Tin Complexes Research Articles

SYNTHESIS, STRUCTURE OF MONO- AND BINUCLEAR COMPLEXES OF Sn(IV) WITH DIHYDRAZONES OF AROMATIC ALDEHYDES

By interaction of SnCl 4 with condensation products of dihydrazides of oxalic, terephthalic, malonic acids and R-benzoic aldehydes (R = Н, 4-N(CH 3 ) 2 , 2-OH) in acetonitrile, the following complexes were synthesized: with oxaloyl- [SnCl 4 (H 2 Oxb)]∙CH 3 CN (R = Н, I ), [SnCl 4 (Oxdb∙2H)]·2CH 3 CN (R = 4-N(CH 3 ) 2 , II ), [SnCl 4 (H 4 Oxs)]∙CH 3 CN (R = 2-OH, III ), терефталоїл- [(SnCl 4 )2(μ-Tfdb·2H)]∙2CH 3 CN (R = 4-N(CH 3 ) 2 , IV ), [SnCl 4 (μ-H 2 Tfs)]∙CH 3 CN (R = 2-OH, V ), malonoyldihydrazones- [SnCl 4 (μ-Maldb·2H)]·2CH 3 CN (R = 4-N(CH 3 ) 2 , VI ), [SnCl 4 (μ-H 2 Mals)] ∙ CH 3 CN (R = 2-OH, VII ). Their composition and structure are established by the methods of elemental analysis, conductometry, thermogravimetry, and IR spectroscopy. It was established that in the absence of a spacer (X = 0) in the dihydrazone molecules of R-benzoic aldehydes (R = H, 2-OH, 4-N(CH 3 ) 2 ) – oxaloyl dihydrazones, regardless of the presence of functional groups (CН=N, OH) as part of these molecules, SnCl 4 forms only mononuclear complexes I-III with the same O,O- coordination and composition of the coordination node, the charge of which is determined by a substituent (R) in the aldehyde fragment: R = H, 2-OH – {SnCl 4 O 2 }, R = 4-N(CH 3 ) 2 – {SnCl 4 O 2 } 2- . In the presence of a spacer in dihydrazone molecules, regardless of their stereochemical rigidity (X = -C 6 H 4 -, -CH 2 -), only if R = 2-OH, 4-N(CH 3 ) 2 , binuclear Sn(IV) complexes are formed with spatially separated coordination nodes, the composition of the nodes and the dihydrazone denatism is been determined by the substituent (R): R = 4-N(CH 3 ) 2 – {SnCl 4 ON} 2 - (tetra- in IV, VI ), R = 2-OH – {SnCl 3 O 2 N} (hexacoordinated ligand in V, VII ). Coordination of dihydrazones in a enol form, both in mono- ( II ) and in binuclear complexes ( IV, VI ), is a consequence of the presence of vacant nitrogen atoms in the aldehyde fragments of their molecules (R = 4-N(CH3)2); due to their protonation, a negative charge is compensated, which is localized in this case at the coordination sites of the zwitterionic complexes {SnCl 4 O 2 } 2- ( II ) and {SnCl 4 ON} 2- ( IV , VI ). The patterns of the formation of each spatially separated coordination node and the tautomeric form of the ligands in IV-VII are the same as in mononuclear tin(IV) complexes.

Unprecedented isolation of a dinuclear tin (II) complex stabilized by pyridine‐2,6‐dimethanol: structure, DFT and in vitro screening of cytotoxic properties

In this work, we report a novel dinuclear Sn (II) complex, [Sn2(Hpdm)2(H2O)6] 2H2O 2Cl (1) (H2pdm = pyridine‐2,6‐dimethanol), which has been crystallized out and characterized by elemental analysis, FTIR, 1H and 13C NMR, single crystal X‐ray studies and Density Functional Theory (DFT) analysis. X‐ray structure of 1 has confirmed it to be a dinuclear alkoxo‐bridged Sn (II) species where each metal adopts a seven coordinate distorted pentagonal bipyramidal (pbp) geometry. This is the first hepta‐coordinated Sn (II) complex ever isolated apart from already reported stannylenes. Spin density plots from DFT support the +2 oxidation state of each tin metal. Hirshfeld surface analysis reveals the presence of various H‐bonding interactions in the molecule and molecular docking results along with DFT confirm higher binding affinity of the present complex towards DNA. Moreover, the complex exhibits promising anticancer activities against HeLa and A549 cancer cell lines.

