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The dialkyl-ortho-biaryl class of phosphines, commonly known as Buchwald-type ligands, are among the most important phosphines in Pd-catalyzed cross-coupling. These ligands have also been successfully applied to several synthetically valuable Ni-catalyzed cross-coupling methodologies and, as demonstrated in this work, are top performing ligands in Ni-catalyzed Suzuki Miyaura Coupling (SMC) and C-N coupling reactions, even outperforming commonly employed bisphosphines like dppf in many circumstances. However, little is known about their structure-reactivity relationships (SRRs) with Ni, and limited examples of well-defined, catalytically relevant Ni complexes with Buchwald-type ligands exist. In this work, we report the analysis of Buchwald-type phosphine SRRs in four representative Ni-catalyzed cross-coupling reactions. Our study was guided by data-driven classification analysis, which together with mechanistic organometallic studies of structurally characterized Ni(0), Ni(I), and Ni(II) complexes allowed us to rationalize reactivity patterns in catalysis. Overall, we expect that this study will serve as a platform for further exploration of this ligand class in organonickel chemistry as well as in the development of new Ni-catalyzed cross-coupling methodologies.

Sterically demanding 2,6‐dibenzhydryl‐4‐methylphenyl and 1,2,3‐triazole based tertiary phosphines, [Ar*{1,2,3‐N3C(Ph)C(PR2)}] (R=Ph, 3; R=iPr, 4) were obtained by the temperature‐controlled lithiation of 1‐(2,6‐dibenzydryl‐4‐methyl)‐5‐iodo‐4‐phenyl‐1H‐1,2,3‐triazole (2) followed by the reaction with R2PCl (R=Ph, iPr). Treatment of 3 with H2O2, elemental sulfur and selenium yielded chalcogenides [Ar*{1,2,3‐N3C(Ph)C(P(E)Ph2)}] (E=O, 5; E=S, 6; E=Se, 7). The reaction of 3 with [Pd(COD)Cl2] in 1 : 1 molar ratio, afforded dimeric complex [Pd(μ2‐Cl)Cl{Ar*{1,2,3‐N3C(Ph)C(PPh2)}‐κ1‐P}]2 (8), whereas the reactions of 3 and 4 with [Pd(η3‐C3H5)Cl]2 in 2 : 1 molar ratios produced complexes [Pd(η3‐C3H5)Cl{Ar*{1,2,3‐N3C(Ph)C(PR2)}‐κ1‐P}] (R=Ph, 9; R=iPr, 10). Treatment of 3 with [Pd(OAc)2] in 1 : 1 molar ratio afforded a rare trinuclear complex [{Pd3(OAc)4}{Ar*{1,2,3‐N3C(C6H4)C(PPh2)}‐κ2‐C,P}2] (11). Treatment of 3 and 4 with [AuCl(SMe2)] resulted in [AuCl{Ar*{1,2,3‐N3C(Ph)C(PR2)}‐κ1‐P}] (R=Ph, 12; R=iPr, 13). Bulky phosphine 4 was very effective in Suzuki‐Miyaura coupling and amination reactions with very low catalyst loading. Molecular structures of 3–5, and 8–13 were confirmed by single‐crystal X‐ray diffraction studies. [ABSTRACT FROM AUTHOR]

α,β-Butenolides with ≥96% enantiomeric excess are synthesized from β,γ-butenolides via a novel Cu(I)-ligand cooperative catalysis. The reaction is enabled by a chiral biphenyl-2-ylphosphine ligand featuring a remote tertiary amino group. Density functional theory studies support the cooperation between the metal center and the ligand basic amino group during the initial soft deprotonation and the key asymmetric γ-protonation. Remarkably, other coinage metals, that is, Ag and Au, can readily assume the same role as Cu in this asymmetric isomerization chemistry.

Polyalkyl furans are widespread in nature, often performing important biological roles. Despite a plethora of methods for the synthesis of tetrasubstituted furans, the construction of tetraalkyl furans remains non-trivial. The prevalence of alkyl groups in bioactive furan natural products, combined with the desirable bioactivities of tetraalkyl furans, calls for a general synthetic protocol for polyalkyl furans. This paper describes a Michael-Heck approach, using sequential phosphine-palladium catalysis, for the preparation of various polyalkyl furans from readily available precursors. The versatility of this method is illustrated by the total syntheses of nine distinct polyalkylated furan natural products belonging to different classes, namely the furanoterpenes rosefuran, sesquirosefuran, and mikanifuran; the marine natural products plakorsins A, B, and D and plakorsin D methyl ester; and the furan fatty acids 3D5 and hydromumiamicin.

We report a proximity-driven crosslinking strategy featuring bioorthogonal cyclopropenones. These motifs react with phosphines to form electrophilic ketene-ylides. Such intermediates can be trapped by neighboring proteins to form covalent adducts. Successful crosslinking was achieved using a model split reporter, and the rate of crosslinking could be tuned using different phosphine triggers. We further demonstrated that the reaction can be performed in cell lysate. Based on these features, we anticipate that cyclopropenones will enable unique studies of protein-protein and other biomolecule interactions.

