RN (R＝CH3, CH3CH2)异构化及脱氢反应的量子拓扑研究

利用量子化学从头算CASSCF方法在6-311＋G (d, p)基组水平上对单线态和三线态RN (R＝CH₃, CH₃CH₂)异构化反应及RN脱氢反应的微观机理进行了理论研究. 在MP2/6-311＋G (d, p)和CCSD/6-311＋G (d, p)水平上进行了单点能校正. 单态和三态势能面的交叉点(ISC)的存在清楚地说明了基态反应物³RN异构化为基态产物¹R'NH (R'＝CH₂, CH₃CH)的过程. 电子密度拓扑分析显示在整个异构化过程中有两种类型的结构过渡态: 单态反应通道为T型过渡态, 三态反应通道为环状过渡态. 单线态RN脱氢反应通道中“原子-分子键”的存在说明两个H原子是以H₂的形式从RN中脱去的.     

The DFT study on mechanisms for NCO with C2H5 reaction

A detailed investigation has been performed at the QCISD(T)/6‐311++G(d,p)//B3LYP/6‐311+G(d,p) level for the reaction of NCO with C₂H₅ by constructing singlet and triplet potential energy surfaces (PES). The results show that the title reaction is more favorable on the singlet PES than on the triplet PES. On the singlet PES, the initial addition processes are barrierless and release lots of energy. The dominant channel occurs via the fragmentations of the initial adduct C₂H₅NCO and C₂H₅OCN to form C₂H₄ + HNCO and HOCN, respectively. With higher barrier heights, other products such as CH₄ + HNC + CO, CH₃CHNH + CO, CH₃CH + HNCO, and CH₃CN + H₂ + CO are less competitive. On the triplet PES, the entrance reactions surpass significant barriers; therefore, it could be negligible at the normal atmospheric condition. However, the most feasible channel on the triplet PES is the direct hydrogen abstraction channel to form CH₂CH₂ + HNCO. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Syntheses and structures of two new uranyl complexes [UO2(DPDPU)2(NO3)2](C6H5CH3) and [UO2(PMBP)2(DPDPU)](CH3C6H4CH3)0.5

Two new uranyl complexes [UO₂(DPDPU)₂(NO₃)₂](C₆H₅CH₃) (1) and [UO₂(PMBP)₂ (DPDPU)](CH₃C₆H₄CH₃)_0.5 (2), (DPDPU?=?N,N′-dipropyl-N,N′-diphenylurea, HPMBP?= 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5) were synthesized and characterized. The coordination geometry of the uranyl atom in 1 is distorted hexagonal bipyramidal, coordinated by two oxygen atoms of two DPDPU molecules and four oxygen atoms of two bidentate nitrate groups. The coordination geometry of the uranyl atom in 2 is distorted pentagonal bipyramidal, coordinated by one oxygen atom of one DPDPU molecule and four oxygen atoms of two chelating PMBP molecules.     

Synthesis,Supramolecular Behavior,and In Vitro Photodynamic Activities of Novel Zinc(II) Phthalocyanines “Side‐strapped” with Crown Ether Bridges

Two new tetra‐ or di‐α‐substituted zinc(II) phthalocyanines 5 and 6 have been prepared through a “side‐strapped” method. In the molecules, the adjacent benzene rings of the phthalocyanine core are linked at α‐position through a triethylene glycol bridge to form a hybrid aza‐/oxa‐crown ether. The tetra‐α‐substituted phthalocyanine 5 shows an eclipsed self‐assembly property in CH₂Cl₂ and the effect on the di‐α‐substituted analogue 6 is significantly weakened. Furthermore, the crown ethers of these compounds can selectively complex with Fe³⁺ or Cu²⁺ ion in DMF, leading to formation of J‐aggregated nano‐assemblies, which can be disaggregated in the presence of some organic or inorganic ligands, such as triethylamine, tetramethylethylenediamine, CH₃COO^?, or OH^?. In addition, both compounds are efficient singlet oxygen generators with the singlet oxygen quantum yields (Φ_Δ) of 0.54‐0.74 in DMF relative to unsubstituted zinc(II) phthalocyanine (Φ_Δ=0.56). They exhibit photodynamic activities toward HepG2 human hepatocarcinoma cells, but the compound 6 , which has more than 40‐fold lower IC₅₀ value (0.08 μM ) compared to the analogue 5 (IC₅₀=3.31 μM ), shows remarkablely higher in vitro photocytotoxicity due to its significantly higher cellular uptake and singlet oxygen generation efficiency. The results suggest that these compounds can serve as promising multifunctional materials both in (opto)electronic field and photodynamic therapy.     

