Interaction of the buchwald seven-membered zirconacyclocumulene complex with carbonyl compounds

The interaction of the Buchwald seven-membered zirconacyclocumulene Cp2Zr[4-Me3SiC4(SiMe3)-C(C2SiMe3)=CSiMe3] (1) with a 2-fold excess of benzophenone in toluene at 100 °C for 20 h results in the formation of Me3SiCC-CCSiMe3 and a nine-membered dioxazirconacycle Cp2Zr[2-OC(Ph)2C(SiMe3)C2C(SiMe3)C(Ph)2O] (5) containing [3]cumulene group in the ring. Analogous metallacycle (6) is formed on heating of 1 with fluorenone in toluene at 100 °C. A treatment of 5 with HCl in dioxane at 20 °C affords Cp2ZrCl2 and cis-[3]cumulenic diol Ph2(HO)C(Me3Si)CC2C(SiMe3)C(OH)Ph2 (7) in 85% yield. The reaction of 1 with benzil (PhCO)2 at 80 °C in benzene proceeds differently than with benzophenone and fluorenone. In this case, a nine-membered dioxazirconacycle Cp2Zr[2-Me3SiCaC(C2SiMe3)-C(SiMe3) C(C2SiMe3)OC(Ph) C(Ph)O] (10) is produced. The nature of products formed in the interaction of 1 with acenaphthenequinone proved to be temperature dependent. Thus, on carrying out the reaction at 20 °C, an 11-membered trioxazirconacycle (11) containing three CaC bonds in the ring was isolated from the mixture, whereas at 80 °C the reaction gave a ten-membered tetraoxadizirconacycle (12) and octasubstituted cyclooctatetraene [(Me3Si)CaC(CCSiMe3)]4 (13). The structures of 5-7 and 10-13 have been determined by X-ray diffraction. The mechanism of the reactions found is discussed. © 2019 American Chemical Society

Coordination Chemistry of Anticrowns. Isolation of the Chloride Complex of the Four-Mercury Anticrown {[(o,o′-C6F4C6F4Hg)4]Cl}- from the Reaction of o,o′-Dilithiooctafluorobiphenyl with HgCl2 and Its Transformations to the Free Anticrown and the Complexes with o-Xylene, Acetonitrile, and Acetone

The paper reports that the interaction of o,o′-dilithiooctafluorobiphenyl with HgCl2 in ether results in the formation of the lithium chloride complex Li{[(o,o′-C6F4C6F4Hg)4]Cl} (11) of the four-mercury anticrown (o,o′-C6F4C6F4Hg)4 (12) along with the earlier isolated and characterized three-mercury anticrown (o,o′-C6F4C6F4Hg)3 (2). The complex was identified by the reaction with 12-crown-4 and determination of the structure of the [Li(12-crown-4)2]{[(o,o′-C6F4C6F4Hg)4]Cl} (13) formed. According to an X-ray analysis, the chloride anion in 13 is simultaneously coordinated with all four Hg centers of the anticrown, forming with them a pyramidal Hg4Cl fragment. The reaction of 11 (in the form of an acetonitrile solvate, 11·nMeCN) with boiling water leads to removal of LiCl from 11 and to the formation of free anticrown 12, the subsequent recrystallization of which from o-xylene affords the o-xylene complex {[(o,o′-C6F4C6F4Hg)4](o-Me2C6H4)2} (14). The obtained 14 forms in the crystal infinite chains consisting of alternating anticrown units and bridging o-xylene moieties. Another o-xylene molecule in each macrocyclic fragment of the chain plays the role of a terminal ligand. In both cases, the o-xylene ligands in 14 are bonded to only one Hg center of the corresponding mercuramacrocycle. The back-conversion of complex 14 into 12 and o-xylene proceeds in the course of its thermal decomposition under vacuum at 100-120 °C. The reaction of 12 with acetonitrile yields the nitrile complex {[(o,o′-C6F4C6F4Hg)4](MeCN)2} (15), which also forms infinite polymeric chains in the crystal. In each monomeric unit of the chain, the corresponding bridging nitrile is bonded to only one mercury atom of the anticrown moiety, whereas the other nitrile ligand is coordinated with two Hg sites. The synthesis and structure of the complex {[(o,o′-C6F4C6F4Hg)4](Me2CO)2(H2O)} (16), containing two acetone and one water ligand per molecule of 12, are also reported. Each acetone molecule in 16 interacts with only one Hg atom of 12, while the water molecule is coordinated with two mercury centers and, in addition, forms H-bonds with the oxygen atoms of the acetone species. © 2017 American Chemical Society

