38800-75-8

Upstream product

• 113533-93-0 tetracarbonyl(di-tert-butoxysilanediyl)chromium⁽⁰⁾-hexamethylphosphoric triamide 
• 603-35-0 triphenylphosphine 
• 697302-50-4 (benzene)tricarbonylchromium 
• 148538-99-2 ([2-[(dimethylamino)methyl]phenyl]hydrosilanediyl)chromium⁽⁰⁾ pentacarbonyl 
• 124406-73-1 potassium hydridopentacarbonylchromate 
• 199620-14-9 chromium⁽⁰⁾ hexacarbonyl 
• 13007-92-6 chromium hexacarbonyl 
• 76647-73-9 tricarbonyl(biphenyl-2,2'-dicarboxylic acid dimethyl ester)chromium 
• 155111-23-2 pentacarbonyl{bis(bis(trimethylsilyl)methyl)isocyanoborane}chromium⁽⁰⁾ 
• 55853-04-8 (η6-2,4,6-trimethylpyridine)tricarbonylchromium(II) 
• 21038-94-8 {(C₂H₅)4N}{(CO)4Cr{P(C₆H₄Cl-p)3}Cl} 
• 138312-84-2 trans-(di-tert-butoxysilanediyl)(triphenylphosphine)chromium⁽⁰⁾ tetracarbonyl-hexamethylphosphoric triamide 
• 86475-63-0 C₄₀H₃₀CrO₄P₂⁽¹⁺⁾ 
• 16800-46-7 tris(acetonitrile)tricarbonylchromium⁽⁰⁾ 

Downstream Products

• 86475-63-0 C₄₀H₃₀CrO₄P₂⁽¹⁺⁾ 
• 108234-40-8 CrBr₂(NO)2(P(C₆H₅)3)2 
• 35039-06-6 trans-(CO)4Cr{P(OC₆H₅)3}2 
• 87246-84-2 trans-[tetracarbonylbis(triphenylphosphine)chromium]⁽¹⁺⁾ perchlorate 
• 87246-85-3 [Cr(CO)4(P(C₆H₅)3)2]⁽¹⁺⁾*PF₆^(1-)=[Cr(CO)4(P(C₆H₅)3)2]PF₆ 

Relevant academic research and scientific papers

Facile displacement of cyclohexadienide ligand from K[Cr(η5-C6H7)(CO)3] to give crystallographically characterized trans-[Cr(CO)4(PPh3)2]

Substitution of K[Cr(η5-C6H7)(CO)3] with triphenylphosphine resulted in cyclohexadienide loss and formation of an unexpected product, trans-[Cr(CO)4(PPh3)2]. The structure of thi

[4-tBu-2,6-{P(O)(OiPr)2}2C6H2Sn(PPh3)Cr(CO)5]ClO4 a salt containing a cationic triphenylphosphanestabilized organostannylene transition metal complex

The isolation and molecular structure of bis(di-iso-propoxyphosphonyl)-4-tert-butyl]phenyl}tin triphenylphosphane perchlorate chromium pentacarbonyl, 2, is reported. It is the first example of an ionic compound containing an organostannylene transition metal complex cation stabilized by a phosphane donor. Slow reaction of compound 2 in acetonitrile gave trans-bis-triphenylphosphane chromium tetracarbonyl, trans-(Ph3P)2Cr(CO)4, in a new crystalline modification.

Rapid synthesis of Group VI carbonyl complexes by coupling borohydride catalysis and microwave heating

Several Group VI tetracarbonyl phosphine and tertiary amine complexes [M(CO)4 L2, M = Cr, Mo, W, L2 = 2PPh 3, dppm, dppe, dppp, dppb, bpy, phen, dppf] were synthesized in minutes in the microwave at moderate temperature, atmospheric pressure, and utilizing NaBH4 as a catalyst. The reactions were optimized by careful solvent selection. The octahedral complexes were isolated in percent yields ranging from 17 to 95. The lower temperatures, shorter reaction times, benign solvents, and lower pressures as compared to the traditional thermal syntheses provide a rapid, eco-friendly synthetic route to these common Group VI complexes.

