Ligand-Unsupported Cuprophilicity in the Preparation of Dodecacopper(I) Complexes and Raman Studies.

Synthesis and characterization of two dodecacopper(I) extended metal atom chains (EMAC) assembled by two hexadentate bis(pyridylamido)amidinate-supported hexacopper(I) string complexes (monomers) via the ligand-unsupported cuprophilicity are described. In addition to short unsupported Cu-Cu contacts, two hexacopper fragments in these two dodecacopper EMACs show a bent conformation based on X-ray crystallography. Compared with their THF-bound hexacopper(I) monomers and protonated ligands, these ligand-unsupported cuprophilic interactions are shown to be weak by Raman spectroscopy. DFT calculations suggest the ligand-unsupported cuprophilicity originate from weak attractive orbital interactions, and the strength is estimated to be 2.4 kcal mol-1 .

A Family of Multiply Bonded Dimolybdenum Boraamidinates with the Formal Mo-Mo Bond Orders of 3, 4, 4.5, and 5.

A boraamidinato ligand [PhB(N-2,6-(i) Pr2 C6 H3 )2 ](2-) was employed to stabilize a new family of multiply bonded dimolybdenum complexes [MoCl(µ-κ(2) -PhB(N-2,6-(i) Pr2 C6 H3 )2 )]2 (4) and [Mo(µ-κ(2) -PhB(N-2,6-(i) Pr2 C6 H3 )2 )]2 (n-) (n=0 (5), 1 (6), 2 (7)), with the respective formal Mo-Mo bond orders of 3, 4, 4.5, and 5. Each metal center in 5-7 is two-coordinate with respect to the ligands. Of particular interest is the quadruply bonded dimolybdenum complex 5, featuring an unprecedented angular conformation. The bent Mo2 N4 core of 5 distorts toward planarity upon reduction. As a result, compound 7 features a planar Mo2 N4 core, while that of 6 is still bent but less significantly than that of 5. Additionally, the Mo-Mo bond lengths of 4-7 systematically decrease as the valency of the central Mo2 units decreases. Complex 7 features the shortest Mo-Mo bond length (2.0106(5) Å) yet reported.

The Mo-Mo Quintuple Bond as a Ligand to Stabilize Transition-Metal Complexes.

Herein, we report the employment of the Mo-Mo quintuple bonded amidinate complex to stabilize Group 10 metal fragments {(Et3P)2M} (M=Pd, Pt) and give rise to the isolation of the unprecedented δ complexes. X-ray analysis unambiguously revealed short contacts between Pd or Pt and two Mo atoms and a slight elongation of the Mo-Mo quintuple bond in these two compounds. Computational studies show donation of the Mo-Mo quintuple-bond δ electrons to an empty σ orbital on Pd or Pt, and back-donation from a filled Pd or Pt dπ orbital into the Mo-Mo δ* level (LUMO), consistent with the Dewar-Chatt-Duncanson model.

Influence of small-dose dexmedetomidine on recovery of patients undergoing vertebral operation / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the influence of small-dose dexmedetomidine infusion on recovery of patients undergoing vertebral operation.</p><p><b>METHODS</b>Sixty ASA I-II patients undergoing vertebral operation were randomly divided into two groups (n=30). In group I, dexmedetomidine infusion was pumped at the rate of 0.5 µg·kg(-1)·h(-1) from tracheal intubation to incision suture, and in group II, 0.9%saline was pumped instead. The mean arterial pressure, heart rate, Riker Sedation-Agitation Scale and Ramesay sedation score were recorded at the time points of autonomous respiration (T1), eye opening (T2), extubation (T3), 1 min after extubation (T4), 10 min after extubation (T5), and 30 min after extubation (T6).</p><p><b>RESULTS</b>The recovery time of autonomous respiration and eye opening time in group I were significantly longer than those in group II, and the extubation time was significantly shorter in group I (P<0.05). Riker Sedation-Agitation Scale scores in group II were significantly higher than those in group I at T2 and T4, and Ramesay sedation scores in group I were significantly higher than those in group II at T1, T2 and T5 (P<0.05). The mean arterial pressure and heart rate at each time point was significantly lower in group I than in group II (P<0.05), especially at T3 and T4 (P<0.01). In both groups, the mean arterial pressure and heart rate at T3 and T4 were significantly higher than those at rest (P<0.05).</p><p><b>CONCLUSIONS</b>Small-dose dexmedetomidine infusion can reduce dysphoria and lower the risks during recovery from general anesthesia following vertebral operation.</p>

Stepwise construction of the Cr-Cr quintuple bond and its destruction upon axial coordination.

