙烯加成生成1,3-二碘六氟丙烷(ICF2CF2CF2I,3).3与烯烃、炔烃和丙二酸二乙酯阴离子发生电子转移反应。     

低价钛还原环化δ-酮腈成环戊酮

四氯化钛-锌粉还原环化δ-酮腈是合成环戊酮的一种简便方法。在同样条件下, 由4-甲基-4-乙酰基庚二腈得到1,5-二甲基双环-[3.3.0]-2,8-辛二酮。     

α-(2-苯并噻唑氧基)烃基膦酸酯的合成性质和生物活性

为探索α-芳(杂 环)磷酸衍生物的生物活性,寻求含磷农药的新母体,合成了十六个未见文献报道的α-(苯并噻唑-2-氧代)烃基膦酸衍生物,所有化合物的结构均IR,HNMR, 元素分析等确证,并对生物活性进行了初步的研究.     

Synthesis,structure, and reactivity of some sterically hindered (Silylamino)phosphines

A series of new (silylamino)phosphines that contain sterically bulky silyl groups on nitrogen were prepared by deprotonation/substitution reactions of the hindered disilylamines t-BuR(2)Si(Me(3)Si)NH (1, R = Me; 2, R = Ph) and (Et(3)Si)(2)NH (3). Sequential treatment of the N-lithio derivatives of 1-3 with PCl(3) or PhPCl(2) and MeLi gave the corresponding (silylamino)phosphines t-BuR(2)Si(Me(3)Si)NP(R')Me (5, R = Me, R' = Ph; 6, R = Ph, R' = Me) and (Et(3)Si)(2)NP(R)Me (11, R = Me; 12, R = Ph) in high yields. Two of the P-chloro intermediates t-BuR(2)Si(Me(3)Si)NP(Ph)Cl (7, R = Ph; 9, R = Me) were also isolated and fully characterized. Hydrolysis of 7 afforded the crystalline PH-substituted aminophosphine oxide t-BuPh(2)SiN(H)P(Ph)(=O)H (10). Thermal decomposition of 7 occurred with elimination of Me(3)SiCl and formation of a novel P(2)N(2) four-membered ring system (36) that contains both P(III) and P(V) centers. Reactions of the N-lithio derivatives of amines 1 and 2 with phosphorus trihalides afforded the thermally stable -PF(2) derivatives t-BuR(2)Si(Me(3)Si)NPF(2) (13, R = Me; 14, R = Ph) and the unstable -PCl(2) analogue 17 (R = Ph). Reduction (using LiAlH(4)) of the SiPh-substituted dihalophosphines 14 and 17 gave the unstable parent phosphine t-BuPh(2)Si(Me(3)Si)NPH(2) (15). The P-organo-substituted (silylamino)phosphines underwent oxidative bromination to afford high yields of the corresponding N-silyl-P-bromophosphoranimines t-BuR(2)SiN=P(R')(Me)Br (18, R = R' = Me; 19, R = Me, R' = Ph; 20, R = Ph, R' = Me) and Et(3)SiN=P(R)(Me)Br (23, R = Me; 24, R = Ph). Subsequent treatment of these reactive PBr compounds with lithium trifluoroethoxide or phenoxide produced the corresponding PO derivatives t-BuR(2)SiN=P(R')(Me)OR' ' (25 and 26, R' ' = CH(2)CF(3); 28-30, R' ' = Ph) and Et(3)SiN=P(R)(Me)OR' (31 and 33, R' = CH(2)CF(3); 32 and 34, R = Ph), respectively. Many of the new compounds containing the bulky tert-butyldiphenylsilyl group, t-BuPh(2)Si, were solids that gave crystals suitable for X-ray diffraction studies. Consequently, the crystal structures of three (silylamino)phosphines (6, 7, and 14), one (silylamino)phosphine oxide (10), one N-silylphosphoranimine (30), and the cyclic compound 36 were determined. Among the (silylamino)phosphines, the P-N bond distances [6, N-PMe(2), 1.725(3) A; 7, N-P(Ph)Cl, 1.68(1) A, 14, N-PF(2), 1.652(4) A] decreased significantly as the electron-withdrawing nature of the phosphorus substituents increased. The N-silylphosphoranimine t-BuPh(2)SiN=PMe(2)OPh (30), which is a model system for poly(phosphazene) precursors, had a much shorter P=N distance of 1.512(6) A and a wide Si-N-P bond angle of 166.4(3) degrees. A similar P=N bond distance [1.514(7) A] and Si-N-P angle [169.9(6) degrees ] were observed for the exocyclic P=N-Si linkage in the ring compound 36, while the phosphine oxide 10 had P-N and P=O distances of 1.637(4) and 1.496(3) A, respectively, and a Si-N-P angle of 134.3(2) degrees.     

