Ni Dimers Research Articles

Machine Learning-Guided Development of Trialkylphosphine Ni(I) Dimers and Applications in Site-Selective Catalysis.

Owing to the unknown correlation of a metal's ligand and its resulting preferred speciation in terms of oxidation state, geometry, and nuclearity, a rational design of multinuclear catalysts remains challenging. With the goal to accelerate the identification of suitable ligands that form trialkylphosphine-derived dihalogen-bridged Ni(I) dimers, we herein employed an assumption-based machine learning approach. The workflow offers guidance in ligand space for a desired speciation without (or only minimal) prior experimental data points. We experimentally verified the predictions and synthesized numerous novel Ni(I) dimers as well as explored their potential in catalysis. We demonstrate C-I selective arylations of polyhalogenated arenes bearing competing C-Br and C-Cl sites in under 5 min at room temperature using 0.2 mol % of the newly developed dimer, [Ni(I)(μ-Br)PAd2(n-Bu)]2, which is so far unmet with alternative dinuclear or mononuclear Ni or Pd catalysts.

A first-principles study of the adsorption of trichloroethylene on vacancy-defected graphene decorated by Cu and/or Ni dimers

The adsorption behavior of trichloroethylene (TCE) on vacancy-defected graphene (VG) decorated by Cu2/Ni2/CuNi dimers (VG-Cu2/Ni2/CuNi) was studied by using first-principles calculation. Results showed that decorating with Cu2/Ni2/CuNi could increase the adsorption performance of VG, thus forming chemical adsorption between TCE and VG-Cu2/Ni2/CuNi. Furthermore, when VG was decorated by CuNi dimer in the configuration of VG-CuNi-2, the substrate exhibited the largest adsorption energy and charge transfer amount with TCE upon its adsorption. After TCE was adsorbed on VG-CuNi-2, the electrical conductivity of the substrate was increased significantly. Therefore, VG-CuNi-2 could be used as a sensing material to detect TCE molecules.

Solvent mediated synthesis of homoleptic tri and tetranuclear nickel complex derived from [Ni2(µ-SeC5H4N)2(dppe)2]2+ and theoretical studies

In the present report, the reactivity of the binuclear complex [Ni2(µ-SeC5H4N)2(dppe)2]2+ towards dichloromethane and methanol has been studied. The complex [Ni2(µ-SeC5H4N)2(dppe)2]2+ in the presence of chlorinated solvent resulted in selenido bridged trinuclear complex of composition [Ni3(µ-Se)2(dppe)2]2+ (1) whereas in the presence of methanol hydrolyzed product having cubane core [Ni4{(C5H4N)2Se}4(μ3OH)4(C6H5COO)(HCOO)]2+ (2) was isolated. Both the complexes were characterized by elemental analysis, IR, 1H, and 31P{1H} NMR spectroscopy. An attempt has also been made to investigate their thermal studies. The molecular structure of both the complex [Ni3(µ-Se)2(dppe)2]2+ (1) and [Ni4{(C5H4N)2Se}4(μ3OH)4(C6H5COO)(HCOO)]2+ (2) were established by single-crystal X-ray diffraction analysis. Broken-symmetry density functional theory (BS-DFT) calculations were carried out on complex 2 to investigate the electronic structure and nature of magnetic exchange interaction. BS-DFT reveals the existence of three different J values i.e. -8.9 cm−1, +18.7 cm−1 and +1.8 cm−1 between different Ni(II) pairs. A strong ferromagnetic interaction was observed between formate/phenylacetate bridged Ni(II) centers. An antiferromagnetic interaction between the ferromagnetically coupled formate and phenylacetate bridged Ni(II) dimers result in isolation of S = 0 spin ground state for complex 2. Molecular orbital, spin-density analyses were performed on the X-ray and optimized geometries to probe the electronic structure of complex 2.