Singlet-Oxygen Ene Reactions of (E)-4-Propyl[1,1,-2H3]oct-4-ene. Short Communication

Rose bengal-sensitized photooxygenation of 4-propyl-4-octene ( 1 ) in MeOH/Me₂CHOH 1:1 (v/v) and MeOH/H₂O 95:5 followed by reduction gave (E)-4-propyl-5-octen-4-ol ( 4 ), its (Z)-isomer 5 , (E)-5-propyl-5-octen-4-ol ( 6 ), and its (Z)-isomer 7 . Analogously, (E)-4-propyl[1,1,1-²H₃]oct-4-ene ( 2 ) gave (E)-4-propyl[1,1,1-²H₃]oct-5-en-4-ol ( 14 ), its (Z)-isomer 15 , (E)-5-[3′,3′,3′-²H₃]propyl-5-octen-4-ol ( 16 ), its (Z)-isomer 17 , and the corresponding [8,8,8-²H₃]-isomers 18 and 19 (see Scheme 1). The proportions of 4–7 were carefully determined by GC between 10% and 85% conversion of 1 and were constant within this range. The labeled substrate 2 was photooxygenated in two high-conversion experiments, and after reduction, the ratios 16/18 and 17/19 were determined by NMR. Isotope effects in 2 were neglected and the proportions of corresponding products from 1 and 2 assumed to be similar (% 4 ≈? % 14 ; % 5 ≈? % 15 ; % 6 ≈? % ( 16 + 18 ): % 7 ≈? % ( 17 + 19 )). Combination of these proportions with the ratios 16/18 and 17/19 led to an estimate of the proportions of hydroperoxides formed from 2 . Accordingly, singlet oxygen ene additions at the disubstituted side of 2 are preferred (ca. 90%). The previously studied trisubstituted olefins 20–25 exhibited the same preference, but had both CH₃ and higher alkyl substituents on the double bond. In these substrates, CH₃ groups syn to the lone alkyl or CH₃ group appear to be more reactive than CH₂ groups at that site beyond a statistical bias.     

A two‐step reaction scheme leading to singlet carbene species that can be detected under matrix conditions for the reaction of Zr(3F) with either CH3F or CH3CN

The results obtained from CASSCF‐MRMP2 calculations are used to rationalize the singlet complexes detected under matrix‐isolation conditions for the reactions of laser‐ablated Zr(³F) atoms with the CH₃F and CH₃CN molecules, without invoking intersystem crossings between electronic states with different multiplicities. The reaction Zr(³F) + CH₃F evolves to the radical products ZrF· + ·CH₃. This radical asymptote is degenerate to that emerging from the singlet channel of the reactants Zr(¹D) + CH₃F because they both exhibit the same electronic configuration in the metal fragment. Hence, the caged radicals obtained under cryogenic‐matrix conditions can recombine through triplet and singlet paths. The recombination of the radical species along the low‐multiplicity channel produces the inserted structures H₃C? Zr? F and H₂C?ZrHF experimentally detected. For the Zr(³F) + CH₃CN reaction, a similar two‐step reaction scheme involving the radical fragments ZrNC· + ·CH₃ explains the presence of the singlet complexes H₃C? Zr? NC and H₂C?Zr(H)NC revealed in the IR‐matrix spectra upon UV irradiation. © 2014 Wiley Periodicals, Inc.     

Enantioselective Intramolecular [2+2] Photocycloaddition Reactions of 4‐Substituted Coumarins Catalyzed by a Chiral Lewis Acid