α-酯甲基硫桥羰基铁配合物(μ-RS)[μ-EtO<(O)CH2S]-Fe2(CO)6的合成及构象分析

通过μ-S2Fe2(CO)6的S-S键被Grignard试剂的还原断裂反应及中间物(μ-RS)(μ-XMgS)Fe2(CO)6(2)对氯代乙酸乙酯的亲核取代反应,合成了一系列铁硫原子簇配合物(μ-RS)[μ-EtOC(O)CH2S]Fe2(CO)6(1).1也可由2经三氟醋酸酸解及中月物(μ-RS)(μ-HS)Fe2(CO)6(3)在三乙胺存在下与氯代乙酸乙酯缩合制得.然而前法较后法既操作简便又原料便宜易得.构象分析表明,各配合物一般为ae.ee和ea三种或其中构象体以一定比例存在的混和物.     

Mechanistic elucidation of the substitution behavior of alkyl cobaloximes in water and methanol as solvents

The ligand substitution behavior of trans-[Co(Hdmg)2(R)S] (R = CH3, PhCH2; Hdmg = dimethylglyoximate; S = H2O and/or MeOH) was studied for imidazole, pyrazole, 1,2,4-triazole, N-acetylimidazole, 5-chloro-1-methylimidazole, NO2-, Ph3P, Ph3As, and Ph3Sb as entering ligands. In all cases, except for Ph3As and Ph3Sb, the observed kinetics shows a linear dependence on the entering nucleophile concentration with no evidence for a back reaction. In the case of Ph3As and Ph3Sb as entering nucleophiles, kinetic evidence for a reverse solvolysis reaction is at hand. Activation parameters (DeltaH++, DeltaS++, and DeltaV++) were determined from the temperature and pressure dependence of all studied reactions and support the operation of a dissociatively activated substitution mechanism. The rate and activation parameters show that there is an increase in the dissociative character from a dissociative interchange to a limiting dissociative mechanism that depends on the nature of R and the entering nucleophile. The crystal structure of trans-[Co(en)2(Me)H2O]2+ was determined by X-ray analysis. The Co-O and Co-C bond lengths were found to be 2.153(6) and 1.995(10) angstroms, respectively. The kinetic and structural data are discussed in reference to a series of earlier studied systems for which data are reported in the literature.     

Regioselective HON-addition of bifunctional hydrazone oximes to Pt(IV)-bound nitriles

Treatment of trans-[PtCl(4)(RCN)(2)](R = Me, Et) with the hydrazone oximes MeC(=NOH)C(R')=NNH(2)(R' = Me, Ph) at 45 degrees C in CH(2)Cl(2) led to the formation of trans-[PtCl(4)(NH=C(R)ON=C(Me)C(R')=NNH(2))(2)](R/R' = Me/Ph 1, Et/Me 2, Et/Ph 3) due to the regioselective OH-addition of the bifunctional MeC(=NOH)C(R')=NNH(2) to the nitrile group. The reaction of 3 and Ph(3)P=CHCO(2)Me allows the formation of the Pt(II) complex trans-[PtCl(2)(NH=C(Et)ON=C(Me)C(Ph)=NNH(2))2](4). In 4, the imine ligand was liberated by substitution with 2 equivalents of bis(1,2-diphenylphosphino)ethane (dppe) in CDCl(3) to give, along with the free ligand, the solid [Pt(dppe)(2)]Cl(2). The free iminoacyl hydrazone, having a restricted life-time, decomposes at 20-25 degrees C in about 20 h to the parent organonitrile and the hydrazone oxime. The Schiff condensation of the free NH(2) groups of 4 with aromatic aldehydes, i.e. 2-OH-5-NO(2)-benzaldehyde and 4-NO(2)-benzaldehyde, brings about the formation of the platinum(II) complexes trans-[PtCl(2)(NH=C(Et)ON=C(Me)C(Ph)=NN=CH(C(6)H(3)-2-OH-5-NO(2))2](5) and trans-[PtCl(2)(NH=C(Et)ON=C(Me)C(Ph)=NN=CH(C(6)H(4)-4-NO(2))2](6), respectively, containing functionalized remote peripherical groups. Metallization of 5, which can be considered as a novel type of metallaligand, was achieved by its reaction with M(OAc)(2).nH(2)O (M = Cu, n= 2; M = Co, n= 4) in a 1:1 molar ratio furnishing solid heteronuclear compounds with composition [Pt]:[M]= 1:1. The complexes were characterized by C, H, N elemental analyses, FAB+ mass-spectrometry, IR, 1H, 13C[1H] and (195)Pt NMR spectroscopies; X-ray structures were determined for 3, 4 and 5.     

