Cyclometalated (N,C) Au(III) Complexes: The Impact of Trans Effects on Their Synthesis, Structure, and Reactivity.

ConspectusThe early years of gold catalysis were dominated by Au(I) complexes and inorganic Au(III) salts. Thanks to the development of chelating ligands, more sophisticated Au(III) complexes can now be easily prepared and handled. The choice of the ancillary ligand has great consequences for the synthesis, properties, and reactivity of the Au(III) complex in question. Among the major factors controlling reactivity are the "trans effect" and the "trans influence" that a ligand imparts at the ligand trans to itself. The kinetic trans effect manifests itself with an increased labilization of the ligand trans to a given ligand and arises from an interplay between ground-state and transition-state effects. The term trans influence, on the other hand, is a ground-state effect only, describing the tendency of a given ligand to weaken the metal-ligand bond trans to itself. Herein, we will use the term "trans effect" to describe both the kinetic and the thermodynamic properties, whereas the term "trans influence" will refer only to thermodynamic properties. We will describe how these trans effects strongly impact the chemistry of the commonly encountered cyclometalated (N,C) Au(III) complexes, a class of complexes we have studied for more than a decade. We found that the outcome of reactions like alkylation, arylation, and alkynylation as well as halide metathesis are dictated by the different trans influence of the two termini of the chelating tpy ligand in (tpy)Au(OAcF)2 (tpy = 2-(p-tolyl)pyridine, OAcF = OCOCF3, tpy-C > tpy-N). There is a strong preference for high trans influence ligands to end up trans to tpy-N, whereas the lower trans influence ligands end up trans to tpy-C. Taking advantage of these preferences, tailor-made (N,C)Au(III) complexes could be prepared. For the functionalization of alkenes at (tpy)Au(OAcF)2, the higher trans effect of tpy-C would suggest that the coordination site trans to tpy-C would be kinetically more available than the one trans to tpy-N. However, due to the thermodynamic preference of having the σ-bonded ligand, resulting from the nucleophilic addition to alkenes, trans to tpy-N, functionalization of alkenes was only observed trans to tpy-N. However, for a catalytic process, the reaction should happen trans to tpy-C, as was observed for the trifluoroacetoxylation of acetylene. When functionalizing acetylene in the coordination site trans to tpy-N, protolytic cleavage of the Au-C(vinyl) bond to release the product did not occur at all, whereas trans to tpy-C protolytic cleavage of the Au-C(vinyl) bond occurred readily, in agreement with the higher trans influence of tpy-C over tpy-N. The large impact of the trans effects in Au(III) complexes is finally exemplified with the synthesis of [(tpy)Au(π-allyl)]+[NTf2]-, which resulted in a highly asymmetric π + σ bonding of the allyl moiety. Here, the bonding is such that the most thermodynamically favorable situation is achieved, with the carbon trans to tpy-N bonded in a σ-fashion and the π-allyl double bond being coordinated trans to tpy-C.

Structural Elucidation, Aggregation, and Dynamic Behaviour of N,N,N,N-Copper(I) Schiff Base Complexes in Solid and in Solution: A Combined NMR, X-ray Spectroscopic and Crystallographic Investigation.

A series of Cu(I) complexes of bidentate or tetradentate Schiff base ligands bearing either 1-H-imidazole or pyridine moieties were synthesized. The complexes were studied by a combination of NMR and X-ray spectroscopic techniques. The differences between the imidazole- and pyridine-based ligands were examined by 1H, 13C and 15N NMR spectroscopy. The magnitude of the 15Nimine coordination shifts was found to be strongly affected by the nature of the heterocycle in the complexes. These trends showed good correlation with the obtained Cu-Nimine bond lengths from single-crystal X-ray diffraction measurements. Variable-temperature NMR experiments, in combination with diffusion ordered spectroscopy (DOSY) revealed that one of the complexes underwent a temperature-dependent interconversion between a monomer, a dimer and a higher aggregate. The complexes bearing tetradentate imidazole ligands were further studied using Cu K-edge XAS and VtC XES, where DFT-assisted assignment of spectral features suggested that these complexes may form polynuclear oligomers in solid state. Additionally, the Cu(II) analogue of one of the complexes was incorporated into a metal-organic framework (MOF) as a way to obtain discrete, mononuclear complexes in the solid state.

A Highly Asymmetric Gold(III) η3 -Allyl Complex.