Eight coumarins, which carry a terminal alkene tethered by a CH₂XCH₂ group to their 4‐position (X=CH₂, CMe₂, O, S, NBoc, NZ, NTs, NBn), were synthesized in overall yields of 51–80 %. Starting materials for the syntheses were either commercially available 4‐hydroxycoumarin or 4‐formylcoumarin. The intramolecular [2+2] photocycloaddition of these coumarins gave diastereoselectively products with a tetracyclic 3,3a,4,4a‐tetrahydro‐1H‐cyclopenta[2,3]cyclobuta[1,2‐c]chromen‐5(2H)‐one skeleton. Direct irradiation at λ=300 nm in dichloromethane (c=10 mM ) led to product formation in good yields for most substrates, presumably via a singlet excited state intermediate. Due to the low coumarin absorption at λ >350 nm the photocycloaddition was slow upon irradiation at λ=366 nm. Addition of a chiral oxazaborolidine‐based Lewis acid (50 mol %) increased the reaction rate at λ=366 nm and induced a significant enantioselectivity in the [2+2] photocycloaddition. Six out of eight coumarin substrates (X=CH₂, CMe₂, O, NBoc, NZ, NTs) gave the respective products in yields of 72–96 % and with 74–90 % enantiomeric excess (ee) upon irradiation in dichloromethane (c=20 mM ) at ?75 °C. The Lewis acid presumably acts by coordination to the coumarin carbonyl oxygen atom, which leads to a bathochromic shift (redshift) of the UV absorption and which increases the singlet state lifetime. A second electrostatic interaction of the hydrogen atom at C3 with the oxygen atom of the oxazaborolidine is likely.     

Synthesis of 3-alkyl-6-phenyl-4(3H)-pteridinones and their 8-oxides. Potential substrates of xanthine oxidase

Synthetic routes for the preparation of 3-alkyl-6-phenyl-4(3H)-pteridinones 6 and their corresponding 8-oxides 5 (R = CH₃, C₂H₅, (CH₂)₂CH₃, (CH₂)₃CH₃, CH(CH₃)C₂H₅, CH(CH₃)₂ and CH(C₂H₅)CH₂OCH(OC₂H₅)₂ are described and their reactivities towards xanthine oxidase from Arthrobacter M-4 are determined. Only the 3-methyl derivative of 6-phenyl-4(3H)-pteridinone and its 8-oxide i. e. 6a and 5a are found to be substrates although their reactivities are still very low. Oxidation takes place at C-2 of the pteridinone nucleus. All the 3-alkyl derivatives are less tightly bound to the enzyme than 6-phenyl-4(3H)-pteridinone. Introduction of the N-oxide at N-8 considerably lowers the binding of the substrates. Inhibition studies have revealed that 3-methyl-6-phenyl-4(3H)-pteridinone ( 6a ) is a non-competitive inhibitor with a Ki-value of 47 μM and the 3-ethyl derivative ( 6b ) an uncompetitive one with a Ki-value of 19.6 μM.     

High-temperature pyrolysis of acetaldehyde

High-temperature (>1000°K) pyrolysis of acetaldehyde (～1% in an atmosphere of pure nitrogen) was examined in a turbulent flow reactor which permits accurate determination of the spatial distribution of the stable species. Results show that the products in order of decreasing importance are CO, CH₄, H₂, C₂H₆, and C₂H₄. Rates of formation were consistent with the Rice–Herzfeld mechanism by including reactions to explain C₂H₄ formation and the possible presence of ketene. A steady-state treatment of the complete mechanism indicates that the overall reaction order decreases from \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{3}{2} $\end{document} to 1, which is supported by the new experimental data. Using earlier low-temperature results, the rate constant for the reaction CH₃CHO → CH₃ + CHO (1) was found as k₁=10^15.85±0.21 exp (?81,775±1000/RT) sec^?1. Also, data for the ratio of rate constants for reactions CH₃CHO + CH₃ → CH₄ + CH₃CO (4) and 2CH₃ → C₂H₆(6) were fitted to the empirical expression k₄/k₆^1/2=10^?13.89±0.03T^6.1 exp(?1720±70/RT) (cm³/mole·sec)^1/2 and causes for the curvature are discussed. The noncatalytic effect of oxygen on acetaldehyde pyrolysis at high temperature is explained.     

Synthesis and Characterization of Diorganotin Compounds {[R2Sn（ON =CHC6H5）]2O}2 and Crystal Structure of {[（C6H5CH2）2Sn（ON=CHC6H5）]2O}2

Introduction Dimeric tetraorganodistannoxanes are a kind of in-teresting organotin oxo clusters and have attracted con-siderable attention during the last several decades, in view of their unique structural features1-5 as well as their applications as biocides6,7 and in homogenous cataly-sis.8,9 In the solid state, they contain characteristic Sn4O2X2Y2 structural motifts with staircase or ladder arrangements, a planar four-membered Sn2O2 ring and, generally, penta-coordination around the tin…     

The Reaction of Singlet Oxygen with Adamantylideneadamantane Mediated by Rose Bengal

