Multiple Bonds Between Metal Atoms / 12-Rhodium Compounds
.pdf
12
Rhodium Compounds
Helen T. Chifotides and Kim R. Dunbar,
Texas A&M University
12.1 Introduction
Dirhodium compounds have a prominent role in the field of metal-metal bond chemistry. Their fascinating properties span diverse fields such as catalysis,1-5 antitumor metallopharmaceuticals,6 phototherapeutic agents,7-9 photochemistry,10-12 and design of supramolecular ar- rays.13-15 A key factor in stabilizing Rh24+ units is the formation of Rh–Rh single bonds, the lengths of which are generally in the range 2.35-2.45 Å. In terms of a simplified molecular orbital picture, eight of the 14 electrons are distributed in the μ-, /-, β-orbitals and the remaining six electrons occupy the /*- and β*-orbitals, resulting in a net Rh–Rh bond order of one and no unpaired electrons.
Paddlewheel dirhodium compounds with Rh24+ and Rh25+ cores are the focus of the present chapter. These generally possess one or two axial (ax) ligands but the Rh–Rh bond length is essentially insensitive to the presence of μ-donor ax ligands. This has recently been supported by the synthesis of a dirhodium tetracarboxylate compound entirely lacking ax ligation.16 Mononuclear Rh(II) compounds are comparatively rare17 and are not currently discussed. An excellent review of Rh24+ chemistry that covers the literature up to mid-1981, published by T. R. Felthouse,18 is complemented by another comprehensive review published in 1983.19 A number of additional but shorter reviews that cover specific aspects of Rh24+ chemistry have been published since the early 1980s.20-25 The last two decades have witnessed an exponential growth of the number of structurally characterized dirhodium compounds and an effort has been made to compile them in the present chapter. The compounds have been classified according to the ligands that are coordinated to the dirhodium core in equatorial (eq) positions. The bridging ligands generally are uninegative, bent, trinuclear anions of the general type 12.1 with X–Z distances similar to the Rh–Rh distances. The general classification includes compounds supported by: (1) carboxylato (12.2) and thiocarboxylato (12.3) groups, (2) (N, O)
(12.4-12.6), (3) (N, N) (12.7-12.10), (4) (S, N), (S, O) and (S, S) donor and (5) phosphine bridging groups, (6) dianionic bridging ligands, and (7) ligands that do not span the Rh–Rh bond. The last section addresses the applications of dirhodium compounds with the exception of catalysis which is covered in Chapter 13. We apologize to those scientists whose work may have been inadvertently omitted.
465
466Multiple Bonds Between Metal Atoms Chapter 12
12.2 Dirhodium Tetracarboxylato Compounds
12.2.1 Preparative methods and classification
Dirhodium carboxylate complexes are most commonly obtained by reduction of Rh(III) compounds in alcohols which presumably act as the reducing agent, but mechanistic details are unknown. Compounds of the general type Rh2(O2CR)4Ln (n = 1 or 2) were first obtained by refluxing salts of [RhCl6]3- in aqueous formic acid, a reaction that affords the dark-green product Rh2(O2CH)4(H2O).26,27 This compound is believed to exhibit a structure consisting of Rh2(O2CH)4(H2O)2 units and Rh2(O2CH)4 chains.28 Other early preparative methods employed Rh(OH)3·H2O in a refluxing carboxylic acid29 or an alcohol and carboxylic acid mixture,30 but these methods result in low yields due to formation of considerable quantities of rhodium metal. The most efficient general synthetic method for dirhodium tetraacetate involves refluxing RhCl3·3H2O under N2 in a mixture of sodium acetate, acetic acid and ethanol,31-34 as illustrated in the following equation:
Rhodium Compounds 467
Chifotides and Dunbar
