Joel T. Mague

New tetraphosphane ligands {(X2P)2NC6H4N(PX2)2} (X = Cl, F,OMe, OC6H4OMe-o): synthesis, derivatization, group 10 and 11 metal complexes and catalytic investigations. DFT calculations on intermolecular P...P interactions in halo-phosphines.

The reaction of p-phenylenediamine with excess PCl 3 in the presence of pyridine affords p-C 6H 4[N(PCl 2) 2] 2 ( 1) in good yield. Fluorination of 1 with SbF 3 produces p-C 6H 4[N(PF 2) 2] 2 ( 2). The aminotetra(phosphonites) p-C 6H 4[N{P(OC 6H 4OMe- o) 2} 2] 2 ( 3) and p-C 6H 4[N{P(OMe) 2} 2] 2 ( 4) have been prepared by reacting 1 with appropriate amount of 2-(methoxy)phenol or methanol, respectively, in the presence of triethylamine. The reactions of 3 and 4 with H 2O 2, elemental sulfur, or selenium afforded the tetrachalcogenides, p-C 6H 4[N{P(O)(OC 6H 4OMe- o) 2} 2] 2 ( 5), p-C 6H 4[N{P(S)(OMe) 2} 2] 2 ( 6), and p-C 6H 4[N{P(Se)(OMe) 2} 2] 2 ( 7) in good yield. Reactions of 3 with [M(COD)Cl 2] (M = Pd or Pt) (COD = cycloocta-1,5-diene) resulted in the formation of the chelate complexes, [M 2Cl 4- p-C 6H 4{N{P(OC 6H 4OMe- o) 2} 2} 2] ( 8, M = Pd and 9, M = Pt). The reactions of 3 with 4 equiv of CuX (X = Br and I) produce the tetranuclear complexes, [Cu 4(mu 2-X) 4(NCCH 3) 4- p-C 6H 4{N(P(OC 6H 4OMe- o) 2) 2} 2] ( 10, X = Br; 11, X = I). The molecular structures of 1- 3, 6, 7, and 9- 11 are confirmed by single-crystal X-ray diffraction studies. The weak intermolecular P...P interactions observed in 1 leads to the formation of a 2D sheetlike structure, which is also examined by DFT calculations. The catalytic activity of the Pd(II) 8 has been investigated in Suzuki-Miyaura cross-coupling reactions.

Solvent extraction of divalent palladium and platinum from aqueous solutions of their chloro complexes using an N,N-dimethyldithiocarbamoylethoxy substituted calix[4]arene☆

Abstract The compound 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra-(2-bromoethoxy)calix[4]arene has been prepared by first converting 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra-(2-hydroxyethoxy)calix[4]arene into the tosylate, and then to the product by reaction with LiBr. The compound crystallizes in the trigonal space group P3 2 21 with a = 13.160(2), c = 25.595(6) A , a = 90.00(2), β = 90.00(1), γ = 120.000(9) 0 , Z = 3, ϱ calc = 1.40 g cm −3 . The final R value for 2391 unique reflections was 0.061. The compound reacts with excess sodium N , N -dimethyldithiocarbamate to give 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra-(2- N , N -dimethyldithiocarbamoylethoxy)calix[4]arene. This compound is an effective extractant for transferring palladium(II) from an aqueous to a chloroform phase. No extraction of PtCl 4 2− is observed under thermal conditions. Under photochemical conditions using a mixture of PtCl 4 2− and PtCl 6 2− , extraction of platinum into the chloroform layer is observed. An explanation for this observation is given.

“Short-bite” ligands in cluster synthesis

The “short-bite” ligands CH2(PR2)2 or CH(PR2)3 (R = Me, Ph),RN(PX2)2 (R=H, Me, Et;X = F, OR′ (R′= Me, Et, i-Pr, Ph), Ph),RE(CH2ER2)2 (E = P, As;R = Me, Ph ), Ph2 P(2-C5H4N) and related species are particularly versatile for the synthesis of di- and polynuclear complexes which frequently possess metal-metal bonds. In addition to homometallic products, these ligands often permit the directed synthesis of heterometallic complexes. Selected aspects of the chemistry of these complexes are also reviewed.

First examples of methylene insertion into the phosphorus(III)–nitrogen bond

Abstract The reaction of N-substituted phosphinous amides with paraformaldehyde leads to methylene insertion into the P–N bond, followed by the oxidation of phosphorus from P(III) to P(V) state. The product, Ph2P(O)CH2NHPh was characterised by a single-crystal X-ray diffraction study. The reaction not only depends on the acidic proton on the nitrogen, but also on the oxidation state of phosphorus and it is considered to proceed through Staudinger–Wittig pathway.