The photo-oxygenation of adamantylideneadamantane ( 1 ) on siliceous supports using admixed granules of ion-exchange resin fixed to methylene blue (MB) and rose bengal (RB) gave exclusively the corresponding dioxetane derivative 2 for the former sensitizer, while the latter gave 2 and traces of the epoxide 3. RB and the charge-transfer complex produced from N-ethylcarbazole and 2,4,5,6-tetranitrofluoren-9-one both reacted with chemically generated singlet oxygen to give superoxide radical anion. Trapping of the latter with 5,5-dimethyl-1-pyrroline 1-oxide gave an adduct exhibiting a characteristic ESR spectrum. The treatment of 1 in MeOH with 30% aqueous H₂O₂ for 22 h at 60° gave 3 in 100% yield. Repetition of this experiment in the presence of 2,6-di(tert-butyl)-p-cresol caused no significant change. These results indicate that singlet oxygen reacts with 1 , in the presence of RB, by two different processes. The first leads to dioxetane formation. The second process involves conversion of singlet oxygen by RB to superoxide radical anion which subsequently gives H₂O₂ so producing epoxide 3 from 1 .     

Biological Activity of Flavonoids Copper Complexes

Three flavonoid copper(II) complexes Cu₂(quercetin)(CH₃COO)₃(CH₃OH) ( 1 ), Cu(anthrarufin)(CH₃COO)·1/2H₂O ( 2 ) and Cu(naringin)(OCH₃)(CH₃OH)₂ ( 3 ) have been synthesized and characterized by elemental analysis, IR, electronic absorption and EPR (X‐band) spectroscopy. The complexes have a strong protective action over the Δsod1 mutant of S. cerevisiae against reactive oxygen radicals generated by an external source of free radicals (H₂O₂ or the superoxide‐generating, menadione). On the other hand, the complexes cleave DNA efficiently even in the absence of reducing agents. The main reactive oxygen species responsible for the DNA strand cleavage have been determined using radical scavengers. A probably mechanism of the DNA damage is proposed.     

Hydrothermal synthesis and crystal structures of Mn(II) and Cd(II) aminophosphonates with a layered structure

Two new divalent metal aminodiphosphonates with a layered structure, Mn₂[(HL)(H₂O)F]·H₂O (1) and Cd_3.5[(HL)L] (2) (H₄L =?CH₃CH₂CH₂N(CH₂PO₃H₂)₂), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction as well as with infrared spectroscopy, elemental analysis and thermogravimetric analysis. In 1, two MnO₄F₂ and two MnO₅F polyhedra are interconnected via edge-sharing into a tetramer, and such tetramers are bridged by the diphosphonate ligands into a Mn(II) phosphonate layer in the ab-plane. The structure of 2 also features a 2D layered structure, in which the CdO₅N and CdO₆ polyhedra are interconnected into a 1D chain. The chains are then cross-linked via phosphonate oxygen atoms to form Cd(II) phosphonate layers in the ab-plane.     

Living cationic polymerization of vinyl ethers with carboxylic acid/tin tetrahalide initiating systems. II. Effects of steric hindrance of carboxylate counteranions

Effects of steric crowding of the substituent of carboxylate counteranions on living cationic polymerization of isobutyl vinyl ether (IBVE) were investigated with the use of two series of carboxylic acids with various carbonyl substituents [RCOOH; R = (aliphatic series) CH₃CH₂, (CH₃)₂CH, (CH₃)₃C; (aromatic series) C₆H₅CH₂, (C₆H₅)₂CH, (C₆H₅)₃C] in conjunction with tin tetrabromide (SnBr₄) and 1,4-dioxane (DO) in toluene at 0°C. The overall polymerization rate increased with increasing the bulkiness of the substituents R in both the series: R = CH₃ (1) ≃ CH₃CH₂ (1) < (CH₃)₂CH (1.76) < (CH₃)₃C (2.31); C₆H₅CH₂ (0.84) < (C₆H₅)₂CH (0.98) < (C₆H₅)₃C (1.74); the values in the parentheses show the relative polymerization rate. In all the polymerizations, the number-average molecular weight (M_n) of the polymers was directly proportional to monomer conversion and in good agreement with the calculated values, assuming that one RCOOH molecule forms one polymer chain. The living nature of these polymerizations was further confirmed by a linear increase in M_n of the polymers upon sequential addition of a fresh monomer feed to the almost completely polymerized reaction mixtures. In the polymerizations with sterically less hindered carboxylic acids [R = CH₃CH₂, (CH₃)₂CH, C₆H₅CH₂, (C₆H₅)₂CH], the molecular weight distribution (MWD) of the polymers was very narrow (M_w/M_n < 1.1) throughout the polymerizations. In contrast, with bulkier substituent-containing counterparts [R = (CH₃)₃C, (C₆H₅)₃C], the polymerizations led to the polymers of relatively broad MWD (M_w/M_n ≅ 1.5 at ca. 100% monomer conversion). The bulky substituents such as (CH₃)₃C and (C₆H₅)₃C may decrease the interconversion rate between a dormant and an active species and increase the time-average concentration of the active growing species. The stereoregularity of the obtained polymers was not changed much with the steric environment of the counteranion (meso: 66–69%). © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2923–2932, 1999     