Electrochemical Studies of Thiosemicarbazone Derivative and Its Tin(IV) Complex as Corrosion Inhibitor for Mild Steel in 1 M Hydrochloric Acid

Electrochemical Studies of Thiosemicarbazone Derivative and Its Tin(IV) Complex as Corrosion Inhibitor for Mild Steel in 1 M Hydrochloric Acid

The Synthesis of Quinoline‐based Tin Complexes with Pendant Schiff Bases

Whilst pursuing the synthetic utility of quinoline‐based tin complexes, Me2Sn(Quin‐NO2)2 (1) and Ph2Sn(Quin‐NO2)2 (2) (Quin‐NO2 = 5‐nitroquinolino‐8‐oate) were synthesized bearing coordinatively inert nitro groups. Conventional reduction methodologies successfully converted 1 to Me2Sn(Quin‐NH2)2 (3) and 2 to Ph2Sn(Quin‐NH2)2 (4) (Quin‐NH2 = 5‐aminoquinolino‐8‐oate). The synthetically useful amine groups proved difficult to exploit in the presence of the central tin atom, however, a complete Schiff base functionalized Sn complex of the dimethyltin pro‐ligand Me2Sn(Quin‐py)2 (6) was successfully synthesized from 5‐[(pyridin‐2‐ylmethylene)amino]quinolin‐8‐ol (HQuin‐py; 5) in good yield via an alternative strategy exploiting the oxophilic tendencies of tin. All species were fully characterized by NMR (including 119Sn NMR spectroscopy), HR‐ESI MS and single‐crystal X‐ray diffraction, and preliminary studies of their supramolecular potential are also discussed.

Synthesis of Telmisartan Organotin(IV) Complexes and their use as Carbon Dioxide Capture Media.

Novel, porous, highly aromatic organotin(IV) frameworks were successfully synthesized by the condensation of telmisartan and an appropriate tin(IV) chloride. The structures of the synthesized organotin(IV) complexes were elucidated by elemental analysis, 1H-, 13C-, and 119Sn-NMR, and FTIR spectroscopy. The surface morphologies of the complexes were inspected by field emission scanning electron microscopy. The synthesized mesoporous organotin(IV) complexes have a Brunauer–Emmett–Teller (BET) surface area of 32.3–130.4 m2·g−1, pore volume of 0.046–0.162 cm3·g−1, and pore size of around 2.4 nm. The tin complexes containing a butyl substituent were more efficient as carbon dioxide storage media than the complexes containing a phenyl substituent. The dibutyltin(IV) complex had the highest BET surface area (SBET = 130.357 m2·g−1), the largest volume (0.162 cm3·g−1), and was the most efficient for carbon dioxide storage (7.1 wt%) at a controlled temperature (323 K) and pressure (50 bars).

NEW PYRIDINE-3-SULFONATO TIN (IV), ANTIMONY (III) AND (V) HALO ADDUCTS AND COMPLEXES: SYNTHESIS AND INFRARED STUDY

Six new tin (IV), antimony (III) and antimony (V) adducts and complexes have been synthesized. Discrete structures were suggested on the basis of infrared data. Within the structures, the anion behaves as a bidentate, monochelating and monodentate, monodentate and tri O-chelating ligand. The environments around metallic centres are octahedral. Considering preamble of extra hydrogen bonds in compounds containing water molecules and/or OH groups, supramolecular architectures may be given rise.

Syntheses, Structures, and Infrared Spectra of the Hexa(cyanido) Complexes of Silicon, Germanium, and Tin.

The rare octahedral EC6 coordination skeleton type is unknown for complexes with coordination centers consisting of group 14 elements. Here, the first examples of such EC6 species, the hexacoordinate homoleptic cyanido complexes E(CN)62-, E = Si, Ge, Sn, have been synthesized from element halides SiCl4, GeCl4 and SnF4 and isolated as salts with PPN counterions (PPN+ = (Ph3P)2N+) on a scale of 0.2-1 g. Characterization by spectroscopic techniques and by structure determination through single crystal crystallographic methods show that these pseudohalogen complexes have effective octahedral symmetry in solution and in the solid state. Infrared spectra obtained in solution reveal that the T1 u symmetric IR-active vibrations in all three complexes have unusually small oscillator strengths. The observed reluctance of Si(CN)62-, Ge(CN)62-, and Sn(CN)62- to form from chloro-precursors was rationalized in terms of Gibbs free energies, which were found by ab initio calculations at the CCSD(T)-F12b/aug-cc-pVTZ(-PP)-F12 level of theory to be small or even positive. The work demonstrates that E(CN)62- complexes of silicon, germanium and tin are in fact stable at room temperature and exist as well-defined units in the presence of noncoordinating counterions. The results add to our understanding of the chemistry of pseudohalogens and structure and bonding.

