We have found that if bulk water is added to an organic solvent (for example, acetonitrile) that already contains a very small amount of water clusters, then this added water will copy and reproduce these original clusters, forming many new clusters of the same size and chemical reactivity. If the initial sample clusters are small, then all the added water will turn into small chemically reactive clusters, and hydrolysis reactions with them will proceed quickly. And if the solvent initially contains a small number of very large clusters, then the added water will copy them and will consist of the same large chemically inactive clusters, and the rate of hydrolytic reactions will be very low. The chemical reactivity of the resulting water clusters can be easily determined by measuring the rate of their interaction with triethyl phosphite. (Fig. 1)
The ability of bulk water to copy and reproduce dissolved water clusters in a solvent was experimentally confirmed in acetonitrile containing ≤0.02% water. At such a low concentration of water molecules only very small clusters can be stable. They are separated from each other by a large amount of the solvent and therefore cannot spontaneously combine into larger clusters. If a certain amount of bulk water is added to such diluted small clusters, then, contrary to expectations, it will not join them, but rather copy them and form a greater number of the same small chemically reactive clusters. Hydrolytic reactions with this water added to acetonitrile will proceed at a high rate.
The proof of the fact of cluster copying is the following. If water is added to dry acetonitrile, in which there are no clusters for copying, then this water decomposes into larger clusters, which are less active and react noticeably more slowly with triethyl phosphite.
Thus, water added to a wet acetonitrile becomes more chemically reactive than the same water added to a dry one. If this difference occurs due to the copying a small number of little clusters in the wet solvent, then it was logical to suppose that water can copy clusters of different sizes and change its reactivity over a wide range. For example, if a small number of small clusters in the solvent are combined into several very large clusters, then the added bulk water after contact with them, should break up into the same large chemically inert clusters. Indeed, this is well reproduced experimentally.
We have found that upon contact with certain metals, water clusters in an organic solvent quickly combine into very large, low-activity clusters, and hydrolytic reactions immediately slow down very much. This method allows to combine clusters in a solvent even at high dilutions. After that, the added bulk water will copy and reproduce these large clusters and become inert. For example, if copper or silver is placed in acetonitrile containing ≤0.02% water, then all the small water clusters will combine into few very large inactive clusters after a while. The size of the clusters can increase by a factor of about 100 and their concentration in the solvent will proportionally decrease. The degree of clusters enlargement depends on the contact area with metals and on the contact time. For example, if 3 copper wires with the diameter of 1.5 mm are placed in 0.5 ml of acetonitrile in a 5 mm NMR tube for 10 min, then the added water can then react with triethyl phosphite up to 100 times slower than in an experiment, in which acetonitrile had no contact with metal. And if copper was in acetonitrile for 10 hours, then the reaction can slow down up to 500 times.
The fact that the metal acts only on water clusters is confirmed by the absence of any influence of copper and silver on thoroughly dried acetonitrile. Another piece of evidence is that after exposure to metal, large, combined clusters gradually decay back to the original small size and the reactivity of the added water increases again.
Thus, by changing the size of a small number of initial clusters in acetonitrile, one can control the size and chemical reactivity of clusters reproduced by bulk water after its addition.
If water can be structured upon contact with metals and can copy and reproduce a small number of very diluted water clusters, then it would be logical to assume that water molecules can form clusters of different sizes upon contact with molecules of other substances. If it is so, then water should also form large clusters around large organic molecules and become less reactive. This assumption was experimentally confirmed by copying sugar molecules that are rather large (С12Н22О11). If bulk water is added to dry acetonitrile containing a small amount of sugar (0.25%), then the reaction with triethyl phosphite will proceed 2-4 times slower than in the same reaction in the absence of sugar.
Mechanism
A long study of this phenomenon has led to a conclusion regarding its mechanism. The copying process is carried out not by the bulk water itself added to acetonitrile, but by small products of its decomposition, which are formed when mixed with the solvent. These can be very small unstructured aggregates of several water molecules, possibly with the participation of single water molecules, which exist for some time after the breakdown of the common continuous three-dimensional network of hydrogen bonds of bulk water. Such small formations can only be obtained by mixing a small amount of water with a large amount of solvent. In contrast to this, a large amount of added water, due to insufficient dilution with acetonitrile, breaks up into large clusters that cannot reproduce smaller clusters.
This is well confirmed experimentally by copying small clusters in wet acetonitrile containing ≤0.02% water. After adding 1.5–2% of bulk water, all of it will turn into the same small clusters and will quickly hydrolyze triethyl phosphite. And if 10 times more bulk water (15–20%) is added to acetonitrile in one portion, then, contrary to the law of chemical thermodynamics, the hydrolysis after that will proceed not faster, but 5–10 times slower.
In studying this phenomenon, another interesting result emerged. If a large amount of bulk water (15–20%) is added to acetonitrile not in one large portion, but in small portions with an interval of 15–20 minutes, then the first portion will copy the small number of original clusters, and each subsequent portion will continue to copy and keep this original size. In this way, more concentrated solutions of water in acetonitrile, consisting of small or large clusters, can be obtained. The process of copying and reproduction of clusters takes time, therefore, before adding each subsequent portion of water, it is necessary to make an interval of 15-20 minutes. Such successive copying by small portions of bulk water continues stably until the amount of acetonitrile is sufficient to separate the clusters from each other. This is well demonstrated experimentally. Large clusters are stably copied and react slowly with triethyl phosphite until the water concentration increases to 15-20%. Further addition of bulk water leads to a rapid increase in the rate of hydrolysis, which indicates the appearance of less structured forms of water. This effect is especially pronounced at low solar activity.
Influence of the Sun
The ability of water to copy its clusters and other molecular structures is stably recorded but manifests itself with different intensity during the year and the 11-year solar cycle. This is explained by the fact that the stability of water clusters strongly depends on solar activity, which also affects the process of copying and reproduction of water clusters by bulk water. With an increase in solar influence, the copying process accelerates, but the stability of the reproduced clusters decreases, and they decompose faster. This is well manifested in their interaction with triethyl phosphite. The dependence of the rate of this reaction on fluctuations in solar activity was confirmed by regular 6-year (2015-2020) measurements.7,8 (Fig. 2)
The results obtained showed that in different periods of the 11-year solar cycle and within one year, the rate of this reaction can change by 200 times. Therefore, the clusters formed as a result of copying also constantly change their stability and retain their structure much longer during periods of low solar activity. For example, in July, the enlargement of water clusters in acetonitrile upon contact with copper occurs faster than in January. And after the termination of contact with copper, enlarged clusters retain their large size and low reactivity much longer in winter than in summer.
It should also be taken into account that the degree of influence of the Sun on water depends on the geographic latitude.7,8 These studies were carried out in Kyiv and tested in Bremen at 50° and 53° North latitude, respectively. Near the equator, the degree of solar influence is less variable, so the process of copying clusters should be more constant there throughout the year.