Coordination Chemistry of Anticrowns. Isolation of the Chloride Complex of the Four-Mercury Anticrown {[(o,o′-C6F4C6F4Hg)4]Cl}- from the Reaction of o,o′-Dilithiooctafluorobiphenyl with HgCl2 and Its Transformations to the Free Anticrown and the Complexes with o-Xylene, Acetonitrile, and Acetone

The paper reports that the interaction of o,o′-dilithiooctafluorobiphenyl with HgCl2 in ether results in the formation of the lithium chloride complex Li{[(o,o′-C6F4C6F4Hg)4]Cl} (11) of the four-mercury anticrown (o,o′-C6F4C6F4Hg)4 (12) along with the earlier isolated and characterized three-mercury anticrown (o,o′-C6F4C6F4Hg)3 (2). The complex was identified by the reaction with 12-crown-4 and determination of the structure of the [Li(12-crown-4)2]{[(o,o′-C6F4C6F4Hg)4]Cl} (13) formed. According to an X-ray analysis, the chloride anion in 13 is simultaneously coordinated with all four Hg centers of the anticrown, forming with them a pyramidal Hg4Cl fragment. The reaction of 11 (in the form of an acetonitrile solvate, 11·nMeCN) with boiling water leads to removal of LiCl from 11 and to the formation of free anticrown 12, the subsequent recrystallization of which from o-xylene affords the o-xylene complex {[(o,o′-C6F4C6F4Hg)4](o-Me2C6H4)2} (14). The obtained 14 forms in the crystal infinite chains consisting of alternating anticrown units and bridging o-xylene moieties. Another o-xylene molecule in each macrocyclic fragment of the chain plays the role of a terminal ligand. In both cases, the o-xylene ligands in 14 are bonded to only one Hg center of the corresponding mercuramacrocycle. The back-conversion of complex 14 into 12 and o-xylene proceeds in the course of its thermal decomposition under vacuum at 100-120 °C. The reaction of 12 with acetonitrile yields the nitrile complex {[(o,o′-C6F4C6F4Hg)4](MeCN)2} (15), which also forms infinite polymeric chains in the crystal. In each monomeric unit of the chain, the corresponding bridging nitrile is bonded to only one mercury atom of the anticrown moiety, whereas the other nitrile ligand is coordinated with two Hg sites. The synthesis and structure of the complex {[(o,o′-C6F4C6F4Hg)4](Me2CO)2(H2O)} (16), containing two acetone and one water ligand per molecule of 12, are also reported. Each acetone molecule in 16 interacts with only one Hg atom of 12, while the water molecule is coordinated with two mercury centers and, in addition, forms H-bonds with the oxygen atoms of the acetone species. © 2017 American Chemical Society

Coordination Chemistry of Anticrowns. Interaction of the Perfluorinated Three-Mercury Anticrown (o-C₆F₄Hg)₃ with Azacrowns

