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The facile synthesis of the first bis‐N‐heterocyclic imine‐stabilized chlorosilyliumylidene 1 is reported. Remarkably, consecutive reaction of 1 with PPh3AuCl and K2Fe(CO)4 gives rise to the unique heterobimetallic complex 1,2‐(MesNHI)2‐C2H4‐ClSiAuFe(CO)4 (4). The overall neutral complex 4 bears an unusual linear Si−Au−Fe structure and a rare anagostic interaction between the d10‐configured gold atom and a CH bond of the mesityl ligand. According to the computational analysis and 57Fe Mössbauer spectroscopy, the formal Fe‐oxidation state remains at −II. Thus, the electronic structure of 4 is best described as an overall neutral—yet zwitterionic—heterobimetallic "Si(II)+‐Au(I)+‐Fe(‐II)2−"‐silyliumylidene complex, derived from double anion exchange. The computational analysis indicates strong hyperconjugative back donation from the gold(I) atom to the silyliumylidene ligand. [ABSTRACT FROM AUTHOR]

A series of isostructural 3D lanthanoid coordination polymers, {[Ln(µ4-cbpy)2]Br·xsolvent}n (Ln = La(1), Pr(2), Nd(3), Sm(4), Gd(5), Tb(6), Dy(7) and Ho(8), (H2cbpy)Br = 4-carboxy-1-(4-carboxybenzyl)pyridinium bromide), have been solvothermally synthesized and characterized by single-crystal X-ray diffraction, IR and elemental analysis. Powder X-ray diffraction (PXRD) and thermal analyses (TG, DTA and DTA) of 1–8 were also investigated. The single crystal X-ray diffraction analyses revealed that 1–8 were isostructural and crystallized in the monoclinic space group C2/c. In the complexes, each cbpy– acts as a tetrakis(monodentate) to connect to four Ln(III) ions. A pair of Ln(III) ions are coordinated by four carboxylate oxygen atoms to form paddle-wheel {Ln2(RCOO)4} secondary building units which are connected by four cbpy– ligand to form a 3D structure with scu topology. [ABSTRACT FROM AUTHOR]

[Display omitted] • 3,5-Dicarboxy-1-(3-cyanobenzyl)pyridin-1-ium bromide compound was synthesized and characterized. • Four new coordination compounds (1–4) were synthesized and characterized. • In the compounds 1, 2 and 4, the metal centers were bridged by cbpy ligands to form a 2D layers. • The compund 3 exhibited monunuclear structure and the cbpy ligand displays bidentate coordination mode. • The photoreaction property of compound 4 was investigated and it exhibited color change from pale yellow to dark yellow under 365 nm UV light. Four new Cu(II) and Cd(II) coordination compounds, formulated as the {[Cu 2 (μ-cbpy) 2 (μ-cbpy) 2 (H 2 O) 2 ]⋅2H 2 O} n (1), {[Cu(μ-cbpy) 2 ]⋅2H 2 O} n (2), [Cu(cbpy) 2 (im) 2 ]⋅4H 2 O (3) and [Cd(μ-cbpy) 2 (H 2 O) 2 ] n (4) (H 2 cbpyBr: 3,5-dicarboxy-1-(3-cyanobenzyl)pyridin-1-ium bromide, im: imidazole) were synthesized and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction techniques. Structural analysis indicates that compounds 1 , 2 and 4 exhibit 2D layer structures which are are further linked into 3D supramolecular architectures through hydrogen bonding, C−H⋯O, C−N⋯π and π⋯π interactions whereas compound 3 exhibits mononuclear structure. The photoreaction property of compound 4 was investigated and it exhibited color change from pale yellow to dark yellow under 365 nm UV lamp. The thermal properties and phase purities of compounds 1 – 4 were investigated by thermal analyses (TG, DTA and DTA) and powder X-ray diffraction (PXRD) techniques. [ABSTRACT FROM AUTHOR]

