Pub Date : 2024-12-09DOI: 10.1007/s10870-024-01034-1
Noah Forrest, Edward J. Valente, Warren J. L. Wood
Reaction of N-benzyl-1-chloromethanesulfonamide with phenyl isothiocyanate formed N-benzyl-3-phenylimino-1,4,2-dithiazolidine 1,1-dioxide. Crystals of this compound occurred in the monoclinic system, space group P 2(1), a = 26.7099(16) Å, b = 13.2518(5) Å, c = 8.2769(4) Å, β = 97.099(5)o, Z = 8, with four molecules in the asymmetric unit. The structure confirms a prior assignment that the C = S bond of the isothiocyanate was the reactive moiety. Using the same reaction conditions, 3,5-dimethylphenyl isocyanate was reacted N-benzyl-1-chloromethanesulfonamide to produce a product in 81% yield, which was determined to be 2-benzyl-4-(3’,5’-dimethylphenyl)-1,2,4-thiadiazolidin-3-one 1,1-dioxide. Crystals of this compound are monoclinic, space group P 2(1)/n, a = 5.2243(11) Å, b = 15.844(5) Å, c = 18.628(3) Å, β = 96.72(2)o, and Z = 4. This product demonstrated that the C = N bond of the aryl isocyanate reacted to form the 1,2,4-thiadiazolidin-3-one 1,1-dioxide ring system.
Graphical Abstract
Heterocyclic rings formed from N-benzyl-1-chloromethanesulfonamide and phenyl isothiocyanate via the C = S bond (structure on the left) or 3,5-dimethylphenyl isocyanate via the C = N bond (structure on the right)
N-benzyl-1-chloromethanesulfonamide 与苯基异硫氰酸酯反应生成了 N-benzyl-3-phenylimino-1,4,2-dithiazolidine 1,1-dioxide。该化合物的晶体呈单斜体系,空间群为 P 2(1),a = 26.7099(16)埃,b = 13.2518(5)埃,c = 8.2769(4)埃,β = 97.099(5)o,Z = 8,不对称单元中有四个分子。该结构证实了之前的猜测,即异硫氰酸盐的 C = S 键是反应分子。在相同的反应条件下,3,5-二甲基苯基异氰酸酯与 N-苄基-1-氯甲磺酰胺反应,生成的产物收率为 81%,经测定为 2-苄基-4-(3',5'-二甲基苯基)-1,2,4-噻二唑烷-3-酮 1,1-二氧化物。该化合物的晶体为单斜晶系,空间群为 P 2(1)/n,a = 5.2243(11)埃,b = 15.844(5)埃,c = 18.628(3)埃,β = 96.72(2)o,Z = 4。图解摘要 N-苄基-1-氯甲磺酰胺和异硫氰酸苯酯通过 C = S 键(左侧结构)或 3,5-二甲苯基异氰酸酯通过 C = N 键(右侧结构)形成的杂环。
{"title":"Structures of 1,4,2-dithiazolidine 1,1-dioxide and 1,2,4-thiadiazolidin-3-one 1,1-dioxide heterocycles formed from N-benzyl-1-chloromethanesulfonamide and either phenyl isothiocyanate or 3,5-dimethylphenyl isocyanate","authors":"Noah Forrest, Edward J. Valente, Warren J. L. Wood","doi":"10.1007/s10870-024-01034-1","DOIUrl":"10.1007/s10870-024-01034-1","url":null,"abstract":"<div><p>Reaction of <i>N</i>-benzyl-1-chloromethanesulfonamide with phenyl isothiocyanate formed <i>N</i>-benzyl-3-phenylimino-1,4,2-dithiazolidine 1,1-dioxide. Crystals of this compound occurred in the monoclinic system, space group <i>P</i> 2(1), <i>a</i> = 26.7099(16) Å, <i>b</i> = 13.2518(5) Å, <i>c</i> = 8.2769(4) Å, <i>β</i> = 97.099(5)<sup>o</sup>, Z = 8, with four molecules in the asymmetric unit. The structure confirms a prior assignment that the C = S bond of the isothiocyanate was the reactive moiety. Using the same reaction conditions, 3,5-dimethylphenyl isocyanate was reacted <i>N</i>-benzyl-1-chloromethanesulfonamide to produce a product in 81% yield, which was determined to be 2-benzyl-4-(3’,5’-dimethylphenyl)-1,2,4-thiadiazolidin-3-one 1,1-dioxide. Crystals of this compound are monoclinic, space group <i>P</i> 2(1)/<i>n</i>, <i>a</i> = 5.2243(11) Å, <i>b</i> = 15.844(5) Å, <i>c</i> = 18.628(3) Å, <i>β</i> = 96.72(2)<sup>o</sup>, and Z = 4. This product demonstrated that the C = N bond of the aryl isocyanate reacted to form the 1,2,4-thiadiazolidin-3-one 1,1-dioxide ring system.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div><div><p>Heterocyclic rings formed from <i>N</i>-benzyl-1-chloromethanesulfonamide and phenyl isothiocyanate via the C = S bond (structure on the left) or 3,5-dimethylphenyl isocyanate via the C = N bond (structure on the right)</p></div></div></figure></div></div>","PeriodicalId":615,"journal":{"name":"Journal of Chemical Crystallography","volume":"55 1","pages":"67 - 73"},"PeriodicalIF":0.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143668150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-07DOI: 10.1007/s10870-024-01035-0