A highly asymmetric AuIII η3 -allyl complex has been generated by treating Au(η1 -allyl)Br(tpy) (tpy=2-(p-tolyl)pyridine) with AgNTf2 . The resulting η3 -allyl complex has been characterized by NMR spectroscopy and X-ray crystallography. DFT calculations and variable temperature 1 H NMR suggest that the allyl ligand is highly fluxional.

Efficient Z-Selective Semihydrogenation of Internal Alkynes Catalyzed by Cationic Iron(II) Hydride Complexes.

The bench-stable cationic bis(σ-B-H) aminoborane complex [Fe(PNPNMe-iPr)(H)(η2-H2B = NMe2)]+ (2) efficiently catalyzes the semihydrogenation of internal alkynes, 1,3-diynes and 1,3-enynes. Moreover, selective incorporation of deuterium was achieved in the case of 1,3-diynes and 1,3-enynes. The catalytic reaction takes place under mild conditions (25 °C, 4-5 bar H2 or D2) in 1 h, and alkenes were obtained with high Z-selectivity for a broad scope of substrates. Mechanistic insight into the catalytic reaction, explaining also the stereo- and chemoselectivity, is provided by means of DFT calculations. Intermediates featuring a bisdihydrogen moiety [Fe(PNPNMe-iPr)(η2-H2)2]+ are found to play a key role. Experimental support for such species was unequivocally provided by the fact that [Fe(PNPNMe-iPr)(H)(η2-H2)2]+ (3) exhibited the same catalytic activity as 2. The novel cationic bisdihydrogen complex 3 was obtained by protonolysis of [Fe(PNPNMe-iPr)(H)(η2-AlH4)]2 (1) with an excess of nonafluoro-tert-butyl alcohol.

UiO-67-type Metal-Organic Frameworks with Enhanced Water Stability and Methane Adsorption Capacity.

The structure and properties of two new UiO-67-type metal-organic frameworks, along with their linker synthesis and powder and single crystal synthesis, are presented. The new MOFs, UiO-67-Me and UiO-67-BN, are based on 3,3'-dimethylbiphenyl and 1,1'-binaphthyl linker scaffolds, and show a much higher stability to water than the thoroughly investigated UiO-67, which is based on the biphenyl scaffold. On the basis of structure models obtained from single crystal X-ray diffraction, it is seen that these linkers are partly shielding the Zr cluster. The new materials have higher density than UiO-67, but show a higher volumetric adsorption capacity for methane. UiO-67-BN exhibits excellent reversible water sorption properties, and enhanced stability to aqueous solutions over a wide pH range; it is to the best of our knowledge the most stable Zr-MOF that is isostructural to UiO-67 in aqueous solutions.

Insight into the efficiency of cinnamyl-supported precatalysts for the Suzuki-Miyaura reaction: observation of Pd(I) dimers with bridging allyl ligands during catalysis.

Despite widespread use of complexes of the type Pd(L)(η(3)-allyl)Cl as precatalysts for cross-coupling, the chemistry of related Pd(I) dimers of the form (µ-allyl)(µ-Cl)Pd2(L)2 has been underexplored. Here, the relationship between the monomeric and the dimeric compounds is investigated using both experiment and theory. We report an efficient synthesis of the Pd(I) dimers (µ-allyl)(µ-Cl)Pd2(IPr)2 (allyl = allyl, crotyl, cinnamyl; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) through activation of Pd(IPr)(η(3)-allyl)Cl type monomers under mildly basic reaction conditions. The catalytic performance of the Pd(II) monomers and their Pd(I) µ-allyl dimer congeners for the Suzuki-Miyaura reaction is compared. We propose that the (µ-allyl)(µ-Cl)Pd2(IPr)2-type dimers are activated for catalysis through disproportionation to Pd(IPr)(η(3)-allyl)Cl and monoligated IPr-Pd(0). The microscopic reverse comproportionation reaction of monomers of the type Pd(IPr)(η(3)-allyl)Cl with IPr-Pd(0) to form Pd(I) dimers is also studied. It is demonstrated that this is a facile process, and Pd(I) dimers are directly observed during catalysis in reactions using Pd(II) precatalysts. In these catalytic reactions, Pd(I) µ-allyl dimer formation is a deleterious process which removes the IPr-Pd(0) active species from the reaction mixture. However, increased sterics at the 1-position of the allyl ligand in the Pd(IPr)(η(3)-crotyl)Cl and Pd(IPr)(η(3)-cinnamyl)Cl precatalysts results in a larger kinetic barrier to comproportionation, which allows more of the active IPr-Pd(0) catalyst to enter the catalytic cycle when these substituted precatalysts are used. Furthermore, we have developed reaction conditions for the Suzuki-Miyaura reaction using Pd(IPr)(η(3)-cinnamyl)Cl which are compatible with mild bases.

