An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The activation of a CPh−H bond in the phenyl ring of 2-(4-bromophenyl)imidazol[1,2-a]pyridine (HC∧N) by [{Pt(η3-C4H7)(μ-Cl)}2] (η3-C4H7 = η3-2-methylallyl) renders the new cyclometalated complex [{Pt(C∧N)(μ-Cl)}2] (2) with high yield and selectivity. Complex 2 can be achieved directly in a one-pot reaction or step by step through the intermediate [Pt(η3-C4H7)Cl(HC∧N-κN)] (1). Compound 1 could be isolated and fully characterized. The X-ray structure shows the coordination of HC∧N through only the N and the existence of a weak Pt···H−C hydrogen bridging bond (Pt···H1 = 2.78 Å, Pt···C1 = 3.365(3) Å, Pt−H1−C1 = 120.9°). Hence, the formation of this intermediate could be considered the first step in the cyclometalation process. The mononuclear complexes [PtCl(C∧N)L] (L = tht (3), PPh3 (4), CN-Xyl (5), CN-tBu (6)) were obtained by cleavage of the bridging system in [{Pt(C∧N)(μ-Cl)}2] (2) by the neutral ligands, L. The resulting geometry (trans C, Cl) is that expected from the electronic preferences, taking into account the degree of transphobia (T) of pairs of trans ligands, T[C(C∧N)/L(Cl)] < T[C(C∧N)/L(S, P, C)]. Complexes [PtCl(C∧N)L] (L = CN-Xyl (5), CN-tBu (6)) containing two strong-field ligands, a CC∧N σ-bonded and an isocyanide ligand, are luminescent. TD-DFT calculations were performed for the singlet ground state, S0, as well as for the first triplet excited state of 6 in both the gas phase and solution. Calculations indicate that the lowest-lying absorption involves mainly 1IL (C∧N) mixed with a small contribution of 1MLCT/1L′LCT (L = C∧N; L′ = Cl) transitions. Complex 5 exhibits "luminescent thermochromism" in the solid state; at 77 K it shows a green phosphorescence band assigned to 3IL transitions located on the C∧N group of monomer species, while at 298 K an orange-red emission is observed, being tentatively assigned to excited states of emissive aggregates (3MMLCT/3π−π*). However complex 6 shows phosphorescence only at 77 K both in solution and in the solid state with the emissions arising from 3IL and 3L′MLCT excited states of monomer species.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

This work describes the synthesis of the compounds Q[Pt(C∧P)(C⋮CPh)2] (Q = Li+ (1), NBu4+ (2). C∧P = CH2C6H4P(o-tolyl)2-κC,P) and their use as precursors for the preparation of homo- and heteropolynuclear complexes by reactions with Lewis acid species of transition metals, M (M = Cu(I), Ag(I), Tl(I), Pd(II), Pt(II)). These reactions give rise to heteropolynuclear complexes that exhibit different bonding patterns for the bridging alkynyl ligands, depending on M. The reaction of 2 with readily available M+ (M = Cu, Ag) species affords the discrete tetranuclear clusters [{Pt(C∧P)(C⋮CPh)2M}2] (M = Cu (3), Ag (4)). The X-ray structure of 3 shows that in this complex both "Pt(C∧P)(C⋮CPh)2" fragments are connected by two d10 metal centers and are stabilized by alkynyl bridging ligands, showing the stronger preference of the MI centers (MI = Cu, Ag) for the electron-rich alkynyl units than for the basic Pt(II) center. However, the reaction of 2 with TlPF6 rendered the tentatively tetranuclear complex [{Pt(C∧P)(C⋮CPh)2Tl}2] (5), containing Pt→Tl dative bonds, which shows the higher affinity of thallium for the electron density of platinum(II) than for the alkynyl units. Moreover, the reaction of (NBu4)[Pt(C∧P)(C⋮CPh)2] (2) with the neutral complex [Pd(C6F5)2(THF)2] yields the compound (NBu4)[Pt(C∧P)(C⋮CPh)2Pd(C6F5)2] (11), in which the two alkynyl ligands are η2-bonded to Pd(II) in such a way that the "cis-Pt(C⋮CPh)2" fragment acts as a chelate ligand toward Pd(II). Meanwhile the reactions with the cationic and neutral Pt(II) complexes [Pt(C∧P)(THF)2]+ and [Pt(C6F5)2(THF)2] produce the complexes [{Pt(C∧P)(μ-C⋮CPh)}2] (6) and (NBu4)[Pt(C∧P)(μ-C⋮CPh)2Pt(C6F5)2] (12), both containing the double μ2-η2(σ,π)-alkynyl bridging system "Pt2(μ-C⋮CPh)2" as a consequence of an alkynylating process. This bridging system "Pt2(μ-C⋮CPh)2" can be broken by neutral ligands, L, to give mono(σ-alkynyl) complexes of Pt(II). Thus, the complexes [Pt(C∧P)(C⋮CPh)L] (L = CO (7), py (8), tht (9), PPh3 (10)) have been obtained by reaction of 6 with L in a 1:2 molar ratio. When L = PPh3, the substitution reaction takes place with stereoretention, but not when L = CO, py, tht, as was conclusively established by an X-ray study on the complex [Pt(CH2C6H4P(o-tolyl)2)(CCPh)(CO)] (7). The cis or trans disposition of the two σ-C-donor ligands (C(C∧P), σ-C⋮CPh) around the Pt center in complexes 6−10 and 12 seems to depend as much on the transphobia of pairs of trans ligands (T) as on the steric requirements of those in the cis configuration.