The red solution of Rh(III) becomes dark green after c. 1 h of reflux, and the green solid product precipitates from solution. Although prolonged refluxing causes deposition of rhodium metal, the overall yields for most Rh2(O2CCnH2n+1)4 compounds are quite good (80-85%).31 The halocarboxylate compounds (e.g., R = CF3, CCl3, CHCl2) are prepared in a similar fashion but yields are lower.35 Ligand exchange reactions of the acetate with excess carboxylic acid proceed in nearly quantitative yields29,30,36,37 and constitute one of the best methods for preparing various carboxylate derivatives, including those supported by mixed carboxylate ligand sets.38,39 The carbonate complex [Rh2(CO3)4]4- 40 (Section 12.3.6) can also be employed as a starting material for dirhodium carboxylate compounds with yields that range from 50 to 90%.41 Reduction of RhCl3 by dimethylformamide, in the presence of dimethylammonium acetate, has been suggested as a method to synthesize dirhodium tetraacetate in yields that are comparable to those previously described.42
The thermal stabilities of carboxylate complexes vary,43-46 and most decompose at temperatures > 200 ºC with concomitant formation of Rh metal. A notable exception is Rh2(O2CCF3)4, which sublimes at c. 350 ºC prior to decomposition; this property, coupled with its high Lewis acidity, has ushered the way to crystallization of dirhodium adducts with very weak donor molecules that cannot be obtained by conventional methods. These compounds are prepared by a technique referred to as ‘solventless synthesis’,47-60 which is based on a sublimation-deposition procedure in the absence of solvent molecules that very often compete with weak donor ligands for ax coordination. In this manner, the isolation of crystalline dirhodium adducts of ostensibly ‘innocent’ molecules, such as naphthalene and other polycyclic aromatic hydrocarbons, has been achieved.53,57 Liquid secondary ion mass spectrometry has been employed in studying the fragmentation patterns of various dirhodium carboxylate compounds.61
Dirhodium tetracarboxylate complexes generally are air-stable solids that readily form adducts with a variety of donor ligands which occupy ax positions. A conspicuous feature of Rh2(O2CR)4L2 compounds is the sensitivity of their colors to the identity of the ax ligands, due to the influence of ax bonding on the energy of the LUMO (μ*) orbital.16,29,62 Blue or green products are usually obtained with oxygen donors, red or violet with nitrogen donors, and burgundy or orange with sulfur or phosphorus donors.19 The Rh2(O2CR)4L2 adducts with the discrete paddlewheel structure 12.11 comprise the largest class of Rh24+ compounds, due to the extensive range of R groups and the plethora of ligands L (Lewis bases) that coordinate to the ax positions.
12.11
468Multiple Bonds Between Metal Atoms Chapter 12
In addition to the familiar R groups CH3, CF3, C2H5, n-C3H7, n-C3F7, CMe3, C6H5, and C6F5 encountered in Rh2(O2CR)4L2 carboxylate compounds, other substituents include linear chain
n-alkanoates (CnH2n+1CO2−; n = 5, 7 or 11),63,64 CH3OCH2,65 (CH2)nPh (n = 2 or 3),66,67 CPh3,38,68 C6H4-2-Ph,38 C6H2-2,4,6-(p-tol)3,39 C6H2-3,4,5-(OEt)3,69 C6H4-4-OCnH2n+1 (n = 8-14),70 C6H4- 2-OH (salicylate),71-73 sulfosalicylate,74 1,3,5-triisopropylphenyl,16,75 l-adamantyl,38 (1S)-3-
oxo-4,7,7-trimethyl-2-oxabicyclo[2.2.1]heptyl,76 methoxytrifluoromethylphenylmethyl,77-90 2-hydroxy-1,3-propanedicarboxylic acid,91 and Br2calix[4]arene.92 Complexes based on carboxylates derived from the amino acids CH3CH(NH2)CO2H (_-alanine),93 NH2(CH2)2CO2H (`-alanine),94-96 pyrrolidine-2-carboxylic acid (S-proline) and derivatives,97-99 tethered proline rings,100,101 S-leucine98 as well as those of other optically active carboxylate ligands have been studied.33,102-108 Compounds with chiral bridging ligands are presented in detail in Chapter 13 (catalysis). Moreover, compounds supported by glutaric (HO2C(CH2)3CO2H)93 and other chelating dicarboxylic acids109-116 have been reported. Complexes with bridging thiocarboxylate ions such as CH3COS−,117-121 C6H5COS−,122-124 But-COS−,125 and those of thiosalicylic acids126-128 are known as well.
Dirhodium tetracarboxylate complexes that exhibit the paddlewheel structure 12.11 are among the most well-studied M2(O2CR)4Ln (n = 1 or 2) compounds and surpass all others in the plethora of ax ligands. The seemingly infinite variety of ax ligands L that form complexes with Rh2(O2CR)4 includes molecules with almost all common donor atoms such as nitrogen, oxygen, sulfur, carbon, phosphorus, arsenic, antimony, selenium, halogens and others.