First-principles study of the electronic and magnetic properties of Fe, Co, and Ni dimers adsorbed on polycyclic-aromatic-hydrocarbon molecules as well as the laser chirp effect on the ultrafast spin dynamics

We investigate the geometric, electronic, and magnetic properties of ${\mathrm{TM}}_{2}(\mathrm{PAH})$ complexes [transition metal (TM) = Fe, Co, Ni; $\text{polycyclic-aromatic}\phantom{\rule{4.pt}{0ex}}\text{hydrocarbon}\phantom{\rule{4.pt}{0ex}}\text{(PAH)}={\mathrm{C}}_{10}{\mathrm{H}}_{8}, {\mathrm{C}}_{16}{\mathrm{H}}_{10}, {\mathrm{C}}_{24}{\mathrm{H}}_{12}, {\mathrm{C}}_{32}{\mathrm{H}}_{14}]$ as well as the optically induced ultrafast spin dynamics from a first-principles study. Geometrically, the magnetic dimer of each of the complexes [except for ${\mathrm{Ni}}_{2}({\mathrm{C}}_{16}{\mathrm{H}}_{10}$)] turns out to prefer to adsorb above the hollow site of the outer carbon ring of the PAH molecule. The PAH-size effect and TM-element effect on the energy levels and spin localizations are analyzed. It is found that for the structures with the same PAH molecules, the level bands generally get wider from Fe via Co to Ni, while the number of spin-localized states overall decreases in the same order. For the structures with the same TM species [except for the two complexes ${\mathrm{Ni}}_{2}({\mathrm{C}}_{16}{\mathrm{H}}_{10}$) and ${\mathrm{Fe}}_{2}({\mathrm{C}}_{32}{\mathrm{H}}_{14}$)], the low-lying levels are hardly affected by the size of the PAH molecules. Among all the calculated levels for each complex [except for ${\mathrm{Ni}}_{2}({\mathrm{C}}_{16}{\mathrm{H}}_{10}$)], there are always more states with spin localized on the remote magnetic center than those localized on the near center. Driven by nonchirped subpicosecond laser pulses, a series of ultrafast spin-flip and spin-transfer scenarios on these structures are predicted and analyzed, based on which the laser chirp effect is further explored and some rules of thumb about the chirp tolerance and sensitivity are obtained. The results demonstrated in this paper are believed to enrich our understanding of the size- and structure-dependent electronic and magnetic properties of the carbon-based magnetic molecular structures, and further to promote the relevant experimental realization of the spin dynamics and their potential applications in future molecular spin devices.

Azido and thiocyanato bridged dinuclear Ni(II) complexes involving 8-aminoquinoline based Schiff base as blocking ligands: Crystal structures, ferromagnetic properties and magneto-structural correlations

The use of two 8-aminoquinoline-based tridentate N3-donor rigid Schiff base ligands (L1 and L2) with Ni(II) in the presence of the pseudohalides, NaN3 and NaSCN results in the crystallization of the two novel Ni(II) dimers: [Ni2(L1)2(µ1,1′-N3)2(N3)2] (1) and [Ni2(L2)2(µ1,3-NCS)2(NCS)2] (2). Both complexes are centrosymmetric Ni(II) dimers where the Schiff base ligands coordinate the octahedral Ni(II) centres in a mer configuration with one terminal and two bridging pseudohalide ligands in the remaining positions. Complex 1 shows Ni(II) ions connected by a double µ1,1′-N3− bridge whereas in complex 2 the Ni(II) ions are connected by a double µ1,3-NCS− bridge. The magnetic properties show the presence of a weak ferromagnetic coupling in both compounds that can be fit with g = 2.290(6), J = 6.1(2) cm−1, zJ′ = −0.32(1) cm−1 and |D| = 4.34(5) cm−1 for 1 and g = 2.096(2), J = 4.71(5) cm−1, zJ′ = −0.054(2) cm−1 and |D| = 1.52(2) cm−1 for 2 (the Hamiltonian is written as −2JS1S2). Both J values have been rationalized in terms of previous magneto structural correlations based on the Ni-N-Ni bridging angle in 1 and on the asymmetry of the Ni-S-C-N-Ni bridges in 2.

Ni(II) Dimers of NNO Donor Tridentate Reduced Schiff Base Ligands as Alkali Metal Ion Capturing Agents: Syntheses, Crystal Structures and Magnetic Properties

