Different molecular assemblies in two new phosphoric triamides with the same C(O)NHP(O)(NH)<Subscript>2</Subscript> skeleton: crystallographic study and Hirshfeld surface analysis

Different molecular assemblies were compared in two new structures [4-CH₃-C₆H₄C(O)NH]P(O)[NH]₂(CH₂)₃, 1, and [4-CH₃-C₆H₄C(O)NH]P(O)[NHC₆H₃(3,4-CH₃)₂]₂, 2, belonging to the families of “cyclic phosphoric triamide” and “phosphoric triamide”, respectively. The differences in the hydrogen bond motifs were discussed (by single crystal X-ray diffraction) as a result of three factors: (1) action of two N atoms with a non-planar environment in 1 as an H-bond acceptor, (2) different orientations of three N–H bond vectors in two molecules and (3) different conformations of C=O and P=O groups. These differences lead to more complicated hydrogen bond pattern of 1, with respect to that of 2, as structure 1 may be considered as a model of four-acceptor–three-donor versus a two-acceptor–three-donor system in 2. The main discrepancies of 1 and 2, monitored by the Hirshfeld surface analysis, are related to the contribution portions of O···H/H···O contacts, in which compound 1 not only involves the greater existence of classical hydrogen bonds but also contains the further C–H···O weak interactions in its crystal packing with respect to compound 2. Instead, in 2, the shortage of O···H/H···O contacts has been partially compensated by the C···H/H···C interactions, due to the presence of more unsaturated carbon acceptors. The differences in assemblies are also reflected in the solid-state IR spectra, especially for the N–H vibration frequencies. The new compounds were further studied by 1D NMR experiments (¹H, ¹³C, ³¹P), 2D NMR techniques [HMQC and HMBC (H–C correlation), HSQC (N–H correlation)], high-resolution ESI–MS, EI–MS spectrometry and IR spectroscopy.     

Three new phosphoric triamides with a [C(O)NH]P(O)[N(C)(C)]2 skeleton: a database analysis of C—N—C and P—N—C bond angles

In N,N,N′,N′‐tetraethyl‐N′′‐(4‐fluorobenzoyl)phosphoric triamide, C₁₅H₂₅FN₃O₂P, (I), and N‐(2,6‐difluorobenzoyl)‐N′,N′′‐bis(4‐methylpiperidin‐1‐yl)phosphoric triamide, C₁₉H₂₈F₂N₃O₂P, (II), the C—N—C angle at each tertiary N atom is significantly smaller than the two P—N—C angles. For the other new structure, N,N′‐dicyclohexyl‐N′′‐(2‐fluorobenzoyl)‐N,N′‐dimethylphosphoric triamide, C₂₁H₃₃FN₃O₂P, (III), one C—N—C angle [117.08 (12)°] has a greater value than the related P—N—C angle [115.59 (9)°] at the same N atom. Furthermore, for most of the analogous structures with a [C(=O)NH]P(=O)[N(C)(C)]₂ skeleton deposited in the Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B 58 , 380–388], the C—N—C angle is significantly smaller than the two P—N—C angles; exceptions were found for four structures with the N‐methylcyclohexylamide substituent, similar to (III), one structure with the seven‐membered cyclic amide azepan‐1‐yl substituent and one structure with an N‐methylbenzylamide substituent. The asymmetric units of (I), (II) and (III) contain one molecule, and in the crystal structures, adjacent molecules are linked via pairs of N—H...O=P hydrogen bonds to form dimers.     

Study on H-bond patterns in phosphoric triamides having a P(O)NHC(O) skeleton, a gauche orientation of P(O) vs C(O) in new compounds

The crystal and packing structures of new phosphoric triamides, in a rare gauche orientation of P(O) versus C(O), with the formula (CCl₂HC(O)NH)X₂P(O), X = NC₄H₈ (1), N(C₂H₅)₂ (2), N(CH₃)(C₆H₁₁) (3) and (CCl₂HC(O)NH)(Y)P(O), Y = NHCH₂C(CH₃)₂CH₂NH (4) have been investigated. This article also reviews 91 similar structures deposited in the CSD aiming to classify hydrogen bond patterns in this category of phosphorus compounds. The present X-ray structural analysis shows that the H-bond pattern in the studied structures strongly depends on the conformation in the P(O)NHC(O) skeleton and the kind of amide linked to the P atom. The spectroscopic features (³¹P{¹H}, ¹H and ¹³C NMR, IR) of the new compounds have been investigated.     