[Display omitted] • Copper(II) zwitterionic coordination polymers as effective catalysts for cyanosilylation of aldehydes. • Reaction assisted by non-covalent interactions (cation-π and tetrel bondings). • High yield of cyanohydrin trimethylsilyl ethers is achieved in methanol at room temperature. • Catalytic properties can be tuned by varying organic linkers in coordination polymers. The new 1D copper(II) coordination polymers (CPs) [Cu(μ -L1)(H 2 O)] n (1 , H 2 L1 = 2-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)benzoic acid) and [Cu(μ -H 2 L2)(H 2 O)] n (2 , H 4 L2 = (Z)-2-(2-(1,3-dioxo-1-(phenylamino)butan-2-ylidene)hydrazinyl)terephthalic acid) and the known zwitterionic 1D CP [Cu 2 (H 2 O) 2 (μ -H 2 L3)(μ -L3)] n (3 , H 3 L3 = 2-(2-(4,4-dimethyl-2,6-dioxocyclo-hexylidene)hydrazinyl)terephthalic acid) were synthesized and tested as homogeneous catalysts for cyanosilylation of a variety of aldehydes to the corresponding cyanohydrin trimethylsilyl ethers. Among these polymeric catalysts, 3 , with a zwitterionic charater, is the most effective one, giving 86–99% yield of the ethers upon reaction of aliphatic and aromatic aldehydes with trimethylsilyl cyanide in methanol at room temperature in 4 h. Non-covalent interactions (cation-π and tetrel bondings) involving the aldehyde substrate are proposed to assist the cyanosilylation reaction. [ABSTRACT FROM AUTHOR]

New ligand precursors with different pendent alky chain length were obtained in a single step by reacting appropriate 1-alkyl-2-methyl-1 H -imidazoles with chloroacetone in THF at 80 °C overnight. Zwitterionic palladium complexes were prepared by reacting PdCl 2 with these new imidazole derivatives in DMF with the presence of pyridine and Cs 2 CO 3 as base at room temperature for 5 h. These new compounds were characterized by 1 H and 13 C{ 1 H} NMR spectroscopy, elemental analysis, and electrospray ionization mass spectrometry. They were effectively applied as recyclable catalysts for mediating Mizoroki–Heck reactions in ionic liquids. Transmission emission microscopy revealed that palladium nanoparticles were formed during the catalytic process. [ABSTRACT FROM AUTHOR]

In aqueous medium at pH 6, cadmium acetate dihydrate combines with 4,6-dimethylpyrimidine-2-thiol to form a centrosymmetric Cl, S-bridged complex having zwitterionic terminals. The zwitterionic nature of this complex is evidenced by its pH and conductance values in methanol solution. It crystallizes in the space group P2/c (Z = 4 asymmetric units, two molecules), each molecule being uncommonly characterized by a centric Cd(II)SClN as well as two acentric and anionic Cd(II)SClN coordination chromophores with counter cationic ligands. Relevant literature reports indicate a template relation between the structural designs of this complex and hydrated cadmium acetate, the metalorganic precursor. Packing of molecular motifs through weak C-H···N and strong charge-enhanced N-H···N interactions generate the crystal structure with numerous screw-glide related small voids. Attempt has been made to rationalize the crystallochromic nature of the complex (pale green in solution, pale orange while crystalline) by time dependent DFT and ZINDO/S studies. Graphical Abstract: In aqueous medium, cadmium acetate combines with 4,6-dimethylpyrimidine-2-thiol to form a centrosymmetric, trinuclear complex with zwitterionic terminals. The crystallochromic behaviour of this complex is investigated by quantum chemical treatment.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: A flexible dicarboxylic acid having composition [(CH(o-C5H4N)(p-C6H4OCH2CO2H)2] derived from corresponding bis-phenol reacts with various metal(II) acetates such as manganese(II), cobalt(II) and nickel(II) acetate leads to zwtterionic complexes with compositions [CH(o-C5H4N)(p-C6H4OCH2CO2){p-C6H4OCH2CO2M(H2O)5}].6H2O (where M = Mn, Co, Ni). The complexes are characterised by X-ray crystallography. These complexes have chiral center due to unsymmetric structure conferred to the ligand through coordination at only one carboxylate group of the ligand. In solid state these complexes are racemic. [Copyright &y& Elsevier]