Give me five! Terdentate 2,6-diamidopyridyl ligands were used to stabilize the Cr-Cr quintuple bond and have made it possible to isolate and characterize not only the Cr-Cr quintuple-bonded complex, but also the mixed-valent intermediates (Cr(I) and Cr(II)), which are important species in the formation of type I quintuple-bonded complexes.

Ligand-controlled synthesis of vanadium(I) ß-diketiminates and their catalysis in cyclotrimerization of alkynes.

Three dimeric vanadium(I) ß-diketiminates [V{µ-(η(6)-ArN)C(Me)CHC(Me)C(N-Ar)}](2) (Ar = 2,6-Me(2)C(6)H(3) (2), 2,6-Et(2)C(6)H(3) (3), 9-anthracenyl (4)) were prepared and isolated upon reduction of their corresponding dichloro precursors VCl(2)(Nacnac). Compounds 2-4 all show a structure with each vanadium atom being η(2) bonded to the ß-diketiminate framework and η(6) bonded to a flanking ring of a ß-diketiminato ligand, attached to the other vanadium centre within the dimer. No metal-metal bonding interactions are observed in these dimers due to long vanadium-vanadium separations. Compounds 2-4 display an antiferromagnetic exchange between the two vanadium centres. An imido azabutadienyl complex (η(2)-PhCC(H)C(Ph)NC(6)H(3)-2,6-(i)Pr(2))VN(C(6)H(3)-2,6-(i)Pr(2))(OEt(2)) (5) was isolated from the reduction of VCl(2)(HC(C(Ph)NC(6)H(3)-2,6-(i)Pr(2))(2)) by KC(8). Compounds 2-4 and the inverted-sandwich divanadium complex (µ-η(6):η(6)-C(6)H(5)Me)[V(HC(C(Me)NC(6)H(3)-2,6-(i)Pr(2))(2))](2) (1) reduce Ph(2)S(2) to give two vanadium dithiolates V(SPh)(2)[(HC(C(Me)NC(6)H(3)-2,6-R(2))(2))] (R = Et (6), (i)Pr (7)) through an oxidative addition. Most notably, 1 and 3 catalyze the cyclotrimerization of alkynes, giving tri-substituted benzenes in good yields and a 1,3,5-triphenylbenzene coordinated intermediate 8 was isolated and characterized.

[Circumferential pulmonary vein with additional linear ablation for persistent and permanent atrial].

OBJECTIVE: To investigate the safety and efficacy of circumferential pulmonary vein with additional linear ablation in treatment of persistent and permanent atrial fibrillation (AF), and to identify possible predictors of recurrence of AF. METHODS: The clinical data of 127 patients with persistent and permanent AF who had undergone circumferential pulmonary vein with additional linear ablation from January 2006 to December 2006 in multiple electrophysiological centers were collected, success rate and recurrence rate, cardiac function and atrial arrhythmias after ablation, and complications were analyzed. The relationship between the recurrent AF and clinical and echocardiographic variables was investigated. RESULTS: A mean follow-up of 9 +/- 4 months showed that the success rate and recurrence rate were 68.5% and 31.5% respectively. After, both the left atrium diameter, left ventricular end diastole diameter, and left ventricular ejection fraction of the patients with successful ablation were (41 +/- 8) mm, (49 +/- 7) mm, and (61 +/- 8)% respectively, all not significantly different from those before ablation [(43 +/- 7) mm, (48 +/- 6) mm, and (62 +/- 10)% respectively, all P > 0.05]. After ablation the episodes of atrial tachyarrhythmias and atrial premature beat significantly increased (P < 0.05 and P < 0.01). The only complication was ecchymoma that occurred in 3 patients (2.4%). Female gender and left atrium enlargement were risk factors of recurrent AF (P < 0.05 and P < 0.05). CONCLUSION: Circumferential pulmonary vein with additional linear ablation is a safe and moderately effective treatment for persistent and permanent atrial fibrillation.

[Mechanism and re-ablation strategy for postablation atrial tachyarrhythmia in atrial fibrillation patients].