The packing states of luminescent molecules can be affected by external stimuli, leading to changes in the emission energy. Compared with the traditional organics and metal−organic frameworks, closely packed coordination polymers (CPs) have more transition types and better stabilities, respectively. However, little attention is paid to the closely packed CPs in the field of piezochromism, and much less to the corresponding optical mechanism. For studying the effect of molecular structure and the energy transfer on piezochromism, ten [Cu2I2] cluster‐based CPs with bridging aromatic ligands and terminal triphenylphosphine ligands are constructed to explore the pressure‐dependent luminescence, especially the influences of bridging ligand length, supramolecular interactions, and halogen atoms on the wavelength shift for luminescent piezochromism. In these CPs, the conformational and structural flexibilities can be effectively increased by lengthening the bridging ligand and addition of pendent methyl groups in the phosphine ligands, respectively, resulting in more obvious piezochromism. In addition, the XLCT/MLCT ratios are efficiently modulated by adjusting the flexibility of halogen electron cloud, which further affects the piezochromic property. Upon the combined effect of multiple flexibilities, a closely packed CP with a large wavelength shift (77 nm) and reversible piezochromism is found. [ABSTRACT FROM AUTHOR]

Herein we present the synthesis, full characterization and systematic investigation of intramolecular Lewis pairs incorporating Lewis acidic N‐heterocyclic nitrenium salts linked to phosphine Lewis bases. Intramolecular Lewis adducts and frustrated Lewis pairs (FLPs) were obtained, depending on different modification to the molecular structure. Several different aryl and alkyl groups were utilized as substituents on the core naphthotriazinium and phosphine components, which were linked by an alkyl chain of variable length. Whereas an intermolecular Lewis adduct of nitrenium with a relatively weak phosphine donor (Ph2PMe) was not observed, the corresponding intramolecular version (Ph2PR) was detected both in a dissociated Lewis pair form and as a coordinated Lewis adduct simultaneously. Additionally, one set of modifications led to a unique rearrangement of the nitrenium core, resulting in a fused heterocycle. The mechanism of this rearrangement was analyzed computationally. [ABSTRACT FROM AUTHOR]

We report a new ligation of cyclopropeniminium ions with bioorthogonal phosphines. Cyclopropeniminium scaffolds are sufficiently stable in biological media and, unlike related isomers, react with functionalized phosphines via formal 1,2-addition to a π-system. The ligation can be performed in aqueous solution and is compatible with existing bioorthogonal transformations. Such mutually compatible reactions are useful for multicomponent labeling.

A robust synthetic route from L-hydroxyproline (L-Hyp) to phosphines has established an expandable library of six chiral aminophosphines, which were then applied to the phosphine-catalyzed [4 + 2] allene-imine annulation. The enantioinduction in the annulations-induced by a purely steric effect-were moderate (up to 57% ee). A switch of the reaction site from the γ- to the β'-carbon atom of the allenoate was observed during the annulations performed using sterically demanding chiral phosphines.

The asymmetric isomerization of alkyne to allene is the most efficient and the completely atom-economic approach to this class of versatile axial chiral structure. However, the state-of-the-art is limited to tert-butyl alk-3-ynoate substrates that possess requisite acidic propargylic C-H bonds. Reported here is a strategy based on gold catalysis that is enabled by a designed chiral bifunctional biphenyl-2-ylphosphine ligand. It permits isomerization of alkynes with nonacidic α-C-H bonds and hence offers a much-needed general solution. With chiral propargylic alcohols as substrates, 2,5-disubstituted 2,5-dihydrofurans are formed in one step in typically good yields and with good to excellent diastereoselectivities. With achiral substrates, 2,5-dihydrofurans are formed with good to excellent enantiomeric excesses. A novel center-chirality approach is developed to achieve a stereocontrol effect similar to an axial chirality in the designed chiral ligand. The mechanistic studies established that the precatalyst axial epimers are all converted into the catalytically active cationic gold catalyst owing to the fluxional axis of the latter.

• Reactions of 4,6-dimethylpyrimidine-2-thiolate with various palladium and platinum precursors have been investigated. • All the synthesized complexes have been characterized using the techniques like elemental analyses, NMR (1H, 13C{1H}, 31P{1H}) and UV–Vis spectroscopy. • The molecular structures of [Pd{ƙ 2 -S, N: SC 4 H(4,6-Me) 2 N 2 }{SC 4 H(4,6-Me) 2 N 2 }(PPh 3)] (1a), [Pt{SC 4 H(4,6-Me) 2 N 2 } 2 (PPh 3) 2 ].2C 6 H 6.2CH 3 CN (1b), [Pd 2 (µ 2 -S){SC 4 H(4,6-Me) 2 N 2 } 2 (µ 2 -dppm) 2 ] (2a) and [Pd{κ 2 -SC 4 H(4,6-Me) 2 N 2 } 2 ] (2c) were established through Single Crystal X-ray diffraction analyses. • DFT studies were carried out to study the reactivity of [PdCl 2 (P-P)] (P-P = dppm, dppe, dppp) against 4,6-dimethylpyrimidine-2-thiolate. Group 10 thiolate complexes have been in the quest zone of research due to pertinent catalytic potential. The present work unravels the role of precursor phosphine's feature in their reactivity towards 4,6-dimethylpyrimidine-2-thiol and subsequent thiolate complex. Synthesized thiolate complexes were thoroughly characterized using elemental analyses, NMR (1H, 13C{1H}, 31P{1H}), UV–Vis spectroscopy and Single Crystal X-ray diffraction analyses. Treatment of [MCl 2 (PPh 3) 2 ] (M = Pd, Pt) with two equivalents of NaSC 4 H(4,6-Me)N 2 resulted in chelated [Pd{κ-S, κ-N: SC 4 H(4,6-Me) 2 N 2 }{SC 4 H(4,6-Me) 2 N 2 }(PPh 3)] (1a) as well as an expected trans compound [Pt{SC 4 H(4,6-Me) 2 N 2 } 2 (PPh 3) 2 ] (1b). A similar reaction with the chelating phosphine 'dppm' (dppm = 1,1-bis(diphenylphosphino)methane) as an ancillary ligand resulted in the serendipitous product of composition [Pd 2 (µ 2 -S){SC 4 H(4,6-Me) 2 N 2 } 2 (µ 2 -dppm) 2 ] (2a) depending upon competitive cleavage of S-S and S-C bond. The reaction of [PdCl 2 (dppe)] afforded a cis configured compound [Pd{2-SC 4 H(4,6-Me) 2 N 2 } 2 (dppe)] (2b). Contrary, the similar reaction of [PdCl 2 (dppp)] results in removal of 'dppp' (1,3-bis(diphenylphosphino)propane) yielding the chelated complex [Pd{κ-S, κ-N: SC 4 H(4,6-Me) 2 N 2 } 2 ] (2c). Above all, the reactivity of 4,6-dimethylpyrimidine-2-thiol significantly differs compared to unsubstituted pyrimidyl, pyridyl analogue which has been attributed to the additional richness of electrons/activation in the ring which in turn facilitates competitive reactivity pattern of S-S and S-C bond. The virtue of such activation can easily be understood by the isolation of complex [Pd 2 (µ 2 -S){SC 4 H(4,6-Me) 2 N 2 } 2 (µ 2 -dppm) 2 ] (2a). Rationalization of results via DFT calculation reveals that projection angle P-M-P (ranging from ∼75 to 92°) driven structural change in the chelating phosphine and associated degree of softness in ligand molecule played a crucial role in governing the resulting product of substitution reaction as dimeric, monomeric and chelated complexes. Thus, projection angle- driven geometrical and electronic structure and variation provide opportunity and direction to efficiently derive biologically as well as academically important complexes. [Display omitted] [ABSTRACT FROM AUTHOR]

