Mono complexes effect

Reactions in Water.—The ultrasonic absorption technique has been applied to silver(i) thiosulphate in solutions of which the predominant species is the ion [Ag(S203)2] . Both of the relaxation effects observed over the 15—230 MHz frequency range were attributed to the stepwise mutual approach of [AgS203] and [SaOal - with the elimination of co-ordinated water. At 25 °C the rate constant for this association reaction is 1.0 x 10 1 mol s, which is close both to the value calculated on the basis of the process being essentially diffusion controlled and to the literature value for the reaction of a second molecule of phen with the mono-complex [Ag(phen)]+. The authors favour an associative mechanism for these reactions of Ag+, with the bound ligand having essentially no effect on kr. 

Mixtures of a titanium complex of saturated diols, such as TYZOR OGT, and a titanium acylate, such as bis- -butyl-bis-caproic acid titanate, do not have a yellowing or discoloring effect on white inks used to print polyolefin surfaces (506). The complexes formed by the reaction of one or two moles of diethyl citrate with TYZOR TPT have an insignificant color on their own and do not generate color with phenol-based antioxidants (507). The complexes formed by the addition of a mixture of mono- and dialkyl phosphate esters to TYZOR TBT are also low color-generating, adhesion-promoting additives for use in printing polyolefin films (508). 

The mechanism of interaction with DNA is suggested. Ethidium bromide (EB) displacement assay was performed. We determine the binding constant of Tb-E to DNA to be in the order of Ig K = 6.47 0.4. The bathochromic and hypsochromic effects in the absorption spectra of investigated complex were observed and the interaction is assumed to be mainly of the mono-intercalating type. 

The scope of the present paper is limited to those cyclopentadienyl ligands that contain more than two bulky substituents and transition metal complexes derived thereof in order to be able to focus on the specific effects of these ligand systems. A selection of some mono-substituted cyclopentadienyl ligands will be treated also. Among the numerous reviews highlighting special aspects of cyclopentadienyl... 

The guanidinate-supported titanium imido complex [Me2NC(NPr02l2Ti = NAr (Ar = 2,6-Me2C6H3) (cf. Section IILB.2) was reported to be an effective catalyst for the hydroamination of alkynes. The catalytic activity of bulky amidinato bis(alkyl) complexes of scandium and yttrium (cf. Section III.B.l) in the intramolecular hydroamination/cyclization of 2,2-dimethyl-4-pentenylamine has been investigated and compared to the activity of the corresponding cationic mono(alkyl) derivatives. 

The effect of adding 2,2 -bipyridyl is more complicated"" it does seem that the mono- and bis-complexes of Fe(Il) are capable of reducing peroxide although the rate coefficients can only be given within limits. 

The reductions by ferrous ion and mono- and bis-bipyridyl complexes of Fe(II) are also simple second-order with (for the Fe reaction at zero ionic strength ). 2 = TO X 10 exp(—12.1 X 10 /Rr) l.mole . sec . This reaction generates an intermediate capable of oxidising ethanol but the effect is suppressed by addition of Cl , Br and acrylonitrile, the latter being polymerised. 

The complexes [Cu(NHC)(MeCN)][BF ], NHC = IPr, SIPr, IMes, catalyse the diboration of styrene with (Bcat) in high conversions (5 mol%, THF, rt or reflux). The (BcaO /styrene ratio has also an important effect on chemoselectivity (mono-versus di-substituted borylated species). Use of equimolecular ratios or excess of BCcat) results in the diborylated product, while higher alkene B(cat)j ratios lead selectively to mono-borylated species. Alkynes (phenylacetylene, diphenylacety-lene) are converted selectively (90-95%) to the c/x-di-borylated products under the same conditions. The mechanism of the reaction possibly involves a-bond metathetical reactions, but no oxidative addition at the copper. This mechanistic model was supported by DFT calculations [68]. 

However, pMBCl 42 has a thermal stability issue and is expensive (Aldrich price 25 g for 69.90 the largest bottle). On the other hand, pMBOH 43 is stable and economically viable (Aldrich price 500 g for 84.90 the largest bottle). It was found that mono-N-alkylation of 36 proceeded well by slow addition (over 3 h) of 43 to a solution of 36 in acetonitrile in the presence of a catalytic amount of acid (p-TsOH) at 70 °C, as shown in Scheme 1.16. Slow addition of alcohol 43 minimized the self-condensation of 43 to form symmetrical ether 44, which was an equally effective alkylating agent. The product 41 was then directly crystallized from the reaction mixture by addition of water and was isolated in 90% yield and in >99% purity. A toluene solution of 41 can be used for the next reaction without isolation but the yield and optical purity of the asymmetric addition product were more robust if isolated 41 was used. In general, the more complex the reaction, the purer the starting materials the better. 

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