Synthesis and coordination chemistry of a photoswitchable bis(phosphine) ligand

A 1,2-dithienylethene compound bearing bis(phosphine) groups (1o) represents a new class of photoresponsive ligands where there are steric and electronic differences between two photogenerated isomers. The coordination chemistry of this ligand class is demonstrated by preparing a gold(I) complex (2o) and a phosphine selenide (3o).     

Synthesis and coordination chemistry of tetrabutyldithioimidodiphosphinates

Butyl substituted imidodithiophosphinates R₂P(S)NP (S)R′₂ (R=ⁿBuⁱBu^sBuR′=ⁿBuⁱBu^sBu) have been synthesised via an HBr elimination reaction between R₂P(S)NH₂ and R′₂P(S)Br The compounds were characterised spectroscopically Crystallographic and spectroscopic studies reveal ⁿBu₂P(S)NHP(S)ⁿBu₂ and ^sBu₂P(S)NHP(S)ⁱBu₂ to be hydrogen bonded transoid dimers and ⁱBu₂P(S)NHP(S)ⁱBu₂ to be a transoid hydrogen bonded chain Reactions of the imidodithiophosphinates with ZnCl₂ or MCl₂COD gave the coordination complexes M[R₂P(S)NP (S)R′₂]₂ (R=ⁿBuⁱBu^sBuR′=ⁿBuⁱBu^sBuM=ZnPd: R=ⁿBuⁱBu^sBuPt).     

Expanding the utility of proteins as platforms for coordination chemistry

Whether for constructing advanced materials and complex biological devices or for building sophisticated coordination complexes with diverse metal-based functions, proteins are nature's favorite building blocks. Yet, our ability to control the assembly of proteins or to use them as ligand platforms for inorganic chemistry has been somewhat limited. In this review, we highlight our work from the past four years, which has aimed to exploit the utility of a protein scaffold in both regards. First, by considering proteins as “simple” ligand platforms and controlling the metal coordination chemistry on their surfaces, we show how their self-assembly can be readily dictated by metal binding. Second, we show how metal-mediated protein self-assembly leads to novel metal centers buried within protein interfaces. While on one hand our studies have pointed out the challenges of using proteins as ligands, they have also revealed how the extensive, chemically-rich protein surfaces can be exploited to form a network of covalent and non-covalent interactions around interfacial metal centers, providing a powerful handle to control their coordination chemistry.     

Extraction and coordination behavior of diphenyl hydrogen phosphine oxide towards actinides

Extraction behavior of some selected actinides like U(VI), Th(IV), and Am(III) was investigated with three different H-phosphine oxides, viz. diphenyl hydrogen phosphine oxide (DPhPO), dihexyl hydrogen phosphine oxide (DHePO) and diphenyl phosphite (DPP). The H-phosphine oxides exhibited a dual nature towards the extraction of actinides where the ligand not only extracts the metals by cation exchange but also by coordination with the phosphoryl group at lower and higher acidic concentrations, respectively. Among all ligands employed, DPhPO showed highest extraction with actinides with a substituent dependent trend as follows: DPhPO > DHePO > DPP. This trend emphasizes the importance of substituents around the phosphine oxide towards their extraction of actinides. The coordination behavior of DPhPO was studied by investigating its corresponding complexes with Th(NO₃)₄ and UO₂(NO₃)₂. The metal complexes of these actinides were characterized using FT-IR, ¹H and ³¹P NMR spectroscopic techniques. Density Functional Theory (DFT) calculations were also performed to understand the electronic and geometric structure of the ligand and the corresponding metal complexes.     

