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The conformational statistics of a normal alkane-type chain is studied by describing a random walk on a diamond lattice. The progress of the chain is governed by two probability parameters. The mathematical methods of a Markoff chain are used to calculate the expected square of the end-to-end distance for an oriented chain. The problem of excluded volume is not considered.

Pure polymeric sulphur free of dissolved S 8 monomer is a semi-crystalline polymer with a T g of 75°C. Quick-quenched (from 200°C) elastic sulphur, if maintained under conditions which prevent crystallization, is a solution of polymeric sulphur and S 8 rings, both polymer and monomer being in an amorphous state. The T g of this plasticized polymer is −30°C.

A study of the complexation reactions of dialkyltin dichloride with catechol has been carried out by potentiometric method and the correctness of the observed formation of 1:1 complex has been confirmed by preparative studies both in aqueous and non-aqueous media.

The theory of cell model for diffuse phase transition has been applied to explain charge induced helix coil transitions in polyglutamic acid and leucineglutamic acid copolymers in aqueous solutions. The experimental data of Snipp, Miller and Nylund have been utilized. Uninterrupted sequence lengths in the helical and random coil regions have also been calculated.

A number of distillable complexes have been obtained from reaction between dibutyltin diethoxide and acetylacetone, methyl acetoacetate or ethyl acetoacetate. The products are monomeric, which indicates possible octahedral configuration. The triethyltin acetylacetonate has also been shown to be monomeric in benzene, and may contain a five-coordinated tin atom. Trimethyltin methoxide also is only slightly associated in benzene or either.

Hermans' orientation factor can be evaluated only when the diatropic and paratropic interferences arise from planes which form an orthogonal set. This is only approximately satisfied in case of both cellulose I and cellulose II. In the present communication an exact expression has been derived which can be evaluated from x-ray measurements, angle between face normals of paratropic interferences, and the optical constants.

Using Wilson's GF matrix method a normal coordinate analysis of the triamino‐trinitrobenzene molecule is made and the Urey–Bradley force field is obtained. Inelastic neutron spectrum is obtained by the time‐of‐flight method and the frequency distribution is calculated in the one phonon and cubic approximation. Group frequency assignments are made and discussed.

The general equation of suppressor-controlled transconductance of a pentode contains three constants K, n and A of these, the constants K and n were determined by simple methods, but an approximate method was employed earlier to determine the constant A In this paper a simple approach for the determination of the constant A is presented along with the theoretical and experimental results obtained.

The synthesis of tetra-alkylthiostannanes, Sn(SR) 4 , (where R = C 2 H 5 , n-C 2 H 7 , iso-C 2 H 7 , n-C 4 H 9 , iso-C 4 H 9 tert-C 4 H 9 , n-CP 12 H 25 , C 6 H 5 and C 6 H 5 ·CH 2 ) through an alternative convenient route employing ammonia as a proton acceptor is described. Stannic isopropoxide also exchanges its isopropoxy groups with thiols. Thiolysis reactions of Sn(SEt) 4 and Sn(SPr) 4 with higher thiols have been investigated for the first time.

Inelastic incoherent neutron spectra are obtained for L-alanine and the frequency distribution is calculated in the one phonon and cubic approximation. Possible assignments for the peak positions are given and discussed.

A normal coordinate analysis for cyclic tetra-L-alanine molecule is reported. A comparison of amide modes and other low-frequency vibrations sensitive to conformational changes is made with those in poly-L-alanine. Intramolecular coupling coefficients are calculated using perturbation treatment.

A statistical thermodynamic approach based on the application of the Ising model for ferromagnetism is outlined to explain the phase transition in isolated single-stranded helical macromolecules. The transition is characterized by the degree of helicity and the lengths of uninterrupted helical and random-coil regions. The theoretical predictions for the temperature dependence of helicity in case of poly-l-lysine and poly(l-glutamic acid) are compared with the experimental results of Applequist and Doty and Doty, Yang, and others. The application of the theory to the crystalline–amorphous transition in polyethylene and polypropylene is also suggested and some preliminary results are reported. Une approche thermodynamique statistique basee sur l'application du modele de Ising pour le ferromagnetisme est soulignee pour expliquer la transition de phases dans des macromolecules isolees et helicoidales. La transition est caracte risee par le degre d'helicite et par la longueur des regions helicoidales et empelotonnees ininterrompues. Les predictions theoriques en ce qui concerne la dependance thermique de l'helicite dans le cadre de la poly-l-lysine et de l'acide poly-l-glutamique sont comparees avec des resultats experimentaux de Applequist, Doty et Doty, Yang et autres. L'application de la theorie a la transition cristallin–amorphe dans le cas du polyethylene et du polypropylene a ete egalement suggeree et certains resultats preliminaires sont rapportes. Ein statistisch-thermodynamischer, auf der Anwendung des Ising-Modells fur den Ferromagnetismus beruhender Erklarungsversuch der Phasenumwandlung in isolierten, einstrahnigen helixformigen Makromolekulen wird beschrieben. Die Umwandlung wird durch den Grad an Helixcharakter und die Lange der ununterbrochenen Helix- und Knauelbereiche gekennzeichnet. Die theoretischen Voraussagen fur die Temperaturabhangigkeit des Helixcharakters im Falle von Poly-l-lysin und Poly-l-glutaminsaure werden mit den Versuchsergebnissen von Applequist und Doty sowie Doty, Yang und anderen verglichen. Eine Anwendung der Theorie auf die kristallin–amorphe Umwandlung in Polyathylen und Polypropylen wird ebenfalls vorgeschlagen und einige vorlaufige Ergebnisse werden mitgeteilt.