Exploring the coordination chemistry and reactivity of dialkylamino- and bis(dialkylamino)-phosphines in the coordination sphere of metals

The coordination chemistry of a range of dialkylamino- and bis(dialkylamino)-phosphines, RxP(NR′2) 3-x (x = 1 or 2; R = Cl, Me, Ph, C6F5; R′ = Et, Pri), 1-7, has been studied and the resulting Group 6 tetracarbonyl and platinum dichloride bis(phosphine) complexes fully characterised. Subsequently, the reactivity of the P-N bonds of the metal-bound phosphines was probed. Treatment of R″OH (R″ = Me, Et, allyl) solutions of the bis(dialkylaminodiphenylphosphine) complexes with anhydrous HCl gas led to substitution of NR′2 by OR″; the resulting P-alkoxy complexes were isolated in excellent yields. Acidification of ethylene glycol solutions of the aminophosphine complexes afforded the corresponding bis(chlorodiphenylphosphine) derivatives. Following reaction of trans-[W(CO)4(P{NEt2}Ph2)2] with either aqueous HCl or H2SO4, trans-[W(CO) 4(P{OH}Ph2)2] could be isolated as its dichloromethane solvate in excellent yield (81%). Reactions of the bis(bis{dialkylamino} phenylphosphine) complexes under identical conditions yielded a range of unidentified products. Reactions of ligands 1-7 with [{RhCl(CO)2}2] and elemental selenium have been undertaken and the products used to assess the phosphines' donor capabilities. Depending on the substituents at phosphorus, either trans-diphosphine or cis-dicarbonyl complexes result from reaction with [{RhCl(CO)2} 2]. The sterically demanding phosphine P(NPr2 i)2Ph (5) proved unreactive towards complexation with metals, although its selenide could be prepared and isolated. In order to probe the observed lack of oxidation or complexation the molecular structure P(NPr2i)2(C6F5) has been determined by X-ray crystallography. The Royal Society of Chemistry 2003.

Ligand substitution processes on carbonylmetal derivatives. 3.1 Reaction of hydridopentacarbonylchromates with phosphines

The reaction of K+[HCr(CO)5]- with phosphanes PR3 (R = Et, Ph, NMe2) in THF at 65 °C affords the disubstituted complexes trans-Cr(CO)4(PR3)2 isolated in 57-70% yield.

Improved synthesis of KHCr(CO)5 and comparative coordination chemistry from KHCr(CO)5 and KHFe(CO)4

A practical procedure for the selective preparation of KHCr(CO)5 is described. The use of a potassium cation in the coordination chemistry of the [HFe(CO)4]- anion is completed and extended to the coordination chemistry of the [HCr(CO)5]- anion: CO-substitution by phosphites, phosphines and phosphinites, and H-abstraction by aminophosphines. Most of the observed differences in reactivity between KHFe(CO)4 and KHCr(CO)5 can be rationalized by the stronger acidity of KHFe(CO)4.