The interaction of the three-mercury anticrown (o-C6F4Hg)3 (1) with various azacrowns such as 2,9,16,23-tetra-tert-butylphthalocyanine (TBPC), octaazapentacyclooctacosane (OAOC), 1,4,8,11-tetraazacyclotetradecane (cyclam), and N,N,N-trimethyl-1,3,5-triazacyclohexane (TACH) has been studied. It has been shown that the reaction of 1 with TBPC in CH2Cl2 at 20 °C affords 1:1 complex {[(o-C6F4Hg)3](TBPC)} (2) according to elemental analysis, and the interaction of 1 with OAOC·0.5H2O in ether results in the formation of complex {[(o-C6F4Hg)3]2(OAOC)(H2O)2} (3). The molecules of azacrown and water in 3 are located between the parallel planes of two mercuramacrocycles strongly laterally shifted relative to one another and are bonded to them through Hg-N and Hg-O secondary interactions. An especially interesting complex, [(CH2)10(NH2)2(NH)2]{[(o-C6F4Hg)3]2Cl2} (4), has been obtained by the reaction of 1 with cyclam [(CH2)10(NH)4] in CH2Cl2 at 20 °C. The complex has a structure of a double-decker sandwich wherein two chloride anions and the diprotonated molecule of cyclam as a counterdication are disposed between the parallel planes of two molecules of 1. Each chloride anion in 4 is η3-coordinated with the Hg centers of the neighboring anticrown, whereas the NH and NH2+ groups of the diprotonated cyclam form three H-bonds with each of these chloride anions. The mechanism of the formation of this unusual sandwich is discussed. The synthesis and structure of an analogous complex, [(CH2)10(NH2)2(NH)2]{[(o-C6F4Hg)3]Cl2}·2(CH3)2CO, which forms polydecker sandwiches in the crystal are also described. The interaction of 1 with cyclam in aqueous THF at 20 °C gives a complex, {[(o-C6F4Hg)3][(CH2)10(NH)4](THF)(H2O)} (6), also forming infinite polymeric chains in the crystal. A characteristic structural feature of 6 is the presence in each its monomeric unit of a bipyramidal fragment formed by 1 and two different η3-coordinated Lewis bases (THF and water). From the reaction of 1 with TACH, a complex having a unique double-cage structure, {[(o-C6F4Hg)3](TACH)2} (7), has been isolated

Coordination Chemistry of Anticrowns. Interaction of the Perfluorinated Three-Mercury Anticrown (o-C6F4Hg)3 with Azacrowns

The interaction of the three-mercury anticrown (o-C6F4Hg)3 (1) with various azacrowns such as 2,9,16,23-tetra-tert-butylphthalocyanine (TBPC), octaazapentacyclooctacosane (OAOC), 1,4,8,11-tetraazacyclotetradecane (cyclam), and N,N,N-trimethyl-1,3,5-triazacyclohexane (TACH) has been studied. It has been shown that the reaction of 1 with TBPC in CH2Cl2 at 20 °C affords 1:1 complex {[(o-C6F4Hg)3](TBPC)} (2) according to elemental analysis, and the interaction of 1 with OAOC·0.5H2O in ether results in the formation of complex {[(o-C6F4Hg)3]2(OAOC)(H2O)2} (3). The molecules of azacrown and water in 3 are located between the parallel planes of two mercuramacrocycles strongly laterally shifted relative to one another and are bonded to them through Hg-N and Hg-O secondary interactions. An especially interesting complex, [(CH2)10(NH2)2(NH)2]{[(o-C6F4Hg)3]2Cl2} (4), has been obtained by the reaction of 1 with cyclam [(CH2)10(NH)4] in CH2Cl2 at 20 °C. The complex has a structure of a double-decker sandwich wherein two chloride anions and the diprotonated molecule of cyclam as a counterdication are disposed between the parallel planes of two molecules of 1. Each chloride anion in 4 is η3-coordinated with the Hg centers of the neighboring anticrown, whereas the NH and NH2+ groups of the diprotonated cyclam form three H-bonds with each of these chloride anions. The mechanism of the formation of this unusual sandwich is discussed. The synthesis and structure of an analogous complex, [(CH2)10(NH2)2(NH)2]{[(o-C6F4Hg)3]Cl2}·2(CH3)2CO, which forms polydecker sandwiches in the crystal are also described. The interaction of 1 with cyclam in aqueous THF at 20 °C gives a complex, {[(o-C6F4Hg)3][(CH2)10(NH)4](THF)(H2O)} (6), also forming infinite polymeric chains in the crystal. A characteristic structural feature of 6 is the presence in each its monomeric unit of a bipyramidal fragment formed by 1 and two different η3-coordinated Lewis bases (THF and water). From the reaction of 1 with TACH, a complex having a unique double-cage structure, {[(o-C6F4Hg)3](TACH)2} (7), has been isolated. © 2019 American Chemical Society