Synthesis and coordination chemistry of tri-substituted benzamidrazones

A series of N(1),N(1),N(3)-tri-substituted benzamidrazones of the general formula [PhC(NHR)=NNMe(2)] (R = Me, n-Pr, i-Pr, n-Bu, Bn, Ph; 1a-f) was synthesized via condensation of 1,1-dimethylhydrazine with the corresponding imidoyl chloride, [PhC(Cl)=NR]. Multinuclear NMR data, and zero-point energy DFT calculations conducted with the B3LYP functional and 6-31G+(d,p) basis set, suggest that these compounds exist as a single tautomer in solution; possessing a weak intramolecular hydrogen bond and a structure dominated by the localised resonance structure ArC(NHR)=N-NMe(2). An X-ray crystallographic study upon PhC(NHPh)=NNMe(2) (1f) demonstrated that this compound adopts an identical tautomer in the solid state. Reactions of [PhC(NHMe)=NNMe(2)] (1a) with [LMCl(2)](2) (M = Ru, L = cymene; M = Rh, Ir, L = Cp*) results in the stoichiometric formation of products of the formula [LM{PhC(=NMe)NHNMe(2)}Cl](+)Cl(-) (2a-c) in which the amidrazone chelates the metal in a κ(2)-N(1),N(3)-coordination mode. Formation of this five-membered chelate occurs with a concomitant tautomerisation of the amidrazone ligand to an alternative tautomer, i.e. [PhC(=NMe)NHNMe(2)], the latter tautomer is expected to be readily energetically accessible based upon the aforementioned DFT calculations. This series of salts may be deprotonated with lithium hexamethyldisilazide to form the corresponding charge neutral complexes [LM{PhC(NMe)=NNMe(2)}] (3a-c). In contrast, the reaction of N(1),N(1),N(3)-tri-substituted benzamidrazones with [(cymene)RuCl(2)](2) in the presence of NaOAc yielded a mixture of cyclometallation (C-H activation) and amidrazone chelation/deprotonation (N-H activation) products. Reaction of 1a yielded an inseparable mixture of products, whilst the reaction of 1c resulted in formation of the cyclometallated product [LM{C(6)H(5)C(=N(i)Pr)NHNMe(2)}] (L = cymene, M = Ru; 4a) in a modest 62% yield. This latter complex could be isolated as a crystalline orange solid, full characterisation including single crystal X-ray diffraction demonstrated that the amidrazone coordinates in a κ(2)-N(2),C-coordination mode.     

Asymmetric synthesis of cyclopropanes and dihydrofurans based on phosphine oxide chemistry

The asymmetric synthesis of gamma-azido trans-cyclopropyl ketones is accomplished via a short, simple and efficient sequence. The cyclopropanation step is achieved by an intramolecular nucleophilic ring closure, with a diphenylphosphinate leaving group, to give trans-cyclopropane exclusively. beta-Keto-diphenylphosphine oxides cyclise to form optically active dihydrofurans. All possible diastereoisomers of dihydrofurans can be prepared selectively starting from the same olefin.     

A novel heterobidentate chiral phosphine and its coordination chemistry in transition metal clusters

The optically active ligand R,R-PHAZAN (1,3-bis[(1R)-1-Phenylethyl]-2-(2-thienyl)-1,3,2-diazaphospholane) has been prepared and the products resulting from the reactions with Rh₆(CO)₁₅NCMe, H₃RhOs₃(CO)₁₂, and H₄Ru₄(CO)₁₂ have been investigated by X-ray crystallography and a variety of multinuclear NMR methods. X-ray studies show that PHAZAN can behave as a bidentate ligand in Rh₆(CO)₁₄(μ₂,κ²-R,R-PHAZAN) (with coordination through P and S) or a monodentate ligand (through P coordination) in H₄Ru₄(CO)₁₁(κ¹-R,R-PHAZAN) and NMR studies show that these structures are retained in solution. In Rh₆(CO)₁₄(μ₂,κ²-R,R-PHAZAN), edge-bridging coordination of PHAZAN results in the formation of an additional two novel chiral centres and these are observed in solution. Reaction of PHAZAN with H₃RhOs₃(CO)₁₂ results in cleavage of the thienyl group and formation of the phosphido cluster, H₂RhOs₃(CO)₁₁(μ₂-PNN), (PNN = 1,3-bis-(1-phenylethyl)-[1,3,2]diazaphospholidine-2-yl). A variety of NMR measurements show that the hydride site-occupancies in the solid state are retained in solution and there is evidence for interaction of an ortho-phenyl hydrogen and a hydride through “dihydrogen” bonding.     

Synthesis and coordination chemistry of perfluoroalkylated dithiophosphate ligands

Dithiophosphoric acids [HS₂P(OC₂H₄C_nF_2n+1)₂] (n = 4, 6) have been prepared in high yields. Deprotonation and reaction with transition metal substrates affords fluorous metal complexes which have been characterised by elemental analysis, mass spectrometry, IR and NMR spectroscopies. The structures of [Cu{S₂P(OC₂H₄C_nF_2n+1)₂}(PPh₃)₂] (n = 4, 6) and [Cu{-S₂P(OC₂H₄C₄F₉)₂}(PPh₃)]₂ have been determined by single crystal X-ray diffraction.     

Synthesis and coordination chemistry of fluorinated xanthate ligands

Alkali metal, copper, nickel and rhodium complexes of alkylated [S₂COC₈H₁₇] and fluoroalkylated xanthate ligands [S₂COC_mH_2mC_nF_2n+1] (m = 2, n = 4, 6; m = 3, n = 1, 8) have been prepared in high yields and characterised by elemental analysis, mass spectrometry, IR and NMR spectroscopies. The structures of [Cu(S₂COC₈H₁₇)(PPh₃)₂], [Cu(S₂COC₃H₆CF₃)(PPh₃)₂], [Ni(S₂COC₃H₆CF₃)₂], [Cp^*RhCl(S₂COC₈H₁₇)] and [Cp^*RhCl(S₂COC₃H₆CF₃)] have been determined by single crystal X-ray diffraction.     