The hallmark of nucleophilic phosphine catalysis is the initial nucleophilic addition of a phosphine to an electrophilic starting material, producing a reactive zwitterionic intermediate, generally under mild conditions. In this Review, we classify nucleophilic phosphine catalysis reactions in terms of their electrophilic components. In the majority of cases, these electrophiles possess carbon-carbon multiple bonds: alkenes (section 2), allenes (section 3), alkynes (section 4), and Morita-Baylis-Hillman (MBH) alcohol derivatives (MBHADs; section 5). Within each of these sections, the reactions are compiled based on the nature of the second starting material-nucleophiles, dinucleophiles, electrophiles, and electrophile-nucleophiles. Nucleophilic phosphine catalysis reactions that occur via the initial addition to starting materials that do not possess carbon-carbon multiple bonds are collated in section 6. Although not catalytic in the phosphine, the formation of ylides through the nucleophilic addition of phosphines to carbon-carbon multiple bond-containing compounds is intimately related to the catalysis and is discussed in section 7. Finally, section 8 compiles miscellaneous topics, including annulations of the Hüisgen zwitterion, phosphine-mediated reductions, iminophosphorane organocatalysis, and catalytic variants of classical phosphine oxide-generating reactions.

Cyclopropenethiones are reported as new bioorthogonal reagents. These motifs react readily with substituted phosphines to provide thiocarbonyl adducts. In some cases, the ligations are >300-fold faster than analogous reactions with bioorthogonal cyclopropenones. Dialkyl cyclopropenethiones are also stable in aqueous buffers and can be used for biomolecule labeling in vitro and in cell lysate. The rapid reactivity and biocompatibility of cyclopropenethiones suggest that they will be useful probes for cellular studies.

Fifteen water-soluble rhenium compounds of the general formula [Re(CO)3(NN)(PR3)]+, where NN is a diimine ligand and PR3 is 1,3,5-triaza-7-phosphaadamantane (PTA), tris(hydroxymethyl)phosphine (THP), or 1,4-diacetyl-1,3,7-triaza-5-phosphabicylco[3.3.1]nonane (DAPTA), were synthesized and characterized by multinuclear NMR spectroscopy, IR spectroscopy, and X-ray crystallography. The complexes bearing the THP and DAPTA ligands exhibit triplet-based luminescence in air-equilibrated aqueous solutions with quantum yields ranging from 3.4 to 11.5%. Furthermore, the THP and DAPTA complexes undergo photosubstitution of a CO ligand upon irradiation with 365 nm light with quantum yields ranging from 1.1 to 5.5% and sensitize the formation of 1O2 with quantum yields as high as 70%. In contrast, all of the complexes bearing the PTA ligand are nonemissive and do not undergo photosubstitution upon irradiation with 365 nm light. These compounds were evaluated as photoactivated anticancer agents in human cervical (HeLa), ovarian (A2780), and cisplatin-resistant ovarian (A2780CP70) cancer cell lines. All of the complexes bearing THP and DAPTA exhibited a cytotoxic response upon irradiation with minimal toxicity in the absence of light. Notably, the complex with DAPTA and 1,10-phenanthroline gave rise to an IC50 value of 6 μM in HeLa cells upon irradiation, rendering it the most phototoxic compound in this library. The nature of the photoinduced cytotoxicity of this compound was explored in further detail. These data indicate that the phototoxic response may result from the release of both CO and the rhenium-containing photoproduct, as well as the production of 1O2.

Reactions of isocyanates/isothiocyanates with primary and secondary phosphines without solvent at room temperature afforded phosphinecarboxamide/phosphinecarbothioamide, respectively, in excellent yields. Furthermore, palladium complex Pd(COD)Cl2 was allowed to react with Ph2PC(O)NHPh (1a) to afford [Pd{Ph2PC(O)NHPh-κP}2Cl2] (3). On the other hand, the reaction of Pd(COD)Cl2 with 1 eq. of Ph2PC(S)NHPh (2a) afforded [PdCl2{Ph2PC(S)NHPh-κP,S}] (4). In the case of a 1:2 molar ratio, [PdCl{Ph2PC(S)NHPh-κP,S}{Ph2PC(S)NHPh-κP}]Cl (5) was formed. The newly obtained compounds were fully characterized using multielement NMR measurements and elemental analyses. In addition, the molecular structures of Ph2PC(O)NH(CH2)2Cl (1j), Ph2PC(S)NHPh(4-Cl) (2c), and 3–5 were determined using single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