Three trinuclear Ni(II)-Na(I) complexes,[Ni2(L1)2NaCl3(H2O)]·H2O (1), [Ni2(L2)2NaCl3(H2O)] (2), and [Ni2(L3)2NaCl3(OC4H10)] (3) have been synthesized using three different NNO donor tridentate reduced Schiff base ligands, HL1= 2-[(3-methylamino-propylamino)-methyl]-phenol, HL2= 2-[(3-methylamino-propylamino)-methyl]-4-chloro-phenol, and HL3= 2-[(3-methylamino-propylamino)-methyl]-6-methoxy-phenol that had been structurally characterized. Among these complexes, 1 and 2 are isostructural in which dinuclearNi(II) units act as metalloligands to bind Na(I) ions via phenoxido and chlorido bridges. The Na(I) atom is five-coordinated, and the Ni(II) atom possesses hexacordinated distorted octahedral geometry. In contrast, in complex 3, two -OMe groups from the dinuclear Ni(II) unit also coordinate to Na(I) to make its geometry heptacordinated pentagonal bipyramidal. The magnetic measurements of complexes 1–3 indicate ferromagnetic interactions between dimeric Ni(II) units with J = 3.97 cm−1, 4.66 cm−1, and 5.50 cm−1for 1–3, respectively, as is expected from their low phenoxido bridging angles (89.32°, 89.39°, and 87.32° for 1–3, respectively). The J values have been calculated by broken symmetry DFT method and found to be in good agreement with the experimental values.

Electronic and magnetic properties of DUT-8(Ni).

First principles calculations using density functional theory (DFT) have been performed to investigate the electronic and magnetic properties of DUT-8(Ni) (DUT - Dresden University of Technology). This flexible metal-organic framework (MOF) exists in two crystalline forms: DUT-8(Ni)open and DUT-8(Ni)closed. To identify the energetically favoured magnetic ordering, the density of states (DOS) and the energy difference between a low-spin (LS) and a high-spin (HS) coupling ΔELS-HS for those crystalline structures have been computed. Calculations on supercells have been carried out to include a variety of different magnetic couplings beyond a single unit cell. Several molecular model systems have been employed to further investigate the magnetic behaviour by introducing a diversity of chemical environments to the magnetic centers. The magnetic ground state of both crystalline structures has been found to be the low-spin state (S = 0). This low-spin ordering can be seen in the DOS as well as from ΔELS-HS calculations. Additionally, the calculations on the supercells confirm that the local character of the ordering (i.e. within the Ni dimers) is the most favoured one. However, the model systems indicate a change from the low-spin (S = 0) to a high-spin (S ≠ 0) ordering by introducing certain alterations into the chemical environment. Such alterations could be incorporated into the crystalline systems which should lead to similar results.

Influence of interconfigurational electronic States On Fe, Co, Ni-silicene materials selection for spintronics.

Growth through controlled adsorption of ferromagnetic elements such as Fe, Co and Ni on two-dimensional silicene provides an alternative route for silicon-based spintronics. Plane wave DFT calculations show that Fe, Co and Ni adatoms are strongly chemisorbed via strong sigma bonds, with adsorption energies (1.55 - 2.29 eV) that are two to six times greater compared to adsorption on graphene. All adatoms adsorb more strongly at the hole site than at the atom site, with Ni adsorbing strongest. Of the dimer configurations investigated, the hole – hole, b-atom – hole, vertically stacked at hole, vertically stacked at b-atom and bridge sites were found to be stable. The Co and Ni dimers are most stable when adsorbed in the hole-hole configuration while the Fe dimer is most stable when adsorbed in the atom-hole configuration. Metal-to-silicene and interconfigurational s-to-d electron transfer processes underpin the trends observed in adsorption energies and magnetic moments for both adatoms and dimers. Adsorption of these metals induces a small band gap at the Dirac Cone. In particular Co adatom adsorption at the hole site induces the largest spin-polarized band gaps of 0.70 eV (spin-up) and 0.28 eV (spin-down) making it a potential material candidate for spintronics applications.

Theoretical DFT study of homonuclear and binary transition-metal dimers

A DFT study of homonuclear, and heteronuclear Pd–M, Pt–M (M=Cu, Ag, Au, Ni) and Pt–Pd neutral dimers is presented using different XC functionals. Ground state bond lengths and vibrational frequencies were determined. Doublet and triplet states were obtained for heteronuclear dimers. Dissociation energy exhibits unambiguous dependency on the HF exchange term. Electronic configurations were determined for Pd–Ag (2Σ) and Pt–Ni (3Σ) dimers. Hybrid functionals results agree with experimental data for Pt–Ni, Pt–Pd, and Pd–Ni dimers. mPW1PW91 predicts a D0 value for Pt–Cu dimer of ∼3.3eV. PBE and B3PW91 are reliable to predict bond lengths and harmonic frequencies of heteronuclear dimers.