At pH 5.5, coordination between Cd and 4,6-dimethylpyrimidine-2-thiol was studied using CdCl and Cd(NO). For both of these, the same complex, bis-4,6-dimethylpyrimidinium-2-thiolato cadmium (II) chloride was invariably formed. It crystallized from water in the space group P2/c, Z = 4 (a = 12.955(2) Å, b = 8.429(1) Å, c = 15.727(2) Å, β = 97.19(0)°), displaying a distorted tetrahedral molecular geometry characterized by a [CdClS] chromophore. The negative charge on the coordination zone is intramolecularly compensated by protonation of one azomethine N in each of the two thiolpyrimidine ligands, resulting in a tripolar zwitterion; its aqueous solution is consequently acidic and highly conducting. The crystal structure is mainly characterized by two kinds of charge-driven H-bonding interactions generated in pairs by the inversion symmetry of the space group and translation symmetry of its periodic lattice. This ultimately results in extensive intermolecular interactions, forming left handed zigzag H-bond networks and a consequent supramolecular growth along b. Spectroscopic studies agree well with the proposed molecular structure. The aqueous solubility of the complex and a high 50% lethal dose (mice) of its ligand seem to indicate development of the pyrimidinethiol moiety into a prospective antidote to Cd toxicity. Graphical Abstract: (DMPT)ClCd(II)-a tripolar zwitterion generating zigzag supramolecules through charge-augmented H-bonds in solid state.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: Reactions of ω-diphenylphosphinofunctionalized alkyl phenyl sulfides Ph2P(CH2) n SPh (n = 1, 1a; 2, 2a; 3, 3a), sulfoxides Ph2P(CH2) n S(O)Ph (n = 1, 1b; 2, 2b; 3, 3b) and sulfones Ph2P(CH2) n S(O)2Ph (n = 1, 1c; 2, 2c; 3, 3c) with dinuclear chlorido bridged rhodium(I) complexes [(RhL2)2(μ-Cl)2] (L2 = cycloocta-1.5-diene, cod, 4; bis(diphenylphosphino)ethane, dppe, 5) afforded mononuclear Rh(I) complexes of the type [RhCl{Ph2P(CH2) n S(O) x Ph-κP}(cod)] 1 [1] Here and in the following the letters a, b, and c in the numbering schemes refer to a sulfanyl (x = 0), sulfinyl (x = 1) and sulfonyl (x = 2) functionality, respectively. (n/x = 1/0, 6a; 1/1, 6b; 1/2, 6c; 2/0, 8a; 2/1, 8b; 2/2, 8c; 3/0, 10a; 3/1, 10b; 3/2, 10c) and [RhCl{Ph2P(CH2) n S(O) x Ph-κP}(dppe)] (n/x = 1/0, 7a; 1/1, 7b; 1/2, 7c; 2/0, 9a; 2/1, 9b; 2/2, 9c; 3/0, 11a; 3/1, 11b; 3/2, 11c) having the P^S(O) x ligands κP coordinated. Addition of Ag[BF4] to complexes 6–11 in CH2Cl2 led with precipitation of AgCl to cationic rhodium complexes of the type [Rh{Ph2P(CH2) n S(O) x Ph-κP,κS/O}L2][BF4] having bound the P^S(O) x ligands bidentately in a κP,κS (13a–18a, 15b–18b) or a κP,κO (13b, 14b, 13c–18c) coordination mode. Unexpectedly, the addition of Ag[BF4] to 6a in THF afforded the trinuclear cationic rhodium(I) complex [Rh3(μ-Cl)(μ-Ph2PCH2SPh-κP:κS)4][BF4]2·4THF (12·4THF) with a four-membered Rh3Cl ring as basic framework. Addition of sodium bis(trimethylsilyl)amide to complexes 6–11 led to a selective deprotonation of the carbon atom neighbored to the S(O) x group (α-C) yielding three different types of organorhodium complexes: a) Organorhodium intramolecular coordination compounds of the type [Rh{CH{S(O) x Ph}CH2CH2PPh2-κC,κP}L2] (22a–c, 23a–c), b) zwitterionic complexes [Rh{Ph2PCHS(O) x Ph-κP,κS/O}L2] having κP,κS (21a, 21b) and κP,κO (20b/c, 21c) coordinated anionic [Ph2PCHS(O) x Ph] ligands, and c) the dinuclear rhodium(I) complex [{Rh{μ-CH(SPh)PPh2-κC:κP}(cod)}2] (19). All complexes were fully characterized spectroscopically and complexes 15b, 15c, 12·4THF and 19·THF additionally by X-ray diffraction analysis. DFT calculations of zwitterionic complexes gave insight into the coordination mode of the [Ph2PCHS(O)Ph] ligand (κP,κS versus κP,κO). [Copyright &y& Elsevier]