A novel series of [PtTl(2)(C[triple chemical bond]CR)(4)](n) (n = 2, R = 4-CH(3)C(6)H(4) (Tol) 1, 1-naphthyl (Np) 2; n = infinity, R = 4-CF(3)C(6)H(4) (Tol(F)) 3) complexes has been synthesized by neutralization reactions between the previously reported [Pt(C[triple chemical bond]CR)(4)](2-) (R = Tol, Tol(F)) or novel (NBu(4))(2)[Pt(C[triple chemical bond]CNp)(4)] platinum precursors and Tl(I) (TlNO(3) or TlPF(6)). The crystal structures of [Pt(2)Tl(4)(C[triple chemical bond]CTol)(8)]4 acetone, 14 acetone, [Pt(2)Tl(4)(C[triple chemical bond]CNp)(8)]3 acetone1/3 H(2)O, 23 acetone 1/3 H(2)O and [[PtTl(2)(C[triple chemical bond]CTol(F))(4)](acetone)S](infinity) (S = acetone 3 a; dioxane 3 b) have been solved by X-ray diffraction studies. Interestingly, whereas in the tolyl (1) and naphthyl (2) derivatives, the thallium centers exhibit a bonding preference for the electron-rich alkyne entities to yield crystal lattices based on sandwich hexanuclear [Pt(2)Tl(4)(C[triple chemical bond]CR)(8)] clusters (with additional Tlacetone (1) or Tlnaphthyl (2) secondary interactions), in the C(6)H(4)CF(3) (Tol(F)) derivatives 3 a and 3 b the basic Pt(II) center forms two unsupported Pt-Tl bonds. As a consequence 3 a and 3 b form an extended columnar structure based on trimetallic slipped PtTl(2)(C[triple chemical bond]CTol(F))(4) units that are connected through secondary Tl(eta(2)-acetylenic) interactions. The luminescent properties of these complexes, which in solution (blue; CH(2)Cl(2) 1,2; acetone 3) are very different to those in solid state (orange), have been studied. Curiously, solid-state emission from 1 is dependent on the presence of acetone (green) and its crystallinity. On the other hand, while a powder sample of 3 is pale yellow and displays blue (457 nm) and orange (611 nm) emissions, the corresponding pellets (KBr, solid) of 3, or the fine powder obtained by grinding, are orange and only exhibit a very intense orange emission (590 nm).