A gold exchange: a mechanistic study of a reversible, formal ethylene insertion into a gold(III)-oxygen bond.

The Au(III) complex Au(OAc(F))2(tpy) (1, OAc(F) = OCOCF3; tpy = 2-p-tolylpyridine) undergoes reversible dissociation of the OAc(F) ligand trans to C, as seen by (19)F NMR. In dichloromethane or trifluoroacetic acid (TFA), the reaction between 1 and ethylene produces Au(OAc(F))(CH2CH2OAc(F))(tpy) (2). The reaction is a formal insertion of the olefin into the Au-O bond trans to N. In TFA this reaction occurs in less than 5 min at ambient temperature, while 1 day is required in dichloromethane. In trifluoroethanol (TFE), Au(OAc(F))(CH2CH2OCH2CF3)(tpy) (3) is formed as the major product. Both 2 and 3 have been characterized by X-ray crystallography. In TFA/TFE mixtures, 2 and 3 are in equilibrium with a slight thermodynamic preference for 2 over 3. Exposure of 2 to ethylene-d4 in TFA caused exchange of ethylene-d4 for ethylene at room temperature. The reaction of 1 with cis-1,2-dideuterioethylene furnished Au(OAc(F))(threo-CHDCHDOAc(F))(tpy), consistent with an overall anti addition to ethylene. DFT(PBE0-D3) calculations indicate that the first step of the formal insertion is an associative substitution of the OAc(F) trans to N by ethylene. Addition of free (-)OAc(F) to coordinated ethylene furnishes 2. While substitution of OAc(F) by ethylene trans to C has a lower barrier, the kinetic and thermodynamic preference of 2 over the isomer with CH2CH2OAc(F) trans to C accounts for the selective formation of 2. The DFT calculations suggest that the higher reaction rates observed in TFA and TFE compared with CH2Cl2 arise from stabilization of the (-)OAc(F) anion lost during the first reaction step.

Solid-state structure and calculated electronic structure, formation energy, chemical bonding, and optical properties of Zn4O(FMA)3 and its heavier congener Cd4O(FMA)3.

The equilibrium solid-state structure of the experimentally synthesized but incompletely characterized Zn4O(FMA)3 is revised with the help of density functional theory computational methods. The electronic structure, formation energy, chemical bonding, and optical properties of Zn4O(FMA)3 and its heavier congener Cd4O(FMA)3 have been systematically investigated. The calculated bulk moduli for Zn4O(FMA)3 and Cd4O(FMA)3 are similarly small (and slightly smaller than the previously reported values for MOF-5), indicative of relatively soft materials. Their estimated band-gap values are ca. 3.2 eV (somewhat lower than that of MOF-5, 3.4-3.5 eV), indicating semiconducting character. The optical properties including dielectric function ε(ω), refractive index n(ω), absorption coefficient α(ω), optical conductivity σ(ω), reflectivity R(ω), and electron energy-loss spectrum L(ω) of M4O(FMA)3 (M = Zn, Cd) were systematically studied. Analysis of chemical bonding reveals that the M-O bonds are largely ionic, with an increase in ionicity from Zn to Cd. The total energy calculations establish that compounds M4O(FMA)3 have large negative formation energies, ca. -80 and -70 kJ·mol(-1) for Zn and Cd, respectively. Whereas Zn4O(FMA)3 has already been synthesized, the results suggest that the heavier congener Cd4O(FMA)3 might be experimentally accessible.

Di-µ-chlorido-bis-[(2,2'-bipyridine-5,5'-dicarb-oxy-lic acid-κ(2)N,N')chloridocopper(II)] dimethyl-formamide tetra-solvate.

