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archives@tulane.edu / This dissertation is dedicated to the study of the synthesis, crystal structures, properties, and reactivity of heteroleptic metallodithiolene complexes of the Group 10 metals. In this work, we report a systematic survey of the reactivity of [(Ph2C2S2)2M] (M = Ni, Pd, Pt) toward ligand substitution. The upshots of the survey are the clarification of the attributes of the incoming ligand that facilitate ligand displacement, creation of a new set of heteroleptic dithiolene complexes, [M(Ph2C2S2)(C≡NR)2] (M = Ni, Pd, Pt; R = Me, Bn, Cy, tBu, 1-Adamantyl, Ph), and improvement in the efficiency by which mixed-ligand “push-pull” compounds are made. The scope of dithiolene ligand displacement by incoming ligands was expanded beyond the already reported phosphine and diimine ligands. Spectroscopic and physical characterization techniques including S K-edge X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) were used in conjunction with DFT computational methods to establish the properties of the compounds prepared in this study. Representative [(Ph2C2S2)Pt(C≡NR)2] (R = aryl) complexes exihibited low temperature luminscence in frozen solvent glasses with relatively long lifetimes. The relevance of the dithiolene redox non-innocence in the ligand substitution mechanism has also been elucidated, thereby giving an insight into the fate of the displaced dithiolene ligand. Redox disproportionation between two radical monoanionic dithiolene ligands leads to the creation of a dithione, which is an enhanced leaving group and an inherently reactive species. When displacement of dithiolene ligand from [(Ph2C2S2)2Ni] was conducted with a twofold excess of C≡NCy, 4,5-diphenyl-1,3-dithiol-2-cyclohexylimine could be isolated. The identification and characterization of this compound is consistent with the creation of dithiobenzil during the ligand substitution. The reactive α-dithione is also capable of undergoing rapid irreversible polymerization, thereby providing the thermodynamic impetus for the dithiolene ligand substitution. Chemical oxidation of [Pt(Ph2C2S2)(C≡NtBu)2] with [N(C6H4Br-4)3][SbCl6] was undertaken to form [Pt(Ph2C2SˉS‧)(C≡NtBu)2]2[SbCl6]2. Structural determination of the dication revealed appreciable shortening and lengthening of C─S and C─C bond distances, respectively, within the dithiolene ligand as compared to the charge-neutral complex, an observation which confirmed the dithiolene ligand as the locus of the redox activity in the heteroleptic monodithiolene complexes. The utility of [M(Ph2C2S2)(C≡NMe)2] (M= Ni, Pd, Pt) as synthons in their own right for heteroleptic compounds not directly attainable by ligand substitution from [M(Ph2C2S2)2] was also explored. The panorama of outcomes when [M(S2C2Ph2)(CNMe)2] (M = Ni2+, Pd2+, Pt2+) are introduced to new ligands intended to substitute for CNMe has been thoroughly defined. The most significant breakthrough was the isolation of the dicyanide complex, [Et4N]2[Ni(S2C2Ph2)(C≡N)2], which is a potentially useful precursor toward cyanide-bridged multimetallic architectures. Finally, the synthesis and structural characterization of multimetallic complexes bridged by bis(diphenylphosphine) ligands and redox active dithiolenes as end capping ligands are described. The electrochemistry study revealed that the dimetallic compounds support reversible oxidation to dications, which likely have singlet diradical - triplet states in close equilibrium. The use of dithiolene ligands as electron spin hosts offers new possibilities for the application of metallodithiolene complexes in molecule-based spintronic devices, such as quantum bits (qubits). / 1 / Antony Obanda