Tin(IV) Schiff base complexes: Synthesis, thermodynamic and anti bacterial investigation, experimental and theoretical studies

A series of five coordinated diorganotin(IV) unsymmetrical Schiff base complexes have been synthesized. The structure determination and characterization of these complexes were made on the basis of UV-Vis, IR, ( 1 H and 119 Sn) NMR spectroscopy as well as elemental analysis. The binding site of the ligand was identified by IR spectroscopic measurement. Computational analyses at the level of DFT were performed to study its electronic and molecular structures. The molecular geometry, infrared vibrational frequencies, HOMO-LUMO energy gap, dipole moment, Mulliken charges, HF energies were calculated. The theoretical results were consistent with the experimental data reported. The Schiff base ligands and synthesized tin(IV) complexes were screened for their in vitro growth inhibiting activity against different strains of bacteria. Results indicated that the complexes exhibited good antibacterial activities than the ligands. Also the thermodynamic formation constants of the Schiff bases as donors with Me 2 SnCl 2 as an acceptor were measured using UV-Vis spectrophotometric titration for 1:1 complex formation at constant ionic strength (I = 0.1 M NaClO 4 ) and at 25 oC. KEY WORDS : Tin(IV) complexes, Thermodynamic parameter, Biological activity, Computational analyses Bull. Chem. Soc. Ethiop. 2019 , 33(1), 77-90 DOI: https://dx.doi.org/10.4314/bcse.v33i1.8

Template Synthesis of Tin(IV) Complexes with Tridentate Iminopyridine Ligands

Six-coordinate metal complexes containing tridentate Schiff bases with an ONN-chelating moiety were prepared by template synthesis on tin tetrachloride using various aminophenols and α-carbonyl-substituted pyridines. The structures of five compounds were studied by X-ray diffraction (CIF files CCDC nos. 849152–1849156). The UV/Vis spectra of the obtained series of compounds were found to be highly sensitive to the nature of substituents in the moieties of organic ligand.

N → Sn coordination in the complexes of tin halides with pyridine: A comparison between Sn(II) and Sn(IV)

The experimentally well‐known complexation of tin(II) and tin(IV) halides with pyridine (py) leads to structures showing N → Sn coordination. In the present work, the complexes SnXn·mpy (where X = F, Cl, Br, I; n = 2, 4; m = 1, 2) possessing this kind of coordination were studied using a computational quantum chemical approach. Various aspects in the theoretical picture of these complexes were examined to find similarities and differences in their N → Sn coordination. The aspects included, among others, the physical nature of intermolecular interactions, and their role in establishing the structure and energetic stabilization of the complexes. In this context, the effect of tin valency was inspected in great detail. As proven by several theoretical methods, a largely ionic character with a certain covalent component can be attributed to the studied N → Sn coordination, irrespective of tin valency. All complexes are destabilized by py‐py and three‐body interactions, but the Sn(II) complexes experience it to a greater extent. Marked differences are observed in the structural behavior of N → Sn and SnXn during complex formation. This affects the energetics of complexation and, in consequence, the penta‐coordinated Sn(IV) center shows a higher propensity to expand its coordination number, compared with the tri‐coordinated Sn(II) center. The present study supplements the experimental characterization of SnXn·mpy and, in general, it sheds light on the coordination of heteroaromatic nitrogen to tin. The survey of the Cambridge Structural Database revealed that such coordination occurred in a number of crystal structures.

