Mercury Coordination Compounds: Classification and Analysis of Crystallographical and Structural Data

Holloway, Clive Ε.; Melnı́k, Milan

doi:10.1515/mgmc.1994.17.11-12.799

Cited by 27 publications

(8 citation statements)

References 131 publications

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“…The most interesting feature is the presence of metal-metal bonds which are not reinforced by bridging ligands. Considerable attention in cadmium chemistry has been given to "Hoffmann-type" clathrates of the composition Cd(LN) x Ni(CN) 4 .nG (where χ = 1 or 2, and G is guest molecule(s)). However, the Ge-Ni-Cd and Cd-Ni-Cd angles between the stool legs are decreased to about 86° (ideal 90°) due to the steric requirements of the cyclopentadienyl ligand.…”

Section: Heterodimeric Compoundsmentioning

confidence: 99%

“…The nickel atom has a "piano-stool" coordination and an 18electron shell. For example, in the orange derivative Cd(2,2'-bpy)Ni(CN) 4 [45], the Ni(CN) 4 " 2 ion bridges four Cd(ll) atoms to form an infinite two-dimensional folded network stacking along the b-axis. Each cadmium atom is digonal (Cd(1) linear and Cd (2) .…”

Section: Heterodimeric Compoundsmentioning

confidence: 99%

“…behaviour of heteronuclear compounds of the Group 2B metals, zinc [3], cadmium and mercury [4], About ninety cadmium compounds have been examined and the structures classified according to nuclearity. Within each subgroup, the derivatives are referenced in order of decreasing ratio of cadmium atoms and increasing number of heterometal units.…”

Section: Introductionmentioning

confidence: 99%

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Cadmium Heterometallic Compounds: Classification and Analysis of Crystallographic and Structural Data

Holloway¹,

Melnı́k²

1995

Main Group Metal Chemistry

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Cadmium chemistry is an important area of research from both an industrial and environmental point of view. This review surveys the structural determination of almost ninety heterometallic complexes of cadmium. The cadmium atom is found mostly in the oxidation state of +2, but there are also examples of +1 and zero. The coordination numbers observed range from two to eight, with six occurring most frequently. The heterometal atoms include both transition and non-transition metals. A range of derivatives from dimers to polymers contain two or more metal atoms, however, there appears to be no evidence to suggest the existence of a direct Cd-Cd metal bond.Each metal atom is four coordinate, almost tetrahedral but with distortion towards a trigonal bipyramid. The other derivative [6] has an almost planar [Οά(μl) 2 Hg] ring, with the metals being four coordinate Cdl 4 and Hgl 2 P 2) respectively. The former is a slightly distorted tetrahedron while the latter is highly irregular. In particular, the P-Hg-P angle of 152.8(1)° may be attributable to the strong s-donor abilities of triphenylphosphine coupled with the tendency of mercury(ll) to adopt linear coordination [2]. The mean Cd-I(bridge) bond distance of 287.4(1) pm is about 19.3 pm shorter than that of the Hg-I(bridge) distance of 306.7(1) pm (Table 1A). HETEROTRIMERIC COMPOUNDSThe structural and crystallographic data for nine heterotrimetallic derivatives of cadmium are given in Table 1B. The orange yellow compound (NMe 4 ){Na[Cd(PhCOS) 3 ] 2 } [7] has at the centre a sodium atom, and the two cadmium atoms are part of the ligand system around it. This is illustrated in Figure 2. The anion has a crystallographicaliy imposed centre of symmetry, with the Na(l) atom sitting at the inversion centre. It is bonded to each of the PhCOS ligands via oxygen which gives it a distorted octahedral NaO e environment. Each Cd(ll) atom is S-bonded to three thiobenzoate ions and also interacts weakly with three oxygen atoms at distances of 265.9 to 282.8(5) pm. The Cd-Na separation is 355.7(1) pm and does not involve any direct metal-metal bonding. C23 FIGURE 2. Structure of {NalCdiPhCOSJalJ [η There are four orange-red derivatives of composition LCd[Mn(CO) 5 ] 2 [8-10] in which cadmium is the central atom and the two Mn(CO) 5 moieties are part of the ligand 424 Brought to you by | Purdue University Libraries system. In two of these [8,10] the cadmium atom is coordinated by a terdentate ether [8], or terpyridyl [9] molecule (Cd-0 range from 254.1(7) to 269.6(7) pm [8] and Cd-N range from 240.5(12) to 249.3(14) pm [9]), and two Mn(CO) s units (Cd-Mn, 270.7(2) and 271.4(2) pm [8] and 276.0 and 279.9(5) pm [9]) in a very distorted trigonal bipyramidal arrangement. There is considerable distortion of the octahedral manganese coordination (MnC 5 Cd) as seen in Table 1B. Two structures LCd[Mn(CO) s ] z (L is 2,2'-bipyridyl or 1,10-phenanthroline [9]) are very similar. The cadmium atom is coordinated by two nitrogen atoms of L and two manganese atoms creating a distorted tetrahedral arr...