Abstract: Complexation between Zn2+ and 4,6-dimethylpyrimidine-2-thiol was attempted with ZnO, ZnSO4 and Zn(OAc)2. In all cases, the same compound, tris-4,6-dimethylpyrimidine-2-thiolato zinc (II) was generated without anion incorporation. It crystallized from methanol in the space group P21/a, Z =4. The molecular structure exemplifies an uncommon coordination of 3 ligands to Zn(II) through their thiolate centres; one of the ligands is protonated to effectively form a zwitterionic complex, which exhibits capped rectangular pyramidal coordination geometry of an anionic ZnN2S3 chromophore. In crystalline state, the ligand moieties differ in respect of orientations and interactions while in solution they behave as identical components of a symmetric molecule. The crystal structure is stabilized by π stacking and periodic H-bonding interactions along a . The presence of a protonated azomethine N in one of the ligands is confirmed from the high conductance and acidic pH of an aqueous methanolic solution of the complex. [Copyright &y& Elsevier]

Abstract: Treatment of TeCl4 with either K[{N(C6H3Pri 2-2,6)C(H)}2CPh] [≡K(L)] (1) in thf/Et2O or [H2(L)]Cl (2) in Et2O furnished [Cl4 ClHHOEt2]·0.5(Et2O) (3), whilst 2TeCl4 with a mixture of single equivalent portions of 2,6-Pri 2C6H3NH2 and H(L) produced [Cl4 ] (4). The X-ray structures of each of crystalline 3 and 4 show that the Te atom is at the centre of an only slightly distorted square pyramid, with a Cl atom of 3 or a C of 4 in the axial position. The N1 and N2 atoms of the π-delocalised β-dialdiminium moiety of 3 have H-bond contacts, involving short N1–HOEt2 and N2–HCl5 distances. The two longer of the four Te–Cl bonds of 4 are close to the N atom of the neighbouring molecule; whilst two of the H atoms of each H3 fragment are H-bonded to the O atoms of the two thf ligands, the third being close to two Cl atoms of an adjacent molecule, thus forming H-bonded chains of molecules. [Copyright &y& Elsevier]

Abstract: The reactions of phosphonium salt, [PPh2CH2PPh2CH2C(O)Ph]Br with Hg(II) halides in methanol formed the zwitterionic products with the composition [HgCl2(Br)(PPh2CH2PPh2CH2C(O)Ph)] (2), [HgBr3(PPh2CH2PPh2CH2C(O)Ph)] (3), [HgBr2(I)(PPh2CH2PPh2CH2C(O)Ph)] (4). A product of composition, [HgCl3(PPh2CH2PPh2CH2C(O)Ph)] (5) was obtained when the ylide, Ph2PCH2PPh2 was treated with HgCl2 in CH2Cl2 and crystallized under aerobic conditions. The complexes were characterized by elemental analysis, IR, 1H, 31P NMR spectra and also by X-ray crystallography. The absence of significant coordination chemical shifts in the 31P NMR spectra indicates the presence of formal negative charge on mercury. The single crystal X-ray structures confirm the presence of Hg–P bond and also reveal a distorted tetrahedral geometry around the mercury atom in all the structures. [Copyright &y& Elsevier]

The SPh functionalized vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)=Cβ(SPh)Cα=N(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] [R = Xyl, R′ = Me, 2a; R = Me, R′ = Me, 2b; R = 4-C6H4OMe, R′ = Me, 2c; R = Xyl, R′ = CH2OH, 2d; R = Me, R′ = CH2OH, 2e; Xyl = 2,6-Me2C6H3] are generated in high yields by treatment of the corresponding vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)=Cβ(H)CαN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (1a–e) with NaH in the presence of PhSSPh. Likewise, the diruthenium complex [Ru2{μ-η1:η3-Cγ(Me)=Cβ(SPh)Cα=N(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] (2f) was obtained from the corresponding vinyliminium complex [Ru2{μ-η1:η3-Cγ(Me)=Cβ(H)Cα=N(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (1f). The synthesis of 2c is accompanied by the formation, in comparable amounts, of the aminocarbyne complex [Fe2{μ-CN(Me)(4-C6H4OMe)}(SPh)(μ-CO)(CO)(Cp)2] (3).The molecular structures of 2d, 2e and 3 have been determined by X-ray diffraction studies. [Copyright &y& Elsevier]

