Sulfur ligands coordination ability

The coordinating ability (i.e. the stability constants of the complexes) of sulfur-containing ligands increases with the dipole moment in the order H2S < RSH < R2S. The stability of the complexes decreases in the order S2 > RS > R2S. Here the polarizability and the number of lone pairs are the dominant factors. 

Sulfur ligands, 633-655 coordination ability, 516 Sulfur monoxide metal complexes instability, 636 Superoxide dismutase, 773 copper complexes, 772 Superoxo complexes, 315-330 binuclear, 323, 325 reactions, 330 bridged... 

The simplicity of this preparative method, coupled with the versatile coordination ability of the ReCp(CO)2 and ReCp (CO)2 fragments, provides a good model for the studies on coordinative activation of less usual ligands and molecules, many of which do not have an autonomous existence as free molecular entities. One example is the formation of ReCp(CO)2(CE) (E = S, Se), together with EPPh3, on reaction of (89) with CE2 and PPh3. Reaction of (89) with elemental sulfur (Sg) gives a mixture of several structurally characterized... 

RuCl2(PPh3)2 reacts with 4-R2P-dibenzothiophene (R = Ph, p-Tol) and forms 303, in which the dibenzothiophene ligand is coordinated to ruthenium via the phosphorus and sulfur atoms [84JA5379, 87JOM(318)409]. The donor ability of the sulfur atom is relatively weak. Complex 303 (R = Ph) is able to add carbon monoxide and yield the monocarbonyl adduct. 

Regular pyrimidines are less effective ligands for Ni11 ions. They may use, inter alia, their C=0 donor to yield monodentate coordination.1835 Insertion of a sulfur atom into a pyrimidine moiety increases considerably its binding ability.1836 Thiolation of uridine at C(2) or C(4) results in formation of a quite effective S,N3 four-membered chelate in the complexes with Ni11. Thiolation of purine at C(6) increases the stability constant by 3.5 orders of magnitude. 

Important aspects of the coordination chemistry of binary chalcogen-nitrogen ligands include (a) the ability of metals to stabilize labile neutral and anionic binary S-N ligands, (b) the applications of metal complexes as reagents for the preparation of other S-N compounds, and (c) the possible incorporation of metals into sulfur-nitrogen chains to produce conducting materials. 

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