Rüdiger W. Seidel, Richard Goddard, Tom U. Schlegel, Adrian Richter, Ines Rudolph, Peter Imming
8-Nitrobenzo-1,3-thiazin-4-ones (BTZs) are a promising class of antitubercular agents with a novel mechanism of action, viz. suicide inhibition of decaprenylphosphoryl-β-D-ribose 2’-epimerase 1 (DprE1), an enzyme crucial for cell wall synthesis in the pathogen Mycobacterium tuberculosis. 8-Nitro-2-(piperidin-1-yl)-6-(trifluoromethyl)-4H-benzo-1,3-thiazin-4-one (1) is a chemically simplified analogue of the anti-tuberculosis phase 2 clinical drug candidate BTZ-043. Structural elucidation of 1 in the solid-state has been carried out by X-ray crystallography and two polymorphic forms of 1 have been revealed. 1-I crystallizes in the triclinic system (space group P-1, Z = 6) with one molecule exhibiting whole-molecule disorder with a preferred orientation. The crystal structure of 1-II belongs to the tetragonal system (space group P43, Z = 4) and exhibits positional disorder in several parts of the molecule.
Graphical Abstract
X-ray crystallography revealed a triclinic (space group P-1, Z = 6) and a tetragonal (space group P43, Z = 4) polymorph of the antimycobacterial agent 8-nitro-2-(piperidin-1-yl)-6-(trifluoromethyl)-4H-benzo-1,3-thiazin-4-one
8-硝基苯-1,3-噻嗪-4-酮(BTZs)是一类很有前途的抗结核药物,具有新的作用机制,即自杀抑制十烯丙基磷酸基-β- d -核糖2 ' - epimase 1 (DprE1), DprE1是结核分枝杆菌细胞壁合成的关键酶。8-硝基-2-(胡椒苷-1-基)-6-(三氟甲基)- 4h -苯并-1,3-噻嗪-4-one(1)是抗结核2期临床候选药物BTZ-043的化学简化类似物。利用x射线晶体学对固态中的1进行了结构解析,发现了2种1的多晶形态。1-I在三斜体系(空间群P-1, Z = 6)中结晶,其中一个分子表现出具有优先取向的全分子无序。1-II的晶体结构属于四方体系(空间群P43, Z = 4),在分子的几个部分表现出位置紊乱。x射线结晶学显示抗真菌剂8-硝基-2-(胡椒苷-1-基)-6-(三氟甲基)- 4h -苯并-1,3-噻嗪-4- 1具有三斜(空间群P-1, Z = 6)和四方(空间群P43, Z = 4)多晶型
{"title":"Polymorphism and Whole-Molecule Disorder of an Antitubercular 8-Nitrobenzothiazinone","authors":"Rüdiger W. Seidel, Richard Goddard, Tom U. Schlegel, Adrian Richter, Ines Rudolph, Peter Imming","doi":"10.1007/s10870-024-01035-0","DOIUrl":"10.1007/s10870-024-01035-0","url":null,"abstract":"<div><p>8-Nitrobenzo-1,3-thiazin-4-ones (BTZs) are a promising class of antitubercular agents with a novel mechanism of action, viz. suicide inhibition of decaprenylphosphoryl-β-D-ribose 2’-epimerase 1 (DprE1), an enzyme crucial for cell wall synthesis in the pathogen <i>Mycobacterium tuberculosis</i>. 8-Nitro-2-(piperidin-1-yl)-6-(trifluoromethyl)-4<i>H</i>-benzo-1,3-thiazin-4-one (<b>1</b>) is a chemically simplified analogue of the anti-tuberculosis phase 2 clinical drug candidate BTZ-043. Structural elucidation of <b>1</b> in the solid-state has been carried out by X-ray crystallography and two polymorphic forms of <b>1</b> have been revealed. <b>1</b>-I crystallizes in the triclinic system (space group <i>P</i>-1, <i>Z</i> = 6) with one molecule exhibiting whole-molecule disorder with a preferred orientation. The crystal structure of <b>1</b>-II belongs to the tetragonal system (space group <i>P</i>4<sub>3</sub>, <i>Z</i> = 4) and exhibits positional disorder in several parts of the molecule.