For a collector coupled astable multivibrator, employing the conditions for a stable operation, expressions are derived for the maximum half period and the quality factor which is a measure of the sharpness of the pulses.

The theory of diffuse transition is applied to study melting of short-chain hydrocarbons. An adjustable nucleation parameter reported earlier for polyethylene is used. Experimental data of Flory and Vrij are utilized.

Dibutyltin diethoxide was found to interchange its ethoxy groups readily with thiols forming Bu2Sn(SR)2. These thiolates can also be synthesized by refluxing the crude Bu2SnO with thiols in the presence of benzene. Molecular weight determinations showed them monomeric. Some of these higher homologues can be prepared by displacement reactions with higher thiols. The reaction of dipropanethiodibutylstannane with ethanol is very slow even in the presence of catalyst.

The configurational statistics of a simple macromolecular chain is studied by applying the mathematical methods of Markov chains. The progress of the chain is governed by a transition probability matrix involving two probability parameters p and α. In terms of these parameters a few useful properties of the system such as the degree of helicity and expected square of the end-to-end distance are calculated. The same properties are also calculable when the formalism of the Ising model is applied to the macromolecular chain. This leads to the evaluation of p and α as a function of temperature in terms of the thermodynamic quantities such as heat of fusion and change of entropy. The self-consistency of p and α is checked from the value of the expected square of the end-to-end distance which agrees well with the data of Hoeve and others.

A molecular model for completely unoriented polymer chains which can be formed on a square lattice is presented. Using the mathematical methods of the Markoff formalism, expressions for the dimensions of the molecular chain, values for the per cent crystallinity and sequence length in amorphous and crystalline regions are derived in terms of two probability parameters. The problem of excluded volume is not considered.

A molecular model for an oriented fiber is presented. Using the mathematical method of the Markoff chain, values for the percent crystallinity, sequence length in amorphous and crystalline regions, and expressions for the dimensions of the molecular chains are presented in terms of two probability parameters.

Pulse generators are commonly used in laboratories and colleges in many measurement applications. All applications do not demand high precision pulse generators but for general purpose applications a simple one may be more useful. With this point in view, the development of a simple transistorized pulse generator, employing the locally available transistors, is presented in this paper. The experimental results obtained along with a brief cost estimate of the unit are also included for completeness. In the second part of this paper the complete design details are presented of the various circuits employed in fabricating the pulse generator.

Thioloxy germanes of the type Ge(SR)4(R = C2H5, C3H7n, C3H7iso, C4H9n, C4H7iso, C12H25n, C6H5CH2 and C6H5) have been synthesized by the ammonia method in good yields. Germanium tetra-isopropoxide has been found to interchange its isopropoxy groups with thiols in the presence of a catalyst. Reactions of Ge(SPrn)4 with ethanol (anhydrous) and of Ge(SBun)4 with water have been studied. A higher homologue Ge(SCH2C6H5)4 has also been obtained by a displacement reaction of Ge(SPrn)4 with toluene α-thiol.

The development of a simple, shorter and more accurate method than the NF method for the determination of benzyl benzoate in Benzyl Benzoate Lotion NF is discussed. Hydrolyzed benzyl benzoate was measured spectrophotometrically. Interference from other ingredients of the lotion, oleic acid and triethanolamine was almost negligible. The proposed method was completed in approximately 15 minutes, as opposed to the two hours required by the NF procedure.

Three techniques--ultraviolet, high pressure liquid chromatography (HPLC) and acid dye--were compared as stability-indicating assay methods. Investigations on six drugs (codeine phosphate, ephedrine hydrochloride, morphine sulfate, procaine hydrochloride, pyrilamine maleate and thiamine hydrochloride) indicate that HPLC is the most reliable method.

