Alkali Metal & Alkaline-Earth Metal Complexes of Various Amidophosphines having P, N, Chalcogen and Borane as Donor atoms/group – Syntheses, Structures and Ring-Opening Polymerization of Caprolactone

During the last decade, heavy alkaline-earth organometallic chemistry has emerged from obscurity to becoming a vibrant area of research, owing to a number of synthetic pathways that provide reliable access to these highly reactive target compounds. The complexes of heavy alkaline-earth metals were employed in various catalytic applications such as ring-opening polymerization of various cyclic esters, polymerization of styrene and dienes, and hydroamination and hydrophosphination reactions of alkenes and alkynes. Particularly, Group 2 metal complexes have been received considerable attention as initiators for the ROP of cyclic esters and some of them have demonstrated impressive results. Aliphatic polyesters are currently considered as alternatives to synthetic petrochemical-based polymers. Their biodegradable and biocompatible nature along with their mechanical and physical properties make them prospective thermoplastics with broad commercial applications such as single-use packaging materials, medical sutures and drug delivery systems. Ring-opening polymerization (ROP) of cyclic esters promoted by alkaline-earth & rare-earth metal initiators proved to be the most efficient way for preparing polyesters with controlled molecular weight and microstructure and narrow molecular-weight distribution. Therefore, the design and synthesis of new well-defined single-site catalysts that exhibits good activity, productivity and selectivity for cyclic ester polymerization is needed

Synthesis of monomeric and polymeric alkali and alkaline earth metal complexes using a phosphinoselenoic amide ligand in metal coordination sphere

We report the monomeric complexes of magnesium and calcium of composition [M(THF)n{η 2-Ph2P(Se)N(CMe3)}2] [M = Mg (3), n = 1 and M = Ca (4), n = 2)] and polymeric complexes of potassium and barium of composition [K(THF)2{Ph2P(Se)N(CMe3)}]n (2) and [K(THF)Ba{Ph2P(Se)N(CMe3)}3]n(5) respectively. The potassium complex 2 was readily prepared by the reaction of potassium bis(trimethylsilyl)amide with phosphinoselenoic amide ligand (1) at ambient temperature. The calcium complex 4 was prepared by two synthetic routes: in the first method, commonly known as salt metathesis reaction, the potassium complex 2 was made to react with alkaline earth metal diiodide at room temperature to afford the corresponding calcium complex. The metal bis(trimethylsilyl)amides were made to react with protic ligand 1in the second method to eliminate the volatile bis(trimethyl)silyl amine. The magnesium complex 3and barium complex 5 were prepared only through the first method. Solid-state structures of all the new complexes were established by single crystal X-ray diffraction analysis. The smaller ionic radii of Mg2+ (0.72 Å) and Ca2+ (0.99 Å) ions form the monomeric complex, whereas the larger ions K+ (1.38 Å) and Ba2+ (1.35 Å) were found to form one-dimensional polymeric complexes with monoanionic ligand 1. Compound 2 serves an example of magnesium complex with a Mg-Se direct bond

Group 1 and group 2 metal complexes supported by a bidentate bulky iminopyrrolyl ligand: synthesis, structural diversity, and ε-caprolactone polymerization study

We report here a series of alkali and alkaline earth metal complexes, each with a bulky iminopyrrolyl ligand [2-(Ph3CN[double bond, length as m-dash]CH)C4H3NH] (1-H) moiety in their coordination sphere, synthesized using either alkane elimination or silylamine elimination methods or the salt metathesis route. The lithium salt of molecular composition [Li(2-(Ph3CN[double bond, length as m-dash]CH)C4H3N)(THF)2] (2) was prepared using the alkane elimination method, and the silylamine elimination method was used to synthesize the dimeric sodium and tetra-nuclear potassium salts of composition [(2-(Ph3CN[double bond, length as m-dash]CH)C4H3N)Na(THF)]2 (3) and [(2-(Ph3CN[double bond, length as m-dash]CH)C4H3N)K(THF)0.5]4 (4) respectively. The magnesium complex of composition [(THF)2Mg(CH2Ph){2-(Ph3CN[double bond, length as m-dash]CH)C4H3N}] (5) was synthesized through the alkane elimination method, in which [Mg(CH2Ph)2(OEt2)2] was treated with the bulky iminopyrrole ligand 1-H in 1 : 1 molar ratio, whereas the bis(iminopyrrolyl)magnesium complex [(THF)2Mg{2-(Ph3CN[double bond, length as m-dash]CH)C4H3N}2] (6) was isolated using the salt metathesis route. The heavier alkaline earth metal complexes of the general formula {(THF)nM(2-(Ph3CN[double bond, length as m-dash]CH)C4H3N)2} [M = Ca (7), Sr (8), and n = 2; M = Ba (9), n = 3] were prepared in pure form using two synthetic methods: in the first method, the bulky iminopyrrole ligand 1-H was directly treated with the alkaline earth metal precursor [M{N(SiMe3)2}2(THF)n] (where M = Ca, Sr and Ba) in 2 : 1 molar ratio in THF solvent at ambient temperature. The complexes 7–9 were also obtained using the salt metathesis reaction, which involves the treatment of the potassium salt (4) with the corresponding metal diiodides MI2 (M = Ca, Sr and Ba) in 2 : 1 molar ratio in THF solvent. The molecular structures of all the metal complexes (1-H, 2–9) in the solid state were established through single-crystal X-ray diffraction analysis. The complexes 5–9 were tested as catalysts for the ring-opening polymerization of ε-caprolactone. High activity was observed in the heavier alkaline earth metal complexes 7–9, with a very narrow polydispersity index in comparison to that of magnesium complexes 5 and 6