Mechanism and rate constants of the CH2 + CH2CO reactions in triplet and singlet states: A theoretical study

Ab initio and density functional CCSD(T)-F12/cc-pVQZ-f12//B2PLYPD3/6-311G** calculations have been performed to unravel the reaction mechanism of triplet and singlet methylene CH₂ with ketene CH₂CO. The computed potential energy diagrams and molecular properties have been then utilized in Rice–Ramsperger–Kassel–Marcus-Master Equation (RRKM-ME) calculations of the reaction rate constants and product branching ratios combined with the use of nonadiabatic transition state theory for spin-forbidden triplet-singlet isomerization. The results indicate that the most important channels of the reaction of ketene with triplet methylene lead to the formation of the HCCO + CH₃ and C₂H₄ + CO products, where the former channel is preferable at higher temperatures from 1000 K and above. In the C₂H₄ + CO product pair, the ethylene molecule can be formed either adiabatically in the triplet electronic state or via triplet-singlet intersystem crossing in the singlet electronic state occurring in the vicinity of the CH₂COCH₂ intermediate or along the pathway of CO elimination from the initial CH₂CH₂CO complex. The predominant products of the reaction of ketene with singlet methylene have been shown to be C₂H₄ + CO. The formation of these products mostly proceeds via a well-skipping mechanism but at high pressures may to some extent involve collisional stabilization of the CH₃CHCO and cyclic CH₂COCH₂ intermediates followed by their thermal unimolecular decomposition. The calculated rate constants at different pressures from 0.01 to 100 atm have been fitted by the modified Arrhenius expressions in the temperature range of 300–3000 K, which are proposed for kinetic modeling of ketene reactions in combustion. © 2018 Wiley Periodicals, Inc.     

Reactions of nickelocene with lithium and magnesium alkyls containing β-hydrogen atoms

The reaction of nickelocene with BrMgR, where R=CH₂CH(CH₃)C₆H₅, C₂H₅, (CH₂)₇CH₃ and CH₂CH₂CH₃, have been studied. It was found that the presence of β-hydrogen in R did not cause the total splitting of the carbon–nickel bond but alkylidynetrinickel clusters were formed. It is the first example of the synthesis of alkylidynetrinickel clusters (NiCp)₃CR′ from the organonickel species possessing β-hydrogen. Besides trinickel clusters, the following compounds were always formed in all the studied reactions: (NiCp)₄H₂, (NiCp)₆, CpNi(η³-C₅H₇) and (NiCp)₂(μ-C₅H₆). The structure of (NiCp)₃CCH(CH₃)Ph has been determined by a single-crystal X-ray diffraction study.     

Theoretical mechanistic study on the radical-molecule reaction of CH2Br/CHBrCl with NO2

The radical-molecule reaction mechanisms of CH₂Br and CHBrCl with NO₂ have been explored theoretically at the UB3LYP/6-311G(d, p) level. The single-point energies were calculated using UCCSD(T) and UQCISD(T) methods. The results show that the title reactions are more favorable on the singlet potential energy surface than on the triplet one. For the singlet potential energy surface of CH₂Br + NO₂ reaction, the association of CH₂Br with NO₂ is found to be a barrierless carbon-to-oxygen attack forming the adduct IM1 (H₂BrCONO-trans), which can isomerize to IM2 (H₂BrCNO₂), and IM3 (H₂BrCONO-cis), respectively. The most feasible pathway is the 1, 3-Br shift with C–Br and O–N bonds cleavage along with the N–Br bond formation of IM1 lead to the product P1 (CH₂O + BrNO) which can further dissociate to give P4 (CH₂O + Br + NO). The competitive pathway is the 1, 3-H-shift associated with O–N bond rupture of IM1 to form P2 (CHBrO + HNO). For the singlet potential energy surface of CHBrCl + NO₂ reaction, there are three important reaction pathways, all of which may have comparable contribution to the reaction of CHBrCl with NO₂. The theoretically obtained major products CH₂O and CHClO for CH₂Br + NO₂ and CHBrCl + NO₂ reactions, respectively, are in good agreement with the kinetic detection in experiment.     