A new cyclic borazine species B(8)(NH)(4)(NMe(2))(8) containing a twelve-membered B(8)N(4) ring

The reaction between B(2)(NMe(2))(4) and two equivalents of [NH(4)][PF(6)] in thf at room temperature affords the new cyclic borazine B(8)(NH)(4)(NMe(2))(8) containing a non-planar twelve-membered ring with alternating B(2)(NMe(2))(2) and NH units.     

Three new [XC(O)NH]P(O)[N(CH2C6H5)2]2 phosphoric triamides (X = CClF2, 3‐F‐C6H4 and 3,5‐F2‐C6H3): a database analysis of tertiary N‐atom geometry in compounds with a C(O)NHP(O)[N]2 core

In the phosphoric triamides N,N,N′,N′‐tetrabenzyl‐N′′‐(2‐chloro‐2,2‐difluoroacetyl)phosphoric triamide, C₃₀H₂₉ClF₂N₃O₂P, (I), N,N,N′,N′‐tetrabenzyl‐N′′‐(3‐fluorobenzoyl)phosphoric triamide, C₃₅H₃₃FN₃O₂P, (II), and N,N,N′,N′‐tetrabenzyl‐N′′‐(3,5‐difluorobenzoyl)phosphoric triamide, C₃₅H₃₂F₂N₃O₂P, (III), the tertiary N atoms of the dibenzylamido groups have sp² character with minimal deviation from planarity. The sums of the three bond angles about the N atoms in (I)–(III) deviate by less than 8° from the planar value of 360°. The geometries of the tertiary N atoms in all phosphoric triamides with C(O)NHP(O)[N]₂ skeletons deposited in the Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B 58 , 380–388] have been examined and the bond‐angle sums at the two tertiary N atoms (SUM1 and SUM2) and the parameter ΔSUM (= SUM1 − SUM2) considered. It was found that in compounds with a considerable ΔSUM value, the more pyramidal N atoms are usually oriented so that the corresponding lone electron pair is anti with respect to the P=O group. In (I), (II) and (III), the phosphoryl and carbonyl groups, separated by an N atom, are anti with respect to each other. In the C(O)NHP(O) fragment of (I)–(III), the P—N bond is longer and the O—P—N angle is contracted compared with the other two P—N bonds and the O—P—N angles in the molecules. These effects are also seen in analogous compounds deposited in the CSD. Compounds with [C(O)NH]P(O)[N]X (X≠ N), such as compounds with a [C(O)NH]P(O)[N][O] skeleton, have not been considered here. Also, compounds with a [C(O)NH]₂P(O)[N] fragment have not been reported to date. In the crystal structures of all three title compounds, adjacent molecules are linked via pairs of P=O...H—N hydrogen bonds, forming dimers with C_i symmetry.     

Synthesis and catalytic epoxidation activity with TBHP and H2O2 of dioxo-, oxoperoxo-, and oxodiperoxo molybdenum(VI) and tungsten(VI) compounds containing monodentate or bidentate phosphine oxide ligands: crystal structures of WCl2(O)2(OPMePh2)2, WCl2(O)(O2)(OPMePh2)2, MoCl2(O)2dppmO2.C4H10O, WCl2(O)2dppmO2, Mo(O)(O2)2dppmO2, and W(O)(O2)2dppmO2

The dioxo tungsten(VI) and molybdenum(VI) complexes WCl2(O)2(OPMePh2)2, WCl2(O)2dppmO2, and MoCl2(O)2dppmO2, the oxoperoxo compounds WCl2(O)(O2)(OPMePh2)2, WCl2(O)(O2)dppmO2, and MoCl2(O)(O2)dppmO2, and the oxodiperoxo complexes, W(O)(O2)2dppmO2 and Mo(O)(O2)2dppmO2 have been prepared and characterized by IR spectroscopy, 31P NMR spectroscopy, elemental analysis, and X-ray crystallography. The structural and X-ray crystallographic data of compounds WCl2(O)2(OPMePh2)2, WCl2(O)(O2)(OPMePh2)2, MoCl2(O)2dppmO2.4H10O, WCl2(O)2dppmO2, Mo(O)(O2)2dppmO2, and W(O)(O2)2dppmO2 are also detailed. All complexes were studied as catalysts for cis-cyclooctene epoxidation in the presence of tert-butyl hydroperoxide (TBHP) or H2O2 as an oxidant. The Mo-based catalysts showed a superior reactivity over W-based catalysts in the TBHP system. On the other hand, in the H2O2 system, the W-based catalysts (accomplishing nearly 100% epoxidation of cyclooctene in 6 h) are more reactive than the Mo catalysts (<45% under some conditions). Various solvent systems have been investigated, and ethanol is the most suitable solvent for the H2O2 system.     