OBJECTIVE: To investigate the mechanism and re-ablation strategy of recurrent atrial tachyarrhythmia (ATA) following circumferential ablation of pulmonary veins (PV) in patients with atrial fibrillation (AF). METHODS: Fifteen patients with recurrent ATA following first AF ablation procedure were included in this study. Under CARTO guidance, PVs were remapped and ablated subsequently for relapse of left atrium to PV conduction. The whole atrium was then remapped and individualized ablation was made to eliminate inducible ATA. RESULTS: Left atrium to PV conduction relapses were evidenced in 14 patients. After re-ablation, there were no inducible ATA in 9 patients, inducible left atrial macro-reentry tachycardia in 3 patients and all were terminated by further linear ablation on the roof and left atrial isthmus, inducible atrial focal tachycardia from left atrial isthmus in 1 patient and was eliminated after additional focal ablation, inducible right atrial macro-reentry tachycardia in 2 patients and were eliminated by right isthmus linear ablation. During 1 - 16 (5.5 +/- 4.4) months follow-up, ATA was disappeared in 13 patients and reduced in another 2 patients. CONCLUSIONS: Relapse of left atrium to PV conduction is one of the main mechanisms for postablation ATA in patients with AF. Atrial macro-reentry tachycardia and focal atrial tachycardia were less common mechanisms for postablation ATA. Re-ablation focused on closing the PV gaps and additional individualized focal and lineal ablation strategies were helpful for treating postablation ATA in AF patients.

Structural transformations in dinuclear zinc complexes involving Zn-Zn bonds.

Reduction of Zn(2)(mu-eta(2)-Me(2)Si(NDipp)(2))(2) with 4 equiv. of KC(8) resulted in a dramatic structural transformation into [(eta(2)-Me(2)Si(NDipp)(2))ZnZn(eta(2)-Me(2)Si(NDipp)(2))](2-) featuring a Zn-Zn bond instead of [Zn(2)(micro-eta(2)-Me(2)Si(NDipp)(2))(2)](2-); the mechanism of the observed structural transformations arising from the Zn-Zn bond formation involving the intermediate of [Zn(2)(mu-eta(2)-Me(2)Si(NDipp)(2))(2)](-) was elucidated by elaborate computations.

Different clinical features, biochemical profiles, echocardiographic and elctrocardiographic findings in older and younger patients with idiopathic dilated cardiomyopathy.

OBJECTIVE: To study the clinical features, biochemical profiles, echocardiographic and electrocardiographic findings in the elderly and younger with idiopathic dilated cardiomyopathy (IDCM). METHODS: We measured biochemical profiles and reviewed the clinical features, echocardiographic and electrocardiographic findings in 40 elderly (group A) and 70 younger (group B) patients with IDCM. RESULTS: The aldosterone level in group A was higher than in group B (304.8 +/- 69.1 vs. 213.3 +/- 54.5 pmol/l, P < 0.05). Triiodothyronine (T3) and free T3 in group A were lower than in group B (0.78 +/- 0.21 and 2.87 +/- 0.73 vs. 1.26 +/- 0.33 nmol/l and 3.55 +/- 0.64 pmol/l, all P < 0.05). The incidence of ventricular arrhythmia in group A was lower than in group B (61.3% vs. 92.1 %, P < 0.01). The incidence of hypokalaemia and hypomagnesaemia were higher in group A (51.3% and 27.5%). 28.8% patients in group A were susceptible to digitalis intoxication. Disease duration and mean survival period in group A were longer than in group B (11.0 +/- 4.7 and 6.9 +/- 4.2 vs. 5.2 +/- 2.5 y and 3.4 +/- 2.7 y, all P < 0.05). The main cause of death in group A was congestive heart failure (78.9%) and ventricular arrhythmia (61.9%) in group B. CONCLUSIONS: The prognosis in group A was better than in group B. The patients in group A usually showed low T3 syndrome. Ventricular arrhythmia in group A may be due to heart failure, electrolyte imbalance and sympathetic activation.

Hypercoagulability existing in the local left atrium of patient with mitral stenosis.