Crystal growth, thermal and magnetic characterizations of a new ferromagnetic Ni(II) dimer

Single crystals of 1-methylpiperazine-1,4-diium hexaaquatetrachlorodinickel(II) dichloride, (C5H14N2)[Ni2Cl4(H2O)6]Cl2, were grown by hydrothermal techniques in aqueous solution. The compound was characterised by differential thermal analysis (TG-TDXD), single crystal X-ray diffraction, and variable temperature magnetic susceptibility. The compound crystallizes in the triclinic system (space group P-1, Z = 2) with the following unit cell dimensions: a = 6.611(3) A, b = 8.776(4) A, c = 17.457(8) A, α = 101.34(2)°, β = 96.31(2)°, and γ = 105.38(2)°. The structure was solved using 4,243 independent reflections and refined to R = 0.024. The structure of (C5H14N2)[Ni2Cl4(H2O)6]Cl2 can be described as mixed organic–inorganic layers along the [−101] direction. The Ni dimers show ferromagnetic exchange (J ~ 15 K), while the interactions between the dimers are antiferromagnetic (J ~ −3 K). The 3D network is further linked by three types of hydrogen bonds (N–H···Cl, OW–H···Cl, and N–H···O), in order to build cation–anion cohesion. Dehydration of the precursor proceeds through three stages, leading to crystalline intermediary hydrate phases and an anhydrous compound.

Structure, magnetic, and electric properties of bismuth niobates doped with d-elements: IX. State of nickel in the Bi2BaNi x Nb2−x O9−δ solid solutions with layered perovskite-like structure

The study of magnetic susceptibility of the Bi2BaNi x Nb2−x O9−δ solid solutions has shown that paramagnetic nickel atoms are present in diluted solutions as exchange-bound dimers formed by Ni(III) atoms in the high-spin state and characterized by the exchange parameter J of 12 cm−1. As the concentration of the solid solutions increases, clusters consisting of pairs of ferromagnetic Ni(III) dimers with antiferromagnetic exchange type and J = −170 cm−1 are formed.

An Unusual Example of Hypervalent Silicon: A Five‐Coordinate Silyl Group Bridging Two Palladium or Nickel Centers through a Nonsymmetrical Four‐Center Two‐Electron Bond

AbstractPd and Ni dimers supported by PSiP ligands in which two hypervalent five‐coordinate Si atoms bridge the two metal centers are reported. Crystallographic characterization revealed a rare square‐pyramidal geometry at Si and an unusual asymmetric M2Si2 core (M=Pd or Ni). DFT calculations showed that the unusual structure of the core is also found in a model in which the phosphine and Si centers are not part of a pincer group, thus indicating that the observed geometry is not imposed by the PSiP ligand. NBO analysis showed that an asymmetric four‐center two‐electron (4c‐2e) bond stabilizes the hypervalent Si atoms in the M2Si2 core.

An Unusual Example of Hypervalent Silicon: A Five‐Coordinate Silyl Group Bridging Two Palladium or Nickel Centers through a Nonsymmetrical Four‐Center Two‐Electron Bond

Pd and Ni dimers supported by PSiP ligands in which two hypervalent five-coordinate Si atoms bridge the two metal centers are reported. Crystallographic characterization revealed a rare square-pyramidal geometry at Si and an unusual asymmetric M2 Si2 core (M=Pd or Ni). DFT calculations showed that the unusual structure of the core is also found in a model in which the phosphine and Si centers are not part of a pincer group, thus indicating that the observed geometry is not imposed by the PSiP ligand. NBO analysis showed that an asymmetric four-center two-electron (4c-2e) bond stabilizes the hypervalent Si atoms in the M2 Si2 core.

Nickel Dimers Adsorbed on Graphene: First-Principles Study

The structural stabilities, electronic, and magnetic properties of Ni dimers adsorption on pure and single-vacancy graphene were studied using a first-principle method. It was found that structures of the Ni dimer adsorbed on single-vacancy graphene are more stable than those structures of the Ni dimer adsorbed on pure graphene. Total energy calculation results demonstrated that for Ni dimer adsorption on single-vacancy graphene and pure graphene, the most stable structure is PV2 where the Ni dimer is positioned perpendicular to the vacancy site and PH1 where Ni dimer standing perpendicular to hollow site. Furthermore, it indicated covalent bond was formed between Ni atoms and their nearest C atoms, suggestive of chemisorption. The structures where Ni dimer lay horizontal to the pure graphene layer (H(T1–T3), H(B1–B2), H(B1–B3)) showed strong magnetism, while the structures of dimer-adsorption structures on single-vacancy graphene do not exhibit magnetism. The electronic origin of magnetic states was located on Ni atoms, specifically the d orbit. The Ni dimer, positioned parallel to the graphene plane, offers the possibility for the formation of Ni atom chain or wire on graphene, which might have potential nanoelectronic applications.