Reaction of the trinuclear Pt(III)-Pt(III)-Pt(II) [(C6F5)2Pt(III)(mu-PPh2)2Pt(III)(mu-PPh2)2Pt(C6F5)2] (2) derivative with NBu4Br or NBu4I results in the formation of the trinuclear Pt(II) complexes [NBu4][(PPh2C6F5)(C6F5)Pt(mu-PPh2)(mu-X)Pt(mu-PPh2)2Pt(C6F5)2] [X = I (3), Br (4)] through an intramolecular PPh2/C6F5 reductive coupling and the formation of the phosphine PPh2C6F5. The trinuclear Pt(II) complex [(PPh2C6F5)(C6F5)Pt(mu-PPh2)Pt(mu-PPh2)2Pt(C6F5)2] (5), which displays two Pt-Pt bonds, can be obtained either by halide abstraction in 4 or by refluxing of 2 in CH2Cl2. This latter process also implies an intramolecular PPh2/C6F5 reductive coupling. Treatment of complex 5 with several ligands (Br-, H-, and CO) results in the incorporation of the ligand to the cluster and elimination of one (X = H-) or both (X = Br-, CO) Pt-Pt bonds, forming the trinuclear complexes [NBu4][(PPh2C6F5)(C6F5)Pt(mu-PPh2)(mu-X)Pt(mu-PPh2)2Pt(C6F5)2] [X = Br (6), H (7)] or [(PPh2C6F5)(C6F5)Pt(mu-PPh2)2Pt(mu-PPh2)(CO)Pt(C6F5)2(CO)] (8). The structures of the complexes have been established on the basis of 1H, 19F, and 31P NMR data, and the X-ray structures of the complexes 2, 3, 5, and 7 have been established. The chemical relationship between the different complexes has also been studied.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The reactions of cis-[Pt(C6F5)2(PPh2)2]2− with [AuClPPh3] or [Ag(OClO3)PPh3] yield the neutral heterotrinuclear complexes [M2Pt(μ-PPh2)2(C6F5)2(PPh3)2] (M = Au, Ag). Their structures have been established by X-ray diffraction studies and both complexes display M⋯M interactions but not Pt–M bonds. They are dynamic in solution, as demonstrated by 19F NMR spectroscopy, and M⋯M interactions seem to be present at low temperature.

The two-electron oxidation reactions of the neutral [(C6F5)(2)M(mu-PR2)(2)M'(NCCH3)(2)] (M = M' = Pt or Pd, M = Pt, M' = Pd) complexes using I-2 as oxidant have been investigated by experimental (R = Ph) and electronic structure calculation methods (R = H). It was found that a reductive coupling of PR, and C6F5 takes place along the reaction pathway for all oxidized complexes. The most salient structural features of the [(C6F5)(2)Pt(mu-PR2)(2)Pd(C6F5)(2)](2-), [(C6F5)(2)Pd(mu-PR2)(2)Pd(acac)](-), and [(C6F5)(2)Pt(mu-PR2)(2)PtI2] complexes (experimental R = Ph) are reproduced very well by the B3LYP/lan12dz calculations (R = H).

Treatment of (NBu4)2[PtR4] (R = C6F5) with 1 or 0.5 equiv of TlNO3 in EtOH/H(2)O produces colorless crystals of trinuclear complex (NBu4)3[Tl{PtR4}2], 1, in which the Tl+ center is complexed by two [PtR4]2- fragments (Pt-Tl = 2.9777(4) and 3.0434(4) A). The expected mixed complex with a Pt/Tl composition of 1:1, 2, is generated as an orange microcrystalline solid by treating [PtR4]2- with a large excess of TlNO3 (approximately 8 equiv). Crystallographic analysis of 2 reveals the formation of a novel one-dimensional (1D) heterometallic linear chain (NBu4)(infinity)[Tl{PtR4}](infinity), 2, formed by alternating a [PtR4]2- fragment and a Tl+ center with a uniform Pt-Tl bond separation along the chain of 3.0321(2) A. Surprisingly, treatment of (NBu4)2[PtR4] with 1 equiv of TlPF6 in EtOH yields pale greenish-yellow needles of an unusual adduct, 2.{(NBu4)(PF6)}(infinity) (3), which was found to form a similar extended linear chain, {TlPtR4}(infinity), constructed by two alternating Pt-Tl separations, a shorter (3.1028(6) A) one and a longer (3.2306(6) A) one. The solid state and solution photophysical properties have been examined. While complex 1 shows a high-energy MM'CT blue phosphorescence (450 nm), the extended chain in 2 exhibits a lower-energy emission (582 nm) than that in adduct 3 (505 nm). For products 2 and 3, interesting luminescence thermochromism is observed in frozen solutions. The emissions are found to be strongly dependent on the solvent, concentration, and excitation wavelength.