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Orientador: Prof. Dr. André Sarto Polo / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Ciência & Tecnologia - Química, 2014. / O trabalho desenvolvido teve como foco sintetizar compostos tris-heterolepticos de rutenio(II), o cis-[Ru(phen)(dcbH2)(NCS)2], o cis-[Ru(Me2-phen)(dcbH2)(NCS)2] e o cis-[Ru(Ph2-phen)(dcbH2)(NCS)2]. Estes compostos foram sintetizados pela rota one-pot que forneceu rendimentos superiores a 60%. A escolha dos substituintes nas posicoes 4 e 7 da fenantrolina foram feitas com o intuito de analisar o efeito causado por um grupo retirador de eletrons (Ph - fenila) e por um grupo doador de eletrons (Me - metila). Os compostos sintetizados foram caracterizados por analise elementar, espectroscopia eletronica, espectroscopia vibracional, emissao e ressonancia magnetica nuclear de 1H. Pelo espectro vibracional constatou-se que o aumento da densidade eletronica causado pelo grupo doador de eletrons desloca o ¿Þ(CN)NCS para uma regiao de maior energia e apresenta um efeito contrario para o grupo retirador de eletrons. Com o auxilio da ressonancia magnetica nuclear de 1H foi possivel comparar os sinais dos protons H2 e verificou-se que o composto com o substituinte com o grupo doador de eletrons foi deslocado para campo alto em relacao ao composto com o substituinte com o grupo retirador de eletrons. Os grupos substituintes influenciam muito pouco nas propriedades eletronicas dos compostos sintetizados. Os espectros de emissao dos compostos apresentam bandas largas e nao estruturadas, tipicas de emissao proveniente do estado thexi 3MLCT. Os tres compostos foram utilizados como corantes sensibilizadores de celulas solares. Com este trabalho observou-se que pela escolha adequada dos grupos substituintes e possivel modular as propriedades dos corantes sensibilizadores. O desempenho fotoeletroquimico foi avaliado por testes de curvas de corrente potencial e apresentaram os seguintes resultados: cis-[Ru(phen)(dcbH2)(NCS)2]: Voc = 0,733 V, Jsc = 8,67 mA cm-2, ff = 0,61 e £b = 3,78%; cis-[Ru(Me2-phen)(dcbH2)(NCS)2]: Voc = 0,683 V, Jsc = 12,72 mA cm-2, ff = 0,55 e £b = 4,60%; cis-[Ru(Ph2-phen)(dcbH2)(NCS)2]: Voc = 0,738 V, Jsc = 13,28 mA cm-2, ff = 0,63 e £b = 6,18%. / The developed work focused on synthesizing compounds tris-heteroleptic ruthenium(II), cis-[Ru(phen)(dcbH2)(NCS)2], cis-[Ru(Me2-phen)(dcbH2)(NCS)2] and were synthesized cis-[Ru(Ph2-phen)(dcbH2)(NCS)2]. These compounds were synthesized by one-pot route which provided higher yields at 60%. The choice of the substituents at positions 4 and 7 of phenanthroline were made in order to analyze the effect caused by an electron withdrawing group (Ph - phenyl) and an electron donating group (Me - methyl). The synthesized compounds were characterized by elemental analysis, electronic spectroscopy, vibrational spectroscopy, emission and 1H nuclear magnetic resonance. For the vibrational spectrum it was found that increasing the electron density caused by the electron donating group displaces the ¿Þ(CN)NCS for a higher energy region and has an opposite effect to the electron withdrawing group. With the aid of 1H nuclear magnetic resonance was possible to compare the signals of the protons H2, and it was found that the compound of the substituent with electron donating group was shifted upfield compared to the compound with the substituent withdrawing group electrons. The substituent groups very little influence on the electronic properties of the synthesized compounds. Emission spectra of the compounds show broad and unstructured bands, typical of emission from the 3MLCT thexi state. The three compounds were used as sensitizing dyes of solar cells. With this work it was observed that with the appropriate choice of substituents is possible to modulate the properties of the dyes. The photoelectrochemical performance was evaluated by testing current and potential curves showed the following results: cis-[Ru(phen)(dcbH2)(NCS)2]: Voc = 0.733 V, Jsc = 8.67 mA cm- 2, ff = 0.61 and £b = 3.78 %; cis-[Ru(Me2-phen)(dcbH2)(NCS)2]: Voc = 0.683 V, Jsc = 12.72 mA cm-2, ff = 0.55 and £b = 4.60 %; cis-[Ru(Ph2-phen phen)(dcbH2)( NCS)2]: Voc = 0.738 V, Jsc = 13.28 mA cm-2, ff = 0.63 and ç = 6.18 % .