Phosphanylidenephosphoranes of the type R–P(PR′3), also known as phospha-Wittig reagents, can be utilized in a variety of bond activation reactions exploiting their phosphinidenoid reactivity. Herein, we thoroughly show that a facile PMe3 for H2O exchange gives access to various primary phosphine oxides of the general formula RP(H)2O (R = Mes*, MesTer, DipTer) and the molecular structure of DipTerP(O)H2 was determined. However, phosphanylidenephosphoranes are described to be highly nucleophilic as well. We show that the attachment of main group Lewis acids such as GaCl3 and GaI3 to R–P(PMe3) yielded the highly sensitive, yet stable coordination compounds [(RPGaX3)PMe3] (R = Mes*, DipTer) or [(RPPMe3)2GaCl2]GaCl4 (R = MesTer). In contrast to the free phosphanylidenephosphoranes, these species reacted differently with H2O, which was demonstrated for [(Mes*PPMe3)GaI3]. Here the formation of the phosphino-phosphonium cation [Mes*P(H)PMe3]+ and different anions was observed with combined NMR spectroscopic and SC-XRD (SC-XRD = single crystal X-ray diffraction analysis) studies. This work demonstrates that the ambiphilic character of phosphanylidenephosphoranes can be utilized to manipulate the reactivity of R–P(PMe3) towards water, giving primary phosphine oxides, whereas the Lewis acid adducts [(RPGaX3)PMe3] gave phosphino-phosphonium species. [ABSTRACT FROM AUTHOR]

Addition of 2-aminobenzothiazole (abt) and substituted derivatives to Hg(OAc)2 leads to the high yield formation of ortho-cyano-aminothiophenolate (ocap) complexes [Hg{SC6H3XN(C≡N)}]n (X = H, Me, Cl, Br, NO2) resulting from dehydrogenation and C–S bond cleavage. The reaction appears to be unique to Hg(OAc)2 and with HgCl2 the product [HgCl2(abt)]n contains an intact abt ligand, but reacts with acetate to afford the ocap complex [Hg{SC6H4N(C≡N)}]n. Binding of abt to Hg(II) has previously been probed in molecular structures of [Hg(sac)2(abt)L] (L = MeOH, DMSO) and these have been reexamined to understand the perturbation of abt upon coordination. When the reaction of abt and Hg(OAc)2 was carried out at low temperatures the intermediate [Hg(κ2-OAc)(EtOH)(μ-HNCNSC6H4)]2 was isolated resulting from a single ligand deprotonation thus allowing a mechanism for ring-opening to be proposed. Reactions of [Hg{SC6H3XN(C≡N)}]n with mono- and bidentate phosphines have been studied, affording a series of complexes in which the ocap ligands adopt four different binding modes in the solid state, as shown by a number of crystallographic studies. In all, the ligand chelates to a single mercury centre but spans to the second via either: (i) a simple S,N-chelate, (ii) coordination through nitrogen of the C≡N group, (iii) the sulfur acting as a thiolate-bridge, (iv) both thiolate bridging and cyanide coordination. With PPh3 two different binding modes are seen in complexes [Hg{SC6H3XN(C≡N)}(PPh3)]2 being dependant upon the nature of the arene-substituent, while addition of excess PPh3 affords mononuclear [Hg{SC6H3XN(C≡N)}(PPh3)2]. With dppm, binuclear [Hg{SC6H3XN(C≡N)}(κ1-dppm)]2 result in which the diphosphine binds in a monodentate fashion. With the more flexible diphosphines, dppe and dppb, coordination polymers [Hg{SC6H3XN(C≡N)}(κ1,κ1-diphosphine)]n result in which ocap binds in a simple chelate fashion. Somewhat unexpectedly, with dppp, binuclear complexes [Hg2{SC6H3XN(C≡N)}2(μ,κ1,κ1-dppp)] result in which two diphosphines bridge the Hg2 centre, while with dppf mononuclear chelates are proposed to result. Thus, the simple and high-yielding ring-opening of 2-aminobenzothiazole and substituted derivatives by mercuric acetate provides ready access to a range of novel ortho-cyano-aminothiophenolate complexes, being shown to be a highly versatile ligand that can adopt a number of different coordination modes. [ABSTRACT FROM AUTHOR]

• A multidonor amidophosphine ligand was prepared using an alternative route. • The ligand reacts with group 10 metal dichloride precursors to produce P,N,N-chelate complexes. • Spontaneous HCl elimination occurs during the complexation. • Terminal chloride ligand can be replaced for a phosphine. • The complexes were fully characterized and possess similar molecular structures. The multidonor amidophosphine 2-Ph 2 PC 6 H 4 NHC(O)C 5 H 4 N, where C 5 H 4 N is a 2-pyridyl substituent, reacted with the synthetic equivalents of group 10 metal dichlorides, viz. [NiCl 2 (dme)], [PdCl 2 (MeCN) 2 ] or [PtCl 2 (cod)] (dme = 1,2-dimethoxyethane, cod = cycloocta-1,5-diene), to produce neutral bis-chelate complexes [MCl(Ph 2 PC 6 H 4 NC(O)C 5 H 4 N-κ3 P,N,N ′)] (M = Ni, Pd, and Pt). During the complexation reaction, spontaneous HCl elimination occurred, possibly as the result of overall structural stabilization by the deprotonation of the amide nitrogen, which is brought toward the metal centers by initial P,N(pyridine)-coordination of the amidophosphine ligand. Subsequent reaction of 3 as the representative with AgClO 4 and triphenylphosphine produced the cationic bis(phosphine) complex [Pd(PPh 3)(Ph 2 PC 6 H 4 NC(O)C 5 H 4 N-κ3 P,N,N ′)]ClO 4 (5), which converted back to parent chloride complex in the presence of chloride ions. All complexes were fully characterized using NMR and IR spectroscopy, mass spectrometry, and elemental analysis. X-ray diffraction analysis for 2, 3, 4 ·½ CH 2 Cl 2 and 5 ·Me 2 CO revealed that compounds 2 – 4 exhibit similar coordination geometry, which is rather marginally affected upon replacement of the chloride for a bulkier phosphine ligand. [Display omitted] [ABSTRACT FROM AUTHOR]