Nitrogen-donor adducts of the dirhodium carboxylate family constitute the largest class of compounds. Adducts have been reported with molecular nitrogen,129 ammonia,26,27,29,72,130-133
aliphatic and cyclic amines,29,30,66,130,134,135 pyridines27,29,30,39,66,93,110,112,124,130-133,136-153 and other
aromatic nitrogen containing ligands,65,135,154-160 4-ferrocenylpyridine and ferrocenyl-4-pyri- dylacetylene,161,162 pyrimidines,146,163-165 aromatic,112,155,158,166 and polyfunctional amines such as ethylenediamine,72 guanidine and its derivatives,133,167 durene diamine,155 phenazine,155 sulfadiazine,168 and triazenes.146,169 In addition, ax adducts with N,N'-di-p-tolylformamidine (HDTolF),170 2,2'-dipyridylamine (Hdpa),171 cyclam and other triand tetradentate nitrogen containing macrocycles,172 imidazole and substituted imidazole ligands,66,67,141,173-177 isonicotinate groups,178 nicotinamide and isonicotinamide,179,180 various nucleobases and their derivatives,181-191 tRNAphe,192 the ester of vitamin B1,193 cytochrome c174,194 as well as with amino acids and peptides are known.141,174 Other ax ligands with nitrogen donors include ni- triles,29,38,75,136,137,142,195-199 cyanide based electron acceptors,200-203 cyanoscorpionate ligands,204 tpy,205,206 pyrazines and substituted pyrazines,207-209 1,8-pyrazine-capped 5,12-dioxocyclams,210 thiazepines,211 substituted thiazoles,212-214 diphenylcarbazides,215 nitric oxide,29,134,216-218 nitrite,26,27 N-bound nitroxide free radicals,219 and [NCX]− (X = O, S, Se) anions.220,221
Axial complexes with H2O222 and DMSO29 are among the first oxygen-donor carboxylate adducts to be studied and subsequently were further investigated.28, 51,131,142,196,223-229 Adducts with other oxygen-donor molecules include those with methanol38,76,186,230,231 ethanol,68,71,106,232 acetone,75,233 THF,49,106,142,196 DMF,142,231,234,235 urea,236 dimethylsulfone,237 dimethylselenoxide,238 ax acetate groups,144,239,240 sterically hindered lanostanols,241 quinones,242 and O-bound organic nitroxide radicals219,243-246 or their 4-hydroxyl substituted counterparts.247
Sulfur-donor adducts with S-bound DMSO have been reported for the tetraacetate, propionate, butyrate, benzoate and tetrakis(trifluoroacetate) dirhodium dimers.51,226,227,248,249 Other sulfur-donor adducts include those with diethylsulfide43 and dibenzylsulfide,250,251 benzylthiol,252 sulfur containing aminoacids,253 tetrahydrothiophene,226 tetrathiafulvalene,254 N,N'-dimethylthioformamide (DMTF),255 thiourea and thioacetamide,72,166,256,257 N,N'-di- methyl-O-ethylthiocarbamate (DMTC),255 other thiocarbonyl donors,258 thiosemicarbazidedi-
Rhodium Compounds 469
Chifotides and Dunbar
acetate,166,259 1,4,7-trithiacyclononane,172 and cyclooctasulfur (S8);56 the S8 adduct was obtained by the ‘solventless’ synthesis method. The gas-phase reaction of Rh2(O2CCF3)4 with Me2SeO affords the unusual compound [Rh2(O2CCF3)4(Me2Se)] wherein the Se atom is coordinated to the dirhodium core.238
Ligands that form ax Rh–C bonds with dirhodium carboxylato compounds include CN-,260 CO 136,261-263 (Rh2(µ-O2CCH3)4(CO)2 is prepared at -20° C in CH2Cl2),261 various isocyanides,264-266 and olefins.267-273 The first reported dirhodium tetrakis(trifluoroacetate) olefin 1:2 complex is that with (−)-trans-caryophyllene,274 which was followed by two other compounds with arene coordination to ax sites of the dirhodium core.75,92 It was not until the introduction of the ‘solventless synthesis’ strategy that adducts of the extremely strong Lewis acid dirhodium tetrakis- (trifluoroacetate) with weak /-donor molecules such as ethene,55 substituted alkynes,52,59 benzene and hexamethylbenzene,48,53 as well as with a series of polycyclic aromatic hydrocarbons,57 the geodesic polyarene corannulene58 and hemibuckminsterfullerene59 were isolated and structurally characterized. Direct attachment of C=C double bonds to ax positions of the dirhodium unit is observed in the 1:1 polymeric chain complex of 1,4-benzoquinone.275,276 In the same vein, ax interactions are established between the carbene CH2: group and the Rh24+ core in the carbenoid 1,3,4,5-tetramethylimidazol-2-ylidene (temyl) adduct Rh2(O2CCMe3)4(δ1-temyl).277
Investigations of ax phosphorus-donor adducts initiated with PPh3,30,35 followed by preparative and structural studies of Rh2(O2CCH3)4 with PF3,217,261 PPh3,278,279 P(OPh)3,261,278 P(OMe)3,217,261 Ph2P(MeOC6H4),280 bicyclic phosphites281,282 and 2-pyridylphosphine ligands.283 In addition, products were isolated from the reaction of Rh2(O2CCF3)4 with PPh3 and P(OPh)3,284 Rh2(O2CC2H5)4 with PPr3i and PCy3,285 and Rh2(OSCR)4 (R = CH3, But or Ph) with PPh3.125 Detailed multinuclear NMR and UV-visible spectral studies have been reported for the 1:1 and 1:2 adducts of Rh2(O2CR)4 (R = CH3, C2H5, C3H7 or Ph) with phosphines and phosphites which exist in equilibrium in solution,286-289 whereas 19F and 31P NMR spectra of Rh2(O2CCF3)4 adducts with PX3 (X = Ph, OPh, Cy) have been employed to distinguish ax from mixed ax/eq coordination of the PX3 ligands.142,290 Carboxylate adducts with As or Sb as donor atoms, i.e., Rh2(O2CR)4(YPh3)2,250,291 Y = As, Sb and Rh2(O2CR)4L2, L = Ph2AsCH2PPh2 or Ph2As(CH2)nAsPh2,292 n = 2, 4, have been reported.