In the title compound, [Cu(2)Cl(4)(C(12)H(8)N(2)O(4))(2)]·4C(3)H(7)NO, which contains a chloride-bridged centrosymmetric Cu(II) dimer, the Cu(II) atom is in a distorted square-pyramidal 4 + 1 coordination geometry defined by the N atoms of the chelating 2,2'-bipyridine ligand, a terminal chloride and two bridging chloride ligands. Of the two independent dimethyl-formamide mol-ecules, one is hydrogen bonded to a single -COOH group, while one links two adjacent -COOH groups via a strong accepted O-H⋯O and a weak donated C(O)-H⋯O hydrogen bond. Two of these last mol-ecules and the two -COOH groups form a centrosymmetric hydrogen-bonded ring in which the CH=O and the -COOH groups by disorder adopt two alternate orientations in a 0.44:0.56 ratio. These hydrogen bonds link the Cu(II) complex mol-ecules and the dimethyl-formamide solvent mol-ecules into infinite chains along [-111]. Slipped π-π stacking inter-actions between two centrosymmetric pyridine rings (centroid-centroid distance = 3.63 Å) contribute to the coherence of the structure along [0-11].

Properties of IRMOF-14 and its analogues M-IRMOF-14 (M = Cd, alkaline earth metals): electronic structure, structural stability, chemical bonding, and optical properties.

The chemical bonding, electronic structure, and optical properties of the experimentally available metal-organic framework IRMOF-14 and its metal-substituted analogues M-IRMOF-14 (M = Zn, Cd, Be, Mg, Ca, Sr, Ba), which contain a pyrene-2,7-dicarboxylate linker group, have been systematically investigated using DFT calculations. The unit cell volume and atomic positions were optimized with the Perdew-Burke-Ernzerhof (PBE) functional and showed good agreement between experimental and theoretical equilibrium structural parameters for Zn-IRMOF-14. The calculated bulk moduli indicate that the whole M-IRMOF-14 series are soft materials. The estimated band gap from DOS calculations for the M-IRMOF-14 series is ca. 2.5 eV, essentially independent of the metal ion and indicative of nonmetallic character. The band gap value is distinctly different from those calculated previously for the M-IRMOF-1 (benzene-1,4-dicarboxylate linker; ca. 3.5 eV) and M-IRMOF-10 (biphenyl-4,4'-dicarboxylate linker; ca. 3.0 eV) series and this confirms that the identity of the linker is a key parameter to control band gaps in an isoreticular series of main-group MOFs. In view of potential uses of MOFs in organic semiconducting devices such as field-effect transistors, solar cells, and organic light-emitting devices, the linear optical properties of these materials were also investigated. Comparisons are made with the M-IRMOF-1 and M-IRMOF-10 series.

Synthesis of substituted (N,C) and (N,C,C) Au(III) complexes: the influence of sterics and electronics on cyclometalation reactions.

Cyclometalated Au(III) complexes are of interest due to their catalytic, medicinal, and photophysical properties. Herein, we describe the synthesis of derivatives of the type (N,C)Au(OAcF)2 (OAcF = trifluoroacetate) and (N,C,C)AuOAcF by a cyclometalation route, where (N,C) and (N,C,C) are chelating 2-arylpyridine ligands. The scope of the synthesis is explored by substituting the 2-arylpyridine core with electron donor or acceptor substituents at one or both rings. Notably, a variety of functionalized Au(III) complexes can be obtained in one step from the corresponding ligand and Au(OAc)3, eliminating the need for organomercury intermediates, which is commonly reported for similar syntheses. The influence of substituents in the ligand backbone on the resulting complexes was assessed using DFT calculations, 15N NMR spectroscopy and single-crystal X-ray diffraction analysis. A correlation between the electronic properties of the (N,C) ligands and their ability to undergo cyclometalation was found from experimental studies combined with natural charge analysis, suggesting the cyclometalation at Au(III) to take place via an electrophilic aromatic substitution-type mechanism. The formation of Au(III) pincer complexes from tridentate (N,C,C) ligands was investigated by synthesis and DFT calculations, in order to assess the feasibility of C(sp3)-H bond activation as a synthetic pathway to (N,C,C) cyclometalated Au(III) complexes. It was found that C(sp3)-H bond activation is feasible for ligands containing different alkyl groups (isopropyl and ethyl), although the C-H activation is less energetically favored compared to a ligand containing tert-butyl groups.

Highly cis-selective Rh(I)-catalyzed cyclopropanation reactions.