The reaction of heterocyclic phosphine ligand, 1,3-di-p-tolyl-5-(5'-allyl-2'-ethoxybenzyl)-1,3-diaza-5-diazaphosphacyclohexane (L), containing a functional substituent at phosphorus, with (1,5-cyclooctadiene)dichloroplatinum(II) and nickel(II) chloride gave complexes PtCl2L2 (I) and NiCl2L2 (II), respectively, with the cis- and trans-configurations of the central ion. The structure of the complexes was determined by X-ray diffraction (CIF files CCDC no. 2097704 (I), 2097705 (II)). [ABSTRACT FROM AUTHOR]

The gas-phase molecular structure of iso-propyl(tert-butyl)(trichlorosilyl)phosphine has been determined using a combination of gas electron diffraction and computational methods. The structure presents a conformational challenge that required use of the SARACEN method to combine theoretical observations into the least-squares refinement process, a great advance on the techniques used to solve the structure of the parent trisilyl phosphine. Five conformers were found on the potential-energy surface for iso-propyl(tert-butyl)(trichlorosilyl)phosphine using the UCONGA program, and following a series of individual structure refinements a combined model with the two most abundant confirmers was evaluated. Key structural parameters (ra) include rP–Si [225.5(6) pm], rSi–Clmean [204.0(1) pm] and rP–Cmean [204.0(1) pm], ∠P–C–H 101.5(5)°, ∠C–C–C (iPr) 110.5(5)°, ∠C–C–C (tBu) 109.2(5)° and ∠C–P–C 105.4(5)°. [ABSTRACT FROM AUTHOR]

Crystal structure of pentacarbonyl-( 2-propane-1,3-dithiolato- 4S:S,S':S')-(diphenyl(o-tolyl)phosphine- 1P)diiron (Fe-Fe), C27H23Fe2O5PS2 The Fe1-Fe2 bond length [2.5085(4) Å] is slightly shorter than that of the diiron hexacarbonyl complex [Fe SB 2 sb (CO) SB 6 sb ( -SCH SB 2 sb CH SB 2 sb CH SB 2 sb S)] [2.5103(11) Å] [[10]], indicating that the phosphine ligand does not affect the Fe-Fe bond length. The position of the phosphine ligand is apical of the pseudo-octahedral geometry of the Fe2 atom, in accord with other analogues containing monosubstituted ligands [[9]]. [Extracted from the article]

Crystal structure of pentacarbonyl-( 2-propane-1,3-dithiolato- 4S:S,S':S')-(diphenyl(o-tolyl)phosphine- 1P)diiron (Fe-Fe), C27H23Fe2O5PS2 The Fe1-Fe2 bond length [2.5085(4) Å] is slightly shorter than that of the diiron hexacarbonyl complex [Fe SB 2 sb (CO) SB 6 sb ( -SCH SB 2 sb CH SB 2 sb CH SB 2 sb S)] [2.5103(11) Å] [[10]], indicating that the phosphine ligand does not affect the Fe-Fe bond length. The position of the phosphine ligand is apical of the pseudo-octahedral geometry of the Fe2 atom, in accord with other analogues containing monosubstituted ligands [[9]]. [Extracted from the article]

The reaction of [PtCl2(COD)] (COD=1,5‐cyclooctadiene) with diisopropyl‐2‐(3‐methyl)indolylphosphine (iPr2P(C9H8N)) led to the formation of the platinum(ii) chlorido complexes, cis‐[PtCl2{iPr2P(C9H8N)}2] (1) and trans‐[PtCl2{iPr2P(C9H8N)}2] (2). The cis‐complex 1 reacted with NEt3 yielding the complex cis‐[PtCl{κ2‐(P,N)‐iPr2P(C9H7N)}{iPr2P(C9H8N)}] (3) bearing a cyclometalated κ2‐(P,N)‐phosphine ligand, while the isomer 2 with a trans‐configuration did not show any reactivity towards NEt3. Treatment of 1 or 3 with (CH3)4NF (TMAF) resulted in the formation of the twofold cyclometalated complex cis‐[Pt{κ2‐(P,N)‐iPr2P(C9H7N)}2] (4). The molecular structures of the complexes 1–4 were determined by single‐crystal X‐ray diffraction. The fluorido complex cis‐[PtF{κ2‐(P,N)‐iPr2P(C9H7N)}{iPr2P(C9H8N)}] ⋅ (HF)4 (5 ⋅ (HF)4) was formed when complex 4 was treated with different hydrogen fluoride sources. The Pt(ii) fluorido complex 5 ⋅ (HF)4 exhibits intramolecular hydrogen bonding in its outer coordination sphere between the fluorido ligand and the NH group of the 3‐methylindolyl moiety. In contrast to its chlorido analogue 3, complex 5 ⋅ (HF)4 reacted with CO or the ynamide 1‐(2‐phenylethynyl)‐2‐pyrrolidinone to yield the complexes trans‐[Pt(CO){κ2‐(P,C)‐iPr2P(C9H7NCO)}{iPr2P(C9H8N)}][F(HF)4] (7) and a complex, which we suggest to be cis‐[Pt{C=C(Ph)OCN(C3H6)}{κ2‐(P,N)‐iPr2P(C9H7N)}{iPr2P(C9H8N)}][F(HF)4] (9), respectively. The structure of 9 was assigned on the basis of DFT calculations as well as NMR and IR data. Hydrogen bonding of HF and NH to fluoride was proven to be crucial for the existence of 7 and 9. [ABSTRACT FROM AUTHOR]