Formation Mechanism and Nucleation Effect of Ti2O3–TiN Complex Nucleus at Solidification Front of 18Cr Ferritic Stainless Steel

Formation mechanism of Ti2O3–TiN complex nucleus and its nucleation effect on δ-Fe at solidification front of Fe-18Cr ferritic stainless steel was investigated through experimental and theoretical methods. According to the equilibrium calculation, Ti2O3 will crystallize in the molten steel before solidification and TiN will not form until the solid phases appear. However, complex nucleus and equiaxed grains exist in the edge of Ti-bearing ingot, where the solidification velocity and temperature gradient are high. Therefore, complex nucleus is indicated to be formed at solidification front and a non-equilibrium solidification model for multi-component alloy was established to investigate the dendrite tip interface phenomenon. The calculation results exhibit an element enrichment at solidification front and explain well with the formation of complex nucleus before solidification. It is also found that there is approximate lattice matching between TiN, and Ti2O3, δ-Fe on the basis of disregistry theory. These results are consistent with the observed complex nucleus and the increased equiaxed zone ratio (EZR) of Ti-bearing ferritic stainless steel.

Computational Thermochemistry of Mono- and Dinuclear Tin Alkyls Used in Vapor Deposition Processes.

Hexamethylditin has been reported to be a more effective precursor compared to monotin analogs in hybrid molecular beam epitaxy depositions of perovskite oxides. To understand the differences, a library of 68 monotin- and ditin-containing molecules bearing hydrido and/or carbon-based ligands was generated, and their structures were optimized using density functional theory. On the basis of a modified W1-F12 composite thermochemical method, thermochemical data (enthalpy of formation, entropy, and heat capacity) were calculated for each structure over a range of temperatures (298-5000 K). The application of the modified W1-F12 method to heavy element compounds was benchmarked against existing experimental and computational studies of mononuclear hydrido, alkyl, and mixed hydridoalkyl complexes of silicon, germanium, and tin. The library of thermodynamic data was used in partial equilibrium calculations from 300 to 1500 K to determine gas phase compositions resulting from the pyrolysis of tetramethyltin and hexamethylditin at 10-6 and 760 Torr.

Sonochemical synthesis of a nanodandelion tin(IV) complex with carbacylamidophosphate ligand as anti-Alzheimer agent: Molecular docking study

The dandelion-shaped nanostructure of an organotin complex with formula Sn(CH3)2Cl2}NC5H4C(O)NHP(O)[NHC6H11]2}2 (C1) was synthesized by means of a sonochemical method. Nano-structures were characterized by elemental analysis, NMR, SEM-EDS, XRD, UV–Vis, and FT-IR spectroscopy. The thermal stability of the complex C1 has been studied by thermal gravimetric analysis (TGA), and compared to the bulk form (C2). Both the morphology and the size of the ultrasound-assisted synthesized organotin complex have been investigated using scanning electron microscopy (SEM) by changing such parameters as the concentration of initial reactants and the sonication frequency. Two different forms of the organotin complex (C1, C2) and the corresponding ligand (L) were evaluated by a modified Ellman’s method on acetyl- and butyrylcholinesterase enzymes. Nanodendalion C1 and ligand L showed the best activity against AChE and BChE, respectively, with the IC50 values being 326.59 μg/ml and 426.68 μg/ml. Further, Lineweaver Burk plots indicated that these compounds are mixed inhibitors. The synthesized compounds and cholinesterase enzymes were simulated by molecular docking for more details concerning the conformation and the orientations of these compounds in the active site of the receptor.

Electrochemical Studies on Corrosion Inhibition Behaviour of Synthesised 2-acetylpyridine 4-ethyl-3-thiosemicarbazone and Its Tin(IV) Complex for Mild Steel in 1 M HCl Solution

Electrochemical Studies on Corrosion Inhibition Behaviour of Synthesised 2-acetylpyridine 4-ethyl-3-thiosemicarbazone and Its Tin(IV) Complex for Mild Steel in 1 M HCl Solution

Schiff Bases and their Metal Complexes as Potential Anticancer Candidates: A Review of Recent Works.