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div><div><p>X-ray crystallography revealed a triclinic (space group <i>P</i>-1, <i>Z</i> = 6) and a tetragonal (space group <i>P</i>4<sub>3</sub>, <i>Z</i> = 4) polymorph of the antimycobacterial agent 8-nitro-2-(piperidin-1-yl)-6-(trifluoromethyl)-4<i>H</i>-benzo-1,3-thiazin-4-one</p></div></div></figure></div></div>","PeriodicalId":615,"journal":{"name":"Journal of Chemical Crystallography","volume":"55 1","pages":"56 - 65"},"PeriodicalIF":0.4,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10870-024-01035-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143667836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The study about the supramolecular interactions in the organic–inorganic hybrids will be significant for the design of new photo/electrical functional materials. In this work, 1,ω-bis(isoquinoline)alkane cations with different spacer lengths (n = 3, 5, 6) have been incorporated with iodobismuthates to construct three new hybrids, which have been formula as [BIQPP]2[Bi4I16] (1), [BIQPT]2[Bi4I16] (2) and [BIQHX]2[Bi4I16] (3) through X-ray single crystal diffraction method (BIQPP2+ = 1,3-bis(isoquinoline)propane, BIQPT2+ = 1,5-bis(isoquinoline) pentane, BIQHX2+ = 1,6-bis(isoquinoline)hexane). The centrosymmetric [Bi4I16]4− anions are constructed from four edge-sharing BiI6 octahedra. Interestingly, with the elongation of spacer length on isoquinoline from 3, 5 to 6, the iodobismuthate anions exhibit 0-D [Bi4I16]4− tetramers (n = 3, 6 for 1 and 3) and pseudo 3-D [Bi4I16]n4n− network (n = 5, for 2) based on I···I interactions. Supramolecular interactions including π–π stacking interactions and C–H···I hydrogen bonds contribute to their structural extensions. Consequently, the enhanced red emission intensity and the lower thermochromic temperature can be observed in 2. The clarification on the spacer effect on the supramolecular interactions and functional properties of this work will be beneficial for the design of new functional materials.
Graphical Abstract
Different iodobismuthate anions and photo-physical properties including red emission intensity and thermochromism can be achieved by elongating the spacer lengths in 1,ω-Bis(isoquinoline)alkane cations
{"title":"The Supramolecular Structures and Photo-Physical Properties Modulated by Spacer Lengths in 1,ω-Bis(isoquinoline)Alkane/(Bi4I16)4− Hybrids","authors":"Peng Wang, Wen-Wen Sheng, Ying-Sheng Xu, Zhi-Rong Chen","doi":"10.1007/s10870-024-01033-2","DOIUrl":"10.1007/s10870-024-01033-2","url":null,"abstract":"<div><p>The study about the supramolecular interactions in the organic–inorganic hybrids will be significant for the design of new photo/electrical functional materials. In this work, 1,<i>ω</i>-bis(isoquinoline)alkane cations with different spacer lengths (n = 3, 5, 6) have been incorporated with iodobismuthates to construct three new hybrids, which have been formula as [BIQPP]<sub>2</sub>[Bi<sub>4</sub>I<sub>16</sub>] (<b>1</b>), [BIQPT]<sub>2</sub>[Bi<sub>4</sub>I<sub>16</sub>] (<b>2</b>) and [BIQHX]<sub>2</sub>[Bi<sub>4</sub>I<sub>16</sub>] (<b>3</b>) through X-ray single crystal diffraction method (BIQPP<sup>2+</sup> = 1,3-bis(isoquinoline)propane, BIQPT<sup>2+</sup> = 1,5-bis(isoquinoline) pentane, BIQHX<sup>2+</sup> = 1,6-bis(isoquinoline)hexane). The centrosymmetric [Bi<sub>4</sub>I<sub>16</sub>]<sup>4−</sup> anions are constructed from four edge-sharing BiI<sub>6</sub> octahedra. Interestingly, with the elongation of spacer length on isoquinoline from 3, 5 to 6, the iodobismuthate anions exhibit 0-D [Bi<sub>4</sub>I<sub>16</sub>]<sup>4−</sup> tetramers (n = 3, 6 for <b>1</b> and <b>3</b>) and pseudo 3-D [Bi<sub>4</sub>I<sub>16</sub>]<sub>n</sub><sup>4n−</sup> network (n = 5, for <b>2</b>) based on I···I interactions. Supramolecular interactions including π–π stacking interactions and C–H···I hydrogen bonds contribute to their structural extensions. Consequently, the enhanced red emission intensity and the lower thermochromic temperature can be observed in <b>2</b>. The clarification on the spacer effect on the supramolecular interactions and functional properties of this work will be beneficial for the design of new functional materials.</p><h3>Graphical Abstract</h3><p> Different iodobismuthate anions and photo-physical properties including red emission intensity and thermochromism can be achieved by elongating the spacer lengths in 1,ω-Bis(isoquinoline)alkane cations</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":615,"journal":{"name":"Journal of Chemical Crystallography","volume":"55 1","pages":"47 - 55"},"PeriodicalIF":0.4,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143668408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-28DOI: 10.1007/s10870-024-01036-z
Makenna R. Miller, Ryann A. Carlotz, Jeremiah E. Stevens, Daniel R. Griffith, Chip Nataro
The structures of [Fe(CO)3(η4-6-exo-(tri-m-tolylphosphine)cyclohepta-2,4-dien-1-one][BF4] [tetragonal, a = 35.6005(7), b= 35.6005(7), c = 10.5456(3), space group I41/a] and [Fe(CO)3(η4-6-exo-(tri-p-fluorophenylphosphine)cyclohepta-2,4-dien-1-one][BF4] [triclinic, a = 9.8852(3), b= 10.0996(4), c = 16.0526(4), α = 99.813(3), β = 94.164(2), g = 102.911(3) space group P-1] have been determined. Both structures contain a disordered CH2Cl2 molecule. The tetrafluoroborate ion in [Fe(CO)3(η4-6-exo-(tri-m-tolylphosphine)cyclohepta-2,4-dien-1-one][BF4] is also disordered. There are no close contacts indicative of hydrogen bonding within either structure, but there is π-π stacking observed for [Fe(CO)3(η4-6-exo-(tri-m-tolylphosphine)cyclohepta-2,4-dien-1-one][BF4].
Graphical Abstract
Addition of PAr3 (Ar = m-C6H4CH3 or p-C6H4F) to [Fe(CO)3(η5-cyclohepta-2,4-dien-5-yl-1-one)][BF4] results in attack at the coordinated ring in a position exo- to the iron atom forming the corresponding [Fe(CO)3(η4-6-exo-(PAr3)cyclohepta-2,4-dien-1-one][BF4] compounds, which were structurally characterized
确定了[Fe(CO)3(η - 4-6-外显-(三-m-托基膦)环庚-2,4-二烯-1-one][BF4][四方,a = 35.6005(7), b = 35.6005(7), c = 10.5456(3),空间群I41/a]和[Fe(CO)3(η - 4-6-外显-(三-对氟苯基膦)环庚-2,4-二烯-1-one][BF4][三斜,a = 9.8852(3), b = 10.0996(4), c = 16.0526(4), α = 99.813(3), β = 94.164(2), g = 102.911(3)空间群P-1]的结构。这两种结构都包含一个无序的CH2Cl2分子。[Fe(CO)3(η - 4-6-外显-(三-m-甲基膦)环庚-2,4-二烯-1- 1][BF4]中的四氟硼酸盐离子也是无序的。在这两种结构中都没有紧密的接触,但在[Fe(CO)3(η - 4-6-外氧-(三-m-甲基膦)环庚-2,4-二烯-1- 1][BF4]中观察到π-π堆积。在[Fe(CO)3(η -5- cyclohepta-2,4-dien-5-yl-1-one)][BF4]中加入PAr3 (Ar = m-C6H4CH3或p-C6H4F),在铁原子外位的配位环上发生攻击,形成相应的[Fe(CO)3(η - 4-6-exo-(PAr3)cyclohepta-2,4-dien-1-one][BF4]化合物,并对其结构进行了表征
{"title":"The X-ray Structures of [Fe(CO)3(η4-6-exo-(PAr3)cyclohepta-2,4-dien-1-one][BF4] (Ar = m-C6H4CH3 or p-C6H4F)","authors":"Makenna R. Miller, Ryann A. Carlotz, Jeremiah E. Stevens, Daniel R. Griffith, Chip Nataro","doi":"10.1007/s10870-024-01036-z","DOIUrl":"10.1007/s10870-024-01036-z","url":null,"abstract":"<div><p>The structures of [Fe(CO)<sub>3</sub>(η<sup>4</sup>-6-<i>exo</i>-(tri-<i>m</i>-tolylphosphine)cyclohepta-2,4-dien-1-one][BF<sub>4</sub>] [tetragonal, <i>a</i> = 35.6005(7), <i>b</i> <b>=</b> 35.6005(7), <i>c</i> = 10.5456(3), space group I4<sub>1</sub>/a] and [Fe(CO)<sub>3</sub>(η<sup>4</sup>-6-<i>exo</i>-(tri-<i>p</i>-fluorophenylphosphine)cyclohepta-2,4-dien-1-one][BF<sub>4</sub>] [triclinic, <i>a</i> = 9.8852(3), <i>b</i> <b>=</b> 10.0996(4), <i>c</i> = 16.0526(4), <i>α</i> = 99.813(3), <i>β</i> = 94.164(2), <i>g</i> = 102.911(3) space group P-1] have been determined. Both structures contain a disordered CH<sub>2</sub>Cl<sub>2</sub> molecule. The tetrafluoroborate ion in [Fe(CO)<sub>3</sub>(η<sup>4</sup>-6-<i>exo</i>-(tri-<i>m</i>-tolylphosphine)cyclohepta-2,4-dien-1-one][BF<sub>4</sub>] is also disordered. There are no close contacts indicative of hydrogen bonding within either structure, but there is <i>π</i>-<i>π</i> stacking observed for [Fe(CO)<sub>3</sub>(η<sup>4</sup>-6-<i>exo</i>-(tri-<i>m</i>-tolylphosphine)cyclohepta-2,4-dien-1-one][BF<sub>4</sub>].</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div><div><p>Addition of PAr<sub>3</sub> (Ar = <i>m</i>-C<sub>6</sub>H<sub>4</sub>CH<sub>3</sub> or <i>p</i>-C<sub>6</sub>H<sub>4</sub>F) to [Fe(CO)<sub>3</sub>(η<sup>5</sup>-cyclohepta-2,4-dien-5-yl-1-one)][BF<sub>4</sub>] results in attack at the coordinated ring in a position <i>exo</i>- to the iron atom forming the corresponding [Fe(CO)<sub>3</sub>(η<sup>4</sup>-6-<i>exo</i>-(PAr<sub>3</sub>)cyclohepta-2,4-dien-1-one][BF<sub>4</sub>] compounds, which were structurally characterized</p></div></div></figure></div></div>","PeriodicalId":615,"journal":{"name":"Journal of Chemical Crystallography","volume":"55 1","pages":"41 - 46"},"PeriodicalIF":0.4,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10870-024-01036-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143667869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-17DOI: 10.1007/s10870-024-01031-4
Stephanie M. Ingwer, Christopher J. Yoler, Todd Reynolds, Daniel R. Griffith, Chip Nataro
The structures of [Fe(CO)3(η4-6-exo-(methyldiphenylphosphine)cyclohepta-2,4-dien-1-one][BF4] [orthorhombic, a = 12.3269(4), b = 13.5243(5), c = 13.7127(4), space group Pna21] and [Fe(CO)3(η4-6-exo-(tert-butyldiphenylphosphine)cyclohepta-2,4-dien-1-one][BF4] [monoclinic, a = 9.7947(3), b = 12.8766(3), c = 20.2168(5), β = 91.089(3), space group P21/c] have been determined. The disordered tetrafluoroborate ion in [Fe(CO)3(η4-6-exo-(methyldiphenylphosphine)cyclohepta-2,4-dien-1-one][BF4] sits between two of the cations and displays interactions with hydrogen atoms in the ortho- position of the phenyl rings, the methyl group and the 6-position of the seven-membered ring. There is also close contact between the ketone oxygen atom and two protons in another cation, a proton of the methyl group and the proton in the 5-position of the seven-membered ring. The tetrafluoroborate anion in [Fe(CO)3(η4-6-exo-(tert-butyldiphenylphosphine)cyclohepta-2,4-dien-1-one][BF4] is not disordered and shows close contacts with protons in three cation units. In one cation the interaction is with two protons from separate methyl groups of the tert-butyl substituent. The remaining interactions are with a proton in the ortho- position of a phenyl ring in one cation and the proton in the 2-position of the seven-membered ring. There is also an interaction between the ketone oxygen and a proton from the tert-butyl group in another cationic unit.
Graphical abstract
Addition of PPh2R (R = Me or tBu) to [Fe(CO)3(η5-cyclohepta-2,4-dien-5-yl-1-one)][BF4] results in exo- attack at the coordinated ring forming the [Fe(CO)3(η4-6-exo-(PPh2R)cyclohepta-2,4-dien-1-one][BF4] compounds, both of which were structurally characterized.