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Section: Heterodimeric Compoundsmentioning

confidence: 99%

Section: Heterodimeric Compoundsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cadmium Heterometallic Compounds: Classification and Analysis of Crystallographic and Structural Data

Holloway¹,

Melnı́k²

1995

Main Group Metal Chemistry

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“…In view of the well-known affinity of mercury for sulfur, as illustrated by the fact that mercury forms compounds with a diverse array of sulfur donor ligands (including thiolate [10-12], thioether [13] and thione [14,15] derivatives), much attention has been directed towards the use of sulfur-containing ligands in chelation therapy [1-3]. For example, a common feature of the chelating agents illustrated in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…13 (selected bond lengths and angles are listed in Table 4). In this regard, well-defined, three-coordinate anionic mercury thiolate compounds are precedented [11,12,28], with the first structurally characterized mononuclear example, namely [Hg(SPh) 3 ] − , having been reported by Christou [11a]. Furthermore, the [HgS 3 ] coordination environment is present in the MerR metalloregulatory protein [29].…”

Section: Resultsmentioning

confidence: 99%

Structural characterization of 1,3-propanedithiols that feature carboxylic acids: Homologues of mercury chelating agents

et al. 2013

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The molecular structures of a series of 1,3-propanedithiols that contain carboxylic acid groups, namely rac- and meso-2,4-dimercaptoglutaric acid (H4DMGA) and 2-carboxy-1,3-propanedithiol (H3DMCP), have been determined by X-ray diffraction. Each compound exhibits two centrosymmetric intermolecular hydrogen bonding interactions between pairs of carboxylic acid groups, which result in a dimeric structure for H3DMCP and a polymeric tape-like structure for rac- and meso-H4DMGA. Significantly, the hydrogen bonding motifs observed for rac- and meso-H4DMGA are very different to those observed for the 1,2-dithiol, rac-2,3-dimercaptosuccinic acid (rac-H4DMSA), in which the two oxygen atoms of each carboxylic acid group hydrogen bond to two different carboxylic acid groups, thereby resulting in a hydrogen bonded sheet-like structure rather than a tape. Density functional theory calculations indicate that 1,3-dithiolate coordination to mercury results in larger S–Hg–S bond angles than does 1,2-dithiolate coordination, but these angles are far from linear. As such, κ2-S2 coordination of these dithiolate ligands is expected to be associated with mercury coordination numbers of greater than two. In vivo studies demonstrate that both rac-H4DMGA and H3DMCP reduce the renal burden of mercury in rats, although the compounds are not as effective as either 2,3-dimercaptopropane-1-sulfonic acid (H3DMPS) or meso-H4DMSA.

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Mercury: Inorganic & Coordination ChemistryBased in part on the article Mercury: Inorganic & Coordination Chemistry by Gregory J. Grant which appeared in the Encyclopedia of Inorganic Chemistry, First Edition .

Bebout

2005

Encyclopedia of Inorganic Chemistry

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Mercury is one of the oldest known elements. The element exhibits surprisingly different chemistry from its congeners zinc and cadmium, and it is the only group 12 member without a known beneficial biological role. Unique properties associated with the element and its compounds have led to diverse applications. However, many of these are being phased out to minimize further increases in the environmental and atmospheric burden with this toxic heavy metal. Motivations to study the compounds and complexes of mercury include potential for discovery of novel properties such as high‐temperature superconductivity and improved understanding of its interactions in physiological systems. Valuable characterization of mercury‐containing compounds is possible with 199 Hg NMR techniques. Mercury is the only group 12 member to have a stable monovalent state. Observed primarily in the oldest known and most common of all metal polycations, Hg 2 2+ , this metal–metal bonded species readily disproportionates into Hg 2+ and Hg 0 . Mercury(I) compounds, typically, have a linear structure of type XHgHgX. Halides, oxy salts, oxides, and coordination compounds with oxygen and weakly basic nitrogen‐donor ligands are best known for Hg 2 2+ . The most prevalent ionization state of mercury, Hg 2+ , is a d 10 metal ion, which lacks strong coordination number and geometry preferences. As a result, structural characterization of its compounds by X‐ray crystallography is particularly critical. A wide range of halides, pseudohalides, and chalcogenides of Hg 2+ are known. The softness of Hg 2+ has led to an investigation of coordination, with a wide variety of sulfur ligands and physiological sulfur donors being assumed to be the most important. Mercury(II) typically has a stronger affinity for S‐, N‐, and P‐donors than any other divalent metal ion. However, Hg 2+ also has a tendency to undergo incredibly rapid ligand exchange. Recent studies have shown that sterically demanding multidentate ligand systems can suppress ligand exchange processes.

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Mercury Coordination Compounds: Classification and Analysis of Crystallographical and Structural Data

Cited by 27 publications

References 131 publications

Cadmium Heterometallic Compounds: Classification and Analysis of Crystallographic and Structural Data

Cadmium Heterometallic Compounds: Classification and Analysis of Crystallographic and Structural Data

Structural characterization of 1,3-propanedithiols that feature carboxylic acids: Homologues of mercury chelating agents

Mercury: Inorganic & Coordination ChemistryBased in part on the article Mercury: Inorganic & Coordination Chemistry by Gregory J. Grant which appeared in the Encyclopedia of Inorganic Chemistry, First Edition .

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