New deoxygenative transformations; reactions of (CO)4Fe[Si(CH3)3]2 with acyclic ethers

The reaction of cis-(CO)₄Fe[Si(CH₃)₃]₂ (I) with CH₃OSi(CH₃)₃ and C₆H₅CH₂-OSi(CH₃)₃ at 80°C affords good yields of [(CH₃)₃Si]₂O and the deoxygenation products RSi(CH₃)₃ (R = CH₃, C₆H₅CH₂). These reactions are proposed to occur via (CO)₄Fe(R)Si(CH₃)₃ intermediates. This is supported by the observed formation of cis-(CO)₄Fe(CH₃)Si(CH₃)₃ (II) during the more rapid reaction of I with (CH₃)₂O; subsequent (CH₃)₄Si elimination occurs. With (C₆H₅CH₂)₂O, I reacts at 80°C to yield C₆H₅CH₂Si(CH₃)₃ and C₆H₅CH₂OSi(CH₃)₃ as primary products. With C₆H₅CH₂OCH₃, I effects regioselective benzyl---oxygen bond cleavage.     

Synthesis and Characterization of Diphenyltin(IV) Dicarboxylates Containing Germanium

Twelve new germanium substituted diphenyltin dipropionates with the general formula (R¹GeCHR²‐CHR³COO)₂SnPh₂ where R¹ = N(CH₂CH₂O)₃, (C₆H₅)₃ and (CH₃C₆H₄)₃, R² = H, CH₃, C₆H₅, p‐CH₃C₆H₄, p‐CH₃OC₆H₄, p‐ClC₆H₄, and R³ = H, CH₃ have been synthesized by the reaction of diphenyltin oxide with a germanium substituted propionic acid. All the compounds were characterized by elemental analysis, IR, multi‐nuclear (¹H, ¹³C, ¹¹⁹Sn) NMR and Mössbauer spectroscopies as well as mass spectrometry. The in vitro antibacterial activity of selected compounds is also reported.     

Magnetische Untersuchungen an Komplexen von La(III), Pr(III) und Nd(III) mitSchiffschen Basen

Specific magnetic susceptibilities (_s) of several newly synthesized chelates of some of the lanthanons [La(III), Pr(III) and Nd(III)] are reported. These derivatives are of the general type,Ln(O-i-C₃H₇)_3–n (C₆H₅CHNRO) _n [where,Ln=La(III), Pr(III) or Nd(III);n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄] and have been prepared by the reaction of the alkoxides of the lanthanons withSchiff bases such as benzylidene-2-hydroxyethylamine (C₆H₅CHNCH₂CH₂OH), benzylidene-2-hydroxy-n-propylamine (C₆H₅CHNCH₂CHOHCH₃) and benzylidene-o-aminophenol (C₆H₅CHNC₆H₄OH) in different molar relations in dry benzene.The resulting crystalline derivatives are non-volatile, light to deep yellow or blackish in colour. These tend to polymerize on keeping as shown by their insoluble nature and higher melting points, the polymerisation possibly occurring by the intermolecular coordination through oxygen atoms as reported earlier¹.UsingGouy method², the bis-isopropoxy mono-Schiff base and mono-isopropoxy bis-Schiff base complexes of La(III) have been shown to be diamagnetic, with _s values being in the range of –0.32 to –0.45×10^–6 and –0.39 to –0.55×10^–6 c.g.s. units at 305 K respectively.In the remaining derivatives, Pr(O-i-C₃H₇)_3–n (C₆H₅CH NRO) _n and Nd(O-i-C₃H₇)_3–n (C₆H₅CHNRO) _n (where,n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄) the magnetic moment values range between 3.25 to 3.32 and 3.30 to 3.33 _B respectively indicating their paramagnetic nature.