The performance of recently reported highly cis-diastereoselective Rh(I) cyclopropanation catalysts has been significantly improved by a systematic study of different reaction parameters (catalyst activation, solvent, temperature, stoichiometry). The catalyst efficiency and diastereoselectivity were enhanced by changing the activating agent from AgOTf to NaBArf. With this new system, the Rh(I) catalyst was shown to be a highly efficient and cis-diastereoselective cyclopropanation catalyst in reactions between α-diazoacetates and a range of different alkenes and substituted derivatives. Particularly noteworthy is the remarkable reactivity and cis-diastereoselectivity displayed in the reactions between ethyl diazoacetate and cyclopentene, 2,5-dihydrofuran, and benzofuran, with yields up to 99% and cis-selectivities greater than 99%.

Revisiting isoreticular MOFs of alkaline earth metals: a comprehensive study on phase stability, electronic structure, chemical bonding, and optical properties of A-IRMOF-1 (A = Be, Mg, Ca, Sr, Ba).

Formation energies, chemical bonding, electronic structure, and optical properties of metal-organic frameworks of alkaline earth metals, A-IRMOF-1 (where A = Be, Mg, Ca, Sr, or Ba), have been systemically investigated with DFT methods. The unit cell volumes and atomic positions were fully optimized with the Perdew-Burke-Ernzerhof functional. By fitting the E-V data into the Murnaghan, Birch and Universal equation of states (UEOS), the bulk modulus and its pressure derivative were estimated and provided almost identical results. The data indicate that the A-IRMOF-1 series are soft materials. The estimated bandgap values are all ca. 3.5 eV, indicating a nonmetallic behavior which is essentially metal independent within this A-IRMOF-1 series. The calculated formation energies for the A-IRMOF-1 series are -61.69 (Be), -62.53 (Mg), -66.56 (Ca), -65.34 (Sr), and -64.12 (Ba) kJ mol(-1) and are substantially more negative than that of Zn-based IRMOF-1 (MOF-5) at -46.02 kJ mol(-1). From the thermodynamic point of view, the A-IRMOF-1 compounds are therefore even more stable than the well-known MOF-5. The linear optical properties of the A-IRMOF-1 series were systematically investigated. The detailed analysis of chemical bonding in the A-IRMOF-1 series reveals the nature of the A-O, O-C, H-C, and C-C bonds, i.e., A-O is a mainly ionic interaction with a metal dependent degree of covalency. The O-C, H-C, and C-C bonding interactions are as anticipated mainly covalent in character. Furthermore it is found that the geometry and electronic structures of the presently considered MOFs are not very sensitive to the k-point mesh involved in the calculations. Importantly, this suggests that sampling with Γ-point only will give reliable structural properties for MOFs. Thus, computational simulations should be readily extended to even more complicated MOF systems.

(5,5'-Dimethyl-2,2'-bipyridine)-iodido-trimethyl-platinum(IV).

In the title compound, [Pt(CH(3))(3)I(C(12)H(12)N(2))], the Pt(IV) atom is six-coordinated in a slightly distorted octa-hedral configuration with one CH(3) group and the I atom forming a near perpendicular axis relative to the square plane formed by the bipyridine ligand and the two remaining CH(3) groups. The CH(3) group trans to the I atom has a slightly elongated bond to Pt compared to the other CH(3) groups, indicating a difference in trans influence between iodine and the bipyridine ligand.

4,7,13,18-Tetra-oxa-1,10-diazo-nia-bicyclo-[8.5.5]icosane bis-(hexa-fluorido-phosphate).

The asymmetric unit of the title structure, C(14)H(30)N(2)O(4) (2+)·2PF(6) (-), contains the anion and half of the cation, the latter being completed by a crystallographic twofold axis. The cation has a cage structure with the ammonium H atoms pointing into the cage. These H atoms are shielded from inter-molecular inter-actions and form only intra-molecular contacts. There are short inter-molecular C-H⋯F inter-actions in the structure, but no conventional inter-molecular hydrogen bonds.

4,7,13,18-Tetra-oxa-1,10-diazo-nia-bicyclo-[8.5.5]icosane hexa-fluorido-silicate.

The asymmetric unit of the title molecular salt, C(14)H(30)N(2)O(4) (2+)·SiF(6) (2-), contains half of both the anion and the cation, both ions being completed by a crystallographic twofold axis passing through the Si atom. The cation has a cage structure with the ammonium H atoms pointing into the cage. These H atoms are shielded from inter-molecular inter-actions and form only intra-molecular contacts. There are short inter-molecular C-H⋯F inter-actions in the structure, but no conventional inter-molecular hydrogen bonds.

Gold(I) N-heterocyclic carbene precursors for focused electron beam-induced deposition.