This article describes the preparation, characterization, and optical properties of new bi- and trinuclear tweezer-type platinum cadmium derivatives, stabilized by eta(2)-alkyne-cadmium bonding. Treatment of Q(2)[cis-Pt(C6F5)(2)(C equivalent to CR)(2)] (1a-1c) with CdCl2 center dot 2,5 H2O (1:1) produces dinuclear Pt-Cd adducts Q(2)-R [{cis-Pt(C6F5)(2)(mu-kappa C-alpha:eta(2)-C equivalent to CR)(2)}(CdCl2)] (Q = NBu4, R = t-Bu 2a; Q = PMePh3, R = Ph 2b; R = Tol 2c). However, reaction of (NBu4)[cis-Pt(C6F5)(2)(C equivalent to CR)(2)] with Cd(NO3)(2)center dot 4H(2)O produces trinuclear Pt2Cd dianionic complexes (NBu4)(2)[{cis-Pt(C6F5)(2)(mu-kappa C-alpha:eta(2)-C equivalent to CR)(2)}(2)Cd] (3a-3c). The analogous (PMePh3)(2)[{cis-Pt(C6F5)(2)(mu-kappa C-alpha:eta(2)-C equivalent to CR)(2)}(2)Cd] (R = Ph 3b'; Tol 3c') were prepared similarly starting from (PMePh3)(2)[{cis-Pt(C6F5)(2)(C equivalent to CR)(2)]. The crystal structures of 2c and 3a,b show that the cadmium center is well embedded by the cis-bis(alkyne)platinate entities, leading to planar PtC4Cd cores. In the heterometallic species, the low-energy absorption, which is ascribed to an admixture of pi ->pi*(C equivalent to CR) IL/d pi(Pt) -> pi*(C equivalent to CR) MLCT, exhibits a clear hypsochron-tic shift compared to its precursors, probably due to the existence of a lesser delocalization on the alkynyl fragments upon the eta(2)-complexation. The arylalkynyl derivatives (b, c) display intense structured emission bands, arising from (3)pi pi*(C equivalent to CR) (IL) and/or mixed (3)pi pi*/Pt(d(pi))(C equivalent to CR) -> pi*(C equivalent to CR) ((MLCT)-M-3) manifolds with a predominant IL character.

The compound [Pd(Hdmpz)(4)](O2CCH2NHCOCH3)(2) (1; (Hdmpz = 3,5-dimethylpyrazole) has been obtained by treatment of [Pd(dmpz)(2)(Hdmpz)(2)] (A) with two equivalents of N-acetylglycine (HO2CCH2NHCOCH3). The X-ray study on a crystal of 1 revealed that the N-acetylglycinate anion links to the cationic complex [Pd(HdmpZ)(4)](2+) through the carboxylate group by charge assisted N-H(+)...O(-) hydrogen bonds. Additionally, the remaining N-H and C=O groups allow the N-acetylglycinate anions to self-assemble through N-(HO)-O-... hydrogen bonds to generate infinite chains. The compounds [Pd-2(mu-dmpz)(2)(O2CCH2NHCOCH3-kO)(2)(Hdmpz)(2)] (2) and [Pd-2(mu-dmpz)(2)(O2CC6H4-R-kO)(2)(Hdmpz)(2)] [R = m-NO2 (3a), p-N(CH3)(2) (3b), p-NH2 (3c), p-OCH3 (3d), p-OH (3e)] have been obtained by treatment of [Pd-2(mu-dmpz)(2)(dmpz)(2)-(Hdmpz)(2)] (B) with two equivalents of the monocarboxylic acids N-acetylglycine (HO2CCH2NHCOCH3) and the benzoic derivatives HO2CC6H4R [R = m-NO2, p-N(CH3)(2), p-NH2, p-OCH3, p-OH] respectively. The X-ray study on complexes 3d and 3e shows that in these complexes the carboxylate anion bonded to one Pd atom and the terminal Hdmpz group bonded to the other one have the right arrangement to establish an N-(HO)-O-... hydrogen bond. The (HO)-O-... and (NO)-O-... distances are in the range of those corresponding to charge-assisted N-H(+)...O(-) interactions. In complexes 3a-3e, the H atoms of the terminal Hdmpz groups can be replaced by Ag+ to give the mixed-metal complexes [Pd2Ag2(mu-dmpz)(4)(mu-O2CC6H4-R-kO)(2)(Hdmpz)(2)] [R = m-NO2 (4a), p-N(CH3)(2) (4b), p-NH2 (4c), p-OCH3 (4d), p-OH (4e)]. Compounds 4a-4e, which exhibit a transoid conformation of the carboxylate groups with respect to the (PdPd)-Pd-... line, isomerise to the cisoid species (4a'-4e'). The X-ray structure of the DMSO adduct of 4d' is also reported. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).