The assortment of ax ligands for dirhodium carboxylate [Rh2(O2CCH3)4X2]2- (X = Cl, Br, I) complexes includes halide anions; several of the salts have been structurally characterized.42,293-296 The betaine complex [Rh2(O2CCH2NMe3)4Cl2]Cl2·4H2O, which contains axially coordinated chloride ligands,297 and the unprecedented diiodine bridged adduct {[Rh2(O2CCF3)4I2]·I2} 54 have been the subject of single crystal X-ray studies.
12.2.2 Structural studies
The first accurate structural determination of a Rh2(O2CR)4L2 compound was reported in 1970 for Rh2(O2CCH3)4(H2O)2 (Fig. 12.1);223,224 this structure serves as the prototype for all Rh2(O2CR)4L2 structures. In Table 12.1 a compendium of the structural data for Rh24+ tetracarboxylate complexes, including monothiocarboxylate (12.2) and chelating dicarboxylic acid compounds, is provided. The entries in Table 12.1 are grouped according to the type of carboxylate ligand and within the subgroup by the donor atom of the ax ligand. With a few exceptions noted below, the majority of tetracarboxylato Rh–Rh distances are in the range 2.35-2.45 Å. The Rh−Rh bond length is rather insensitive to the presence of μ-donor ax ligands. The latter is corroborated by comparing structural data for Rh2(TiPB)4 (TiPB: anion of 2,4,6-triisopropyl benzoic acid), which lacks entirely ax interactions, and Rh2(TiPB)4(Me2CO)2.16,75 The Rh–Rh distance in the former (2.350(1) Å) is only slightly shorter, by 0.02 Å, than that in the latter (2.370[1] Å), which has ax ligands. In contrast, the Cr–Cr bond in Cr2(TiPB)4 is dramatically
470Multiple Bonds Between Metal Atoms Chapter 12
shortened by c. 0.4 Å when deprived of ax ligands.16,75 The shortest Rh–Rh distances for tetracarboxylate compounds are encountered in Rh2(TiPB)4 with no ax ligands (2.350(1) Å) and the monoadduct Rh2(TiPB)4(NCCH3) (2.354(1) Å).16,75 Other tetracarboxylate complexes with short Rh–Rh distances are [Rh2(TiPB)3(µ-O2CCH3)(TiPBH)]2 (2.358[1] Å)75 and {Rh2(O2CC3H7)4} (2.366(1) Å),298 which have one or both ax sites associated with a neighboring dirhodium unit, as well as Rh2(O2CCPh3)4(EtOH)2 (2.365(1) Å) with two exogenous ax ligands.68 The longest Rh–Rh distances are encountered among the tetracarboxylate compounds with phosphine and nitric oxide ax ligands, e.g., Rh2(O2CCF3)4(PPh3)2 (2.486(1) Å),284 Rh2(O2CC2H5)4(NO)2 (2.512(2) Å),218 Rh2(O2CCH3)4(NO)2 (2.513(1) Å),218 and Rh2(O2CC3H7)4(NO)2 (2.519(1) Å).218 The monothiocarboxylate compounds Rh2(OSCBut)4(PPh3)2125 and Rh2(µ-OSCCH3)4- (CH3CSOH)2117,118 exhibit Rh–Rh distances of 2.584(1) Å and 2.550(3) Å, respectively, which are longer than those in Rh2(O2CR)4L2.121 These long distances apparently are a consequence of the large ‘bite’ angle of RCSO− type ligands.299 Efforts have been made to correlate Rh–Rh distances with the Lewis basicity of the ax ligands L,261 but it does not appear that any simple relationship exists; this is presumably due to the fact that electronic and steric factors299-301 as well as packing forces influence the Rh–Rh bond distance (e.g., comparison of the Rh–Rh and Rh–N distances for Rh2(O2CCH3)4L2, L = py and Et2NH, indicates that both are longer for the Et2NH adduct; see Table 12.1).134,138 The difference of 0.01 Å between the Rh–Rh bond distances of Rh2(O2CCF3)4(DMSO)2227 and the deuterated analog Rh2(O2CCF3)4(DMSO-d6)2,228 which are two chemically identical compounds that differ only in the crystal packing arrangements, lends further credibility to this argument.