OBJECTIVE: To investigate the pathogenesis of thromboembolism in patients with mitral stenosis in a pre-thrombotic state. METHODS: The biochemical markers' levels in plasma for platelet activity [soluble P-selectin (GMP-140)], states of thrombin generation [antithrombin III (AT III) and protein C (PC)], fibrinolysis [D-dimer (DD), plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (t-PA) and FDP] and von Willebrand factor (vWF) were determined from blood specimens obtained from the femoral veins and arteries and the right and left atria of 43 consecutive patients (20 with atrial fibrillation and 23 with sinus rhythm) with mitral stenosis (MS), undergoing percutaneous mitral valvuloplasty. The same parameters were compared with those of 15 control subjects, who had no detectable heart disease, but with paroxysmal supraventricular tachycardia undergoing radiofrequency catheter ablation of the left accessory pathway through a transseptal passage. RESULTS: Blood from the left atrium contained an excessive amount of platelet activity, thrombin generation and fibrinolysis compared with the blood from the right atrium, and the femoral veins and arteries. However blood from the right atrium was much lower in these activities when compared with those from the left atrium, and the femoral veins and arteries in both groups. Compared with those in the control subjects, GMP-140 in the left atrium was significantly higher (P < 0.05) and AT III was significantly lower (P < 0.05) in patients with MS. Compared with the patients with MS and spontaneous left atrial echocontrast (LASEC) /= 2 had significantly higher levels of GMP-140 in plasma (P < 0.05), and significantly lower levels of AT III (P < 0.05) and PC (P < 0.01) levels in the left atrium. However, there were no significant differences between patients with atrial fibrillation and those with sinus rhythm regarding amounts of plasma coagulation markers in the left atrium. Univariate regression analysis revealed that LASEC was negatively correlated with plasma levels of blood from the left atria in the patients with MS. CONCLUSION: Coagulability is increased in the left atria of patients with MS and is positively correlated with LASEC.

[Study on the correlation of between infection, inflammation and coronary artery disease].

OBJECTIVE: Recently studies showed infections of Chlamydia pneumoniae (Cp), Helicobacter pylori (Hp) and cytomegalovirus (CMV) played roles in the development of atherosclerosis. The aim of this study was to study relationship between infection of Cp, Hp and CMV, systemic inflammation and coronary artery disease (CAD). METHODS: Fourty-five patients with at least one coronary artery stenosis > 50% and 33 control subjects with negative coronary angiography were recruited for this case-control study from May 2000 to October 2001. Antibodies against Cp, Hp and CMV were measured and serum C-reactive protein (CRP) levels determined for each case. CRP level > 0.8 mg/dl was defined at elevated CRP level. RESULTS: The prevalence of Cp IgG, Hp IgG or Hp IgA antibody was associated with CAD (P = 0.017, P < 0.001, P = 0.009). After adjustment for age, gender, smoking, hypertension, hyperlipidemia and diabetes, the association was still seen. Mean CRP value was significantly higher in patients with CAD, compared to those without CAD (P < 0.001). Multivariate analysis showed statistical significance (P = 0.03). Elevated levels of CRP were found to be an important parameter for CAD (P = 0.032). The prevalence of Cp IgG antibody, Hp IgG and CMV IgG antibody all showed no association with elevated levels of CRP (P = 0.391, P = 0.253, P = 0.724). The ratio of elevated levels of serum basic CRP in the group with IgG antibodies to 3 pathogens was 32.1% while in the group with IgG antibodies to

[Radiofrequency catheter ablation autonomic nerve injury]

OBJECTIVE: To investigate the correlation between RFCA catheter cumulative energy and autonomic nerve injury. METHODS: Forty-one patients with paroxysmal supraventricular tachycardia were enrolled, Patients were excluded if they had Diabetes, Hypertension, Congestive Heart Failure or other organic heart disease. HRV and biochemical markers were measured before and after the RFCA. RESULTS: Compared with pre-ablation values,there was significantly decrease in post-ablation low frequency (LF) and high frequency (HF). This was noted in both the septal group (AVNRT and septal pathway) and free wall group (free wall accessory pathway).Post-procedure,the sensitivity of cardiac troponin I(cTnI) for myocardial injury detection was 58.3%, AST was 41.7%. This was significantly higher than other markers(CK:4.2%, CK-MB:10.4%, LDH:20.8%). The post-ablation sensitivity of cTnI was 54.2%, 6.3% and 52.1%at 1 hour, 12 hours, and 24 hours respectively. A significant correlation between cumulative energy and delta HF(r=0.688,P=0.01) or delta LF (r=0.462, P<0.05).was noted in free wall group.(delta HF=pre-ablation HF-post-ablation HF/pre-ablation HF x 100%). There was no significant correlation between biochemical markers and either delta HF or delta LF. CONCLUSION: RFCA induced injury on cardiac autonomic nerves related to both cumulative energy and ablation site,but not size of myocardial injury as determined by cTnI measurement. cTnI is an excellent biochemical marker of myocardial injury.