Bis(2-diphenylphosphinoxynaphthalen-1-yl)methane: transition metal chemistry, Suzuki cross-coupling reactions and homogeneous hydrogenation of olefins

Transition metal complexes of bis(2-diphenylphosphinoxynaphthalen-1-yl)methane (1) are described. Bis(phosphinite) 1 reacts with Group 6 metal carbonyls, [Rh(CO)2Cl]2, anhydrous NiCl2, [Pd(C3H5)Cl]2/AgBF4 and Pt(COD)I2 to give the corresponding 10-membered chelate complexes 2, 3 and 5-8. Reaction of 1 with [Rh(COD)Cl]2 in the presence of AgBF4 affords a cationic complex, [Rh(COD){Ph2P(-OC10H6)(mu-CH2)(C10H6O-)PPh2-kappaP,kappaP}]BF4 (4). Treatment of 1 with AuCl(SMe2) gives mononuclear chelate complex, [(AuCl){Ph2P(-OC10H6)(mu-CH2)(C10H6O-)PPh2-kappaP,kappaP}] (9) as well as a binuclear complex, [Au(Cl){mu-Ph2P(-OC10H6)(mu-CH2)(C10H6O-)PPh2-kappaP,kappaP}AuCl] (10) with ligand 1 exhibiting both chelating and bridged bidentate modes of coordination respectively. The molecular structures of 2, 6, 7, 9 and 10 are determined by X-ray studies. The mixture of Pd(OAc)2 and effectively catalyzes Suzuki cross-coupling reactions of a range of aryl halides with aryl boronic acid in MeOH at room temperature or at 60 degrees C, giving generally high yields even under low catalytic loads. The cationic rhodium(I) complex, [Rh(COD){Ph2P(-OC10H6)(mu-CH2)(C10H6O-)PPh2-kappaP,kappaP}]BF4 (4) catalyzes the hydrogenation of styrenes to afford the corresponding alkyl benzenes in THF at room temperature or at 70 degrees C with excellent turnover frequencies.

Complexes of the tripod ligand, tris(diphenylphosphino)methane

Abstract Tris(diphenylphosphino)methane (TPM) is shown to exhibit a variety of coordination modes. In [Fe(CO) 4 (TPM)], [Mo(CO) 5 (TPM)] it is monodentate while in [Fe(CO) 3 (TPM)] and cis -[Mo(CO) 4 (TPM)], two of the three phosphorus atoms chelate to the metal. The uncoordinated arms of TPM in the mono- and bidentate complexes can coordinate other metals to give the homo- and heterobimetallic complexes [(OC) 4 Fe(μ-TPM)Fe(CO) 3 ], ((OC) 4 Fe(μ-TPM)Mo(CO) 4 and trans -[RhCl(CO)( cis -Mo(CO) 4 (TPM)) 2 ]. In the last, an unusual virtually-coupled 31 P NMR spectrum is seen. With [RCCo 3 (CO) 9 ] (R = H, Cl) under mild conditions is formed [RCCo 3 (CO) 7 (TPM)] in which the ligand functions in a bidentate, bridging fashion while under more strenuous conditions the ligand-capped clusters [RCCo 3 (CO) 6 (TPM)] form.

Synthesis and structural characterization of non-planar perfluoro phthalonitriles

Abstract Perfluoropropene reacts with 1,2-dicyano-3,4,5,6-tetrafluorobenzene to give the first perfluoroalkyl substituted phthalonitriles. The X-ray structures of the bis- and tris-substituted products reveal planar, undistorted rings and head-to-head and head-to-tail preferred conformations for the isopropyl substituents, respectively. As a result, the CF3 groups impart global non-planar character to the new molecules.

Resorcinol Based Acyclic Dimeric and Cyclic Di- and Tetrameric Cyclodiphosphazanes: Synthesis, Structural Studies, and Transition Metal Complexes