Novel ruthenium(ii) complexes containing the N-phosphorylated iminophosphorane-phosphine ligand Ph(2)PCH(2)P{[double bond, length as m-dash]NP([double bond, length as m-dash]O)(OEt)(2)}Ph(2): a new coordination mode of its methanide anion

The reactivity of complex [Ru(eta(6)-p-cymene)(kappa(3)P,N,O-Ph(2)PCH(2)P{[double bond, length as m-dash]NP([double bond, length as m-dash]O)(OEt)(2)}Ph(2))][SbF(6)](2) towards a variety of mono- and bidentate neutral ligands has been studied, allowing the high-yield synthesis of the novel half-sandwich Ru(ii) derivatives [Ru(eta(6)-p-cymene)(L)(kappa(2)P,O-Ph(2)PCH(2)P{[double bond, length as m-dash]NP([double bond, length as m-dash]O)(OEt)(2)}Ph(2))][SbF(6)](2) (L = N[triple bond, length as m-dash]CMe , N[triple bond, length as m-dash]CEt , PMe(3), PMe(2)Ph , PMePh(2), PPh(3), P(OMe)(3), P(OEt)(3), P(OPh)(3), py , kappa(1)P-dppm , kappa(1)P-dppe ), as well as the octahedral species [Ru(Ninsertion markN)(2)(kappa(2)P,O-Ph(2)PCH(2)P{[double bond, length as m-dash]NP([double bond, length as m-dash]O)(OEt)(2)}Ph(2))][SbF(6)](2) (Ninsertion markN = bipy , phen ). Deprotonation of complexes ,, upon treatment with an excess of NaOH in CH(2)Cl(2), generates the monocationic derivatives [Ru(Ninsertion markN)(2)(kappa(2)P,N-Ph(2)PC(H)[double bond, length as m-dash]P{NP([double bond, length as m-dash]O)(OEt)(2)}Ph(2))][Cl] (Ninsertion markN = bipy , phen ) in which the methanide anion adopts an unprecedented kappa(2)P,N bidentate coordination mode. The structures of compounds , and have been determined by single-crystal X-ray diffraction methods.     

The double H‐atom acceptability of the P=O group in new XP(O)(NHCH2C6H4‐2‐Cl)2 phosphoramidates [X = C6H5O– and CF3C(O)NH–]: a database analysis of compounds having a P(O)(NHR) group

In the hydrogen‐bond patterns of phenyl bis(2‐chlorobenzylamido)phosphinate, C₂₀H₁₉Cl₂N₂O₂P, (I), and N,N′‐bis(2‐chlorobenzyl)‐N′′‐(2,2,2‐trifluoroacetyl)phosphoric triamide, C₁₆H₁₅Cl₂F₃N₃O₂P, (II), the O atoms of the related phosphoryl groups act as double H‐atom acceptors, so that the P=O...(H—N)₂ hydrogen bond in (I) and the P=O...(H—N_amide)₂ and C=O...H—N_C(O)NHP(O) hydrogen bonds in (II) are responsible for the aggregation of the molecules in the crystal packing. The presence of a double H‐atom acceptor centre is a result of the involvement of a greater number of H‐atom donor sites with a smaller number of H‐atom acceptor sites in the hydrogen‐bonding interactions. This article also reviews structures having a P(O)NH group, with the aim of finding similar three‐centre hydrogen bonds in the packing of phosphoramidate compounds. This analysis shows that the factors affecting the preference of the above‐mentioned O atom to act as a double H‐atom acceptor are: (i) a higher number of H‐atom donor sites relative to H‐atom acceptor centres in molecules with P(=O)(NH)₃, (N)P(=O)(NH)₂, C(=O)NHP(=O)(NH)₂ and (NH)₂P(=O)OP(=O)(NH)₂ groups, and (ii) the remarkable H‐atom acceptability of this atom relative to the other acceptor centre(s) in molecules containing an OP(=O)(NH)₂ group, with the explanation that the N atom bound to the P atom in almost all of the structures found does not take part in hydrogen bonding as an acceptor. Moreover, the differences in the H‐atom acceptability of the phosphoryl O atom relative to the O atom of the alkoxy or phenoxy groups in amidophosphoric acid esters may be illustrated by considering the molecular packing of compounds having (O)₂P(=O)(NH) and (O)P(=O)(NH)(N)groups, in which the unique N—H unit in the above‐mentioned molecules almost always selects the phosphoryl O atom as a partner in forming hydrogen‐bond interactions. The P atoms in (I) and (II) are in tetrahedral coordination environments, and the phosphoryl and carbonyl groups in (II) are anti with respect to each other (the P and C groups are separated by one N atom). In the crystal structures of (I) and (II), adjacent molecules are linked via the above‐mentioned hydrogen bonds into a linear arrangement parallel to [100] in both cases, in (I) by forming R₂²(8) rings and in (II) through a combination of R₂²(10) and R₂¹(6) rings.     