Fig. 12.1. Molecular structure of Rh2(O2CCH3)4(H2O)2.
Table 12.1. Structural data for paddlewheel Rh24+ tetracarboxylato compounds |
|
|
|
|
|||||||||
|
|
|
|
|
|
|
|
Compound |
r (Rh–Rh)a (Å) |
r (Rh–Lax)b (Å) |
Donor |
ref. |
|
|
|
|
|
|
|
|
|
atom(s) |
|||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Rh2(O2CH)4(H2O) |
|
|
|
|
|
2.38c |
2.45c |
O |
28,302 |
||||
Na[Rh2(µ-O2CH)4(µ3-δ1:δ1:δ1-O2CH)(H2O)]·H2O |
2.390(1) |
2.257(2)d |
O |
235 |
|||||||||
|
|
|
|
|
|
|
|
|
|
|
2.309(2)d |
|
|
Rh2(O2CH)4(DMF)2 |
|
|
|
|
2.397(1) |
2.261(1) |
O |
235 |
|||||
[Rh2(O2CCH3)4] e |
|
|
|
|
|
2.415(3) |
2.506(2)f |
Og |
312 |
||||
Rh2(O2CCH3)4(H2O)2 |
|
|
|
2.386(1) |
2.310(3) |
O |
223,224 |
||||||
Na[Rh |
2 |
(µ-O |
2 |
CCH |
) |
(δ1-O |
CCH |
)(δ1-HO |
CCH )]h |
2.383(1) |
2.279(2) |
Oh |
240 |
|
|
3 |
4 |
2 |
3 |
2 |
3 |
|
|
|
|
||
Na2[Rh2(O2CCH3)4Cl2]·4H2O |
|
|
2.387(1) |
2.564(1) |
Cl |
296 |
|||||||
Li2[Rh2(O2CCH3)4Cl2]·8H2O |
|
|
2.397(1) |
2.601(1) |
Cl |
294 |
|||||||
[Rh2(O2CCH3)4Cl2](Me2NH2)2 |
|
|
2.399(1) |
2.563(1) |
Cl |
42 |
|||||||
|
|
|
|
|
|
|
|
|
|
|
2.592(1) |
|
|
|
|
|
|
|
|
|
|||||||
(GudH)2[Rh2(O2CCH3)4Cl2] |
|
|
2.397(2) |
2.571(6) |
Cl |
293 |
|||||||
|
|
|
|
|
|
|
|
|
|
|
2.610(5) |
|
|
|
|
|
|
|
|
|
|||||||
[C(NH2)3]2[Rh2(O2CCH3)4Cl2] |
|
|
2.396(1) |
2.585(1) |
Cl |
295 |
|||||||
Rh2(O2CCH3)4(MeOH)2 |
|
|
|
2.378(1) |
2.288(3) |
O |
230 |
||||||
Rh2(O2CCH3)4(DMF)2 |
|
|
|
2.383(3) |
2.308(4) |
O |
234 |
||||||
[Rh2(O2CCH3)4(Me2SeO)2]·2CH2Cl2 |
|
2.394(1) |
2.290(5) |
O |
238 |
||||||||
Rh2(O2CCH3)4(CO)2 |
|
|
|
|
2.420(1) |
2.092(4) |
C |
217,261 |
|||||
Rh2(O2CCH3)4(NHEt2)2 |
|
|
|
2.402(1) |
2.301(5) |
N |
134 |
||||||
Rh2(O2CCH3)4(NO)(NO2) |
|
|
|
2.454(1) |
1.933(4)i |
N |
134,217 |
||||||
|
|
|
|
|
|
|
|
|
|
|
2.010(4)i |
|
|
Rh2(O2CCH3)4(NO)2 |
|
|
|
2.513(1) |
1.947(3) |
N |
218 |
||||||
Rh2(O2CCH3)4(Ds-im)2 |
|
|
|
2.390(1) |
2.237(3) |
N |
218 |
||||||
Rh2(O2CCH3)4(Ds-pip)2 |
|
|
|
2.398(1) |
2.272(6) |
N |
218 |
||||||
Rh2(O2CCH3)4(1-MeAdo)2·H2O |
|
|
2.401(1) |
2.295(5) |
N |
184 |
|||||||
Rh2(O2CCH3)4(tRNAphe)2 |
|
|
|
2.4j |
2.4j |
N |
192 |
||||||
Rh2(O2CCH3)4(theophylline)2 |
|
|
2.412(6) |
2.23(3) |
N |
185 |
|||||||
Dunbar andChifotides |
|
Compounds Rhodium |
|
471 |
|
|
|
|
|
|
|
|
|
Compound |
r (Rh–Rh)a (Å) |
r (Rh–Lax)b (Å) |
Donor |