The reaction of the intramolecular germylene‐phosphine Lewis pair (o‐PPh2)C6H4GeAr* (1) with Group 15 element trichlorides ECl3 (E=P, As, Sb) was investigated. After oxidative addition, the resulting compounds (o‐PPh2)C6H4(Ar*)Ge(Cl)ECl2 (2: E=P, 3: E=As, 4: E=Sb) were reduced by using sodium metal or LiHBEt3. The molecular structures of the phosphine‐stabilized phosphinidene (o‐PPh2)C6H4(Ar*)Ge(Cl)P (5), arsinidene (o‐PPh2)C6H4(Ar*)Ge(Cl)As (6) and stibinidene (o‐PPh2)C6H4(Ar*)Ge(Cl)Sb (7) are presented; they feature a two‐coordinate low‐valent Group 15 element. After chloride abstraction, a cyclic germaphosphene [(o‐PPh2)C6H4(Ar*)GeP] [B(C6H3(CF3)2)4] (8) was isolated. The 31P NMR data of the germaphosphene were compared with literature examples and analyzed by quantum chemical calculations. The phosphinidene was treated with [iBu2AlH]2, and the product of an Al−H addition to the low‐valent phosphorus atom (o‐PPh2)C6H4(Ar*)Ge(H)P(H)Al(C4H9)2 (9) was characterized. [ABSTRACT FROM AUTHOR]

We present new insights into the ligand strength of the metalloid [Ge9(Hyp)3]− cluster (Hyp=Si(SiMe3)3) alongside novel neutral Ge9 clusters of the composition R3PAuGe9(Hyp)3 (R=Et, nPr, iPr, nBu, tBu, Cy). These clusters are synthesized in good yields from KGe9(Hyp)3 and R3PAuCl. Further experiments with these new clusters show that the ligand strength of [Ge9(Hyp)3]− is in between aryl and alkyl phosphines. [ABSTRACT FROM AUTHOR]

Three cyclopentadienylmolybdenum(II) propionyl complexes featuring triarylphosphine ligands with different para substituents, namely, dicarbonyl(η5-cyclopentadienyl)propionyl(triphenylphosphane-κP)molybdenum(II), [Mo(C5H5)(C3H5O)(C18H15P)(CO)2], (1), dicarbonyl(η5-cyclopentadienyl)propionyl[tris(4-fluorophenyl)phosphane-κP]molybdenum(II), [Mo(C5H5)(C3H5O)(C18H12F3P)(CO)2], (2), and dicarbonyl(η5-cyclopentadienyl)propionyl[tris(4-methoxyphenyl)phosphane-κP]molybdenum(II) dichloromethane solvate, [Mo(C5H5)(C3H5O)(C21H21O3P)(CO)2]·CH2Cl2, (3), have been prepared from the corresponding ethyl complexes via phosphine-induced migratory insertion. These complexes exhibit four-legged piano-stool geometries with molecular structures quite similar to each other and to related acetyl complexes. The extended structures of the three complexes differ somewhat, with the para substituent of the triarylphosphine of (2) (fluoro) or (3) (methoxy) engaging in non-classical C--H⋯F or C--H⋯O hydrogen-bonding interactions. The structure of (3) exhibits modest disorder in the position of one Cl atom of the dichloromethane solvent, which was modeled with two sites showing approximately equivalent occupancies [0.532(15) and 0.478(15)]. [ABSTRACT FROM AUTHOR]

Four novel phosphine-substituted ruthenium(ii) polypyridine complexes with nitrogen oxides-trans(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (trans-NO2), cis(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (cis-NO2), [Ru(trpy)(dppbz)(NO2)]PF6 (PP-NO2), and cis(P,NO)-[Ru(trpy)(Pqn)(NO)](PF6)3 (cis-NO)-were synthesised (trpy = 2,2':6',2''-terpyridine, Pqn = 8-(diphenylphosphanyl)quinoline, and dppbz = 1,2-bis(diphenylphosphanyl)benzene). The influence of the number and position of the phosphine group(s) on the electronic structure of these complexes was investigated using single-crystal X-ray structural analysis, UV-vis absorption spectroscopy, and electrochemical measurements. The substitution lability of the nitrogen oxide ligand of each complex is discussed in comparison with that of the corresponding acetonitrile complexes.

Four novel phosphine-substituted ruthenium(ii) polypyridine complexes with nitrogen oxides-trans(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (trans-NO2), cis(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (cis-NO2), [Ru(trpy)(dppbz)(NO2)]PF6 (PP-NO2), and cis(P,NO)-[Ru(trpy)(Pqn)(NO)](PF6)3 (cis-NO)-were synthesised (trpy = 2,2':6',2''-terpyridine, Pqn = 8-(diphenylphosphanyl)quinoline, and dppbz = 1,2-bis(diphenylphosphanyl)benzene). The influence of the number and position of the phosphine group(s) on the electronic structure of these complexes was investigated using single-crystal X-ray structural analysis, UV-vis absorption spectroscopy, and electrochemical measurements. The substitution lability of the nitrogen oxide ligand of each complex is discussed in comparison with that of the corresponding acetonitrile complexes.

A series of highly substituted 1,2‐azaborinines, including a phenylene‐bridged bis‐1,2‐azaborinine, was synthesized from the reaction of 1,2‐azaborete rhodium complexes with variously substituted alkynes. 1‐Rhoda‐3,2‐azaborole complexes, which are accessible by phosphine addition to the corresponding 1,2‐azaborete complexes, were also found to be suitable precursors for the synthesis of 1,2‐azaborinines and readily reacted with alkynyl‐substituted 1,2‐azaborinines to generate new regioisomers of bi‐1,2‐azaborinines, which feature directly connected aromatic rings. Their molecular structures, which can be viewed as boron‐nitrogen isosteres of biphenyls, show nearly perpendicular 1,2‐azaborinine rings. The new method using rhodacycles instead of 1,2‐azaborete complexes as precursors is shown to be more effective, allowing the synthesis of a wider range of 1,2‐azaborinines. [ABSTRACT FROM AUTHOR]

The highly selective palladium-catalyzed Negishi coupling of secondary alkylzinc reagents with heteroaryl halides is described. The development of a series of biarylphosphine ligands has led to the identification of an improved catalyst for the coupling of electron-deficient heterocyclic substrates. Preparation and characterization of oxidative addition complex (L)(Ar)PdBr provided insight into the unique reactivity of catalysts based on CPhos-type ligands in facilitating challenging reductive elimination processes.