Facile C-H bond activation: synthesis of the N4C donor set pentadentate ligand 1,4-bis(2-pyridylmethyl)-1,4-diazacyclononane (dmpdacn) and a structural study of its alkyl-cobalt(III) complex [Co(dmpdacn-C)(OH2)](ClO4)2.H2O and its hydroxylated derivative [Co(dmpdacnOH-O)Cl](ClO4)2.C3H6O

The 1,4-bis(2-pyridylmethyl)-1,4-diazacyclononane (dmpdacn) ligand with a N(4)C donor set deprotonates at a CH(2) gamma to an amine under extraordinarily mild conditions (pH 7) and binds as a pentadentate ligand to Co(III) as the [Co(dmpdacn-C)(OH(2))](2+) complex. This complex was characterized by 1D and 2D NMR techniques, and a single-crystal X-ray structure is reported. In an alternative synthesis from Co(II), dmpdacn, and air, the same C-bonded complex is obtained along with a novel hydroxylated Co(III) complex [Co(dmpdacnOH-O)Cl](2+) which has been similarly characterized. Here the carbanion has been oxidized, a C- to O-bonded rearrangement has taken place, and the bound aqua group is replaced by Cl(-). The base hydrolysis kinetics of the hydroxylated Co(III) complex are reported, and mechanisms for this and the unusually facile C-H cleavage and CH(2) oxidation reactions are discussed.     

2‐tert‐Butylamino‐4‐chloro‐6‐ethylamino‐1,3,5‐triazine: a structure with Z′ = 4 containing two different molecular conformations and two independent chains of hydrogen‐bonded R22(8) rings

The title compound (trivial name terbutylazine), C₉H₁₆ClN₅, (I), crystallizes with Z′ = 4 in the space group Pca2₁, and equal numbers of molecules adopt two different conformations for the ethylamine groups. The four independent molecules form two approximately enantiomorphic pairs. Eight independent N—H...N hydrogen bonds link the molecules into two independent chains of R₂²(8) rings, in which the arrangement of the alkylamine substituents in the independent molecules precludes any further crystallographic symmetry. The significance of this study lies in its finding of two distinct molecular conformations within the structure and two distinct ways in which the molecules are organized into hydrogen‐bonded chains, and in its comparison of the hydrogen‐bonded structure of (I) with those of analogous 1,3,5‐triazines and pyrimidines.     

2‐Ethylsulfanyl‐7‐(furan‐2‐yl)‐4‐(thiophen‐2‐yl)pyrazolo[1,5‐a][1,3,5]triazine: π‐stacked chains of hydrogen‐bonded R22(10) dimers

In the title compound, C₁₅H₁₂N₄OS₂, the bond distances in the fused heterocyclic system show evidence for aromatic‐type delocalization in the pyrazole ring with some bond fixation in the triazine ring. The thiophenyl substituent is slightly disordered over two sets of atomic sites having occupancies of 0.934 (4) and 0.066 (4). The non‐H atoms in the entire molecule are nearly coplanar, with the planes of the furanyl substituent and the major orientation of the thiophenyl substituent making dihedral angles of 5.72 (17) and 1.8 (3)°, respectively, with that of the fused ring system. Molecules are linked into centrosymmetric R₂²(10) dimers by C—H...O hydrogen bonds and these dimers are further linked into chains by a single π–π stacking interaction. Comparisons are made with some related 4,7‐diaryl‐2‐(ethylsulfanyl)pyrazolo[1,5‐a][1,3,5]triazines which contain variously substituted aryl groups in place of the furanyl and thiophenyl substituents in the title compound.