Seven gold(I) N-heterocyclic carbene (NHC) complexes were synthesized, characterized, and identified as suitable precursors for focused electron beam-induced deposition (FEBID). Several variations on the core Au(NHC)X moiety were introduced, that is, variations of the NHC ring (imidazole or triazole), of the alkyl N-substituents (Me, Et, or iPr), and of the ancillary ligand X (Cl, Br, I, or CF3). The seven complexes were tested as FEBID precursors in an on-substrate custom setup. The effect of the substitutions on deposit composition and growth rate indicates that the most suitable organic ligand for the gold precursor is triazole-based, with the best deposit composition of 15 atom % gold, while the most suitable anionic ligand is the trifluoromethyl group, leading to a growth rate of 1 × 10-2 nm3/e-.

Theoretical investigations on the chemical bonding, electronic structure, and optical properties of the metal-organic framework MOF-5.

The chemical bonding, electronic structure, and optical properties of metal-organic framework-5 (MOF-5) were systematically investigated using ab initio density functional calculations. The unit cell volume and atomic positions were optimized with the Perdew-Burke-Ernzerhof (PBE) functional leading to a good agreement between the experimental and the theoretical equilibrium structural parameters. The calculated bulk modulus indicates that MOF-5 is a soft material. The estimated band gap from a density of state (DOS) calculation for MOF-5 is about 3.4 eV, indicating a nonmetallic character. As MOFs are considered as potential materials for photocatalysts, active components in hybrid solar cells, and electroluminescence cells, the optical properties of this material were investigated. The detailed analysis of chemical bonding in MOF-5 reveals the nature of the Zn-O, O-C, H-C, and C-C bonds, that is, Zn-O having mainly ionic interaction whereas O-C, H-C, and C-C exhibit mainly covalent interactions. The findings in this paper may contribute to a comprehensive understanding about this kind of material and shed insight into the synthesis and application of novel and stable MOFs.

Ping-pong at gold: proton jump between coordinated phenyl and eta1-benzene ligands, a computational study.

A DFT computational investigation predicts that the Au(III) complex (bpy)Au(C(6)H(5))(2+) reacts with benzene to furnish square planar (bpy)Au(C(6)H(5))(eta(1)-C(6)H(6))(2+). Intramolecular processes that occur within this species have been located, and the energetics of all processes have been quantified. The dynamic processes that have been identified are (1) benzene ring rotation with respect to Au, (2) direct hydrogen transfer from the benzene to the phenyl ligand, (3) hydrogen transfer from the ipso to the ortho positions in the coordinated benzene ligand, and (4) hydrogen transfer from the benzenium ligand formed by the ipso/ortho isomerization to the phenyl ligand. Similarities and differences are seen between the behavior of (bpy)Au(C(6)H(5))(eta(1)-C(6)H(6))(2+) and previously reported isoelectronic Pt(II) complexes. Preliminary experimental results related to this chemistry are reported, and possible consequences for C-H bond activation mediated by gold are discussed.

Poly[tris-(µ-2-amino-benzene-1,4-dicarboxyl-ato)tetra-kis-(N,N-dimethyl-formamide)-diyttrium(III)].

The asymmetric unit of the title coordination polymer, [Y(2)(C(8)H(5)NO(4))(3)(C(3)H(7)NO)(4)](n), contains one Y(3+) ion, three half-mol-ecules of the 2-amino-benzene-1,4-dicarboxyl-ate (abz) dianion and two O-bonded N,N-dimethyl-formamide (DMF) mol-ecules. Each abz half-mol-ecule is completed by crystallographic inversion symmetry and its -NH(2) group is disordered in each case [relative occupancies within the asymmetric unit = 0.462 (18):0.538 (18), 0.93 (2):0.07 (2) and 0.828 (16):0.172 (16)]. The combination of disorder and crystal symmetry means that each of the four C-H atoms of the benzene ring of each of the dianions bears a statistical fraction of an -NH(2) group. The coordination geometry of the yttrium ion is a fairly regular YO(8) square anti-prism arising from its coordination by two DMF mol-ecules, four monodentate abz dianions and one O,O-bidentate abz dianion. The polymeric building unit is a dimeric paddle-wheel with two metal ions linked by four bridging abz dianions. Further bridging linkages connect the dimers into a three-dimensional framework containing voids in which highly disordered DMF mol-ecules are presumed to reside.