The evaluation of N′-(1-(2-pyridyl)ethylidene)nicotinohydrazide (HL) as a linker for the PbII tagged extended structures is described. The reaction of Pb(ClO4)2 or Pb(OAc)2 with HL in MeOH at 60 °C and room temperature, respectively, leads to heteroleptic complexes {[PbL]ClO4}n·nH2O and [PbL(OAc)]2, while the same reaction of Pb(ClO4)2 with HL at 60 °C in the presence of two equivalents of NaOAc or NaNO2 leads to heteroleptic complexes {[Pb(HL)(OAc)]ClO4}n and [PbL(NO2)]n, respectively. Using Pb(NO3)2 as a source of PbII in the same reaction with HL and two equivalents of NaN3 or NaNCS at room temperature yields [PbLN3]n and [Pb2(HL)2(NO3)2(NCS)2], respectively. The room temperature reaction of Pb(NO3)2 with HL in the presence of two equivalents of NaClO4 leads to the transformation of the parent ligand to its perchlorate salt [H2L]ClO4. In all the obtained PbII structures, HL or its deprotonated form L acts both as a chelating and a bridging ligand. The nature of the inorganic anion also influences the final structure. In all complexes the PbII center exhibits a hemidirected coordination geometry with all the covalent bonds being concentrated on one hemisphere of the coordination sphere with the closest approach of two atoms on the other side varying from 151° to 232°. The sterically available PbII ion participates in tetrel bonding as evidenced from the detailed structural analysis of the described complexes. As a result of tetrel bonding, the structures of all the six compounds can be extended to a higher dimensional framework, which is further stabilized by π⋯π stacking interactions between the aromatic rings. The DFT based charge and energy decomposition (ETS-NOCV) calculations are performed in order to shed light on the nature of non-covalent interactions that determine the stability of the obtained structures.

The evaluation of N′-(1-(2-pyridyl)ethylidene)nicotinohydrazide (HL) as a linker for the PbII tagged extended structures is described. The reaction of Pb(ClO4)2 or Pb(OAc)2 with HL in MeOH at 60 °C and room temperature, respectively, leads to heteroleptic complexes {[PbL]ClO4}n·nH2O and [PbL(OAc)]2, while the same reaction of Pb(ClO4)2 with HL at 60 °C in the presence of two equivalents of NaOAc or NaNO2 leads to heteroleptic complexes {[Pb(HL)(OAc)]ClO4}n and [PbL(NO2)]n, respectively. Using Pb(NO3)2 as a source of PbII in the same reaction with HL and two equivalents of NaN3 or NaNCS at room temperature yields [PbLN3]n and [Pb2(HL)2(NO3)2(NCS)2], respectively. The room temperature reaction of Pb(NO3)2 with HL in the presence of two equivalents of NaClO4 leads to the transformation of the parent ligand to its perchlorate salt [H2L]ClO4. In all the obtained PbII structures, HL or its deprotonated form L acts both as a chelating and a bridging ligand. The nature of the inorganic anion also influences the final structure. In all complexes the PbII center exhibits a hemidirected coordination geometry with all the covalent bonds being concentrated on one hemisphere of the coordination sphere with the closest approach of two atoms on the other side varying from 151° to 232°. The sterically available PbII ion participates in tetrel bonding as evidenced from the detailed structural analysis of the described complexes. As a result of tetrel bonding, the structures of all the six compounds can be extended to a higher dimensional framework, which is further stabilized by π⋯π stacking interactions between the aromatic rings. The DFT based charge and energy decomposition (ETS-NOCV) calculations are performed in order to shed light on the nature of non-covalent interactions that determine the stability of the obtained structures.