ref. |
|
|
|
|
|
|
|
|
atom(s) |
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
Rh2(O2CCH3)4(caffeine)2 |
2.395(1) |
2.315(9) |
N |
185 |
||||||||
Rh2(O2CCH3)4(metro)2 |
2.388(1) |
2.240(5) |
N |
67 |
||||||||
Rh2(O2CCH3)4(tmph)2·1.5H2O |
2.405(1) |
2.284(8) |
N |
193 |
||||||||
Rh2(O2CCH3)4(AZ)2·4DMAA |
2.373(3) |
2.23(1) |
N |
188 |
||||||||
Rh2(O2CCH3)4(Roll-3696)2 |
2.399(1) |
2.248(4) |
N |
173 |
||||||||
Rh2(O2CCH3)4(HDTolF)2·CHCl3 |
2.412(1) |
2.309(4) |
N |
170 |
||||||||
Rh2(O2CCH3)4(py)2 |
2.396(1) |
2.223(2) |
N |
138 |
||||||||
|
|
|
|
|
|
|
|
|
|
2.231(3) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Rh |
2 |
(O |
2 |
CCH |
3 |
) |
4 |
(py) k |
2.400(1) |
2.258(4) |
N |
144 |
|
|
|
|
2 |
|
|
|
|
||||
[Rh2(O2CCH3)4(µ2-dapy)] |
2.420(1) |
2.365(5)l |
N |
145 |
||||||||
|
|
|
|
|
|
|
|
|
2.398(1) |
2.325(5)m |
|
|
Rh2(O2CCH3)4(δ1-ampy)2n |
2.417(3) |
2.36(1)l |
N |
145 |
||||||||
|
|
|
|
|
|
|
|
|
2.400(2) |
2.30(1)m |
|
|
[Rh2(O2CCH3)4(µ2-ammpy)·0.5CH3CN] |
2.410(1) |
2.25(1)l |
N |
147 |
||||||||
|
|
|
|
|
|
|
|
|
|
2.31(1)m |
|
|
Rh2(O2CCH3)4(δ1-dmp)2 |
2.414(1) |
2.403(4) |
N |
146 |
||||||||
Rh2(O2CCH3)4(δ1-damt)2 |
2.401(1) |
2.315(9) |
N |
146 |
||||||||
Rh2(O2CCH3)4(δ1-dmapd)2 |
2.412(1) |
2.370(6) |
N |
146 |
||||||||
Rh2(O2CCH3)4(δ1-aampy)2 |
2.411(1) |
2.439(4) |
N |
145 |
||||||||
Rh2(O2CCH3)4(δ1-daapy)2 |
2.404(1) |
2.388(6) |
N |
145,148 |
||||||||
Rh2(O2CCH3)4(δ1-Hdpa)2 |
2.404(1) |
2.294(4) |
N |
171 |
||||||||
Rh2(O2CCH3)4(4-CN-py)2·CH3CN |
2.393(1) |
2.244(4) |
No |
143 |
||||||||
[Rh2(O2CCH3)4(µ2-δ1:δ1-btp)] |
2.387(1) |
2.237(6) |
N |
149 |
||||||||
[Rh2(O2CCH3)4(µ2-δ1:δ1-dmpyethybz)·CH2Cl2] |
2.401c |
2.247c |
N |
150 |
||||||||
[Rh2(O2CCH3)4(µ2-δ1:δ1-tpyethebz)·2CH2Cl2] |
2.408(1) |
2.300(3) |
N |
305 |
||||||||
|
|
|
|
|
|
|
|
|
2.407(1) |
2.306(3) |
|
|
|
|
|
|
|
||||||||
Rh2(O2CCH3)4(δ1-tpy)2p |
2.401(1) |
2.337(7) |
N |
205 |
||||||||
Rh2(O2CCH3)4(δ1-tpy)2q |
2.408(1) |
2.323(2) |
N |
206 |
||||||||
Rh2(O2CCH3)4(δ1-Cl-tpy)2 |
2.405(1) |
2.359(6) |
N |
206 |
||||||||
|
472 |
|
12 Chapter |
|
Bonds Multiple |
|
||
|
|
Atoms Metal Between |
|
|
|
|
|
|
|
|
|
|
Compound |
r (Rh–Rh)a (Å) |
r (Rh–Lax)b (Å) |
Donor |
ref. |
|
|
|
|
|
|
|
|
|
|
atom(s) |
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||||
Rh2(O2CCH3)4(plpyz)2 |
|
|