Bis(phosphinoselenoic amides) as versatile chelating ligands for alkaline earth metal (Mg, Ca, Sr and Ba) complexes: syntheses, structure and ε-caprolactone polymerisation

We report here a series of heavier alkaline earth metal complexes with N,N′-(ethane-1,2-diyl)bis(P,P-diphenylphosphinoselenoic amide) using two synthetic routes. In the first route, the heavier alkaline earth metal bis(trimethylsilyl)amides [M{N(SiMe3)2}2(THF)n] (M = Ca, Sr, Ba), when treated with phosphinoselenoic amine [Ph2P(Se)NHCH2CH2NHPPh2(Se)] (1), afforded the corresponding alkaline earth metal complexes of the composition [(THF)3M{Ph2P(Se)NCH2CH2NPPh2(Se)}] [M = Ca (2), Sr (3), Ba (4)]. The metal complexes 2–4 were also obtained from a one-pot reaction, where potassium phosphinoselenoic amide was generated in situ by the reaction of compound 1 and [KN(SiMe3)2], followed by the addition of the respective metal diiodides in THF at room temperature. The magnesium complex [(THF)3Mg{Ph2P(Se)NCH2CH2NPPh2(Se)}] (5) was also prepared. The solid-state structures of alkaline earth metal complexes 2–5 were established by single crystal X-ray diffraction analysis. In the solid state, all the metal complexes are monomeric but in complexes 2–4, ligand 1 is chelated in a tetra-dentate fashion to each metal ion but in complex 5, ligand 1 behaves as a bidentate ligand. Complexes 2–4 were tested as catalysts for the ring-opening polymerisation of ε-caprolactone and a high level of activity for the barium complex 4 was observed, with narrow polydispersity. We also report the synthesis and structure of the bis(amidophosphino borane) ligand [Ph2P(BH3)NHCH2CH2NHPPh2(BH3)] (6) and the corresponding barium complex [(THF)2Ba{Ph2P(BH3)NCH2CH2NPPh2(BH3)}]2 (7)

Synthesis and Structures of Dimeric Zinc Complexes Supported by Unsymmetrical Rigid Bidentate Imino- acenapthenone Ligand

We report two zinc complexes of molecular formulae [ZnCl 2 (Mes - BIAO)] 2 ( 3 ) and [ZnCl 2 (Dipp - BIAO)] 2 ( 4 ) ( Mes = Mesityl, Dipp = 2,6 - diisopropylphenyl) of rigid unsymmetrical bidentate iminoacenapthenone ligands (Mes - BIAO) ( 1 ) and Dipp - BIAO) ( 2 ). The zinc complexes 3 and 4 can be achieved by the reaction of ZnCl 2 and neutral [ N - (mesityl) - iminoacenapthenone] ( 1 ) and [ N - (2,6 - diisopropylphenyl) - iminoacenapthenone] ligand ( 2 ) respectively in dichloromethane at ambient temperature. The solid state structures of the complexes 3 and 4 were established by single crystal X – ray diffraction analysis. In the solid state structures, bo th the complexes are dimeric in nature. In complexes 3 and 4 , each of the zinc coordination polyhedron is formed by the ligation of imine nitrogen, carbonyl oxygen atoms of the ligand 1 and 2 respectively along with three chlorine atoms. Out these three ch lorine atoms, two are 2 bridged with adjacent zinc atom to form the dimer. Thus overall zinc atom is penta - coordinated and the geometry can be best described as a distorted trigonal bipyramidal or a distorted square pyramidal