First-principles studies of BN sheets with absorbed transition metal single atoms or dimers: stabilities, electronic structures, and magnetic properties

BN sheets with absorbed transition metal (TM) single atoms, including Fe, Co, and Ni, and their dimers have been investigated by using a first-principles method within the generalized gradient approximation. All of the TM atoms studied are found to be chemically adsorbed on BN sheets. Upon adsorption, the binding energies of the Fe and Co single atoms are modest and almost independent of the adsorption sites, indicating the high mobility of the adatoms and isolated particles to be easily formed on the surface. However, Ni atoms are found to bind tightly to BN sheets and may adopt a layer-by-layer growth mode. The Fe, Co, and Ni dimers tend to lie (nearly) perpendicular to the BN plane. Due to the wide band gap of the pure BN sheet, the electronic structures of the BN sheets with TM adatoms are determined primarily by the distribution of TM electronic states around the Fermi level. Very interesting spin gapless semiconductors or half-metals can be obtained in the studied systems. The magnetism of the TM atoms is preserved well on the BN sheet, very close to that of the corresponding free atoms and often weakly dependent on the adsorption sites. The present results indicate that BN sheets with adsorbed TM atoms have potential applications in fields such as spintronics and magnetic data storage due to the special spin-polarized electronic structures and magnetic properties they possess.

Extended X-ray Absorption Fine Structure and X-ray Diffraction Examination of Sputtered Nickel Carbon Binary Thin Films for Fuel Cell Applications

Extended X-ray absorption fine structure (EXAFS) and X-ray diffraction (XRD) are used to study the structure of sputtered binary nickel carbon alloy films (5–44 atom % Ni) for use as potential electrocatalysts in acidic solutions. Three compositional regions are identified: “low” (5 atom % Ni), where the structure consists mainly of isolated Ni atoms or dimers in a carbon matrix; “medium” (11–24 atom % Ni), where the Ni–Ni nearest-neighbor coordination is increased but there is little longer-range order; and “high” (35–44 atom % Ni), where crystalline Ni3C is formed. This indicates a threshold concentration of Ni of between 25 and 35 at% before Ni3C starts to form.

Catalytic Reactivity of CuNi Alloys toward H2O and CO Dissociation for an Efficient Water–Gas Shift: A DFT Study

Density functional theory (DFT) calculations are employed to study H2O and CO dissociations on a set of CuNi bimetallic surfaces aiming at exploring the optimal Ni ensemble on Cu(111) for an efficient water–gas shift (WGS) process, i.e., splitting H2O with high reactivity and avoiding CO activation. We found that Ni additives in the Cu(111) surface layer including a Ni monomer can remarkably enhance water splitting. Meanwhile, H2O dissociation barriers (Eact) are strongly correlated with the H adsorption energies (Ead): the larger Ead, the smaller Eact. Moreover, H2O dissociation may be more practical via the dissociated H* rather than OH closing to Ni atoms. For the scission of the C–O bond, the process is unfavorable on Ni monomers, though it is obviously promoted on Ni dimers, trimers, and other ensembles with higher Ni content. It is deduced that the selectivity of the Cu–Ni bimetallic catalysts toward WGS would decrease with increasing Ni concentration. These findings suggest that the bimetallic CuNi...

Weak Interactions Modulating the Dimensionality in Supramolecular Architectures in Three New Nickel(II)-Hydrazone Complexes, Magnetostructural Correlation, and Catalytic Potential for Epoxidation of Alkenes under Phase Transfer Conditions