Schiff bases and their metal complexes are emerging as key classes of medicinal compounds, possessing an enormous potential of biological activities like anticancer, anticonvulsant and antioxidant etc. The aim of this review is to examine the anticancer activity of different classes of Schiff bases and their metal complexes. Anticancer activity of the already synthesized as well as the novel Schiff bases and their metal complexes was studied using different assays such as 3- [4,5-dimethyltiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT), PI staining, Sulforhodamine, Allium cepa, Sulfo- Rhodamine-B-stain(SRB), viability and potato disc against various human and animal cancer cell lines. The test results indicated significant differences in anticancer activity between subclasses of Schiff base compounds as well as between the Schiff base ligands and their metal complexes. Quinazolines showed a very high activity against HepG2 and MCF-7 cell lines. Pyrazole-naphthalene derivatives exhibited high activity against numerous carcinoma cells while [Ni(HL1)2(OAc)2] showed the highest. Azosal and its tin(IV) complexes displayed high activity against U-1242 MG and excellent activity against HCT-116 cell lines. 2-thiouracil sulfonamides displayed high activity against MCF7, CaCo-2 carcinoma cells. Vitamin-B6 and its oxovanadium complex showed good activity against MCF-7, 3T3 and cervical cancer HeLa cancer cell lines in the presence of visible light. Indoles displayed high activity against AMJ13. Porphyrines derivatives exhibited good activity while its binuclear(Y and K) complexes displayed high activity against several carcinoma cells. Chitosan complexes of [Pd(II) and Pt(II)] showed a very high anticancer activity against MCF-7 carcinoma cell. Schiff bases possess a high potential to inhibit carcinoma cells which enhanced with complexation, but the mechanism of their antitumor activity is still doubt.

Coordination-induced metal-to-macrocycle charge transfer and effect of cations on reorientation of the CN ligand in the {SnL2Mac}2- dianions (L = CN-, OCN-, Im-; Mac = phthalo- or naphthalocyanine).

A series of anionic coordination complexes of tin(ii) phthalocyanine (Pc) with cyanide, cyanate, and imidazolate (Im) anions (1, 3, and 4, respectively) and tin(ii) naphthalocyanine (Nc) with cyanide anions (2) has been obtained. Two anions coordinate to tin(ii) atoms in 1-4 to form the {SnL2Mac}2- dianions in salts with the general formula {crypt[2.2.2](M+)}2{SnL2Mac}2- (M = K or Na; Mac: Pc or Nc; L = CN-, OCN-, Im-). The coordination of two ligands to SnII stabilizes these atoms in the higher tin(iv) oxidation state, providing transfer of two electrons from SnII to the macrocycle. The formation of tetraanionic (4-) macrocycles is accompanied by the appearance of new absorption bands in the NIR range, essentially blue-shifting both Soret and Q bands, and noticeable distortion in the macrocycles in 2-4, showing alternation of the C-C and C-N bonds. However, such distortions are not observed in 1. The absence of alternation in the case of 1 can be explained by the effect of uncompensated electric field from the surrounding cations, which stabilizes the macrocycle configuration with aligned bonds but nonuniform negative charge distribution on the imine nitrogen atoms. The cyanide ligand coordinates to SnPc by a nitrogen atom in 1, forming a Sn-N bond of 2.339(1) Å in length, whereas the cyanide ligand coordinates to SnNc by a carbon atom in 2, forming a shorter Sn-C bond of 2.266(3) Å in length. DFT calculations support the reorientation of the CN ligand in 1, which is induced by the electrostatic field of closely located cations.

2,6-Bis(benzimidazol-2-yl)pyridine complexes of group 14 elements

Treatment of MCl2 (M = Ge or Sn) with 2,6-bis(benzimidazol-2-yl)pyridine (G-BZIMPY, G = NBn, N(3,5-CF3)Bn, NAllyl and O) yielded the self-ionization products [G-BZIMPYMCl][MCl3] (1-6) in high yields (75-98%). Reduction reactions are examined and the nickel complexes 8 and 9 ([(NBn-BZIMPY)2Ni][MCl3]2) are isolated from the reaction of Ni(COD)2 with 1 and 2 respectively. [NBn-BZIMPYSnCl][SnCl3] shows a significantly stronger MLCT band in the UV-vis absorption spectrum than its germanium counterparts, with germanium complexes exhibiting negative solvatochromism that is not observed in tin complexes.

Neutral and cationic phosphine and arsine complexes of tin(iv) halides: synthesis, properties, structures and anion influence.