2.387(1) |
2.224(3) |
N |
209 |
||||||||
{Rh2(O2CCH3)4[Cu2(1,8-pyrazine-capped 5,12-dioxocyclam)2]2}·CH3CO2C2H5 |
2.389(1) |
2.249(4) |
N |
210 |
||||||||||
Rh2(O2CCH3)4(HDPhTA)2 |
|
|
2.407(2) |
2.301(8) |
N |
169 |
||||||||
Rh2(O2CCH3)4(adbtz)2 |
|
|
2.402(2) |
2.287(8) |
N |
211 |
||||||||
Rh2(O2CCH3)4(admpym)2 |
|
|
2.414(1) |
2.368(3) |
N |
163 |
||||||||
Rh2(O2CCH3)4(admpym)2·H2O |
|
2.415(1) |
2.376(5) |
N |
163 |
|||||||||
Rh2(O2CCH3)4(trimethoprim)2·2C6H6·CH3OH |
2.409(1) |
2.289(2) |
N |
164 |
||||||||||
Rh2(O2CCH3)4(pyrimethamine)2 |
|
2.409(1) |
2.365(3) |
N |
164 |
|||||||||
[Rh |
2 |
(O |
2 |
CCH |
3 |
) |
4 |
(AAMP)·3.5H O] |
|
2.405(1) |
2.293(7)r |
N |
165 |
|
|
|
|
|
|
2 |
|
|
|
|
|||||
|
|
|
|
|
|
|
|
|
|
|
2.404(1) |
2.291(9)s |
|
|
Rh2(O2CCH3)4(NCCH3)2 |
|
|
2.384(1) |
2.258(6) |
N |
195 |
||||||||
Rh2(O2CCH3)4(1,1-TCNE)·C6H6 |
|
2.389(3) |
2.24(3) |
N |
202 |
|||||||||
|
|
|
|
|
|
|
|
|
|
|
2.367(3) |
2.19(3) |
|
|
|
|
|
|
|
||||||||||
Rh2(O2CCH3)4(trans-1,2-TCNE)2·C6H6·C8H10 |
2.372(1) |
2.185(6) |
N |
202 |
||||||||||
|
|
|
|
|
|
|
|
|
|
|
2.373(1) |
2.181(7) |
|
|
|
|
|
|
|
||||||||||
Rh2(O2CCH3)4(NCPhCN)·CH3COCH3 |
2.391(1) |
2.239(5) |
N |
198 |
||||||||||
Rh2(O2CCH3)4(NCPhCN)·2CH3OH |
2.391(1) |
2.236(4) |
N |
198 |
||||||||||
Rh2(O2CCH3)4(NCPhCN)·EtOH |
|
t |
t |
N |
198 |
|||||||||
|
|
|
||||||||||||
Rh2(O2CCH3)4(NCPhCN)·THF |
|
2.383(1) |
2.226(3) |
N |
198 |
|||||||||
Rh2(O2CCH3)4(NCPhCN)·C6H6 |
|
2.389(1) |
2.237(2) |
N |
198 |
|||||||||
[Rh2(O2CCH3)4(stf-CN)2]·6CHCl3 |
2.384(1) |
2.202(7) |
N |
199 |
||||||||||
[Rh2(O2CCH3)4(CNPh)]2 |
|
|
2.398(1) |
2.109(4) |
C |
279 |
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
2.373c,f |
Og |
|
Rh2(O2CCH3)4(CNPh)2 |
|
|
2.427(1) |
2.133(3) |
C |
266 |
||||||||
Rh2(O2CCH3)4(CNPhCF3)2 |
|
|
2.418(1) |
2.122(3) |
C |
266 |
||||||||
Rh2(O2CCH3)4(CNPhNMe2)2 |
|
|
2.424(1) |
2.148(4) |
C |
266 |
||||||||
[Rh2(O2CCH3)4(PPh3)]2 |
|
|
2.407(1) |
2.423(1) |
P |
279 |
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
2.405c,f |
Og |
|
Rh2(O2CCH3)4(PPh3)2 |
|
|
2.451(1) |
2.477(1) |
P |
278 |
||||||||
Dunbar andChifotides |
|
Compounds Rhodium |
|
473 |
|
|
|
|
|
|
|
|
|
|
|
|
|
Compound |
r (Rh–Rh)a (Å) |
r (Rh–Lax)b (Å) |
Donor |
ref. |
|
|
|
|
|
|
|
|
|
|
|
|
atom(s) |
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Rh2(O2CCH3)4(PF3)2 |