O-Trialkylgermaniumamidoximes are prepared by reaction between trialkylgermanium chloride and amidoxime in the presence of triethylamine. These new derivatives are characterised by elemental analysis, molecular weight measurement and infrared spectroscopy.

Chemical Laboratories, University of Rajasthan, Jaipur-302 004 A few new monothio-β-diketones, [RCSCH2COR', where R =Ph, Me ; R' =.C6H4(\(p\)), C6H4Br(\(p\)), C6H4Me(\(p\)), C6H4OCH4(\(p\))]have been synthesized and their metal complexes with CO(II), Ni(II), Co(III) and Fe(III) were prepared. These were characterized by elemental analysis, ir, magnetic measurements, electronic spectra. Molecular weight determination in refining chloroform showed them to be monomeric.

N-methylaminoalkoxides of titanium of the type Ti(OR)4−n(O · CHR′ · CH2 · NR″R‴)n where R = Et and Pr1; n = 1–4; and R′ = R″ = H, R‴ = Me; R′ = H, R″ = R‴ = Me; R′ = R″ = R‴ = Me, synthesized by the reactions of titanium alkoxides with aminoalcohols, show interesting variations in their properties like physical state, volatility and molecular complexity. I.r. and p.m.r. spectra of these derivatives have been recorded. A few interchange reactions with methanol and tert-butanol have also been carried out. These aminoalkoxides get cleaved with acetyl chloride and undergo insertion reactions with phenylisocyanate, thus providing the first examples of insertion reactions in such derivatives. Umsetzungen von Titanalkoxiden mit N-Methylaminoalkoholen N-Methylaminoalkoxide des Titans vom Typ Ti(OR)4−n(O · CHR′ · CH2 · NR″R‴)n, die durch Umsetzungen von Titanalkoxiden mit Aminoalkoholen dargestellt wurden, zeigten interessante Unterschiede in ihren Eigenschaften. IR- und PMR-Spektren wurden registriert sowie Austauschreaktionen mit Methanol und t-Butanol durchgefuhrt. Diese Aminoalkoxide werden mit Acetylchlorid gespalten und gehen Einschubreaktionen mit Phenylisocyanat ein, was ein erstes Beispiel fur Einschubreaktionen bei solchen Verbindungen darstellt.

Chemical Laboratories, University of Rajasthan, Jaipur-302 004 A few new monothio-��-diketones, [RCSCH2COR', where R = Ph, Me ; R' =.C6H4(\(p\)), C6H4Br(\(p\)), C6H4Me(\(p\)), C6H4OCH4(\(p\))] have been synthesized and their metal complexes with CO(II), Ni(II), Co(III) and Fe(III) were prepared. These were characterized by elemental analysis, ir, magnetic measurements, electronic spectra. Molecular weight determination in refining chloroform showed them to be monomeric.

Department of Chemistry, Faculty of science, Banaras Hindu University, Varanasi-221 005 The complexes of Ni(II), Cu(II), Co(ll), Cd(II) and Fe(lll) with dietbylamioo methyl ester of 2-amlno-1-cyclopeateoe-1-dltbiocarboxyllc acid,\( \begin{matrix} RHNCCH_2 CH_ CH_2 C- \\ \mid & \mid \end{matrix}\) C(S)S o' [LH when R=H and R'=CH2 N(C2H5 )2] and Ni(II) with methyl ester of N-methyl acid [L'H when R=R'=CH3] have been synthesized and characterized.

2-(Tributylstannoxy)-, 2(triphenylstannoxy)- and 2-(trimethylsiloxy)-3- hydro-4-alkyl- or -4-phenyl-1,3,5,2-oxadiazaboroles have been synthesized, and their properties examined.

Chemical Laboratories, University of Rajasthan, Jaipur-302004 Manuscript received 24 January 1974; revised 19 August 1974; accepted 20 August 1974 Titanium alkoxides react with N-ethylaminoethanols in stoichiometric ratios to give com­pounds with general formula, (OR)4-n Ti(OCH2CH2NR'R")n [R = Et and Pri; R' = H, R" = Et; R' = R" = Et; n 1-4]. Physical properties like molecular weight, infrared spectra and thermal stability are recorded. Reactions of tetrakisderivatives with phenylisocyanate and acetyl chloride are studied.

A variety of new 3-aryl-4-phenyl-1,3,5,2-oxadiazaboroles of the type (where X = OR, Ph, OSiMe3, OSnBu3, OSnPh3 and and Ar = N-phenyl or N-m-tolyl) have been synthesized by different reaction routes. The products have been characterized by elemental analyses and physicochemical measurements such as IR, PMR and molecular weights.

Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi-221 005 Manuscript received 26 July 1982, accepted 3 August 1983 Thermodynamic Parameters of Dialkyltin(IV)N- Arylhydroxamic Acid Chelates