The condensation reaction of resorcinol with cis-[ClP(μ-N(t)Bu)(2)PN(H)(t)Bu] produced a difunctional derivative 1,3-C(6)H(4)[OP(μ-N(t)Bu)(2)PN(H)(t)Bu](2) (1), whereas the similar reaction with [ClP(μ-N(t)Bu)](2) resulted in the formation of a 1:1 mixture of dimeric and tetrameric species, [{P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](2) (2a) and [{P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](4) (2b), which were separated by repeated fractional crystallization and column chromatography. The reaction of dimer 2a with H(2)O(2) and selenium produces tetrachalcogenides [{(O)P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](2) (3) and [{(Se)P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](2) (4), respectively. The reaction between the dimer (2a) and [Pd(μ-Cl)(η(3)-C(3)H(5))](2) or AuCl(SMe(2)) yielded the corresponding tetranuclear complexes, [{((Cl)(η(3)-C(3)H(5))Pd)P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](2) (5) and [{(ClAu)P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](2) (6) in good yield. The complexes 5 and 6 are the rare examples of phosphorus macrocycles containing two or more exocyclic transition metal fragments. Treatment of 1 with copper halides in 1:1 molar ratio resulted in the formation of one-dimensional (1D) coordination polymers, [(CuX){1,3-C(6)H(4){OP(μ-N(t)Bu)(2)PN(H)(t)Bu}}(2)](n) (7, X = Cl; 8, X = Br; 9, X = I), which showed the helical structure in solid state because of intramolecular hydrogen bonding, whereas similar reactions of 1 with 4 equiv of copper halides also produced 1D-coordination polymers, [(Cu(2)X(2))(2){1,3-C(6)H(4){OP(μ-N(t)Bu)(2)PN(H)(t)Bu}(2)}](n) (10, X = Cl; 11, X = Br; 12, X = I), but containing Cu(2)X(2) rhomboids instead of CuX linkers. The crystal structures of 1, 2a, 2b, 4, 7-9, and 12 were established by X-ray diffraction studies.

Synthesis of the β-1,3-glucan, laminarahexaose: NMR and conformational studies

The synthesis of laminarahexaose is described. NMR studies of several of the intermediates leading to the beta-1,3-glucan show anomalously small coupling constants for some of the C-1 hydrogens. An X-ray structure for the protected hexasaccharide shows that the small coupling constants are due to some of the glucopyranose rings adopting a twist-boat conformation. The X-ray studies also explain other unexpected NMR observations.

An Acyclic Dimer of Cyclodiphosphazane {tBuHN(tBuNP)2OCH2}2 Containing Alkoxo and Amido Functionalities: Synthesis, Derivatization, Bi- (PdII, RhI), and Tetranuclear (PdII, AuI, RhIAuI) Transition Metal Complexes

Acyclic bis(cyclodiphosphazane) [(t)BuHN((t)BuNP)(2)OCH(2)](2) (2) containing alkoxo and amido functionalities was synthesized by reacting cis-[(t)BuHN((t)BuNP)(2)Cl] (1) with ethylene glycol and upon further treatment with 4 equiv of elemental sulfur or selenium affords the corresponding tetrachalcogenides [(t)BuHN((t)BuNPE)(2)OCH(2)](2) (3, E = S; 4, E = Se) in quantitative yield. The reaction of 2 with 2 equiv of elemental sulfur results in the oxidation of only the amido-phosphorus atoms to form the di(sulfide) derivative [(t)BuHN(S)P(mu-(t)BuN)POCH(2)](2) (5). The reaction of 2 with 2 equiv of [PdCl(eta(3)-C(3)H(5))](2) afforded the tetrametallic complex [{Pd(eta(3)-allyl)Cl}(4){(t)BuHN((t)BuNP)(2)OCH(2)}(2)] (7) containing four independent [PdCl(2)(eta(3)-C(3)H(5))] moieties each coordinated to a phosphorus atom. In contrast, the reaction between [Pd(PEt(3))Cl(2)](2) and 2 leads to the addition of two metal atoms with the formation of [{Pd(PEt(3))Cl}(2){(t)BuHN((t)BuNP)(2)OCH(2)}(2)] (8), in which alternating phosphorus atoms of the bis(cyclodiphosphazane) are coordinated to palladium. Interestingly, the palladium(II) atom coordinated to the phosphorus atom bearing the t-butylamino substituent adopts a trans geometry, whereas that coordinated to the phosphorus atom connected to the -OCH(2)CH(2)O- linker prefers a cis conformation. The reaction between 2 and [Rh(COD)Cl](2) produces exclusively the bimetallic complex [{Rh(COD)Cl}(2){(t)BuHN((t)BuNP)(2)OCH(2)}(2)] (6) irrespective of the stoichiometry of the reactants and the reaction conditions. In complex 6, only the alkoxo-phosphorus atoms are coordinated. However, complex 6 upon treatment with AuCl(SMe(2)) in a 1:2 ratio gives the heterometallic tetrasubstituted complex [{Rh(COD)Cl}(2)(AuCl)(2){(t)BuHN((t)BuNP)(2)OCH(2)}(2)] (10). The reaction between 4 equiv of AuCl(SMe(2)) and 2 resulted in the formation of a tetrametallic gold complex [(AuCl)(4){(t)BuHN((t)BuNP)(2)OCH(2)}(2)] (9). The crystal structures of 2-4 and 7-10 are reported.