The zwitterionic vinyliminium complex [Fe2{μ-η1:η3-C(R′)ᆖC(S)CᆖN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (2a) (R′ = p-Me-C6H4 (Tol), Xyl = 2,6-Me2C6H3) undergoes electrophilic addition at the S atom by HSO3CF3, MeSO3CF3, SiMe3Cl, BrCH2Ph, ICH2CHᆖCH2 affording the complexes [Fe2{μ-η1:η3-C(Tol)ᆖC(SX)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][Y] (X = H, Y = SO3CF3, 4a; X = Me, Y = SO3CF3, 4b; X = SiMe3, Y = Cl, 4c; X = CH2Ph, Y = Br, 4d; X = CH2CHᆖCH2, Y = I, 4e). Compound 2a and the corresponding vinyliminium complexes 2b and 2c (R′ = CH2OH, 2b; R′ = Me, 2c) react also with etherated BF3 leading to the formation of the corresponding S-adducts [Fe2{μ-η1:η3-C(R′)ᆖC(SBF3)CᆖN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (R′ = Tol, 5a; R′ = CH2OH, 5b; R′ = Me, 5c). In analogous reactions, the zwitterionic vinyliminium complexes undergo S-metalation upon treatment with in situ generated [Fp]+[SO3CF3]− [Fp = Fe(CO)2(Cp)], leading to the formation of [Fe2{μ-η1:η3-C(R′)ᆖC(S–Fp)CᆖN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3](R′ = CH2OH, 6a; R′ = Me, 6b; R′ = Bun, 6c). Similarly, zwitterionic vinyliminium containing Se in the place of S also undergo Se-electrophilic addition. Thus, the complexes [Fe2{μ-η1:η3-C(R′)ᆖC(SeX)CᆖN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (R = X = Me, R′ = Tol, 7a; R = Xyl, R′ = Me, X = Fp+, 7b) are obtained upon treatment of the neutral zwitterionic precursors with MeSO3CF3 and [Fp][SO3CF3], respectively. Alkylation at the S or Se atom of the bridging ligand is also accomplished by CH2Cl2, used as solvent, although the reaction is slower compared to more efficient alkylating reagents. The complexes formed by this route are [Fe2{μ-η1:η3-C(R′)ᆖC(E-CH2Cl)CᆖN(Me)(R)}(μ-CO)(CO)(Cp)2][X] [E = S, R = Xyl, R′ = Tol, X = Cl, 8a; E = S, R = Xyl, R′ = Me, X = Cl, 8b; E = Se, R = R′ = Me, X = BPh4, 8c]. Finally, treatment of the zwitterionic vinyliminium complexes with I2 results in the oxidative coupling with formation of S–S (disulfide) or Se–Se (diselenide) bond. The reactions, performed in the presence of NaBPh4 afford the tetranuclear complexes [Fe2{μ-η1:η3-C(R′)ᆖC(E)CᆖN(Me)(R)}(μ-CO)(CO)(Cp)2]2[BPh4]2 [R = Xyl, R′ = CH2OH, E = S, 9a; R = Xyl, R′ = Me, E = S, 9b; R = Xyl, R′ = Bun, E = S, 9c; R = Xyl, R′ = Me, E = Se, 9d; R = Me, R′ = Bun, E = Se, 9e]. The molecular structures of 4a, 8c and 9e have been determined by X-ray diffraction studies. [Copyright &y& Elsevier]

Abstract: Formal [3+2] cycloaddition reactions between the bis-sulfonium zirconocene-ate dimer ▪1a and methylpropiolate, benzaldehyde and carbon disulfide afforded stable zwitterionic phosphonium zirconocene-ate complexes 2–4, respectively, with two orthocondensed five-membered heterocycles. X-ray crystal structure of 4 has been determined. Elemental chalcogens (S, Se, Te) gave rise also to a new variety of five-coordinate zirconium(IV) complexes (5–7) by a formal [3+1] cycloaddition reaction. In these bicyclic zirconates, sulfur is included in a five-membered ring while the second chalcogen is in a four-membered one. [Copyright &y& Elsevier]