Ethene has been found to be able to split the electron-deficient pentafluorophenyl bridging system in [NBu4](2)[{M(C6F5)(2)}(mu-C6F5)(2)] to give the corresponding mononuclear compounds [NBu4][M(C6F5)(3)(eta(2)-C2H4)] (M = Pt (1), Pd (2)) in reasonable yield. Compounds 1 and 2 are well-behaved species and have been isolated and characterized by analytical and spectroscopic methods. The crystal structure of 2, as established by X-ray diffraction methods, reveals that the Pd atom is in an approximately SP-4 environment defined by the ipso-C atoms of the three sigma-bound C6F5 groups (C6F5-kappa(1)) and the midpoint between the doubly bonded C atoms of the metal T-bound ethene molecule (eta(2)-C2H4). The ethene molecule is coordinated upright, and the C=C bond length (133.6(6) pm) is the same as in the free ligand (133.7(2) pm). The nickel homologue [NBu4][Ni(C6F5)(3)(eta(2)-C2H4)] (3), formed by the low-temperature reaction of [NBu4](2)[Ni(C6F5)(4)] with B(C6F5)(3) in the presence of C2H4, could not be isolated but only spectroscopically detected in solution. The experimentally established stability of the [M(C6F5)(3)(eta(2)-C2H4)](-) species has been found to follow the trend calculated by DFT methods for the M-(eta(2)-C2H4) bond strength: Pt > Pd > Ni. Furthermore, quantitative estimates of back-bonding in the [M(C6F5)(3)(eta(2)-C2H4)](-) and [MCl3(eta(2)-C2H4)](-) anions were obtained using NBO analyses of electron populations of the relevant donor-acceptor orbitals and the second-order stabilization energy associated with the charge transfer (CT) interactions describing the back-bonding phenomenon.

A series of mononuclear cyclometalated benzo[h]quinolinate platinum and palladium(II) complexes with phosphine ligands, namely, [M(bzq)ClL] (L=PPh2H, Pt 1, Pd 2; PPh2CCPh, Pt 3, Pd 4), [Pt(bzq)(PPh2H)(PPh2CCPh)]ClO4 5, [Pt(bzq)(PPh2C(Ph)=C(H)PPh2)]ClO4 6, and [Pt(bzq)(CCPh)(PPh2CCPh)] (7a, 7b), were synthesized. The X-ray crystal structures of 1, 6.CH3COCH3.1/2CH3(CH2)4CH3, and 7b.CH3COCH3 have been determined. In 1, the metalated carbon atom and the P atom are mutually cis, whereas in 7b they are trans located. For complex 6, C and N are crystallographically indistinguishable. Reaction of [Pt(bzq)(mu-Cl)]2 with PPh2H and excess of NEt3 leads to the phosphide-bridge platinum dimer [Pt(bzq)(mu-PPh2)]2 8 (X-ray). Moderate pi-pi intermolecular interactions and no evident Pt-Pt interactions are found in 1, 7b, and in 8. All of the complexes exhibit absorption bands at high energy due to the intraligand transitions (1IL pi --> pi) and absorptions at lower energy which are attributed to MLCT (5d) pi --> pi (CLambdaN) transition. Platinum complexes show strong luminescence in both solid state and frozen solutions. The influence of the coligands on the photophysics of the platinum complexes has been examined by absorption and emission spectroscopy.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The preparation of the [NBU4][Pt(C6F5)(3)L] complexes (L = triazene, 1; formamidine, 2; 2-aminopyridine, 3) have been carried out. These ligands contain a hydrogen atom, with more or less acidic character, in a position suitable for establishing an intramolecular hydrogen bonding interaction with the metal center. This interaction has been detected in solution for 1; its H-1 NMR spectrum shows that the resonance assignable to this hydrogen has platinum satellites. For 2, this coupling is not observed, and the interaction, if it exists, has to be weaker because of the less acidic character of the hydrogen atom. The 2-aminopyridine ligand is more flexible than the triazene or formamidine, and also in this case, no evidence of the interaction in solution is obtained. Nevertheless, if another potential proton acceptor is present, such as ClO4- in [NBU4](2)[Pt(C6F5)(3)(C5H6N2)](ClO4) (4), a conventional N-(HO)-O-...-Cl hydrogen bond is formed. The crystal structures of complexes 1-4 have been determined by X-ray diffraction.