Base stabilization of functionalized silylene transition metal complexes

The dehydrogenative coupling reaction of primary silanes ArSiH3 [Ar = [2-(Me2NCH2)C6H4], [8-(Me2NCH2)C10H6], [8-(Me2N)C6H4]] with Fe(CO)5, Cr(CO)6, CpCo(CO)2, and RCpMn(CO)3 (R = H, CH3) under photolytic conditions affords an effective access to intramolecular base-stabilized functionalized silanediyl-transition metal complexes of general formula [ArHSi=MLn]. 29Si-NMR investigations of the photochemical reaction of PhSiH3 with Fe-(CO)5 in the presence of 1,3-dimethyl-2-imidazolidinone (DMI) or hexamethylphosphoric triamide indicates a two-step mechanism for the formation of base-stabilized silanediyl-transition metal complexes. The carbonyl displacement reactions of the complex [2-(Me2-NCH2)C6H4]HSi=Cr(CO) 5 in the presence of PPh3 or P(OMe)3 lead to the formation of trans-(PPh3)2Cr(CO)4 or trans-[P(OMe)3]2Cr(CO)4, respectively, either by photolysis or by thermolysis. Photochemical displacement reaction with (diphenylphosphino)ethane furnished [2-(Me2-NCH2)C6H4]HSi=Cr[Ph 2P(CH2)2PPh2](CO)3 by subsequent displacement of two carbonyls of the metal moiety. Exchange reactions of the complex [2-(Me2NCH2)C6H4]HSi=Cr(CO) 5 with Ph3CX (X = Cl, BF4, OSO2CF3) or CH3COX′ (X′ = Cl, Br) provide a direct entry to a series of functionalized complexes [2-(Me2NCH2)C6H4]XSi=Cr(CO) 5. The liberated silylenes from complexes ArHSi(B)=Fe(CO)4 (Ar = Ph, 1-Np) (B = DMI) can be trapped in the presence of tert-butyl alcohol or methanol to give di-tert-butoxysilanes or trimethoxysilanes, respectively.

Mixed-valent interactions in rigid dinuclear systems: Electrochemical and spectroscopic studies of CrICr0 ions with controlled torsion of the biphenyl bridge

Three dinuclear complexes were prepared in which Cr(CO)2(PPh3) moieties are connected through biphenyl linkages. The dihedral (twist) angle of the two are arenes in the biphenyl decreases from 100 to 17 to 0° as the bridging ligand is changed from biphenyl-2,2′-dicarboxylic acid dimethyl ester (in compound 2) to dihydrophenanthrene (3) to fluorene (4). All three compounds are oxidized in two reversible one-electron steps with a voltage separation of ca. 260 mV. Each monocation is shown by IR spectroscopy to be trapped-valent. ESR spectroscopy in frozen glasses gives the same result. IR sampling of the dications is achieved by low-temperature flow electrochemical experiments. The asymmetric stretching frequency of the CO pair assigned to the Cr(0) site in the mixed-valent ion is measurably shifted from that of the original Cr0Cr0 complex, and the amount of shift increases significantly as the biphenyl twist diminishes. It is proposed that although the half-filled orbital is localized on one metal site in the monocations, there is significant transmission of charge between the metals through filled orbitals of the biphenyl linkage. The results support a through-space model for electronic (mixed-valent) delocalization in CrI(μ-biphenyl)Cr0 linkages. Results of studies of the oxidation of (arene)Cr(CO)2L, where L = CO or PPh3, and of (biarene)Cr2(CO)6, prepared as part of this work, are briefly reported.

Synthesis of the sterically hindered complexes . Crystal structure of

The reaction of the dialkylchloroborane BClR2 with a Group 6 pentacarbonyl(cyano)metallate(0) in CH2Cl2 or PhMe gives the thermally stable complexes .Crystalline 2a has a linear Cr-C-N-B skeleton with long Cr-C and B-N bonds and a short C-N bond, consistent (as are the IR, Raman and NMR spectra) with its formulation as -C-BR2>.Key words: Group 6; Boron; Silicon; Crystal structure; Isocyanide; Carbonyl

Structure and photochemistry of new base-stabilized silylene (silanediyl) complexes R2(HMPA)Si=M(CO)n of iron, chromium, and tungsten (R = t-BuO, t-BuS, MesO, 1-AdaO, 2-AdaO, NeopO, TritO, Me, Cl; M = Fe, n = 4; M = Cr, W, n = 5): Sila-Wittig reaction of the base-free reactive intermediate [Me2Si=Cr(CO)5] with dimethyl carbonate