Synthesis and coordination chemistry of fluorinated phosphonic acids

Phosphonic acids [(HO)₂P(O)C₂H₄C_nF_2n+1] (n = 4, 6) and [(HO)₂P(O)C₆H₄-4-C_nF_2n+1] (n = 0, 1, 6) have been prepared in good yields. Deprotonation and reaction with cis-[PtCl₂(PPh₃)₂] affords fluorinated platinum complexes which have been characterised by elemental analysis, mass spectrometry, IR and NMR spectroscopies. The structures of [Pt{O₂P(O)C₆H₄-4-F}(PPh₃)₂], [Pt{O₂P(O)C₆H₄-4-CF₃}(PPh₃)₂] and [Pt{O₂P(O)C₂H₄C₆F₁₃}(PPh₃)₂] have been determined by single crystal X-ray diffraction.     

Synthesis and coordination chemistry of perfluoroalkyl-derivatised β-diketonates

A series of fluorinated β-diketones, R_fC(O)CH₂C(O)R_f′ (R_f=C₆F₁₃, R_f′=CF₃; R_f=R_f′=C₆F₁₃, C₇F₁₅), have been prepared in reasonable yields by a two-step synthesis. On reaction with appropriate metal substrates, deprotonation and concurrent coordination of the perfluoroalkyl-derivatised β-diketonate ligands affords a range of fluorous metal complexes which have been characterised by elemental analysis, mass spectrometry, IR and NMR spectroscopies. The structures of [Cu(L-L)₂(H₂O)₂] {L-L=CF₃C(O)CHC(O)C₆F₁₃, C₆F₁₃C(O)CHC(O)C₆F₁₃} and [Cu(PPh₃)₂{C₇F₁₅C(O)CHC(O)C₇F₁₅}] have been determined by single-crystal X-ray diffraction.     

Synthesis and coordination chemistry of ferrocenyl-1,2,3-triazolyl ligands

"Click" reactions between ethynylferrocene and mono-, bis-, and tris-azido aromatic derivatives yielded mono-, bis-, and tris-1,2,3-ferrocenyltriazoles (1, 2, and 3, respectively) as orange crystals. The X-ray crystal structure of the monoferrocenyltriazole compound 1 was solved with two nearly identical molecules within the asymmetric unit. In both molecules, the two Cp rings make a tilt angle of 2.1(3) degrees [0.7(3) degrees], and they are roughly eclipsed with a twist angle of 2.4(3) degrees [1.8(3) degrees]. Reaction of 1 with [PdCl2(PhCN)2] in dimethylsulfoxide (DMSO) yielded orange crystals of [PdCl2L2] (4; L=1), for which the X-ray crystal structure shows trans coordination to the nitrogen atom close to the ferrocene substitution. The Pd atom is located on an inversion center and displays a nearly perfect square planar environment. In DMSO-d6, 4 reversibly dissociates to regenerate 1, whose (1)H NMR spectrum is then observed. The 1H NMR study also shows that progressive addition of PdCl2 or [PdCl2(NCR)2] (R=Me or Ph) to DMSO-d6 solutions of 1 reversibly leads to the formation of 4 and the addition of excess PdII is necessary to lead to the complete disappearance of the signals of 1. The cyclic voltammograms of 1, 2, and 3 show the reversible oxidation wave of the ferrocenyl group, and that of 4 shows that this wave appears with increased intensity tentatively attributable to redox-catalyzed oxidation.     

Synthesis, solid state structure and spectro-electrochemistry of ferrocene-ethynyl phosphine and phosphine oxide transition metal complexes