Structural and Mechanistic Insights of Substituted Perimidine - Experimental and Computational Studies

We report here the synthesis of phenyl(2 - phenyl - 2,3 - dihydro - 1H - perimidin - 2 - yl)methanone ( 2 ) by the condensation reaction between 1,8 - diaminonaphthalene ( 1 ) and benzil in equimolar ratio at ambient temperature. Further reaction of compound 2 with one equivalent of sodium borohydride at 0 ºC resulted in quantitative conversion of ketone to corresponding alcohol, namely, phenyl(2 - phenyl - 2,3 - dihydro - 1H - perimidin - 2 - yl)methanol ( 3 ). The solid - state structures of both the compounds were established using single - crystal X - ray diffraction analysis. We probed, using quantum mechanics, the mechanism of formation of compound 2 through two of the most plausible routes and observed that it was more plausible that the first route, energy - wise, would result in product 2 . We also calculated the stabilization energy of intermolecular hydrogen bond ing, which leads to the formation of a dimer, which has already been observed in the solid - state structure of compound 3

Synthesis and structural studies of dimeric sodium compounds having pentametallacyclooctane and hexametallacyclo undecane structure using different phosphinamine derivatives

The treatment of two bulky phosphinamines [Ph2PNH(CHPh 2)] (1) and [Ph2PNH(CPh3)] (2) with 30% hydrogen peroxide afforded phosphinicamides [Ph2P(O)NH(CHPh 2)] (3) and [Ph2P(O)NHCPh3] (4) in good yield. When the same phosphinamines are reacted with elemental sulfur, corresponding sulfur compounds [Ph2P(S)NH(CHPh2)] (5) and [Ph 2P(S)NHCPh3] (6) are obtained. Further reactions of 4-6 with sodium bis(trimethylsilyl)amide in THF solution afforded corresponding sodium salts of molecular formula [{(THF)2Na(Ph2P(O) NCPh3)}2] (8), [{(THF)2Na(Ph 2P(S)NCHPh2)}2] (7) and [{(THF) 2Na(Ph2P(S)NCPh3)}{(THF)Na(Ph 2P(S)NCPh3)}] (9) and all the sodium complexes 7-9 are dimeric and form highly strained polymetallacyclic motif in solid state structures. Molecular structure of all the complexes are established by single crystal X-ray diffraction analysi

家族法の未来――その家族像と改正の方向性についての考察

I はじめに　II 家族法の歴史　III 家族法の現在　IV 憲法から見る「家族」　V 家族法の未来　VI おわりに法政研究　別

[026] 文獻探究表紙奥付等

We report the syntheses of N-(2,6-dimethylphenyl)-P,P- diphenylphosphinothioic amide Ph 2P(S)NH-(2,6-Me 2C 6H 3)] (2) and N-(2,6-dimethylphenyl)-P,P- diphenylphosphinoselenoic amide Ph 2P(Se)NH-(2,6-Me 2C 6H 3)] (3) by the reaction of N-(2,6-dimethylphenyl)-P,P- diphenylphosphinamine [Ph 2PNH-(2,6-Me 2C 6H 3)] (1) with elemental sulphur and selenium respectively. When the phosphinamine compound 1 was treated with n-BuLi and subsequently with zirconocenedichloride in an equimolar ratio, the corresponding zirconium complex [{η 5-Cp 2ZrCl(η 2-N(2,6-Me 2C 6H 3)PPh 2}] (5) was obtained in good yield. The solid state structures of all the compounds were established by single crystal X-ray diffraction analysis. In zirconium complex 5, a highly strained three membered metallacycle was observed. In addition, the solid state structure of [Ph 2P(O)NH(2,6-Me 2C 6H 3)] (4) was also determined. In the solid state structure, compound 4 shows extensive intermolecular hydrogen bonding through oxygen atoms, whereas a lesser extent of intermolecular hydrogen bonding was noted in compound 2, due to the presence of the less electronegative sulphur atom

DENSITY ESTIMATION FOR UNIFORM MIXING PROCESS

Let ${ x_n }$ be a stationary uniform sequence of random variables having a probability density function $f(x)$. Based on the first $n$ observations an estimate of $f(x)$ is given by $f_n(x) = (na_n)^{-1} sum_{j=1}^{n}{K(an^{-1}(x - X_j))}$ where $K(y)$ is a known probability density function. Asymptotic properties of $f_n(x)$ have been studied