乙酸烯丙酯的氢硅化反应

本文在对芳醛及环酮的氢硅化反应研究基础上, 进一步研究乙酸烯丙酯的氢硅化反应。(Ph~3P)~3RhCl作催化剂, 反应可在均相进行。采用假一级动力学方法, 以气相色谱法鉴测氢硅化产物生成的速率, 求得其反应速度常数, 进而分析其反应活性与反应物结构的关系, 并提出相应的可能机理。     

Reactions of amides with organoaluminum compounds: factors affecting the coordination mode of aluminum amidates

Factors affecting the coordination mode of an amidato group on aluminum will be presented. The reaction of N-tert-butylalkylacetamide ((t)BuNHCR([double bond]O)) with 1.1 molar equiv of Me(3)Al in refluxing hexane affords a pentacoordinated, dimeric compound [Me(2)Al[eta(2)-(t)BuNC(R)(mu(2)-O)]](2) (3, R = p-(t)Bu-C(6)H(4); 4, R = 2,6-F,F-C(6)H(3); 5, R = Me; 6, R = CF(3); 7, R = p-F(3)C-C(6)H(4)). However, in the presence of 2.2 molar equiv of Me(3)Al, N-tert-butyl-4-tert-butylbenzamide ((t)BuNHC(p-(t)Bu-C(6)H(4))([double bond]O in refluxing hexane gives [Me(2)Al[eta(2)-(t)BuNC(p-(t)Bu-C(6)H(4))(mu(2)-O)]AlMe(3)], 8. In contrast, the reaction of R'NHCR' '([double bond]O) with 1 molar equiv of R(3)Al at room temperature produces tetracoordinated, dimeric, eight-membered ring aluminum compounds [R(2)Al[mu,eta(2)-R'NC(R' ')O]](2) (9, R = Me, R' = 2,6-(i)Pr, (i)()Pr-C(6)H(3), R' ' = Ph; 10, R = Me, R' = (i)Bu, R' ' = Ph; 11, R = Et, R' = Bn, R' ' = Ph; 12, R = Me, R' = Ph, R' ' = CF(3); 13, R = Me, R' = Bn, R' ' = CF(3)). On the other hand, 4'-chlorobenzanilide ((p-Cl-C(6)H(4))NHCPh([double bond]O)) reacts with R(3)Al to produce trimeric, twelve-membered ring aluminum compounds [R(2)Al[mu, eta(2)-(p-Cl-C(6)H(4))NC(Ph)O]](3) (14, R = Me; 15, R = Et). Furthermore, the reaction of 2'-methoxybenzanilide with 1 molar equiv of Me(3)Al in hexane yields a dinuclear aluminum complex [Me(2)Al(o-OMe-Ph)NC(Ph)(O)AlMe(3)], 16.     

Primary and secondary phosphine complexes of iron porphyrins and ruthenium phthalocyanine: synthesis, structure, and P-H bond functionalization

Reduction of [Fe(III)(Por)Cl] (Por = porphyrinato dianion) with Na2S2O4 followed by reaction with excess PH2Ph, PH2Ad, or PHPh2 afforded [Fe(II)(F20-TPP)(PH2Ph)2] (1a), [Fe(II)(F20-TPP)(PH2Ad)2] (1b), [Fe(II)(F20-TPP)(PHPh2)2] (2a), and [Fe(II)(2,6-Cl2TPP)(PHPh2)2] (2b). Reaction of [Ru(II)(Pc)(DMSO)2] (Pc = phthalocyaninato dianion) with PH2Ph or PHPh2 gave [Ru(II)(Pc)(PH2Ph)2] (3a) and [Ru(II)(Pc)(PHPh2)2] (4). [Ru(II)(Pc)(PH2Ad)2] (3b) and [Ru(II)(Pc)(PH2Bu(t))2] (3c) were isolated by treating a mixture of [Ru(II)(Pc)(DMSO)2] and O=PCl2Ad or PCl2Bu(t) with LiAlH4. Hydrophosphination of CH2=CHR (R = CO2Et, CN) with [Ru(II)(F20-TPP)(PH2Ph)2] or [Ru(II)(F20-TPP)(PHPh2)2] in the presence of (t)BuOK led to the isolation of [Ru(II)(F20-TPP)(P(CH2CH2R)2Ph)2] (R = CO2Et, 5a; CN, 5b) and [Ru(II)(F20-TPP)(P(CH2CH2R)Ph2)2] (R = CO2Et, 6a; CN, 6b). Similar reaction of 3a with CH2=CHCN or MeI gave [Ru(II)(Pc)(P(CH2CH2CN)2Ph)2] (7) or [Ru(II)(Pc)(PMe2Ph)2] (8). The reactions of 4 with CH2=CHR (R = CO2Et, CN, C(O)Me, P(O)(OEt)2, S(O)2Ph), CH2=C(Me)CO2Me, CH(CO2Me)=CHCO2Me, MeI, BnCl, and RBr (R = (n)Bu, CH2=CHCH2, MeC[triple bond]CCH2, HC[triple bond]CCH2) in the presence of (t)BuOK afforded [Ru(II)(Pc)(P(CH2CH2R)Ph2)2] (R = CO2Et, 9a; CN, 9b; C(O)Me, 9c; P(O)(OEt)2, 9d; S(O)2Ph, 9e), [Ru(II)(Pc)(P(CH2CH(Me)CO2Me)Ph2)2] (9f), [Ru(II)(Pc)(P(CH(CO2Me)CH2CO2Me)Ph2)2] (9g), and [Ru(II)(Pc)(PRPh2)2] (R = Me, 10a; Bu(n), 10b; Bn, 10c; CH2CH=CH2, 10d; CH2C[triple bond]CMe, 10e; CH=C=CH2, 10f). X-ray crystal structure determinations revealed Fe-P distances of 2.2597(9) (1a) and 2.309(2) A (2bx 2 CH2Cl2) and Ru-P distances of 2.3707(13) (3b), 2.373(2) (3c), 2.3478(11) (4), and 2.3754(10) A (5b x 2 CH2Cl2). Both the crystal structures of 3b and 4 feature intermolecular C-H...pi interactions, which link the molecules into 3D and 2D networks, respectively.     