During the past decade, the use of Au(I) complexes for the catalytic activation of C-C π-bonds has been investigated intensely. Over this time period, the development of homogeneous gold catalysis has been extraordinarily rapid and has yielded a host of mild and selective methods for the formation of carbon-carbon and carbon-heteroatom bonds. The facile formation of new bonds facilitated by gold naturally led to efforts toward rendering these transformations enantioselective. In this Account, we survey the development of catalysts and ligands for enantioselective gold catalysis by our research group as well as related work by others. We also discuss some of our strategies to address the challenges of enantioselective gold(I) catalysis. Early on, our work with enantioselective gold-catalyzed transformations focused on bis(phosphinegold) complexes derived from axially chiral scaffolds. Although these complexes were highly successful in some reactions like cyclopropanation, the careful choice of the weakly coordinating ligand (or counterion) was necessary to obtain high levels of enantioselectivity for the case of allene hydroamination. These counterion effects led us to use the anion itself as a source of chirality, which was successful in the case of allene hydroalkoxylation. In general, these tactics enhance the steric influence around the reactive gold center beyond the two-coordinate ligand environment. The use of binuclear complexes allowed us to use the second gold center and its associated ligand (or counterion) to exert a further steric influence. In a similar vein, we employed a chiral anion (in place of or in addition to a chiral ligand) to move the chiral information closer to the reactive center. In order to expand the scope of reactions amenable to enantioselective gold catalysis to cycloadditions and other carbocyclization processes, we also developed a new class of mononuclear phosphite and phosphoramidite ligands to supplement the previously widely utilized phosphines. However, we needed to judiciously design the steric environment to create "walls" that enclose the gold center. We also successfully applied these same considerations to the development of binuclear carbene ligands for gold. Finally, we describe the design of bifunctional urea-monophosphine ligands used in a gold-catalyzed three-component coupling.

A set of novel polydentate phosphanes featuring one, two and three formamidine substituents was prepared by the reaction of C‐trimethylsilyl N,N,N'‐trialkylformamidines with P(III) chlorides. Chloro‐ and dichlorophosphanes gave tertiary phosphanes. More sterically congested adamantyldichlorophosphane reacted only with the least sterically congested silylformamidine. With phosphorus trichloride, five‐membered heterocycles, namely 1,4,2‐diazaphosphol‐4‐ium chlorides were formed in most cases. A mechanism for the formation of diazaphospholes was proposed and corroborated by DFT calculations. A key chlorophosphane underwent 1,2‐phosphorus shift giving the corresponding carbene that readily cyclized into diazaphospholium salts. The key compounds were studied by X‐ray diffractometry. Analysis of molecular structures of 1,4,2‐diazaphosphol‐4‐ium chloride 13 c and 1H‐1,4,2‐diazaphosphole 14 c revealed that the N‐Cring bonds for the orthogonally oriented i‐propylamino groups are unusually short. Only in the case of N,N‐dimethyl‐N'‐isopropyltrimethylsilylformamidine, we managed to isolate trisphosphane, albeit in a low yield. [ABSTRACT FROM AUTHOR]

8 Hu, X. C., Sun, T. Q., Zheng, C. Y. Synthesis, crystal structures and magnetic properties of two iron (II) tris(pyridyl)phosphine selenides complexes. However, in the reported tris(2-pyridyl)phosphine selenide structure [[10]], all nitrogen atoms point in the same direction (towards Se), which can be related to the steric requirement bearing a methyl group at the 6-position of the pyridyl ring. The nitrogen atoms (N2, N3) are almost form a plane with P1 and C1, while the remaining nitrogen atom (N1) forms a plane with C1, P1 and Se1 (see the figure). [Extracted from the article]

The digold(I) complex [Au2Cl2(Cy2PCH2PCy2)] reacts with 4,4′‐diphenylene diboronic acid to form a triangular macrocyclic complex with twisted Au‐P‐C‐P‐Au groups at the three corners. The synthesis of the complex and its chemical oxidation produced [6]cycloparaphenylene ([6]CPP) in 59 % overall yield. [ABSTRACT FROM AUTHOR]

The gold(I) complexes [μ-LiPr(AuX)2] {X = Cl (1D), Br (2D), and I (3D); LiPr = 1,2-bis[bis(2-isopropylphenyl)phosphino]benzene} were synthesised to investigate the photoluminescence properties of dinuclear Au complexes comprising weak Au(I)–Au(I) bonds. Single crystals of the tetrahydrofuran (THF) adducts 1DOR, 2DOR, and 3DOR were obtained by recrystallisation of 1D, 2D, and 3D from a mixed solution of THF and n-hexane. These THF adducts afford orange emission, with peak wavelengths ranging from 597 to 630 nm, in the crystalline state at 293 K. Recrystallisation of 3D from a mixed solution of acetone and n-hexane afforded single crystals of the acetone adduct 3DGR, which exhibits blue-green emission at 293 K. No crystals of the acetone adduct were obtained from 1D and 2D. The emission spectra and lifetimes of 1DOR, 2DOR, 3DOR, and 3DGR measured in the temperature range 77–293 K indicate that emission from these complexes in the solid state is due to phosphorescence. Notably, although the molecular structure of 3D in the 3DOR crystal is near-similar to that of 3DGR, the phosphorescence spectrum of 3DOR differs markedly from that of 3DGR, with peak wavelengths at 597 and 506 nm, respectively. Theoretical studies revealed that (1) phosphorescence occurs via the electronic transition from the excited triplet state, which is mainly composed of halogen-to-metal–metal charge transfer and metal-centered transitions and (2) the T1-optimised structure of 3D in the 3DGR crystals differs markedly from that in 3DOR, and the differences in the phosphorescence colour observed between 3DGR and 3DOR are ascribed to the differences in their stabilised structures in the excited triplet state. [ABSTRACT FROM AUTHOR]

