Dicomplex systems

Three types of ions are known cations, anions and amphoions. If the complex relations are present between ions of only one type — and these are then necessarily amphoions — we speak of unicomplex systems if they are present between two types of ions — cations and anions — then we call them dicomplex systems if on the other hand the complex relations are present between three types of ions at the same time... 

In the discussion of dicomplex systems we do not begin with the apparently simplest case — the limiting case No. 7 — and by gradually replacing a microion by a colloid ion (No. 5 or 6) finally arrive at the apparently complicated case No. 4 where both ions are colloid ions. Such a treatment is certainly not the way because, going from No. 7 via No. 5 and 6 to No. 4 does not in reality mean a complication but rather a simplification. 

After the dicomplex systems the unicomplex ones will be cursorily discussed and finally we shall deal with the tricomplex systems. 

DICOMPLEX SYSTEMS II. THE VARIANTS COLLOID CATION H- MICRO ANION AND MICRO CATION + COLLOID ANION... 

Positively charged proteins give similar dicomplex systems of the type colloid cation micro anion with suitably chosen anions. ... 

From this and many other examples it appears that not only the valency of a micro ion is of importance but also other specific factors play a role. Since now the the reversal of charge phenomena play a central role in dicomplex systems and one in fact encounters in the ion spectrum of Na nucleate (p. 283, Fig. 13c) for the alkaline earth metals the order for reversal of charge concentration increasing from left to right ... 

DICOMPLEX SYSTEMS, III. THE VARIANT MICRO CATION — MICRO ANION IN CONNECTION WITH THE THEORY OF COMPLEX COACERVATION... 

Although the dicomplex systems can be symbolised by a figure in which only one cation and one anion are depicted, their number is doubled to illustrate the mutual connection with the two other schemes (in which a total of four charges occurs). 

The complex relations, which occur in the scheme for the unicomplex systems, are mutually equal, as also those occurring in the scheme for the dicomplex systems. 

It is quite possible that some heavy metal cations, possibly also the UOa ion, attach themselves to a non-ionogenic group of the protein molecule and this combination of amphoion and cation, since it now carries more positive than negative charges, begins to behave as a colloid cation with respect to the anion and then really forms a dicomplex system with it. 

First of all one must bear in mind then that one can also join the ions which occur in the symbol of the tricomplex systems to the two schemes for the uni- and dicomplex systems. 

Compare Fig. 51 in which this is expressed formally as a reaction equation. We can leave aside the question whether the complex relations a of the unicomplex system, as also those b of the dicomplex system are sufficiently intense to make these systems capable of a separate existence — what is meant is a distinct separated phase next to an equilibrium liquid. 

In the tricomplex system besides b there occur two other complex relations c and d and it is thereby clear that as regards the question whether in a given case a tricomplex system will be produced or not, it will now depend on the intensity of the complex relations in the tricomplex system compared with those in the unicomplex and dicomplex systems together. 

Ifc-I-dtricomplex system would split up into a unicomplex 4- a dicomplex system. In this pne should bear in mind that the schematic pictures have only formal significance and merely depict the complex relations between four charges while in reality these patterns ought to be applied to the actually existing charge distribution in these systems, for example, to a linear arrangement along the kinked macromolecule distributed in space. 

Here also Ca with nucleate results in the separation of a dicomplex system but this turbidity is hardly, or not at all, intensified in the presence of lecithin. This is also not surprising since b is no longer greater than c indeed the nucleate and the lecithin have now the same ionised group (phosphate group). 

In the preceeding subsection we have spoken without further comment of the greater or less intensity of complex relations between micro ions and colloid ions. Naturally what was meant was actually the comparison of the maximum intensities of these complex relations obtainable with the micro ions in question. Indeed, just as this is already the case in the dicomplex systems, colloid cation + micro anion or colloid anion + micro cation, the statement, that the intensity of the complex relations formed by a micro cation is still a function of the concentration, also holds for the tricomplex systems. 

Dicomplex systems I. Variant colloid cation - - colloid anion. 338... 

Dicomplex systems II. The variants colloid cation + micro anion and... 

Dicomplex systems III. The variant micro anion -f micro cation in connection WITH THE theory OF COMPLEX COACERVATION.407... 

Diehl (35, 36) has observed the exchange reactions in BF3-alcohol systems by l9F resonance. The exchange in these systems, where the ratio of BF3 to alcohol is less than one, was attributed to the exchange of alcohol in a hydrogen bonded dicomplex with structure (XIII). 

Thus a micomplex gel is a system with the character of a gel the behaviour of which with regard to certain variables can be understood from the presence of complex relations between amphoions in this gel. Similarly a dicomplex coacervate is a coacervate in which complex relations are present between cations and anions. One can also denote the process by which such a complex system is produced by the same binary nomenclature. The last mentioned coacervate is the result of a dicomplex coacervation. 

The limiting case No. 7, does not really belong to Colloid Science because both ions fall below the agreed dimensions nevertheless No. 4, 5, 6 and 7 form a completely allied group. Characteristic properties of 4 are to be found not only in 5 and 6 where at any rate one colloid is present but also in 7 in which there is no longer any colloid at all. The limiting case No. 7 is therefore theoretically important because it shows us clearly that the essentials of the dicomplex colloid systems No. 4, 5 and 6 cannot be sought in the macromolecular structure of the colloid (or the association nature of the kinetic units in the case of the association colloids) but rather in the electrolyte nature of the macromolecule (or associate). 

The usual way, in which a dicomplex coacervation of this type is brought about, is that a suitably chosen salt is added to a hydrophilic sol. Since the colloid is itself also a salt, consisting of colloid ion + micro ion this dicomplex coacervation is according to the Phase Theory an demixing in an at least quaternary system. (HgO -f salt I + salt II, in which the salts I and II have no common ion see already p. 367 and 387). Of the four ions present there are only two essential complex partners, for example, the underlined ones in the following combinations. 

The demixing of concentrated clupein sulphate sols on cooling is therefore a dicomplex coacervation colloid cation + micro anion in its simplest form, namely as demixing in the binary system HgO -f salt. 

Fig. 50. Schemes for the unicomplex (a), dicomplex (b) and tricomplex (c) systems (see text).

Fig. 51. Formation of a tricomplex system from (or decomposition to) a unicomplex and a dicomplex...

The above formulated condition c + d a + b is not the only one since c + d itself must also exceed a certain minimum value if one is in fact to arrive at the separation of a tricomplex system. The great significance of a small equivalent weight for the realisation of dicomplex flocculations or coacervations (see p. 374, 2r and... 

---