Reduction of (imine)Pt(IV) to (imine)Pt(II) complexes with carbonyl-stabilized phosphorus ylides

A novel method is reported for generation of the difficult-to-obtain (imine)Pt(II) compounds that involves reduction of the corresponding readily available Pt(IV)-based imines by carbonyl-stabilized phosphorus ylides, Ph3P=CHCO2R, in nonaqueous media. The reaction between neutral (imino)Pt(IV) compounds [PtCl4[NH=C(Me)ON=CR1R2]2] [R1R2 = Me2, (CH2)4, (CH2)5, (Me)C(Me)=NOH], [PtCl4[NH=C(Me)ONR2]2] (R = Me, Et, CH2Ph), (R1 = H; R2 = Ph or C6H4Me; R3 = Me) as well as anionic-type platinum(IV) complexes (Ph3PCH2Ph)[PtCl5[NH=C(Me)ON=CR2]] [R2 = Me2, (CH2)4, (CH2)5] and 1 equiv of Ph3P=CHCO2R (R = Me, Et) proceeds under mild conditions (ca. 4 h, room temperature) to give selectively the platinum(II) products (in good to excellent isolated yields) without further reduction of the platinum center. All thus prepared compounds (excluding previously described Delta4-1,2,4-oxadiazoline complexes) were characterized by elemental analyses, FAB mass spectrometry, IR and 1H, 13C[1H], 31P[1H] and 195Pt NMR spectroscopies, and X-ray single-crystal diffractometry, the latter for [PtCl2[NH=C(Me)ON=CMe2]2] [crystal system tetragonal, space group P4(2)/n (No. 86), a = b = 10.5050(10) A, c = 15.916(3) A] and (Ph3PCH2CO2Me)[PtCl3(NCMe)] [crystal system orthorhombic, space group Pna2(1) (No. 33), a = 19.661(7) A, b = 12.486(4) A, c = 10.149(3) A]. The reaction is also extended to a variety of other Pt(II)/Pt(IV) couples, and the ylides Ph3P=CHCO2R are introduced as mild and selective reducing agents of wide applicability for the conversion of Pt(IV) to Pt(II) species in nonaqueous media, a route that is especially useful in the case of compounds that cannot be prepared directly from Pt(II) precursors, and for the generation of systematic series of Pt(II)/Pt(IV) complexes for biological studies.     

Synthesis and structures of a 3-sila-beta-diketiminatomagnesium bromide, ketenimide and triflate

The crystalline compounds [Mg(Br)(L)(thf)].0.5Et2O [L = {N(R)C(C6H3Me2-2,6)}2SiR, R = SiMe3] (1), [Mg(L){N=C=C(C(Me)=CH)2CH2}(D)2] [D = NCC6H3Me2-2,6 (2), thf (3)] and [{Mg(L)}2{mu-OSO(CF3)O-[mu}2] (4) were prepared from (a) Si(Br)(R){C(C6H3Me2-2,6)=NR}2 and Mg for (1), (b) [Mg(SiR3)2(thf)2] and 2,6-Me2C6H3CN (5 mol for (2), 3 mol for (3)), and (c) (2) + Me3SiOS(O)2CF3 for (4); a coproduct from (c) is believed to have been the trimethylsilyl ketenimide Me3SiN=C=C{C(Me)=CH}2CH2 (5).