Three different ONO donor acetyl hydrazone Schiff bases have been synthesized from the condensation of acetic hydrazide with three different carbonyl compounds: salicylaldehyde (HL(1)), 2-hydroxyacetophenone (HL(2)), and 2, 3-dihydroxybenzaldehyde (HL(3)). These tridentate ligands are reacted with Ni(OOCCF(3))(2)·xH(2)O to yield three new Ni(II) complexes having distorted octahedral geometry at each Ni center: [Ni(L(1))(OOCCF(3))(CH(3)OH)](2) (1), [Ni(L(2))(OOCCF(3))(H(2)O)](2) (2), and [Ni(L(3))(L(3)H)](OOCCF(3))(H(2)O)(1.65)(CH(3)OH)(0.35) (3). The ligands and the complexes have been characterized by elemental analysis and IR and UV-vis spectroscopy, and the structures of the complexes have been established by single crystal X-ray diffraction (XRD) study. 1 and 2 are centrosymmetric dinuclear complexes and are structural isomers whereas 3 is a bis chelated cationic monomer coordinated by one neutral and one monoanionic ligand. O-H···O hydrogen bonds in 3 lead to the formation of a dimer. Slight steric and electronic modifications in the ligand backbone provoke differences in the supramolecular architectures of the complexes, leading to a variety of one, two, and three-dimensional hydrogen bonded networks in complexes 1-3 respectively. Variable temperature magnetic susceptibility measurements reveal that moderate antiferromagnetic interactions operate between phenoxo bridged Ni(II) dimers in 1 and 2 whereas very weak antiferromagnetic exchange occurs through hydrogen bonding and π-π stacking interactions in 3. All complexes are proved to be efficient catalysts for the epoxidation of alkenes by NaOCl under phase transfer condition. The efficiency of alkene epoxidation is dramatically enhanced by lowering the pH, and the reactions are supposed to involve high valent Ni(III)-OCl or Ni(III)-O· intermediates. 3 is the best epoxidation catalyst among the three complexes with 99% conversion and very high turnover number (TON, 396).

Spectroscopic and Computational Studies of atrans-μ-1,2-Disulfido-Bridged Dinickel Species, [{(tmc)Ni}2(S2)](OTf)2: Comparison of End-on Disulfido and Peroxo Bonding in (NiII)2and (CuII)2Species

A powerful means of enhancing our understanding of the structures and functions of enzymes that contain nickel-sulfur bonds, such as Ni superoxide dismutase, acetyl-coenzyme A synthase/carbon monoxide dehydrogenase, [NiFe] hydrogenase, and methyl-CoM reductase, involves the investigation of model compounds with similar structural and/or electronic properties. In this study, we have characterized a trans-mu-1,2-disulfido-bridged dinickel(II) species, [{(tmc)Ni}(2)(S(2))](2+) (1, tmc = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) by using electronic absorption, magnetic circular dichroism (MCD), and resonance Raman (rR) spectroscopic techniques, as well as density functional theory (DFT) and time-dependent DFT computational methods. Our computational results, validated on the basis of the experimental MCD data and previously reported (1)H NMR spectra, reveal that 1 is best described as containing two antiferromagnetically coupled high-spin Ni(II) centers. A normal coordinate analysis of the rR vibrational data was performed to quantify the core bond strengths, yielding force constants of k(Ni-S) = 2.69 mdyn/A and k(S-S) = 2.40 mdyn/A. These values provide a useful basis for a comparison of metal-S/O bonding in 1 and related Ni(2)(O(2)), Cu(2)(O(2)), and Cu(2)(S(2)) dimers. In both the disulfido and the peroxo species, the lower effective nuclear charge of Ni(II) as compared to Cu(II) results in a decreased covalency, and thus relatively weaker metal-S/O bonding interactions in the Ni(2) dimers than in the Cu(2) complexes.

Structures and magnetic property studies of four copper(II) and nickel(II) supramolecular complexes derived from diphenic acid constructed by C–H⋯π and π–π interactions

Four one-dimensional metal–organic polymers derived from diphenic acid (H 2dpa) were synthesized in the presence of auxiliary ligands, [Cu(dpa)CH 3OH]( 1), [Ni(dpa)CH 3OH] ( 2), [Cu(bipy) 2(Hdpa) 2(H 2O) 2] ( 3) and [Ni(bipy) 2(Hdpa) 2(H 2O) 2] ( 4) (bipy = 4, 4′-bipyridine). The dinuclear paddle–wheel second building units (SBUs) constructed by four dpa 2− ligands in complexes 1 and 2 are linked by dpa 2− into double chains, which are connected by C–H⋯π interactions forming a two-dimensional rhombic porous structure. In complexes 3 and 4, the metal ions are connected by bipy ligands, and the grid-like network was formed with the π–π interactions between the adjacent phenyl rings of Hdpa −. For 1 and 2, there are strong antiferromagnetic interactions within Cu–Cu and Ni–Ni dimers. It is also strong antiferromagnetic interactions between the dimmers of Cu 2 in 1, while it is weaker of those of Ni 2 in 2. Weaker antiferromagnetic interactions exist among Cu–Cu and Ni–Ni in 3 and 4, in which bipy is the effective coupling media. Thermally gravimetric analyses and differential thermal analyses indicate that the four complexes are all thermal stable.