|
|
|
2.430(3) |
2.42(1) |
P |
261 |
|||||||||
Rh2(O2CCH3)4[P(OPh)3]2·C6H5Me |
2.443(1) |
2.412(1) |
P |
217,261,278 |
||||||||||||
Rh2(O2CCH3)4[P(OMe)3]2 |
|
2.456(1) |
2.437(5) |
P |
261 |
|||||||||||
{Rh2(O2CCΝ3)4[Ph2P(o-MeOC6H4)]}2 |
2.414(1) |
2.455(1)u |
P |
280 |
||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2.043(3)f |
Og |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2.437(3)f |
|
|
Rh2(O2CCH3)4{δ1-(S,R)-CPFA-P}2 |
2.453(1) |
2.561(2) |
P |
311 |
||||||||||||
Rh2(O2CCH3)4(AsPh3)2 |
|
|
|
2.427(1) |
2.576(1) |
As |
250 |
|||||||||
Rh2(O2CCH3)4(SbPh3)2 |
|
|
|
2.421(4) |
2.732(4) |
Sb |
250 |
|||||||||
Rh2(O2CCH3)4(DMSO)2 |
|
|
2.406(1) |
2.451(1) |
S |
226 |
||||||||||
Rh2(O2CCH3)4(DMTF)2 |
|
|
2.418(1) |
2.546(1) |
S |
255 |
||||||||||
Rh2(O2CCH3)4(THT)2 |
|
|
|
2.413(1) |
2.517(1) |
S |
226 |
|||||||||
Rh2(O2CCH3)4(ttf)2 |
|
|
|
2.408(2) |
2.519(4) |
S |
254 |
|||||||||
Rh2(O2CCH3)4(SHCH2Ph)2 |
|
2.402(1) |
2.551(2) |
S |
252 |
|||||||||||
Rh2(O2CCH3)4[S(CH2Ph)2]2 |
2.406(3) |
2.561(5) |
S |
250 |
||||||||||||
Rh2(O2CCH3)4(DMTC)2 |
|
|
2.409(1) |
2.614(3) |
S |
255 |
||||||||||
Rh2(O2CCH3)4(dmptsczda)2 |
2.413(1) |
2.519(2) |
S |
259 |
||||||||||||
{Rh |
2 |
(O |
2 |
CCH |
3 |
) |
4 |
(µ |
-Se C |
H |
)} e |
2.415(3) |
2.625(6)v |
Se |
312 |
|
|
|
|
|
2 |
2 |
5 |
8 |
|
|
|
|
|
||||
Rh2(O2CCH3)4[5-nitro-2-(chromone-2-carboxyl-amino)-1,3-thiazole]2·2CHCl3 |
2.388c |
2.259c |
N |
213 |
||||||||||||
Rh2(O2CCH3)4[5-nitro-2-(2-thienoylamino)-1,3-thiazole]2·CH2Cl2 |
2.383(1) |
2.241(4) |
N |
212 |
||||||||||||
{[Rh2(O2CCH3)4][cis-ReCl2(dppm)2(O2CC5H4N-4)2]·1.5C3H6O·2CH2Cl2·H2O} |
2.417(6) |
2.22(2) |
N |
178 |
||||||||||||
{Rh2(O2CCH3)4(nicotinamide)2·2Me2CO} |
2.397(1) |
2.224(5) |
N |
179 |
||||||||||||
{Rh2(O2CCH3)4(isonicotinamide)2·2Me2CO} |
2.403(1) |
2.205(7) |
N |
179 |
||||||||||||
{[Rh2(O2CCH3)4][Ni(bpbg)2]} |
2.411(2) |
2.319(9) |
N |
148 |
||||||||||||
Rh2(O2CCH3)4(diphenylcarbazide)2 |
2.39(2) |
2.31(4) |
N |
215 |
||||||||||||
Rh2(O2CCH3)4(Acr-4-carboxamide)2 |
2.403(1) |
2.339(6) |
N |
154 |
||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
2.407(1) |
2.349(5)w |
|
|
Rh2(O2CCH3)4(AcrNMe2)2 |
|
2.409(1) |
2.344(3) |
N |
65 |
|||||||||||
|
474 |
|
12 Chapter |
|
Bonds Multiple |
|
||
|
|
Atoms Metal Between |