[N-(2-Benzoylphenyl)benzamido-κ2N,O](η1-benzyl)(trimethylphosphine)Ni(II) (3) is prepared by the reaction of potassium N-(2-benzoylphenyl)benzamide and Ni(η3-CH2C6H5)Cl(PMe3). When 3 is treated with one equivalent of B(C6F5)3, one obtains a zwitterionic complex, [PhC(O)&z.sbnd;C6H4&z.sbnd;N&z.dbnd6;C(Ph)OB(C6F5)3-κ2N,O]Ni(η1-CH2C6H5)(PMe3) (4). When two equivalents of B(C6F5)3 is added, PMe3 is abstracted to give a η3-benzyl zwitterionic complex, [PhC(O)&z.sbnd;C6H4&z.sbnd;N&z.dbnd6;C(Ph)OB(C6F5)3-κ2N,O]Ni(η3-CH2C6H5) (5). Solid structures of 4 and 5 were determined by X-ray crystallography. When ethylene is added to 5, low molecular weight polyethylene is obtained. [Copyright &y& Elsevier]

Reaction of the chelating diamido complexes Zr(ABAn)(CH2Ph)2 [ABA1=N,N′-(SiMe3)2-2-amidobenzylamido, ABA2=N,N′-(SiMePh2)(SiMe3)-2-amidobenzylamido] with B(C6F5)3 leads to formation of the unstable zwitterionic adducts [Zr(ABAn)(CH2Ph)][(η6-PhCH2)B(C6F5)3] 1 (n=1) and 2 (n=2), as shown by low temperature NMR experiments that, moreover, enabled an insight into the molecular structure of these compounds in solution. Two intermediates of the decomposition of 1 and 2, that leads to complexes Zr(ABAn)(C6F5)2, were identified. [Copyright &y& Elsevier]

New mixed‐valence cobalt complexes with ligands derived from pyridoxal were synthesized and characterized, and their application as mimetics of the peroxidase enzyme was investigated. Single‐crystal X‐ray diffraction was used to analyze all complex structures in the solid state and their electrochemical behavior was investigated. A reactivity pattern was observed in the complex synthesis regarding the cobalt compounds from which analogous zwitterionic derivatives were obtained. The importance of these compounds lies in understanding their behavior in an oxidizing environment and evaluating whether they can activate hydrogen peroxide to oxidize phenolic compounds. In nature, enzymes called peroxidases, which efficiently oxidize phenolic compounds, trigger many reactions involving the activation of hydrogen peroxide to oxidize organic substrates. However, these enzymes present several disadvantages, including denaturation and elevated costs. Therefore, these limitations can be overcome by expanding research into the study of synthetic catalysts for the oxidation of phenolic compounds using hydrogen peroxide, which is a highly relevant field of bioinorganic chemistry. [ABSTRACT FROM AUTHOR]

The Fe(II) spin crossover complex [Fe{H 2 B(pz) 2 } 2 (bipy)] (pz = pyrazol-1-yl, bipy = 2,2'-bipyridine) can be locked in a largely low-spin-state configuration over a temperature range that includes temperatures well above the thermal spin crossover temperature of 160 K. This locking of the spin state is achieved for nanometer thin films of this complex in two distinct ways: through substrate interactions with dielectric substrates such as SiO 2 and Al 2 O 3 , or in powder samples by mixing with the strongly dipolar zwitterionic p-benzoquinonemonoimine C 6 H 2 (-⋯ NH 2 ) 2 (-⋯ O) 2 . Remarkably, it is found in both cases that incident X-ray fluences then restore the [Fe{H 2 B(pz) 2 } 2 (bipy)] moiety to an electronic state characteristic of the high spin state at temperatures of 200 K to above room temperature; that is, well above the spin crossover transition temperature for the pristine powder, and well above the temperatures characteristic of light- or X-ray-induced excited-spin-state trapping. Heating slightly above room temperature allows the initial locked state to be restored. These findings, supported by theory, show how the spin crossover transition can be manipulated reversibly around room temperature by appropriate design of the electrostatic and chemical environment., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)