The reaction of the dichlorosilanes R2SiCl2 (R = t-BuO, t-BuS, MesO (Mes = mesityl), 1-AdaO (Ada = adamantyl), 2-AdaO, NeopO (Neop = neopentyl), TritO (Trit = triphenylmethyl), Me, Cl) with the carbonylate dianions M(CO)n2- (M = Fe, n = 4; M = Cr, W, n = 5) in the presence of HMPA (hexamethylphosphoric triamide) affords an effective access to the base-stabilized silylene complexes R2-(HMPA)Si=M(CO)n. Single-crystal X-ray structure analyses of the iron complexes Me2(HMPA)Si=Fe(CO)4 (4) and Cl2(HMPA)Si=Fe(CO)4 (5) and the chromium compounds Me2(HMPA)Si=Cr(CO)5 (7) and Cl2(HMPA)Si=Cr(CO)5 (8) have been performed and are compared with the previously determined structures of (t-BuO)2(HMPA)Si=Fe(CO)4 (1) and (t-BuO)2(HMPA)Si=Cr(CO)5 (6). The structures feature relatively short M-Si bond lengths with d(FeSi) = 2.280 (1)/2.294 (1) (4) and 2.214 (1)/2.221 (1) ? (5) and d(CrSi) = 2.410 (1) (7) and 2.342 (1) (8). In contrast, the Si-O (HMPA) bonds are fairly long (1.735 (3)/1.731 (3) (4), 1.683 (3)/1.676 (3) (5), 1.743 (2) (7), 1.690 (2) ? (8)). The coordination geometry at silicon is significantly distorted from tetrahedral and subject to strong substituent effects. Both metal-silicon bond lengths and the coordination geometry at silicon in the coordination compounds correlate to frontier orbital energies and electron population densities of the free silylenes. Data from cyclic voltammetric measurements are in agreement with this description. A M?ssbauer spectrum of 1 shows an unusual negative isomer shift of -0.477, which indicates particularly for the TBP d8 compounds 1-5 (axial silylene coordination) a high ionic contribution of the Fe-Si bond in the sense of a betaine structure. The relative orientation of the substituents at silicon, as found in the crystal, is reproduced by a force field calculation as the global energy minimum. VT NMR experiments show the fluxionality of the ligand framework of the TBP Fe d8 complexes at room temperature. The free energy of activation for the Berry pseudorotation process is ΔG250.0? = 40.3 (±5) kJ/mol. A reactivity study of the base adducts 1, 4, and 6 shows the photochemical activation of the silylenes: In the presence of triphenylphosphine, the trans phosphine complexes trans-(t-BuO)2Si(HMPA)=Fe(CO)3P(C6H 5)3 (23), trans-Me2Si(HMPA)=Fe(CO)3P(C6H 5)3 (24), and trans-(t-BuO)2Si(HMPA)=Cr(CO)4P(C6H 5)3 (26) are obtained by a photochemical CO displacement reaction. Subsequently, the silylenes are displaced by a further phosphine molecule to yield the trans-bis(phosphine) complexes trans-{P(C6H5)3}2Fe(CO)3 (25) and trans-{P(C6H5)3}2Cr(CO)4 (27). The liberated silylenes form polysilanes; di-tert-butoxysilylene can be trapped in the presence of 2,3-dimethylbutadiene by an 1,4-addition to form the silacyclopentene Si(t-BuO)2CH2C(CH3)=C(CH3)CH 2 (28) (photolysis of 1). As a secondary photolysis product, (2,3-dimethylbutadiene)iron tricarbonyl, (η4-C6H4)Fe(CO)3 (29), is isolated. The base-free complex [Me2Si=Cr(CO)5] is generated in situ from Me2SiCl2 and Na2Cr(CO)5 at -50°C as a reactive intermediate and yields a variety of interesting trapping reactions: in the presence of HMPA the stable HMPA adduct 7 is formed; the thermolabile THF adduct Me2Si(THF)=Cr(CO)5 (32) dimerizes above -40°C to give 21. With dimethyl carbonate as the trapping reagent, [Me2Si=Cr(CO)5] undergoes a sila-Wittig reaction to form hexamethyltrisiloxane, [Me2SiO-]3 (30), and (dimethoxycarbene)chromium pentacarbonyl, (MeO)2C=Cr(CO)5 (31).