The synthesis of ferrocene-ethynyl phosphine platinum dichloride complexes based on (FcCC)_nPh_3−nP (1a, n = 1; 1b, n = 2; 1c, n = 3; Fc = ferrocenyl, (η⁵-C₅H₅)(η⁵-C₅H₄)Fe) is described. Air-oxidation of 1c afforded (FcCC)₃PO (6). Treatment of 1a-1c with [(PhCN)₂PtCl₂] (2) or [(tht)AuCl] (tht = tetrahydrothiophene) (7), respectively, gave the heterometallic transition complexes cis-[((FcCC)_nPh_3−nP)₂PtCl₂] (3a, n = 1; 3b, n = 2; 3c, n = 3) or [((FcCC)_nPPh_3−n)AuCl] (8a, n = 1; 8b, n = 2). Further treatment of these molecules with HCCMc (4a, Mc = Fc; 4b, Mc = Rc = (η⁵-C₅H₅)(η⁵-C₅H₄)Ru) in the presence of [CuI] produced trans-[((FcCC)Ph₂P)₂Pt(CCFc)₂] (5) (reaction of 3a with 4a) and [(FcCC)_nPh_3−nPAuCCMc] (n = 1: 9a, Mc = Fc; 9b, Mc = Rc; n = 2: 11a, Mc = Fc; 11b, Mc = Rc) (reaction of 4a, 4b with 8a, 8b), respectively.The structures of 3a, 5, 6, 8, 9a, and 9b in the solid state were established by single-crystal X-ray structure analysis. The main characteristic features of these molecules are the linear phosphorus-gold-acetylide arrangements, the tetra-coordination at phosphorus and the square-planar surrounding at platinum.The electrochemical and spectro-electrochemical behavior of complexes 5, 8a, 9a, 9b and [(Ph₃P)AuCCFc] was investigated in the UV/Vis/NIR. Near IR bands that are likely associated with charge transfer from the ((FcCC)Ph₂P)₂Pt or the ((FcCC)_nPh_3−nP)Au (n = 0, 1) moieties appear upon oxidation of the σ-bonded ferrocene-ethynyl groups. These bands undergo a (stepwise) blue shift as ferrocene-ethynyl substituents on the phosphine coligands are oxidized.     

Synthesis and coordination chemistry of 1-cymantrenyl-2,3,4,5-tetraphenylborole

In this contribution, we report the synthesis of base-free 1-cymantrenyl-2,3,4,5-tetraphenylborole and two of its Lewis base adducts. In addition, the structural characterization and investigation of the photophysical properties are provided.     

Synthesis of precursors to new tripodal phosphine oxide ligands

Russian Journal of General Chemistry - A number of precursors of new tripodal ligands was obtained by hydroxyethylation of the starting tris(2-hydroxyphenyl)phosphine oxide, followed by conversion...     

Synthesis of dibenzofuran derivatives

Summary In the reaction of p-benzoquinone with 1-morpholinocyclohexene-1 and subsequent acid hydrolysis of the addition product, 2-hydroxy-6,7,8,9-tetrahydrodibenzofuran is formed, in a total yield of 67%.During the preparation of this work for print, this method of synthesis was published by Domschke [G. Domschke, Z. Chem., 4 (I), 26 (1964)] in the form of a Brief Communication, without experimental section.In conclusion, let us express our gratitude to G. A. Kogan for taking the ultraviolet spectra.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya No. 11, pp. 2086–2087, November, 1964     

Preparation and coordination chemistry of N-diallylaminodiphenylphosphine and N-allylaminobis(diphenyl)phosphine

N-diallylaminodiphenylphosphine and N-allylaminobis(diphenyl)phosphine have been prepared by reaction of the appropriate amine with Ph₂PCl. The coordination chemistry of these phosphines has been studied with a range of metals [Pd, Pt, Rh, Ir, Au, Ru, Mo]. Whilst the majority of the complexes are simple bidentate P,P donors, in the case of N-diallylaminodiphenylphosphinecoordination can involve the CC group or the nitrogen centre.     

基于溶液配位化学过程调控的中空单晶氧化铁纳米材料

本文简要综述了本课题组近年来在单晶氧化铁空心纳米结构制备与生长机理研究方面的相关工作.通过采用磷酸根与硫酸根的双阴离子调节,结合反应时间、反应温度等条件的改变,实现了对α-Fe2O3单晶空心纳米结构形貌、尺寸和表面结构的良好调控,并提出一种针对非层状结构纳米环/纳米管新颖生长机理,即"配位辅助的定向溶解机理".以所制备的α-Fe2O3为前驱体,采用气相还原方法,成功制备得到了系列单晶Fe3O4和γ-Fe2O3管状及环状纳米结构,并对单个Fe3O4纳米环的磁学行为进行了考察.     

Novel phosphine ligands bearing 3(5)-pyrazolyl and 4-(2-amino)pyrimidinyl groups: Synthesis and coordination chemistry

Novel triphenyl phosphine ligands bearing pyrazole or 2-aminopyrimidine groups in the ortho or meta position of one or three of the phenyl rings were obtained starting from the corresponding acyl derivatives Ph₂P(o-C₆H₄-COCH₃), Ph₂P(m-C₆H₄-COCH₃), or P(m-C₆H₄-COCH₃)₃. Conversion of the acyl groups into 3-dimethylamino-2-propen-1-onyl units was achieved by reaction with HC(OMe)₂NMe₂ which underwent ring closing with hydrazine or guanidine to yield the desired heterocycles. Two palladium complexes were synthesized using the coordinatively labile precursor (PhCN)₂PdCl₂, one of them could be characterized by X-ray structure analysis.