Substitution of carbonyl ligands of the hydrogenase model complex [Fe2(μ‐SeCH2CH(Me)CH2Se‐μ)(CO)6] (A), by 1,1′‐bis (diphenylphosphino)ferrocene (dppf), 1,2‐bis (diphenylphosphino)benzene (dppbz) or 1,2‐bis (diphenylphosphino)acetylene (dppac) is investigated. It is found that the reaction product depends on the diphosphine used. In the case of dppf, the product is an intramolecular bridged disubstituted complex [Fe2{μ‐SeCH2CH(Me)CH2Se‐μ}(CO)4{μ,κ1,κ1(P,P)‐dppf}] (1), while the dppac‐reaction produces an intermolecular bridged tetra‐iron model [Fe2{μ‐SeCH2CH(Me)CH2Se‐μ}(CO)5]2{μ,κ1,κ1(P,P)‐dppac} (2). However, the dppbz‐reaction gives [Fe2{μ‐SeCH2CH(Me)CH2Se‐μ}(CO)4{κ2(P,P)‐dppbz}] (3) in which the dppbz ligand is bonded to one Fe atom in a chelated manner. The newly prepared complexes (1–3) have been characterized by elemental analysis, IR, 1H‐, 13C{H}‐, 31P{H}‐, 77Se{H}‐NMR spectroscopy and X‐ray structure determination. The electrochemical behavior of 2 and 3, in absence and presence of acid, is described by cyclic voltammetric measurements in CH2Cl2. [ABSTRACT FROM AUTHOR]

New tripodal ligand, tris(2-carbamoylmethoxyphenyl)phosphine oxide, has been synthesized via the alkylation of tris(2-hydroxyphenyl)phosphine oxide with chloroacetamide. The ligand structure has been studied by means of IR and NMR (1H, 31P) spectroscopy as well as X-ray diffraction. [ABSTRACT FROM AUTHOR]

The reductive dehalogenation of a zwitterionic GeII species to make a zwitterionic GeI dimer with a 1,2‐dicationic core is reported herein. To the root of the stability of this compound, the molecular and electronic structures were comprehensively characterized and investigated using crystallographic, spectroscopic, and computational methods. It was determined that the Ge centers are attracted because they are both electron‐rich and positively charged. A comparison to the electronic structure in triphosphenium cations revealed varying degrees of covalent bonding and that this difference can be distinguished spectroscopically. [ABSTRACT FROM AUTHOR]

Graphical abstract Copper(I) complexes with a phenanthroline-phosphine set of ligands were synthesized and characterized. The DNA-binding study of the complexes against ct-DNA showed binding constant values that correspond to the intercalation mode of binding, with notable variations in K b due to the different phosphine ligands. The anticancer activities of complexes show the influence of the different phosphine ligands. The data suggested potential anticancer activities against prostate and breast cancers. Molecular docking studies were conducted, highlighting some of the structural-DNA interactions. Abstract Copper(I) complexes with a phenanthroline-phosphine set of ligands were synthesized by refluxing methanolic solutions of CuBr 2 with at least a four fold molar excess of the phosphine ligands, followed by the treatment of the formed {CuBr(PR 3) 3 complexes [R = phenyl (1a), 4-fluorophenyl (1b), cyclohexyl (1c) or 4-methoxyphenyl (1d)]} with 1 molar equivalent of 1,10-phenanthroline in DCM. The tris(4-methoxyphenyl)phosphine ligand afforded the complex [Cu(P[C 6 H 4 -4-OMe] 3) 2 (phen)]Br (2d), while the other phosphines produced complexes with the general formula CuBr(PR 3)(phen) [R = phenyl (2a), 4-fluorophenyl (2b) or cyclohexyl (2c)]. The new complexes were characterized by elemental analysis, 31P NMR spectroscopy and mass spectrometry. Additional confirmation of the structures of 1b , 2b , 2c and 2d were determined by single crystal X-ray diffraction. A DNA-binding study of the complexes 2a – 2d against ct-DNA showed binding constant values that correspond to the intercalation mode of binding. The notable variations in the binding constants of the complexes suggest some contribution from the phosphine ligands. The lipophilicity of the complexes was evaluated theoretically and the calculated log P value of complex 2d is positive and high, being in the same range of relatively easy membrane penetrating drugs. The calculated log P values of complexes 2a – 2c are negative, indicating a low membrane permeability. Complexes 2a – 2d were examined against four different cancer cell lines. The choice of the phosphine ligand appears to influence the copper(I)-phosphine anticancer activities against the different cancer cell lines. The data suggested that complexes 2a and 2d show potential anticancer activity against prostate and breast cancers. The four copper complexes were docked against four different proteins associated with prostate or breast cancers activities, highlighting some of the structural-DNA interactions. [ABSTRACT FROM AUTHOR]

Reactions of isocyanates with primary and secondary phosphines without solvent at room temperature afforded the corresponding phosphinecarboxamide (RN(H)COPR′2) in excellent yields. This reaction system is applicable for isothiocyanates. The compounds newly obtained were fully characterized using multielement NMR spectroscopy. In addition, the molecular structure of Cl(CH2)2N(H)COPPh2 was studied by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

Compounds of the generic formula [PhPL][OTf]2 with L = bipyridine (bipy) and 4,4′-di( tert-butyl)-2,2′-bipyridine (Bbipy) and [PhPL2][OTf]2 with L = 4-dimethylaminopyridine (dmap), tricyclohexyl-thiophosphine, and tricyclohexyl-selenophosphine have been prepared by the reaction of dichlorophenylphosphine with two equivalents of trimethylsilyl triflate and the respective ligand. The new complexes of the phenylphosphine dication with this variety of ligands expands the scope of coordination complexes involving phosphorus as an acceptor. [ABSTRACT FROM AUTHOR]

Syntheses and molecular structures of the heterometallic complexes of nickel cyclopentadienyl triphenylphosphine tellurophenolate with tungsten carbonyls ( II and III) (CIF files CCDC nos. 1559733 and 1559734, respectively) are described. [ABSTRACT FROM AUTHOR]