The reaction of trans-[SnCl4(PR3)2] (R = Me or Et) with trimethylsilyltriflate (TMSOTf) in CH2Cl2 solution substitutes one chloride to form [SnCl3(PR3)2(OTf)]; addition of excess TMSOTf does not substitute further chlorides. The complexes have been fully characterised by microanalysis, IR and multinuclear NMR (1H, 13C{1H}, 19F{1H}, 31P{1H}, 119Sn) spectroscopy. The crystal structure of [SnCl3(PMe3)2(OTf)] revealed mer-chlorines and trans-phosphines. In contrast, trans-[SnBr4(PR3)2], [SnCl4{Et2P(CH2)2PEt2}], [SnCl4{o-C6H4(PMe2)2}] and [SnCl4{o-C6H4(AsMe2)2}] did not react with TMSOTf in CH2Cl2 solution even after 3 days. The arsine complexes, [SnX4(AsEt3)2] (X = Cl, Br), were confirmed as trans-isomers by similar spectroscopic and structural studies, while attempts to isolate [SnI4(AsEt3)2] were unsuccessful and reaction of SnX4 with SbR3 (R = Et, iPr) resulted in reduction to SnX2 and formation of R3SbX2. trans-[SnCl4(AsEt3)2] is converted by TMSOTf into [SnCl3(AsEt3)2(OTf)], whose X-ray structure reveals the same geometry found in the phosphine analogues, with the triflate coordinated. The salts, [SnCl3(PEt3)2][AlCl4] and [SnCl2(PEt3)2][AlCl4]2 were made by treatment of [SnCl4(PEt3)2] with one and two mol. equivalents, respectively, of AlCl3 in anhydrous CH2Cl2, whereas reaction of [SnCl4(AsEt3)2] with AlCl3 produced a mixture including Et3AsCl2 and [Et3AsCl][Sn(AsEt3)Cl5] (the latter identified crystallographically). In contrast, using Na[BArF] (BArF = [B{3,5-(CF3)2C6H3}4]-) produced [SnCl3(PEt3)2][BArF] and also allowed clean isolation of the arsine analogue, [SnCl3(AsEt3)2][BArF]. [SnCl4{o-C6H4(PMe2)2}] also reacts with AlCl3 in CH2Cl2 to form [SnCl3{o-C6H4(PMe2)2}][AlCl4] and [SnCl2{o-C6H4(PMe2)2}][AlCl4]2. Multinuclear NMR spectroscopy on the [AlCl4]- salts show that δ31P and δ119Sn move progressively to high frequency on conversion from the neutral complex to the mono- and the di-cations, whilst 1J(119Sn-31P) follow the trend: [SnCl3{o-C6H4(PMe2)2}]+ > [SnCl4{o-C6H4(PMe2)2}] > [SnCl2{o-C6H4(PMe2)2}]2+. DFT studies on selected complexes show only small changes in ligand geometries and bond lengths between the halide and triflate complexes, consistent with the X-ray crystallographic data reported and the HOMO and LUMO energies are relatively unperturbed upon the introduction of (coordinated) triflate, whereas the energies of both are ca. 4 eV lower in the cationic species and reveal significant hybridisation across the pnictine ligands.

Nano-Based Systems and Biomacromolecules as Carriers for Metallodrugs in Anticancer Therapy

Since the discovery of cisplatin and its potency in anticancer therapy, the development of metallodrugs has been an active area of research. The large choice of transition metals, oxidation states, coordinating ligands, and different geometries, allows for the design of metal-based agents with unique mechanisms of action. Many metallodrugs, such as titanium, ruthenium, gallium, tin, gold, and copper-based complexes have been found to have anticancer activities. However, biological application of these agents necessitates aqueous solubility and low systemic toxicity. This minireview highlights the emerging strategies to facilitate the in vivo application of metallodrugs, aimed at enhancing their solubility and bioavailability, as well as improving their delivery to tumor tissues. The focus is on encapsulating the metal-based complexes into nanocarriers or coupling to biomacromolecules, generating efficacious anticancer therapies. The delivery systems for complexes of platinum, ruthenium, copper, and iron are discussed with most recent examples.

State of the Art of Boron and Tin Complexes in Second- and Third-Order Nonlinear Optics §

Boron and tin complexes have been a versatile and very interesting scaffold for the design of nonlinear optical (NLO) chromophores. In this paper we present a wide range of reports since the 1990s to date, which include second-order (e.g., second harmonic generation) and third-order (e.g., two-photon absorption) NLO properties. After a short introduction on the origin of the NLO response in molecules, the different features associated with the introduction of these inorganic motifs in the organic-based NLO materials are discussed: Their effect on the accepting/donating capabilities of the substituents, on the efficiency of the π-conjugated linkage, and on the topology of the chromophores which can be tuned from the first generation of “push-pull” chromophores to more sophisticated two- or three-dimensional architectures.