L'addition catalysée des amines ou phosphines sur des substrats insaturés (alcènes, alcynes ou allènes) constitue une méthode efficace pour la production d’amines et phosphines à hautes valeurs ajoutées. Pour ces réactions, les complexes hétéroleptiques des métaux alcalino-terreux ont émergé comme des précatalyseurs effi caces. Cette thèse décrit la synthèse de complexes des alcalino-terreux supportés par des ligands aminoalcoolates fluorés de type [{RO}AeN(SiMe2H)2] ({RO} = aminoalcoolate fluoré; Ae = Ca, Sr). Des études par diffraction de rayons X montrent que ces complexes utilisent des interactions Ae···F–C and β-Si–H···Ae pour être cinétiquement inertes. Étonnamment, la somme de ces interactions non-covalentes dites secondaires est prédominante par rapport à la coordination d'éthers sur le centre métallique. En outre, les ligands aminoalcoolates fluorés ont été utilisés pour préparer de rares exemples de complexes Ae hétéroleptiques impliquant la coordination intramoléculaire de donneurs d'électrons π (i.e. alcènes et alcynes). Ainsi, pour la première fois, des complexes Ae stabilisés par des combinaisons d’interactions Ae···Cπ, Ae···F−C et β-Si−H···Ae ont été synthétisés. La nature de ces interactions a été sondée par des moyens spectroscopiques, cristallographiques et calculatoires (DFT). En revanche, nos efforts pour obtenir des complexes Ca–aryles ont conduit à la formation de complexes trinucléaires originaux présentant des interactions secondaires β-Si-H···Ca extrêmement fortes. Certains de ces complexes de calcium ont ensuite été testés en catalyse d’hydrophosphination du styrène avec la diphénylphosphine. Ils ont démontré des activités remarquables (TOF ≈ 50 h−1) en conditions douces, ainsi qu’une régiosélectivité de 100% vers la formation du produit d'addition anti-Markovnikov. En collaboration avec le Pr. M. Etienne et le Dr C. Dinoi du Laboratoire de Chimie de Coordination (Toulouse), un précatalyseur hétéroleptique de calcium supporté par un ligand tris(indazolyl)borate fluoré a été utilisé pour l’hydroamination intramoléculaire du 2,2-diméthylpent-4-en-1-amine, et a fait preuve d’une activité catalytique parmi les plus élevées à ce jour. / The catalysed additions of amines or phosphines across unsaturated substrates (alkenes, alkynes or allenes) constitute atom-efficient routes for the production of valuable fine chemicals such as amines and phosphines. For these reactions, heteroleptic alkaline-earth complexes have emerged as promising precatalysts. This PhD thesis describes the synthesis and characterisation of a series of alkaline-earth complexes of type [{RO}AeN(SiMe2H)2] supported by fluorinated aminoalkoxides ({RO} = fluorinated aminoalkoxide; Ae = Ca, Sr ). X-ray diffraction studies show that these complexes heavily involve Ae···F–C and β-Si–H···Ae secondary interactions to achieve kinetic stabilisation. Remarkably, these so-called secondary, non-covalent interactions can be more beneficial towards the stabilisation of the metallic species than the coordination of ethers onto the metal centre. Furthermore, fluorinated aminoalkoxo ligands were used to prepare rare examples of Ae heteroleptic complexes featuring intramolecular coordination from π donors (i.e. alkenes and alkynes). For the first time, Ae complexes stabilised by a combination of Ae···Cπ, Ae···F–C and β-Si–H···Ae interactions were described. The structural and electronic features of these unique complexes were probed by crystallographic, spectroscopic and computational (DFT) methods. The utilisation of aryl-containing ligands resulted in the formation of trinuclear complexes featuring a unique pattern of strong β-Si–H···Ca agostic interactions. Some of these calcium heteroleptic complexes were tested in the hydrophosphination of styrene and HPPh2. They displayed high activities (TOF ≈ 50 h–1) under mild conditions with 100% regioselectivity towards the anti-Markovnikov addition product. In a collaboration with Prof. M. Etienne and Dr. C. Dinoi from the Laboratoire de Chimie de Coordination (Toulouse), a heteroleptic calcium complex supported by a fluorinated tris(indazolyl)borate was used in the intramolecular hydroamination of 2,2-dimethylpent-4-en-1-amine, and it displayed excellent performances.